If so, it’s likely your filament is a little damp.

The problem is all 3D printer filaments are hygroscopic. This means in the air, they’ll absorb moisture over time.

In this guide, I’ll explain how I dry out filament using my household oven, and how to use proper 3D filament storage to prevent the problem altogether.

I’ll also share my process to test if formerly wet filament is safe to use again -so you can revive your filament with confidence!

Why Water Damages Thermoplastics

All plastics are polymers or copolymers. Simply put, a polymer is a material that is made up of multiple long molecular chains of a single substance. For example, PVC or polyvinyl chloride consists of a bunch of vinyl chloride molecules.

A copolymer, on the other hand, is a material that is made up of several substances, each of which exists in long molecular chains. ABS is a copolymer and consists of strands of acrylonitrile, butadiene, and styrene molecules all bound together.

Polymers and copolymers are complex substances. They are designed to act in certain ways under specific conditions. For the most part, they fulfill this task admirably.

However, that task-specific complexity comes with a price. What can be built up, can also be broken down and nothing breaks certain polymers or copolymers down quicker than water.

If you looked at a polymer or copolymer under a strong microscope, you’d see that the long molecular strands that make them up are woven and braided together, almost like rough cordage or rope. This means that there is plenty of space between and around these strands.

Because of this, most polymers and copolymers are hygroscopic. This means that as air circulates around and through these strands, the spaces between them pick up and hold the molecular water that is naturally present in the air.

Some filament materials, like Nylon can be extremely sensitive to water – where if they absorb just a little it can lead to problems when printing. 

The more water vapor there is in the air, the more molecular water the copolymer can pick up or absorb.

These water molecules in the spaces between the strands not only increase the size of the material, they also tend to break down and alter the length of some of the molecular chains that comprise the polymer.

This process is caused by hydrolysis. The result is an extruded copolymer plastic that doesn’t perform to design specifications.

How To Store PLA Filament to Keep It Dry

Even a small amount of absorbed water will negatively affect the end result of your print jobs. The best way to avoid this problem is to prevent your print materials from coming into contact with water vapor in the first place.

The easiest way to do this is by storing your filament in an air-tight container that contains desiccants. A filament dry box works well, but these can be necessarily bulky.

When it comes to airtight, however, all containers are not created equally. When most people think of airtight, they think of plastic containers and bags. These are fine short-term solutions for the most part.

It’s better to store your materials in a plastic bag than to leave it unprotected in a drawer or box.

However, over time, plastic containers and bags are slightly water permeable. This means that the longer your printing materials sit in the plastic bag, the more water they are slowly absorbing. If you’re using clear bags or a clear box, UV light can also degrade your filament over time. 

You might be thinking how long does 3D printer filament last? And if I shouldn’t be storing PLA filament (or any other 3D printing material) in clear bags, what should I use?

Well, if you live in a humid climate, this process is accelerated. Eventually, even with the use of desiccants, you wind up with filament that is water damaged.

A better solution is to use high-quality Mylar bags, or bags made of a similar material, to store your thermoplastics. Mylar, as you know, has a metal layer that is embedded between two layers of plastic.

This metal layer keeps any water vapor that permeates the plastic layer away from your printing materials. The result is dry materials that are ready to give you great results every time you print.

Here at rigid.ink, this is the reason we provide a high-quality metallic, sealable bag, along with desiccants, with every order we ship. It makes no sense to sell our customers the world’s most reliable 3D printing thermoplastics and not give them the best means to protect those materials when they are not being used.

How You Can Tell That Your Printing Material Has Absorbed Water

There are two easy methods that you can use before you print in order to determine whether your material has absorbed water. First, you can measure the diameter of the material itself.

Remember, when a polymer absorbs water it begins to increase in size. The more water it absorbs the bigger the size increase will be. If the diameter of your filament has increased by 10% or more, it is likely that absorbed water is the cause.

The other way to determine if your filament has absorbed water is to extrude a small amount of filament prior to printing. We’ve probably all had the experience of sitting next to a fire and listening to it pops and crackles. This occurs because there’s water in the wood that is turning to steam as a result of the heat.

When you extrude thermoplastic that has absorbed water, the same phenomenon occurs. The heat of the print end causes the water in the plastic to expand. As the plastic extrudes, you will hear hissing or popping that is a result of the steam escaping. You may also see bubbling.

If you suspect that your filament has absorbed water you’re going to need to dry it out. In the next section, we’re going to show you how.

How to Dry Filament in Oven

If your filament has absorbed water, you’re going to have to dry it out before you can use it to print. The easiest way to do this is by using your oven to get the job done.

The first thing to do is check out the glass transition temperature for the filament that you are going to dry. You want to make sure that you keep your oven temperature below the transition temperature. In general, about 60-70°C is just about right for most materials, except maybe a bit hot for lower temp materials like PLA. Always keep in mind how hot your oven runs and only use electric ovens.

You also want to be aware, even if the Glass Transition temp is very high, for a material like Nylon or Polycarbonate – the spool your filament is wound on is likely made from an ABS which will soften at lower temperatures than the filament. 

How to Dry PLA Filament in Oven

For drying PLA filament you want to ensure more care, as 70°C will be too hot. We recommend at the very lowest temp your oven will go around 40°C. Even at this temperature, your PLA will soften, so drying PLA in the oven won’t always give you the results you’re after. It’s a small reminder as to the importance of keeping excellent PLA storage.

Once the oven is up to temperature, place the spooled material inside and leave it there for four to six hours. If you have a convection oven, this drying time may be shortened since the circulated air removes more moisture from the material more quickly.

You can also ‘recharge’ the desiccant this way too, placing it in the oven over a low heat. 

Once the time is up, remove the material from the oven, allow it to cool and place it into a water-impermeable container or bag along with desiccants. Make sure that the container or bag is completely sealed.

When you use any material that you have oven-dried to print, be aware that it will slightly more brittle than normal. If you handle the material with care this should pose no problem, especially when you consider the superior results that you can achieve when using a properly dry print material.

Hopefully, this will help answer how to dry filament. For more consideration on drying Nylon filament (which we recommend you do before ever Nylon print, for best results) you can check out our article on Nylon.

If you’ve tried everything above, and that’s still not helped (and your filament is less than a few months old) we recommend getting in touch with your filament supplier and asking for a replacement.

Related articles:

• Best filament storage containers
• Best filament dryers
• Filament calculator – how many meters on a spool
• The complete 3D printer filament guide

Our calculator will tell you how much filament is left in grams and length. The table below also shows popular spool sizes and lengths for filament over a variety of different materials. 

Filament Length Calculator

If you find this calculator useful, please bookmark it and share.

This is a comprehensive list of filament materials and their lengths on 500g, 750g, 1KG, and 3KG spools for both popular 1.75mm and 2.85mm sizes, based on each material’s density.

This should allow you to correctly budget your remaining filament for prints based on the remaining weight of your spool. So you can work out exactly how many meters of filament in a 1KG (or whatever size) spool you’re using. 

What is PLA Density g/cm3?

PLA Density is 1.24g/cm^3.

Here we explain the relationship between filament volume, density and length. Before we can ask how much filament is on a 1kg spool, we first need to know the weight of the empty spool. 

How Much Does an Empty Filament Spool Weigh?

For reference, our empty spools weigh 248g. And this is approximately an industry average.

Using this knowledge you can easily weigh your spool, to see how much filament in weight is left – and knowing the weight, diameter and density of the material, you can work out how much is left on your spool in meters.

How Long is 1kg of PLA Filament?

Wondering how many meters are in a KG of filament? We make it easy for you in the table below. 

Our filament calculator has been made to 6 decimal places, which should be accurate enough given that manufacturers’ resin densities are always rounded to just 2 decimal places.

These lengths are meant as an accurate guide only, not a guarantee of what you will have received on your spool from other suppliers. They are however a guarantee as to what you will have received from us, had you ordered filament from us.

You might be wondering how much does PLA weigh, or any other filament for that matter.

Well, we use a density figure to work out how many grams of filament in each cubic cm. This is represented as usually a figure just over 1. For example, the density of PLA filament is 1.24 grams per CM^3.

This means we know how many meters in a kilogram of PLA 1.75mm to be 335.3 meters. Or if you’re wondering how many grams in a meter is 1,000 Grams / 335 Meters = 2.98 grams per meter. 

To see how many meters is 1KG of filament, look under the 1KG spool column. Move left and right to see lengths for other spool weights.

How Long is a Spool of Filament

Now You Can Work Out How Much Filament is on a Roll

We hope this list of lengths based on weight and density is useful to you. Now you know how many meters of ABS in a 1KG spool. Or you’ll know the answer to how much can you print with 1KG of filament. 

Please comment below if you have any questions, and feel free to provide any constructive feedback if you feel we’ve missed anything. We hope this tool allows you to easily calculate how much filament is on a 1KG spool.

Alternatively, there might be a material we’ve missed, so you cannot work out the length of filament in a 1KG spool – if yours isn’t mentioned, please let us know. 

Related articles:

• Pillowing and stringing during 3D printing – how to fix
• What to do with empty filament spools
• Best 3D printers

Depending on the object that you’re creating and its end purpose, sufficient strength and stiffness can sometimes be difficult to achieve.

One of the best ways to increase the stress tolerance of your printed objects is by annealing your 3D prints. 

Through a relatively simple process, you can actually turn a standard material like PLA into one of the strongest 3D printer filaments.

In this guide, I’m going to explain what 3D print annealing actually is, and provide step-by-step guides for annealing Nylon, PLA or ABS in a simple kitchen oven.

I’ll share all the tips I’ve learned to avoid common beginner mistakes and help you strengthen your prints with confidence – so let’s get on with it!

What Is Annealing?

Annealing is an ancient process, originally used in metallurgy to increase the strength of metal objects. Annealing is one of several “heat treatments” that are used to change the physical properties of metal without changing the metal’s existing shape.

In essence, annealing increases the ductility of a given metal.

The fundamentals of the annealing process have been adapted for use with plastics, but instead of softening them, the process is used to increase their strength and stiffness after an object has been formed.

However, when dealing with plastics, the process is not actually annealing – it’s just many years ago someone coined the term when describing this process in plastics and the name appears to have stuck. 

Confused yet? Don’t worry, we’ll explain all.

Perhaps a more accurate name should have been ‘stress mitigation’ because as we’ll read below, you’re essentially reducing the stress in highly affected areas and dissipating this out more evenly through the print, making it less likely to fracture at any specific point. 

Primarily an industrial plastics technique used as a finishing process, annealing can also be used by anyone with access to a kitchen oven to harden 3D prints.

How Does Annealing Work?

In metallurgy, the process of initially molding and forming a metal object causes crystalline structures, called “grains”, to form within the metal. These grains tend to be large when cooled very slowly and small if cooled quickly.

More often than not, the metal is cooled quickly, forming smaller grains. As a result, the metal is hard but brittle and will crack under stress along the juncture lines between individual grains.

Annealing with metal involves reheating the metal to a temperature below its melting point and then allowing it to cool slowly. This reheating causes larger crystals to form, ‘growing’ from the original grains.

This larger crystalline matrix makes the metal softer and increases ductility. The metal’s shape hasn’t changed, but its characteristics have.

With plastics, the process is a little different. FDM printing necessarily involves heating the print material so that it can be extruded. Once extruded, the material then cools to form the printed object.

Plastic is a fairly poor conductor of heat. This means that heated plastic tends to cool unevenly. This uneven cooling introduces stress into a printed object naturally increased by the print’s layered construction. Let’s take a closer look at the nature of this stress.

As you may know, most thermoplastics used in FDM printing are polymers. A polymer consists of two or more substances. Each substance is made up of long molecular chains. These chains are interwoven around each other, creating the polymer.

At a microscopic level, the structure of the plastic is typically unorganized and rather amorphous. When printed, it is likely to induce banding – small crystals where the plastic cools quickly, and larger where it is a slower process. 

Uneven cooling due to poor heat conduction results in the polymer shrinking in different ways. This, in turn, causes different tensile forces and compression forces building up in the polymer structure.

Annealing plastic involves gently reheating the substance to its glass transition temperature or just above, but below its melting temperature, holding it there for a time, and then slowly allowing it to cool.

Like the annealing of metal, this reheating and extended cooling increases the amount of large crystalline structures in the plastic and redistributes the stresses within the printed part.

Note: While we’ll explain the temperatures to anneal for each material, these are approximations. The ‘same’ material from different suppliers can have slightly varying glass transition temperatures, and ovens can typically have thermostats that are +/-10% out.

So please treat these temps as a guide only, and try it on a scrap print beforehand. You don’t want to warp a print from annealing at a too-high temperature. 

Also, when the polymer approaches or reaches its glass transition temperature, the molecular chains have enough energy to become more amorphous. At this temperature, they are able to rotate, move, stretch, etc. and this releases some of the tensile and compression forces that resulted from uneven cooling.

Being a plastic made up of polymers, the process does not work quite the same way as it does with metals, so instead of getting a soft and ductile object at the end, you end up with a plastic that is stronger, stiffer and more resistant to the stresses that cause failure.

So really, it shouldn’t be called annealing, but ‘toughening’.

Now that you know what annealing is and how it works to make the strongest 3D printing material, let’s take a look at the specific techniques that you can use to anneal objects printed from some commonly used thermoplastics.

Note: We hold no responsibility for any incidents that may happen if you leave plastic in ovens. Ensure you don’t leave it unattended, adhere to sensible temperatures advised and ensure plenty of ventilation. In short, please exercise common sense with annealing plastics. 

How to Anneal PLA

PLA tends to be strong but can be somewhat brittle. It also has a relatively low melting temperature. Both of these facts make it an excellent candidate for annealing. Its low glass transition temperature makes it easier to anneal. In addition, annealing reduces the brittle tendencies of PLA by increasing ductility.

In effect, annealing is the best way to make the PLA strength better. 

PLA heat resistance is low, virtually the lowest of any 3D printing material. The glass transition temperature of regular PLA is 60C to 65C (140F to 150F). Ours is about 6C lower than that due to the grade we use. Its melting temperature is 173C to 178C (343F to 352F). Therefore, you want to set your oven temperature to about 55-65C when annealing PLA.

In some instances, you may need to increase the temperature depending on your oven and the material used to 70C. 

It’s worth noting that our PLA is a lower temperature grade, so annealing would be best done around 60C. Again, you just need to experiment first as your oven can likely run a little hotter or cooler than the temperature it states. 

Generally, if your PLA requires a higher printing temperature, it’s of lower quality. Different ovens have different accuracy in thermostats, so it’s always worth testing with a scrap print first.

If you’re looking to make the strongest prints, you’re best off starting with the strongest PLA filament.

But enough about us…

At 60°C, it’s high enough to allow the baking PLA to soften and become amorphous, releasing some of the stress caused by printing and allowing the polymer strands to rearrange. It is also low enough that the PLA will not melt and flow, losing its shape.

Let the oven come to temperature and then let it sit for about an hour. This waiting period will help ensure that the oven temperature is as uniform as possible, preventing hot and cold spots that can negatively affect the annealing process.

Use an accurate thermometer to confirm that the oven is at the correct temperature before putting your PLA object in the oven.

It should be noted here that when annealing PLA plastic, or any other filament, ovens with convective heating (fan oven) will produce superior annealing results for the same reason that it produces superior bread.

Instead of the heat radiating from one direction, a convective oven circulates heated air around an object, providing a 360° heat source that produces more uniform results.

Note: It’s important you never try annealing prints in a gas-fired oven. The reading may be X degrees, but the flames themselves will be much hotter – potentially melting or setting fire to your prints. Only anneal in an electric oven, and always ensure the heating elements are turned off before placing your prints in. Again, heating elements can get much hotter than the oven reading.  

Once the oven is at temperature, place your PLA object(s) on an oven-safe surface and put them in the oven, turning it off and leaving your prints in there until it has cooled. This should be at least an hour or two. 

This will give the objects enough time to absorb enough heat energy to allow the polymer chains to move, stretch and realign, and recrystallize, forming a sturdier internal matrix. Do not open the oven door during this time, as any loss of heat will result in inferior annealing results.

As the oven gradually loses heat, so will the object or objects. A gradual cooling process will avoid a reoccurrence of the internal stresses that occurred during the more abrupt cooling that happened after printing. It will also reduce incidents of warping which can still occur at annealing temperatures.

Once the oven is back at room temperature, remove the object(s). What you will notice is that the object(s) will have shrunk slightly along the line of its print layers. In addition, you will also notice some expansion perpendicular to the print line.

In other words, the dimensions along the X and Y coordinates will have gotten smaller, while the Z dimension will have grown.

These changes are due to the changes in tension, or rather the changes caused by the release of the internal tensile and compressive forces discussed above. On average, you’ll see PLA shrinkage of about 5% and growth of about 2% along the relevant axes. If this shrinkage and growth is going to be a problem, you can compensate for it beforehand during the design and printing processes.

After heat-treating PLA, you can expect to see some significant improvements in the strength of your PLA object. A 40% increase in strength and durability is not uncommon. Likewise, you can also expect to see a good improvement in stiffness. A 25% improvement here is not unexpected.

Finally, the stability of the annealed PLA at higher temperatures will also be improved. So, if you need stiff, high-tensile PLA parts with good heat resistance, annealing can be the answer.

If you want to learn more about printing with PLA filament, click here. 

How to Anneal ABS

ABS tends to be stronger and less brittle than PLA. It also has a higher melting temperature than PLA. Despite these facts, ABS is also an excellent candidate for annealing.

While ABS will need to be annealed at a higher temperature than PLA, due to its higher glass transition temperature, the annealing process will provide ABS with the same increases in desirable material properties that were seen with PLA.

The glass transition temperature of ABS is 105C (221F). Its melting temperature is 210C to 240C (410F to 464F).  Because of this, you want to set your oven temperature to around 100C (210F). Again, this temperature is high enough to allow the material to soften which will release the stress caused by extrusion while increasing crystallization.

If you want to try higher ABS annealing temperatures you can do, but you may find warp and deformation increase. As was the case with PLA, it is also low enough so that the material will not melt, flow, or significantly deform.

As always, let the oven come to temperature and then let it sit for about an hour in order to ensure temperature uniformity. Use an accurate thermometer to confirm that the oven is at the correct temperature before putting your ABS object in the oven. As with any annealing project, a convection oven is always preferable.

When the oven is at temperature, place your ABS object in the oven on an oven-safe surface for 30 minutes, plus an additional 15 minutes for every 3mm (1/8 inch) of object cross-section.

Again, this will give the object enough time to absorb enough heat energy to allow the polymer chains to move, stretch and realign, and recrystallize, forming a sturdier internal matrix. As always, do not open the oven door during the annealing process.

Once the time is up, turn the oven off, leaving your object in the oven. This gradual cooling process will reduce warping and the reoccurrence of internal stress caused by abrupt cooling.

Once the oven is at room temperature, remove your objects. Once again, you may notice shrinkage and growth along the X, Y, and Z axes. As was the case with PLA, this shrinkage can be compensated for in the design and printing processes.

Also expect to see an improvement in the strength, stiffness, and stability of the annealed object, along with improvements in temperature stability.

How to Anneal Nylon

Nylon 12 is stronger and less brittle than either PLA or ABS. Its melting temperature is higher than ABS. Annealing can significantly increase its heat deflection temperature. When you combine this with its high strength, annealed Nylon 12 makes a great choice for applications where heat and durability are issues.

The glass transition temperature of Nylon 12 is around 98C (208F). However, its melting temperature is a respectable 178C-181C (352F to 358F).  Because of this, you want to set your oven temperature to 130C-140C (266F to 284F).

Again, this temperature is high enough to allow the material to soften which will release the stress caused by extrusion while increasing crystallization.

As is always the case when annealing plastics, it is also low enough so that the material will not melt, flow, or significantly deform.

Again, once the oven is at temperature let it sit for an hour for the sake of temperature uniformity. Use an accurate thermometer to determine temperature prior to starting the annealing process and use a convection oven if possible.

Place the nylon object on an oven-safe surface and put it in the oven for two hours. This time is necessary to allow polymer chain realignment and recrystallization. Don’t open the oven while annealing is underway.

When the two hours are up, turn the oven off, leave the object inside, and let the oven cool incrementally to room temperature. This is to reduce warping and maximize the benefits gained through annealing.

When the oven is at room temperature, remove your objects. Once again, you may notice shrinkage and growth along the X, Y and Z axes. As was the case with PLA, this shrinkage can be compensated for in the design and printing processes.

While you will see a slight improvement in strength, the real improvement will be in temperature stability. Annealing generally increases a nylon object’s heat deflection temperature by over 40%.

The method for annealing Polycarbonate prints is a similar process, using temperatures in the 120-130C range. Polycarbonate although has a higher printing temperature, its softening range is much greater than other materials. 

Summary

Annealing is a fantastic, underutilized method of increasing strength and durability in your thermoplastic 3D prints. 

Looking for these properties in your prints, you really want to start off with good quality filament. Using high-quality materials will naturally give your parts excellent desirable properties to begin with, only to be further enhanced with the annealing process. 

Related articles:

• Infill settings for 3D printing
• How to smooth PLA
• How to acetone smooth ABS
• Types of 3D printer filament

Acetone polishing or smoothing is a safe and easy method of 3D print finishing for smoothing out surface inconsistencies without causing structural damage.

However, you need to know what you’re doing, since acetone is highly flammable and volatile!

In this guide, I will take you through the step-by-step approach to acetone smoothing of ABS and ASA, as well as discuss the differences for other filament types.

I’ll also share a few handy tips for avoiding common beginner mistakes so you can produce crisp 3D prints without the hassle – so let’s get started!

Can I Acetone Vapor Bath my 3D Prints?

All ABS 3D prints can be acetone smoothed. Filaments that can be polished using this process are: ABS, ASA, PMMA, HIPS and Polycarbonate.

Other filament types are either unaffected by acetone or are damaged by it. If you’re looking for other 3D printing post-processing techniques, check out our PLA polishing article for details on smoothing out 3D prints that can’t be acetone smoothed. 

The following photograph is of a shower tray system consisting of a frame and different color removable trays before ABS Acetone Vapour Smoothing. The frame is made of Black ABS, and all trays are made in ABS of varying colors.

The following photograph show the same system after the ABS Vapour smoothing process. 

Not only do the finished parts look better, they now have a higher resistance to water ingress, and they can often be stronger than their non-polished earlier selves once fully hardened.

This is definitely our preferred method when we’re asked how to finish 3D prints – there’s just no better way to easily smooth ABS prints.

Safety Warning

Before continuing further, please make sure you acquaint yourself with the safety regulations pertaining to acetone (propan-2-one) and its use. It is your responsibility to use this solvent safely.

Obvious things to note for safety are:

• Only use in a well-ventilated area
• NO NAKED IGNITION SOURCES – acetone is extremely volatile and the vapors are Highly Flammable
• *NEVER EVER* heat the acetone!! [See above]
• Avoid breathing the fumes
• Avoid skin contact
• Keep away from animals and children
• Be careful that you do not spill any liquid onto surfaces that might be damaged by acetone – most common household plastics are susceptible to some kind of damage from liquid acetone

The Principle Behind Vapor Polishing

You can acetone smooth ABS filament & ASA filament, both with acetone liquid or as vapor.

They dissolve readily in the liquid, and a concentrated atmosphere of the vapor will eventually have the same effect. It’s that ‘eventually’ part we are interested in (and not the acetone 3D print mess you’ll be left with if you leave it too long).

We want to melt the surface of the object just enough that the surface tension of the molten plastic smooths out any surface inconsistencies and then halt the process at that point before any structural damage occurs.

In some cases, it is possible to quickly dip an object into acetone liquid to get a polished surface, but this can be very messy and gives inconsistent results.

If you use the vapors instead you have much more control over the ABS smoothing and the final results. As the vapors can get to all exposed surfaces equally, there are fewer areas of uneven melting. There are also no run-off channels or drip marks induced into the surface of the object that direct exposure to acetone liquid may cause.

What You Will Need –

1. A well-ventilated area to work that has no exposed ignition sources.
2. Wear the appropriate PPE – Safety glasses/goggles, mask, gloves, etc…
3. An acetone-proof container (a large glass vase or a tin) big enough to hold the parts you wish to polish – preferably with at least 30mm clearance in ALL directions around the object to be polished – top, bottom, and sides.
4. A loose-fitting lid, also acetone-proof. If your lower container is not transparent, you may wish to use a sheet of glass as a lid – this removes the need to keep removing the lid in order to see how the polishing is progressing (and not letting the vapours escape or dust get in).
5. A flat, non-porous plate such as glass or metal, to raise the object being polished above any liquid acetone in the bottom of the container – This really needs to be at least 10mm above the surface of any liquid acetone in the container and much larger than the object to be polished as this reduces the chances of liquid acetone creeping up the sides and onto the object itself.
6. Some sheets of plastic-free kitchen roll to use as a ‘wick’ for the liquid acetone.
7. Somewhere dust-free to allow the surface of the polished object(s) to harden.
8. A TIMER! Seriously.

You will walk away, forget it, only to return later to find that amazing print that you were once so proud of has now turned into a hideous misshapen lump of plastic, or at worst some kind of acetone ABS mess.

It might not happen this time or the next, but it will.

Getting Started

Make sure your container is free from contaminants (this will be your acetone bath), then place a few sheets of the kitchen roll up the side and along the bottom of the container. This will allow the liquid acetone to wick up the kitchen roll, helping to produce a strong concentration of vapor at all levels within the container.

Find somewhere to work that has surfaces and materials that will not be damaged by acetone or the fumes. Acetone is a superbly-powerful solvent – you don’t want it dissolving things that you’d rather keep. It is a low-density liquid that has very little surface tension, so it splashes and ‘wets’ surfaces very easily.

To hold the kitchen roll sheets in position, place your metal support (plinth) onto them. Make sure that you arrange the kitchen roll in such a way that when it gets wet with liquid acetone it cannot fall down onto your printed objects, as that will destroy any chances of achieving an acceptable finish.

The following photograph shows the setup used in the acetone bath ABS of the soap trays seen above.

The soap dish is sitting on top of a plinth made from a small piece of glass stood on three 22mm diameter copper plumbing joints – an arrangement that stops any chance of liquid acetone reaching the dish via capillary action (or surface-wetting).

Things to Consider Before Applying Acetone to Your 3D Print

Not all filaments are the same, even from the same supplier. For instance, due to secondary effects from the pigments that go to make up the colors of ABS filaments, different colors polish at different rates. This means you will need to monitor the polishing of different colored objects so that you can remove them at the correct time.

The polishing process not only softens the surface of the object, the fumes also penetrate into the body of the object. Depending on the period of exposure, you will need to ‘air’ the object for a period of time that is commensurate with the time that the object was exposed to acetone vapour.

Usually, this takes a few days. However, in some cases, the full mechanical strength of the object may not be realized until a significant time has passed – for high-density objects, this can take weeks, or even longer!

The polishing process continues for a while after you remove the object from the container – usually for about ten minutes. So don’t be tempted to leave it in too long.

The following photograph shows what happens to a part when exposed to the fumes for an extended period.

The hole in the center at the bottom is supposed to be round, and the lower edges are all supposed to be straight.

The ambient temperature affects the speed of the process – you are evaporating a volatile liquid after all.

• Too cold and it can take ages.
• Too warm, and the process goes too fast.
• Too hot, and you may be looking for a new place to work/eyebrows, so NEVER apply heat.

Finally – you need to have somewhere totally dust-free to place the polished object while the surface hardens. If you don’t, any dust that falls onto the surface will become embedded in it. Permanently.

Polishing

This is the really easy part.

1. Without getting any on your plinth, pour the acetone over the kitchen roll sheets you placed up the side of the container. You need to have enough acetone to cover the bottom of the polishing container to a depth of a millimeter or two.
2. Ensure that there is no liquid acetone present on your plinth.
3. Make sure that you have a fool-proof way of removing the object from the container after polishing without the need to touch it, or you will leave marks all over the surface where you make contact.
4. Quickly place the object in the center of the plinth – try not to touch it again – you have just a few seconds to adjust the final position. The polishing process has already started – it is that quick! You don’t really want to leave fingerprint impressions on your work, do you?
5. Place the lid on the container and start your countdown timer. I personally set the timer to 15-minute intervals for finely-detailed objects, and 30 for large solid objects.

Depending on how rough the surfaces of the object are, and how polished you want the object to be, the process can take from around 15 minutes to several hours.

There is ALWAYS a trade-off between the required surface finish and the loss of fine details. Only you can decide what is acceptable.

Once you are satisfied that the polishing is almost complete, carefully remove the object to a totally dust-free environment that has good ventilation. This stops most of the ever-present dust particles that are suspended in the air from falling onto the semi-molten surface of the object.

Note: The reason you remove the object from the container at the point just before you get the surface finish you require as the polishing process continues for a short while even after the object has been exposed to fresh air.
You can always put it back in the chamber later if you are not satisfied, but once the process has gone too far, the damage is irreversible.

After about 30 minutes, a ‘skin’ will have formed on the polished object that will stop dust particles from becoming embedded in the surface of the object.

Remove the object from your dust-free chamber without touching it, and put it somewhere that has good ventilation to allow the acetone to further leach out of the object. The object at this point has little to no structural integrity so be careful how you do this.

Depending on the solidity and size of the object, the process of removing the acetone can take from a few hours to many weeks before the full strength of the object has been regained.

Once you are certain that a good skin has formed on the object, you can speed up this process of solvent evaporation considerably by using a fan continuously blow air across the surface of the object – smoothing 3D printed parts effortlessly. 

Summary 

To recap, the filaments that can be polished using this process are: ABS, ASA, PMMA, HIPS and Polycarbonate.

Other filament types are either unaffected by acetone or are damaged by it.

What Does Infill Mean in 3D printing?

Most FDM objects are not printed as solid objects, because that would use a ton of filament and take quite a long time to print.

On the other hand, a totally hollow print would be impractical, as it would easily fail under the stress of normal usage.

Infill 3D printing is a compromise between these two positions.

Infill density is the amount of filament printed inside the object, and directly relates to the strength, weight, and printing duration of your print. 

In this article, I’ll explain the methods I use to choose the right infill percentage and patterns for my projects to maximize strength and cost savings. 

We’ll then cover any troubleshooting with infill related problems and how to compensate when using low or no infill. 

We also have an article on the best infill settings for every project and filament type.

How to Choose Infill Percentage in 3D Printing

3D Printer infill patterns, or the internal structure of an object, are a necessary part of printing some 3D objects, especially those that require a measure of strength or sturdiness. That being said, infill is also something of a pain.

If you want your print job to succeed, you’re likely to have to use a solid shell with at least a modicum of infill. However, the more infill you use, the higher the cost and the print time of the object becomes. It’s worth taking a moment to decide your optimum 3D printing infill percentage. 

In this article, we’re going to take a close look at the process of infilling. We’ll examine the pros and cons of 3D printing infill types and density.

We’ll look at how to balance the amount of infill against the object’s intended use, to optimize strength while keeping costs and printing time to a minimum.

Finally, we’ll look at how some of the cutting-edge slicer software that is presently hitting the market is changing the concept of infill. So keep reading to learn the best infill pattern for your prints. 

Basic Object Sections

In general, a routine FDM object consists of four sections. The design criteria of each of these sections can be individually altered so that an optimized design is achieved. The sections are:

• Shell – The outside walls of an object, typically built up vertically along the z-axis.
• Bottom layers – A part of the shell comprised of an outside wall of an object, initially attached to the build plate.
• Top layers – A part of the shell comprised of an outside wall of an object, facing upwards. Usually the last part of an object to print.
• Infill – The material that comprises the interior of the object between the shell or walls.

Infill Shapes

There are several infill shapes typically available in most slicer programs. For example, Cura’s infill patterns include Honeycomb and Triangles among others.

Which one is right for you depends on what type of object you’re planning on creating and the 3D printing infill strength you require. 

• Rectangular – This standard infill pattern provides a reasonable amount of rigidity in all directions. It is also one of the easiest infill patterns to print, requiring a minimum amount of bridging on the part of your print head.
• Triangular – Appropriate when strength is required in the direction of the shell. However, it takes longer to print.
• Wave or Wiggle – As the name implies, a waveform infill pattern. Particularly useful when an object needs to be able to twist or compress. This is great to use for flexible materials. 
• 3D Honeycomb Infill – One of the more popular infill patterns. Provides greater overall strength in all directions than a rectangular pattern, with very little increase in print time. It is generally considered the most commonly used, strongest infill pattern. 

Here are some examples of Cura infill patterns. Some are novelty (like the cross, not pictured) and take longer, whereas others are faster. Honeycomb infill Cura is not currently available. 

Grid / Rectangular is a good default, fast option. Concentric is 2nd best to wave for flexible prints to keep it soft. Triangle is the strongest Cura infill pattern apart from Honeycomb.

Cubic is a great compromise between strength, print speed, and keeping the model light via low filament usage. 

Cura Infill Overlap

Overlap is the amount the edges of your infill is printed into the outer walls of your print. If the overlap is too great, you’ll end up with the infill forcing through the walls – which isn’t a pretty sight.

The default is 10%, which gives room for good consistent adhesion between the infill and walls, without the infill coming through. 

The default in most cases is sufficient, but should you want to change it:

Infill Overlap is hidden by default (as are most options in Cura 2.x/3.x)

To enable Cura Infill Overlap:

1. Click on the little cogwheel next to infill when you mouse over it.
2. Then check the box for infill overlap in the window that pops up.
3. Default is 10% of LineWidth – i.e. 0.04mm for a 0.4mm nozzle.

Using Shell Thickness to Reduce Infill Percentage

The shell of an object consists of layers on the outside of an object. In many designs, the shell is often the first area that is printed in any layer. This means that shell thickness is intimately tied to infill amount and percentage.

When you increase the shell thickness of an object, you are also increasing its strength. This means that the object becomes sturdier and more capable of handling stress without the need for increasing the 3D printing infill density.

The majority of slicer programs will allow you to adjust the density of shell thickness in specific areas of the object, thereby offering localized strength where it is needed most.

Shell thickness is usually measured in print nozzle diameters. If you do decide to slightly increase shell thickness to reduce infill amounts, make sure that the thickness specified in your design is a multiple of your nozzle diameter.

This will help reduce voiding in your walls, bottom and top layers.

It really helps to use good quality filament when printing, especially if you’re looking to maximize strength while cutting back on material used. This is where high-quality filament comes into their own, your prints will be stronger, but with lower (or no) infill, you can use less material and save more time. 

You may even save money with fewer failed prints or unusable parts. 

It should be noted that there are some drawbacks to this approach. Any post-printing finishing process, such as sanding or annealing, will reduce shell thickness and directly affect strength.

This can be offset by increasing shell thickness even further. However, every increase in shell thickness will drive up print costs and time. So, at some point, increasing shell thickness to reduce or eliminate infill amounts becomes a losing proposition.

Experimenting with your designs and slicer settings will help you determine if this approach is right for your particular circumstances.

3D Printer Infill Percentage and Overall Object Strength

To understand infill, think about the doors in your home. Very few doors that are mass-produced are made of solid wood. The cost is simply too prohibitive. The majority of doors available commercially have a wooden or metal outside surface built around a core consisting of a lower density material.

This allows the door to be produced quickly in large volumes while remaining affordable.

So, to an FDM object. The typical FDM design consists of a solid outer surface (the shell) which is built around a lower density infill. As was the case with doors, this arrangement allows the object to be printed as quickly as possible at a reasonable cost.

The majority of slicer programs have a default infill setting somewhere between 18% and 20%. For many designs and objects, this default density is perfectly acceptable. However, when it comes to infill percentage, there is no hard and fast rule that fits all scenarios.

An 18% to 20% infill percentage may work fine for a prototype object where strength takes a backseat to form or shape. However, that same infill percentage will be completely inadequate for an object that has been designed to hold weight, like a bracket.

In general, the strength of an FDM object is directly tied to the infill percentage used during printing. For example, a part utilizing 50% infill is approximately 25% stronger than a part that utilizes 25% infill.

However, the amount of strength gained by increasing infill percentage does not increase linearly. For example, increasing infill percentage from 50% to 75% only results in an additional strength increase of 10%.

In addition to increasing overall object strength, infill percentage is also critical to object feature strength. For example, consider a two-piece object designed to connect together using an integral attachment feature like a snap-fit.

A snap-fit connector is usually designed as a cantilever. This means that its weakest point will be the small area attaching it to the main body of the object.

At a low infill percentage, the internal density of the cantilever is insufficient to withstand the stress of connection. As a result, it will snap off at its connecting point.

Increasing the infill percentage will increase the density of the connection, with a corresponding increase in strength.

The same situation holds true where a multi-part object is designed to be assembled using screws or bolts. Using a low percentage of infill usually will result in a weak connection, due to the fact that the bolt or screw is more likely to gain insufficient purchase or miss the infill altogether when density is low.

Again, if you’re looking to maximize strength, using a higher quality filament with a stronger pure based resin (higher grade and without filler that cheaper makes can use) with better layer to layer adhesion will build more strength into your prints. 

Support Infill Percentage

Much the same way you may want to increase infill in areas that are higher stress, it’s often wise to reduce support infill percentage as much as you can get away with. For very small supports often 0% will be fine.

This allows you to save filament and keep printing speeds lean. 

Infill Problems

This common printing issue, shown in the image above, is often assumed to be a problem with your infill settings. However, this issue is actually a simple case of under extrusion – if a very extreme example. 

Because the infill wall widths are often printed much thinner than the outer walls of your print, under extrusion issues nearly always become more obvious with infill, even if the thicker printed outer walls appear fine at first. 

If you’re getting spongy infill problems, then you may need to look at sorting out your under extrusion issue first. 

Other issues, such at the infill not touching or binding fully with the outer walls of your print (put simply, gaps between infill and outer walls), could be caused by incorrect slicer settings, if not already a symptom of under extrusion mentioned above.

To remedy this, you’ll want to ensure your ‘infill overlap’ settings in your slicer are set correctly. Often the cause is that they’re not set initially, or set to ‘0’.

Experiment with incrementally higher values (start at around 10% and usually don’t exceed 50%) with your specific print until the problem is solved. 

Adaptive Makerbot Infill Patterns

Makerbot has recently released a brand new infill pattern that they call MinFill. MinFill is short for ‘minimum fill’, and that’s exactly what this pattern does.

Using a newly developed algorithm, MinFill determines the minimum amount of interior support required for each section of a printed object.

According to Makerbot, MinFill automatically changes the infill settings depending on an object’s unique geometry. It also makes determinations regarding how much support is needed and where, eliminating user guesswork, testing and tinkering.

The end results are strong, beautiful prints that use less filament and print quicker than objects using traditional slicer infill settings.

Obviously, if you have designed an object that requires a specific amount of strength to function, you will still be required to manually set infill percentages.

However, for a large number of print jobs, MinFill could represent the wave of the future when it comes to determining proper infill percentage.

Summary

In the end, when thinking about infill, you want to remember the unique relationship between strength, cost and print time. Every increase in an object’s strength comes with a corresponding increase in printing cost and time.

The secret to a successful use of infill is to find the sweet spot where sufficient strength is obtained for an object’s designed purpose, with both cost and time being kept within acceptable parameters.

Your print job seems to be running smoothly at first, but sometime later you come back to see that something has obviously gone very wrong.

There are missing print layers, thin printed layers, or even layers that have gaps and holes. Your print has turned out… spongy?

These are the effects of under extrusion!

Under extrusion occurs when your printer is unable to supply the correct amount of material needed to correctly print a layer. There are various reasons why under extrusion occurs, which can make it a tricky issue to diagnose.

In many cases, you can solve the problem in short order simply by knowing what to look for. In this article, we’re going to examine some of the common causes of under extrusion, and give you a quick fix for each.

Why is My 3D Printer Under Extruding?

The most common cause of under-extrusion is printing at temperatures that are either too high or too low for your material. If material is being printed at too low a temperature, it does not melt evenly. The thermoplastic being used becomes thick and viscous. It takes more force to extrude and the flow of the material is uneven as a result.

Likewise, if the material is being printed at a temperature that is too hot, it can begin to fuse or bind to the inside of the hot end. This causes a partial blockage of the nozzle, and under extrusion is the result.

Sometimes, PLA or PVA filaments if printed too hot can burn or crystalize in the nozzle, blocking it.

Check to be sure you are printing within the recommended temperature parameters for the material you are using. That being said, it should be noted that it’s common for thermistors and heated thermostats to be somewhat inaccurate.

So, if you are printing at the correct temperature and you’re still having problems, it’s not a bad idea to try slightly raising or lowering the temperature that’s displayed to see if that clears up the under-extrusion issues.

Often, it can just all be about finding the right temperature for your filament, with your printer. Let’s look at how to fix under extrusion. 

Mechanical Issues

Your printing material passes through the feeder, the bowden tube, and the extruder on its way to becoming a printed object. A malfunction at any one of these points can cause insufficient material to be available for printing when it is needed. The result is under extrusion.

So, if you’re experiencing under extrusion while printing, it’s a good idea to take a look at all of these areas to see if one of them is causing your problem. 

Feeder Problems

The feeder is so named because it feeds the print material into the extruder. Therefore, a malfunctioning or misadjusted feeder will cause the print material to be sent to the extruder in a non-uniform manner. This, in turn, will result in uneven extrusion during the printing process.

One of the first things to look at is the feeder tension settings. If the tension settings are too low, the knurled wheel inside the feeder that grabs the material and moves it towards the print head can’t get enough purchase to steadily move the material.

On the other hand, if the tension is too high, the feeder will grab the material with too much force, causing it to deform. This flattening makes it harder to move the material through the bowden tube and the print head, which causes insufficient material to be available for printing when needed.

Furthermore, high tension can cause the feeder to grind away at the material, causing more deformation and even slower movement.

After you’ve checked your tension settings, make sure that there isn’t a loose or intermittent power connection to the feed motor. A bad connection can cause the motor to run irregularly, slowing the feed to the print head.

This can often be the cause of a clicking or knocking sound when printing – some printer manufacturers are prone to this fault because the cables they use won’t drive the motors reliably enough.

Also, make sure that the knurled wheel isn’t slipping on the feeder motor shaft by tightening the key or grub that holds the wheel to the shaft. This is another common design fault with other manufacturers of printers. You can minimize this if you have one of these machines by upgrading it.

If your tension and feeder mechanics are ok, but you’re still experiencing problems, the issue could be due to increased friction in the bowden tube or a partial blockage in the print head.

Bear in mind, if you’re having under extrusion problems with flexible filaments – the filament could be bunching up between the feeder and the hot end (think ‘pushing string’) – so you might find that your filament isn’t compatible with your feeder. On a side note, we do slightly stiffer flexible filaments that work in a larger variety of stock hot-ends.

Bowden Tube Problems

Once your material leaves the feeder, it enters the bowden tube which guides the material to the print head. If your feeder tension was too high and your material was being ground up, dust from that grinding can collect in the bowden tube causing friction when the print material passes through.

This friction can cause the material to slow in the tube which results in under extrusion. You can solve this problem by regularly cleaning the bowden tube to remove any buildup of dust.

Print End Problems

Another common cause of under extrusion is a partial blockage of the print end nozzle. There are various reasons why this type of blockage occurs. There could be a buildup of carbon or carbonized material in the nozzle.

Alternatively, if you’ve previously used a high-temperature printing material and now are using a lower temperature material there could be unflushed residue of the higher temperature material that’s remained in the nozzle.

Another possibility is that there is a debris particle or particles blocking the nozzle. This is especially common when using a smaller nozzle head with a diameter of 2mm or below. Finally, you may simply be using a poor-quality printing material that isn’t melting evenly and consistently and clogging the nozzle.

Luckily, there are a couple of relatively easy fixes that can take care of a partially blocked print end nozzle.

The first method requires you to first reverse feed all the print material out of the print head. Once this is done, heat up the head to about 260°C. Then take a long thin needle that is the same size, or slightly smaller than your nozzle diameter (surgical or acupuncture needles work well) and insert it into the nozzle, taking care not to burn your hands.

Simply move the needle in and out of the nozzle several times to make sure that the blockage has been thoroughly cleared.

The Atomic Method: How to Fix Under Extrusion Problems

The next fix has been nicknamed the “atomic” method because it uses print material to clean out carbonized gunk and other built-up debris from the top end down. The key to successful atomic cleaning is to use the material that you last printed with as the material you use for the cleaning.

This is a very effective trick if you’ve got particles or carbon build up behind the actual nozzle hole, as it pulls it out from the back. 

Step 1 — The first step is to once again reverse the print material out of the print head. Next, remove the clamp that holds the bowden tube to the print head and gently pull the tube from the head.

Step 2 — Next, heat the print head to the temperature of the material that you last used. While the head is heating, cut about 20cc of the print material from the spool. Use a straight cut and try to straighten the material as much as possible.

Step 3 — Now, take the cut piece of material and insert it all the way down into the print head. Apply a bit of pressure until the material begins to extrude from the nozzle or can’t be inserted further. Lower the print head temperature down to about 145°C for Nylon or other higher temperature materials, 110°C for ABS, and 90°C for PLA.

Wait for the print head to cool to the desired temperature and then quickly and cleanly jerk the print material out of the print head. The goal is to have a clean tip when you remove the material from the head. Repeat the process as necessary until the tip of the removed material is clean.

We cover more in-depth cleaning and unblocking methods in this article. Hopefully this guide has shed a bit more light on the “Why is my printer under extruding” question that may have brought you here. These tips should allow you to diagnose the issue that you’re having, so you can get fixed up and back on track in no time.

Related articles:

• The ultimate 3D printer troubleshooting guide (44+ problems solved)
• Clogged nozzle – here’s how to fix
• Over extrusion: how to fix in your 3D printer
• The best 3D printer hot ends buyer’s guide
• The best 3D printer nozzles
• Best 3D printer extruders

The better you look after your printer, the less time you’ll spend scratching your head over it.

One of my most common frustrations is coming back to my machine printing in ‘thin air’ because it stopped extruding part way through the print.

In some instances, it’s not even a blockage, but an otherwise perfect print finishing with little specks of the previous color filament embedded in it. 

The extruder and nozzle components of your are arguably the most sensitive parts to your printer, and the hardest to keep in top condition – but it’s crucial maintenance if you’re aiming for perfect 3D prints.

How not to clean your nozzle

And that’s where cleaning filament comes in. Use it proactively and it’s the best preventative measure, yet it’ll also help to unblock all but a fully clogged nozzle.

In this article, we’re going to cover everything you need to know to use cleaning filament effectively and discuss how it stacks up against other cleaning methods like the ‘cold pull’ technique.

P.S If you’ve currently got a fully blocked nozzle, you can read our full guide to unclogging your nozzle here. 

How Does Cleaning Filament Work?

You’re likely skeptical that cleaning filament is a bit of a gimmick. Or just as likely, you’re not convinced you even need it.

Never had a blockage before? I don’t believe you It can happen to anyone at any time.

Some think cleaning filament as just made from Nylon or HDPE filament – which is the material of choice for the cold pull method. It isn’t by the way (and you don’t use the cold pull method with cleaning filament).

Or perhaps it’s just a cheap, highly abrasive material that strips everything out? And presumably erodes the inside of your nozzle over time…

Again, no. It’s actually (we can only speak for ours, of course) a non-abrasive industrial-grade compound for purging hard-stuck chemical residues out of injection molding machines.

We’ve sourced the best we could find, modified it for a larger range of operating temperatures, and extruded it into 3D printer-friendly filament form. 

Why Is Cleaning Filament Better Than Other Methods?

First on the left, towards a cleaner nozzle on the right. You can see how this can easily take 5-6 ‘pulls’

The well-known ‘atomic method’ or ‘cold pull’ has long been the method of choice to clean out your nozzle.

Often done after you’ve experienced a full or partial blockage, the general method goes like this:

1. Heat up your nozzle to around 250°C and insert Nylon filament as far as it will go, then cool the nozzle back down to about 30°C while maintaining the pressure.
2. Once cool, quickly pull the Nylon out. Usually takes a good hard yank (you may need one hand on your printer to prevent it from being pulled off the desk).
3. Do this procedure 3-5 times or until the end of the filament you’re pulling out is clear and has a well-defined tip (indicating a clear and residue-free nozzle).

In our opinion, this process is a little bit brutal. The whole process puts a lot of strain on some relatively delicate parts in your machine.

It also takes time to heat and cool your nozzle each time. You don’t want to leave the material hot in the nozzle for too long either; it definitely won’t help your situation).

The other option is if the cold pull method won’t work, you’ll likely need to insert a very thin drill bit or hypodermic needle up there. You’ll want to use the same size as the nozzle.

For 0.4mm nozzles, this is just about possible, but if you’re printing with 0.2mm nozzles or small – you’ll probably be best off just replacing it.

The risk here, apart from the obvious dangers of using very small, thin needles (we don’t recommend it, for the record) is that they can snap off inside the nozzle.

You’ll notice neither of these methods is really foolproof, or that user-friendly. Luckily, there’s a better way that’s fairly new on the scene.

3D Nozzle cleaning filament takes far less time to clean out your nozzle. Often in as little as 30 seconds, and you don’t need to do anything out of the ordinary, except changing filament. Which you should be pretty comfortable with by now…

Disadvantages of Using Cleaning Filament

This wouldn’t be a fair review without telling you what you can’t use it for, and why it’s not for everyone.

1. You can’t unblock a fully clogged nozzle with it. You need to have at least some flow rate to work. That’s why it’s always best to have and use nozzle cleaner filament before you need it.

As long as some filament comes through with a small amount of force, you should be able to unclog your nozzle. And we promise we won’t stand back, arms folded saying “told you so” the whole time…

2. It’s expensive. Well, it isn’t. But at first glance. You see, you really don’t need much. About 0.5 to 1 gram per use, maximum. Luckily you don’t need to buy a whole KG spool of it then (if you did, ours would be £360/KG).

For around £18 you’ll get 50 grams, which will get you a solid 70-100 nozzle purges. That’s just 20p per clean, in 30 seconds. Compared to 20 minutes yanking your 3D printer around for each clean, well – it’s a no-brainer.

What to Consider When Buying Cleaning Filament

Make sure you know what you’re getting. Some cleaner filaments could just be re-branded cheaper materials that don’t perform as advertised. Make sure you read the reviews, and factor in the price.

There may be cheaper ones on the market, but it’s worth weighing up – you may need more grams per clean if they’re not as effective, so it could end up being more expensive overall.

Other known brands we’re aware of are Lulzbot and eSun cleaning filament, so it may be worth doing your own testing.

Reviews are usually a pretty good indicator that it does as advertised. As for where to get it, you can find a few popular brands on Amazon.

How To Use Cleaning Filament

If you’ve bought some already and you’re left wondering what to do with this un-printable filament – or you’re just wanting to read up on cleaning filament instructions before you begin, here we explain what you should and shouldn’t be doing with your new one-stop 3D printer cleaning kit.

For most machines, there’s no need to cut the cleaning material, just load and unload like a regular filament.

For other machines or if you have an under extruding partial blockage, you may wish to unplug the Bowden tube to manually push the Floss filament through the nozzle.

When printing with the same material:

1. Printing with one material like PLA, all the time? How often you need to use your cleaner filament will depend on how often you print, and the quality of filament that you use. Poor quality or cooked/burned filament can leave residue in your nozzle. Even PLA can solidify in the nozzle over time, so we advise flushing it through at least every 200 – 400 printing hours.
2. Depending on your printer design, there are a few ways to use cleaning filament. In most instances, simply unload the previous filament and load your cleaner filament as you would any other filament.
3. Keep the printing temperature the same as your printing filament and begin to extrude the new cleaner material into thin air (don’t try to print with it!). Many printers will extrude a set amount as part of the loading process anyway. Keep extruding until you cannot see residue of the previous material, or contamination specks. Once it runs clear, simply unload and reload with your printing filament. No need to try a cold pull (although you can if you’re still not convinced it worked).

 When printing with different materials:

1. Always run the cleaner filament through at the last printing temperature. So if you were using PLA, and you’re changing materials to ABS, run the cleaner through at around 200C, not 230C. Likewise, if your last material was Nylon and you’re changing down to PETG, you’d run the cleaner through at around 260C. Our Floss cleaning filament has a temperature range of 200-280C+
2. As before, run enough filament through until you’re sure you cannot see any specks or residue. Then just unload and proceed as normal with your new material, ensuring the nozzle is at the correct temperature for the new material before you load it.

And that’s it, that simple. You may need to manually feed it if your nozzle is partially blocked to get some to feed through, just to apply a little extra pressure.

Although don’t force it, if your nozzle is completely blocked unfortunately you’ll just have to use one of the previously mentioned unblocking methods.

In this article, we’ll explore six of the most common slicer settings that make all the difference in producing beautiful and useful 3D printed objects.

From layer height to print speed, we’ll cover what each setting does and how to adjust them to achieve the best results.

So whether you’re a seasoned 3D printing pro or just starting out, read on to learn how to get the most out of your slicer settings!

What is a Slicer?

As you may know, a slicer is a piece of 3D printing software that takes a digitized 3D model and converts it into printing instructions that your printer can then use to turn the model into a physical object.

In essence, the slicer takes the CAD model and “cuts” it into layers. Think of a series of 2D pictures stacked on top of each other to create a 3D model.

It then calculates how much material needs to be used for that layer, where the material should go and how long it will take.

It then converts all of the information for each layer into one GCode file which is sent to your printer. You set up the job and, voila! Sometime later you have a physical representation of the 3D CAD model.

As you can see, the slicer plays an integral role in helping turn your 3D ideas into reality. Therefore, how you use the slicer, specifically how you use the settings, is often a critical difference between printing success and failure.

In this article, we’re going to look at 6 key slicer settings that are common to all the major slicer programs. We’ll tell you what they’re for and we’ll explain how to use them to increase your chances of producing beautiful and useful objects each and every time you print.

Best 3D Printer Slicer Settings

Layer Height

Layer height is the 3D slicer setting that establishes the height of each layer of filament in your print. In some sense, layer height in 3D printing is akin to resolution in photography or videography.

When you choose a thicker layer height, your object will have less fine detail and the layers will be more visible. When you choose a thinner layer height, a higher level of detail is possible and your layers will tend to blend into one another.

However, keep in mind that the thinner you make the layer height, the more time it will take to print the object in question, since there will be more layers to print.

An object with less detail, on the other hand, will print faster with a thicker layer height. It will also have a less smooth surface. Thicker layer height is often chosen for making a prototype of an object, since detailing and surface texture usually doesn’t matter.

Read more: best layer heights in 3D printing, and how layer height affects your results

Shell Thickness

A shell is the outer wall of a designed object. Shell thickness refers to the number of layers that the outer wall will have before infill printing will begin. The higher the setting is for shell thickness, the thicker the outer walls of your object will be.

Obviously, thicker walls make for a sturdier object, so if strength is a quality that you’re after, it pays to increase the shell thickness appropriately.

Obversely, delicate or decorative designs do not usually require strength. Increasing the shell thickness in these instances provides no real benefit and will likely distort the design of the object being printed. 

Retraction

This setting is used to pull the filament slightly back into the print head during times when the head is traveling from one print point on an object to another.

This stops the filament from leaking out of the print nozzle and leaving strings of material across otherwise empty space.

If your CAD design has a discontinuous surface, your slicer program should automatically enable the retraction setting.

Fill Density

Fill density, or infill, is a measure of how much material will be printed inside the outer shell of the object in question. Fill density is usually measured as a percentage of the whole, as opposed to a unit of measure.

This means that if 100% fill density is selected, the printed object will be solid, with no empty space inside the outer shell. Likewise, if 0% is selected, the printed object will be empty inside. Fill density is used to conserve filament while printing and speed up printing times.

However, an object with more infill will be stronger and heavier than an object with less infill. Therefore, if either of these properties will benefit the printed object, consider increasing the fill density as needed.

Read more: optimum infill settings

Print Speed

Print speed is how fast the print head travels while extruding filament. Therefore, optimal speed depends on the object you are printing and the filament material that you are using to fabricate the object.

In general, simple objects with less detail can be printed faster without complication.

On the other hand, more complex objects with more detail will benefit from a slower print speed. Print speed can also affect adhesion to the print surface, cause under or over extrusion and other problems. Because of this, it pays to experiment with your print speed to see what works best for the job you’re printing.

Bottom/Top Thickness

This setting determines how much material will be laid down before the infill printing starts and how much material will be laid down after the infill printing is finished. The thickness of the material at the top and bottom of your object is important for two reasons.

First, thicker material at the bottom of your object will provide a stronger and more stable base. Second, thicker material at the top of your object will prevent sagging and pillowing from occurring when the top layer of material is laid down over the infill lattice.

This is especially important if you are using a smaller layer height setting. In such a case, the thinness of the layer can be insufficient to completely cover the infill unless multiple layers are used.

Setting the bottom/top thickness to be 6 to 8 times greater than the layer height ensures that there is enough material being laid down to adequately cover the infill without complications.

Spiralize – Smooth out the Z Scar

If you’ve printed an object and on one side there appears a vertical scar all the way up the print, this is called a Z scar (also known as a “zipper”). It’s formed from the printer starting and stopping each layer at this point.

This scar can be unsightly, and on very thin prints also significantly weaken the structure.

To remove the Z scar, you’re going to need to activate the Spiralize feature in your slicer. This makes the outer layers print in a continuous line all the way up the print, meaning there’s no definitive stop and start point and therefore no scar formed.

To activate Spiralize feature and remove the vertical scar:

In Cura, it’s called the “Spiralize outer contour” feature, in other slicers it may be slightly different. Make sure this option is checked when you convert your STL file to a Gcode.

It is useful to remember to only change one slicer setting at a time so that you can see the effect that the change is having on your print. If the change is beneficial, write down the change that was made and proceed, if necessary, to change another setting.

Changing multiple settings at the same time can cause chaotic conditions and a positive effect can be canceled out by one or more negative effects.

It may be useful when planning prints to know the length of filament on each size spool for various materials and sizes. To help with this, we’ve created this filament calculator.

Other articles you may be interested in:

• Best 3D slicers
• Best resin 3D slicers
• Best slicers for Ender 3
• Cura Vase Mode: Complete Guide

One of the most frustrating aspects of 3D printing is printing defects. We’ve all been there. You’ve got a great design. You’ve sliced it and everything looks good. You start the job, excited to see the results.

But your object didn’t print out the way you thought it would. You’ve wasted time and filament, and all you’re left with is a shoddy print.

The good news is that most printing defects are easily solvable once you know where to look and what to do.

In this guide, I’ll walk you through three of the most frequent 3D printer problems and solutions:

• Pillowing
• 3D printer stringing
• Layer splitting

We’ll talk about what they are, why they occur, and the techniques I used to prevent them from happening in the first place.

Pillowing 3D Prints

‘Pillowing’ occurs on the top surface of an object. It looks like there are gaps in the surface layer, along with little bumps or pillows.

The above image shows clear gaps have formed, but the ‘pillowing’ pattern isn’t very visible

What Causes 3D Printing Pillowing?

In general, pillowing is caused by a top layer that is too thin and/or improper cooling of that layer. Under certain circumstances, insufficient infill can also contribute to the problem.

Let’s take a look at what you can do to prevent pillowing from happening.

How to Prevent Pillowing in 3D Printing

The easiest way to prevent pillowing is to increase the thickness of the top layer of your object. In most 3D slicer applications, this can be done by going to the advanced settings tab and looking for “Bottom/Top Thickness”.

In most cases, you want to have a top layer that is at least 6 layers thick. This means that if you are printing with a 0.1 mm layer height, you want to set your Bottom/Top Thickness to 0.6 mm.

If this doesn’t solve the problem, you can increase the Bottom/Top Thickness setting to 0.8 mm. In general, the thinner your layer height, the more top layers you’re going to need to sufficiently cover the infill on your object.

On the subject of infill, the less you have the more difficult it becomes to lay down a top layer.

While not a direct cause of pillowing, insufficient infill can contribute to the problem by causing your top layer to droop and sag, especially when you add in additional layers.

Therefore, it is always a good idea to slightly increase your infill percentage when attempting to prevent 3D printer pillowing from occurring.

To learn more about 3D printer infill problems, check out this article. 

Cooling & Overheating Issues

When you’re printing the top layers of your object, it’s very important that you are cooling the print material properly.

If the top layer takes too long to cool, it may sag in between the infill layers and curl up where it touches the infill layers. This is especially true when you are using a thin layer height.

The result is an uneven surface that becomes bumpy and uneven as the top layers are added.

Make sure that your cooling fans are operating correctly both prior to printing and as the top layer of your object is being laid down. Make sure that the fans are pointed in the right direction and are circulating air in the direction of the object that you are printing.

Read more: 3D printer too hot / overheating

How to Prevent Stringing in 3D Printing

Sometimes your object will have thin strands of material where no printing should be occurring, usually across spaces where the print head has traveled from one printing point to another. This problem is known as 3D printing stringing and it can be one of the most annoying defects to deal with.

Similarly, you can get 3D printer blobs ruining your prints, and these are resolved the same way as stringing. This is one of the most common 3D printing problems.

What Causes Stringing or Oozing?

Stringing is usually caused by the print nozzle oozing print material as it moves from one place to another. The oozed material cools and hardens into thin “strings” – hence the name.

Let’s take a look at a couple of adjustments that you can make to combat stringing.

A print suffering from stringing can be really ugly. In mild cases, you can simply sand off the extra wisps of stray filament. But with the right settings, you can learn to fully prevent this altogether. 

PLA stringing and PETG stringing are especially common due to the nature and low viscosity of the material when molten. However, as you’ll read this is easily remedied when using filament of a good, reliable quality. 

Here are the 3 causes of your prints stringing or nozzle oozing. Your symptoms may be caused by one or all of these, so it’s worth trying each out (in order) to diagnose the problem. While 3D print stringing is not the direct effect of over extrusion in 3D printing, they are related symptoms. 

To combat over extrusion, try the same adjustments as listed below for remedying stringing. 

Retraction

Retraction is a slicer setting that is usually activated by default. When retraction is activated, the printing filament is pulled back or retracted into the print head any time the head moves from one print point to another. So, if you’re seeing stringing on your objects, the first thing to do is to check that the retraction setting is indeed active.

If retraction is activated and stringing is still occurring, you can then use the additional settings tab to incrementally increase retraction distance and speed. This will cause the filament to retract farther into the print head more quickly before each new pass. 

Temperature

A common cause of persistent PLA stringing, or other materials; is a print temperature that is too high. When the temperature in the print head is too high for the material being used, the filament becomes too viscous and watery and leaks out the print nozzle.

If you’re still experiencing stringing after checking your retraction settings, try reducing your print temperature in 5°C increments to see if that clears up the problem. Incorrect temperature is one of the biggest causes of 3D print problems.

Speed

If you have lowered your print temperature to prevent stringing, you will also likely need to reduce your print speed to prevent potential problems from under extrusion from occurring. A lower print temperature means that the print material will flow more slowly.

Keeping the print speed where it was can mean that gaps and holes can begin to appear in your object in the places where the extruded material couldn’t keep up with the speed of the print head.

3D Printing Layers Splitting / Cracking

Sometimes a print job will be progressing nicely with no apparent problems. You leave the room, and when you come back you see that your object has developed a split or crack along one of its sides at a point where everything seemed fine before.

Gaps in layers look awful and dramatically weaken your print. They can also be especially common in ABS prints. We’ll advise on how to prevent this below. 

What Causes Splitting or Cracking in my print?

As you know, your printer makes an object by laying down layers of print material, one on top of the other. It is imperative that each new layer binds to the previous one.

Splitting occurs when one layer bonds inadequately with another layer, it’s the 3D printing layers separating. When this happens, as the object cools, a split or crack occurs between the two inadequately bonded layers.

Luckily there are a couple of things that you can do to prevent splitting from occurring when using good quality filament. 

If you’re still experiencing similar issues with poor layer adhesion in PLA or other materials, it could be down to simply using a cheap or poor-quality grade filament. 

How to Solve Splitting or Cracking Layers in 3D Printing

Decrease Layer Height

In order for two layers of print material to bond, the print nozzle needs to apply exactly the right amount of pressure to the layer currently being laid down.

Too much pressure and the layer will move off to one side or smear. Too little pressure and the layer can’t adequately meld to the previous print layer. The result is a crack.

In order to make sure that the print nozzle is applying adequate pressure, make sure that your layer height is about 20% smaller than your print nozzle diameter. That ratio ensures that the nozzle is pressing down enough on the material being extruded to adequately bond it to the previous layer.

Increase Print Temperature

If your material is being extruded at too cool of a temperature, it cannot easily bond with the material that’s already been laid down. Therefore, as it cools, it will shrink and pull away from the layer below it. The result is a split or crack.

To avoid this from happening, increase your print temperature slightly. The slightly higher temperature will ensure that the extruded layer bonds with the previous layer so that both layers essentially cool as one object, thus avoiding the splitting that would otherwise occur. You may also want to play around with reduced cooling, to get a really good layer adhesion. 

Just be careful you don’t go too far and end up with any of the cooling-related issues mentioned earlier in this article. 

If you’re still experiencing splitting layers after this, you may need to print in an enclosed area to keep the ambient temperature higher. This will slow the cooling process and put less strain on the print as it contracts slower.

A simple enclosure can be made using a large box over your printer – although we recommend using the enclosure kits that most printers now offer as an upgrade.

Related articles:

• 3D printer problems: the complete troubleshooting guide
• Underextrusion 3D printing guide
• The best FDM 3D printers

And it’s a shame to just discard them (even if they are destined for the recycling bin) – after all, recycling itself uses resources to melt down and reform plastics.

Luckily, there are plenty of useful things you can do with your old spools!

In this article, we’ll take a look at some of the best uses for empty filament spools, from creating drawer organizers and paint organizers to making your own clock.

These are the projects that I’ve enjoyed most of the past couple of years, and while by no means an exhaustive list, hopefully these picks will spark your imagination for your own creative solutions!

Can Filament Spools Be Recycled?

It would be great if companies could take back old filament spools for reuse.

However, at present, we’re unable to work out a way to return old spools economically, both from a cost perspective and in terms of environmental impact. There’s very little saving gained by getting empty spools sent back, with trucks burning yet more fossil fuels all the while.

Some people like to make their own filament, so can’t these ABS spools be ground down to make new filament?

Sure, if you don’t care about the quality you’re getting (and therefore are fine with the poor finish quality and jams you’ll need to deal with). The ABS we use to make our spools is a significantly lower grade than the ABS in our filament.

And our view on extruding your own filament: on a $300 machine you can bet it isn’t going to give the same results as the near €300,000 extruding equipment we use.

That’s why I’ve compiled my favorite examples of useful ways to reuse or repurpose your empty spools. Keep them around for a variety of uses, and you’ll be surprised just how useful they can be.

Best Uses of Old Filament Spools

Let’s take a look at the novel ways to use those empties:

Drawer Organiser

Need to keep small items, like electronics parts or jewellery, organised? This expandable drawer system is a great solution. Here are two solutions for two different spool sizes by Tanatof and Guardia on Thingiverse.

Spool Up Christmas Lights

Our lazy go-to is usually to just use them for spooling up rope or fairy lights. This is our favorite because it requires absolutely no effort. In fact, when you have to untangle the lights from last year, you’ll quickly realize how much effort it saves you.

Make a Go-kart

OK, so using empty spools as wheels might not be the best use for them; we’re pretty sure it’ll give a really bumpy ride. But it’s a great example of what you can do with a little bit of boredom/ingenuity.

Paint Organiser

A really simple hack we love is just to cut some large holes in one side of the spool disc to fit small paint bottles.

A great way to keep your modeling paints organized. For further functionality, you can print a centerpiece (if required) to hold mixing cartons.

Covert to a Coat Hook

EU Makers’ filament spools convert to a handy coat hook and other interesting projects. Although this would be useful for the first couple of rolls you used, it’s likely those hooks would soon stack up! Still, it’s a novel idea – and you could cut an existing spool in half to create a similar result, although perhaps not as aesthetically pleasing. Aside from storing coats, it may be useful for the garage or workshop to keep longer cables drooped over so they fall straight without kinks.

Print Your Own Clock

With modern, fast 3D printers, it’s possible that some of your prints can be finished in a few mere hours. With that kind of speed, it’s easy for you to lose track of time while you sit next to the printer, eagerly watching the print while it finishes. To solve this, you might want to print your own clock, using the spool as a face like Reddit user Mr_Knight13 did.

It would also be a brilliantly simple project to introduce kids into the world of 3D printing (as the low profile numbers would actually be pretty quick and easy to print).

Here are some fancy-pants Roman numerals if you want to make things a little more historic/confusing.

Hopefully these ideas have sparked your imagination to answer the question of “What to do with old filament spools?”, and have given you some inspiration to come up with some new ideas.

Related articles:

• How to join or fuse filament together
• How to untangle filament
• The complete filament types guide
• Filament calculator – how many meters on each type of filament 1kg spool
• How long does 1kg filament last? And how many models can you print with a 1kg spool?