3D printing filament is the ink used by your 3D printer and its importance cannot be underestimated when aiming for top-quality results. In this article, we’ll share some of our insights on the plastic filament used for 3D printing. We’ll help you better understand why our Super Premium Series filament is so effective and what to look for when buying plastic for your own printer.

There are many types of filament available and we’ve sold several of them at Boots Industries over the years; however, we’ve recently elected to specialize in PLA filaments. Our decision was based on several factors, but the most compelling reasons for us were the fact that PLA (Polylactic acid) is manufactured from renewable sources and is not harmful to your health or the environment when printed parts are discarded. As the 3D printing industry grows, manufacturers, suppliers and retailers must take on a leadership role in providing eco-friendly and sustainable products. In addition, with advances in thermoplastic technology, we’re now able to offer PLA blends that have print characteristics that are very close to those of ABS, without any of the disadvantages

Our 3D printer manufacturing background gives us extensive experience with several 3D printing materials, but most of the examples in this article are based on PLA. That being said, our analysis is in most cases applicable to other types of plastics used for 3D printing and with which we have extensive experience (i.e. Nylon, PC, HIPS, PVA, PET, Conductive, Filled, Synthetic Rubber etc.).

First of all, both PLA and ABS are great materials for 3D printing applications and you can make amazing things with both. To begin this article, we’ve compiled a list of important characteristics for both these plastics.

• PLA (short for Polylactic acid) is a plastic made of renewable starches, such as corn and sugarcane.
• It is biodegradable and does not emit noticeable amounts of ultra-fines particles (UFCs).
• It produces a barely noticeable smell when extruding.
• Depending on the specifications and the color, extrusion temperatures can vary between 190 and 230 °C.
• Parts printed using PLA are more rigid than ABS parts.
• In general, parts printed using PLA have a slightly glossy finish.
• PLA is less prone to warping during the printing process and is much ‘stickier’ than ABS.
• Regular PLA starts to become malleable (heat deflection point) at around 60 °C.
• PLA is a modern material in the history of FDM 3D printers and has a promising future.

• ABS (short for acrylonitrile butadiene styrene) is a common thermoplastic that is essentially petroleum-based.
• ABS can be purchased at a slightly lower price than PLA, due to its petroleum-based origin and higher availability.
• It is a documented fact that ABS produces UFCs when printing. Good ventilation is recommended.
• It produces a ‘burnt plastic’ smell when extruding.
• Depending on the specifications and the color, the extrusion temperature can vary between 220 and 260 °C.
• Parts printed using ABS have a “bend” to them and are less brittle than PLA.
• In general, parts printed using ABS have a glossier finish than PLA parts.
• ABS starts to become malleable (heat deflection point) at around 100 °C (which still makes it less heat resistant than our Super Premium Series PLA formulation).
• ABS has a lower coefficient of friction than PLA and requires slightly less force to be extruded than PLA.
• ABS can be considered the “legacy” filament, as it was used for 3D printing before PLA.
• Fun fact: The world-renowned Lego blocks are made from injection-molded ABS plastic!

• As the filament is lighter per unit of length, the extruder motor displaces less mass.
• Displacing less mass allows designers to create more compact extruders.
• Filament with a smaller diameter can be heated faster (as it takes less time for the heat to reach the center), so you can print faster.
• The faster heating characteristic allows for more compact hot end block designs.
• The smaller nozzles allow for a more precise plastic flow control and reduce the risk of oozing.
• Being smaller, the filament is also more flexible and can be coiled more tightly and turn sharper corners.
• Force required by the extruder to push the plastic in the extruder is lowered because less pressure builds up in the nozzle.

Now that we’ve discussed the reasons behind our affinity for 1.75 mm PLA filament, let’s explain what to look for in a good 3D printing filament. Some considerations are more obvious than others, but some small details are easily overlooked unless you have a lot of experience 3D printing. This article discusses the most important factors so that you can make an informed decision when purchasing filament for your 3D printer.

When printing using any type of FFF 3D printer, it’s important to understand that the software controlling the printer calculates the extrusion volume based on the filament diameter, the diameter of your extruder nozzle, and the extrusion speed (commonly referred to as flow rate – in mm/s). In essence, your 3D printer controls the volume of plastic that is pushed out of the nozzle by turning the extruder wheel and pushing a certain length of filament down the hot end. If you have a filament with an irregular diameter, the volume of extruded plastic varies and the software can’t and won’t adjust the extrusion length to compensate for this diameter variation. Instead, it will keep on printing, expecting a certain ‘theoretical’ amount of plastic to come out. This problem, caused by poor diameter tolerance, is what we refer to as ‘inconsistent extrusion’.

Ideally, your filament should maintain an absolutely constant diameter across the entire spool. However, in real life, due to small imperfections in the manufacturing process, there is always a tolerance within which the diameter will be maintained. The tolerance of a filament describes the variation in diameter that is present in the filament you use. For example, at Boots Industries, our 1.75 mm filament features a diameter tolerance of ± 0.05 mm. This is an excellent tolerance that and is achieved by using four-axis laser gauges and other advanced manufacturing technologies.

Serious issues can arise from an inconsistent filament diameter. A typical example is extruder failure, a condition where the extruder fails and no plastic makes it to the hot end. This can occur if your filament suddenly becomes too thin for the extruder tensioning mechanism, which leads to insufficient pressure gripping the filament. Another effect of a decrease in filament diameter is that back-flow could occur in the hot end (hindering plastic delivery to the head).

The other extreme is when your filament’s diameter is suddenly too wide and the extruder motor is not strong enough to push it through or it does not fit into the hot end opening. Another effect of an increase in diameter is that the extruder gear could shred the surface of the plastic, leaving nothing to grip and stalling your extruder.

In all cases, extruder problems of this nature can be mitigated by a tensioning mechanism that applies and maintains the tension dynamically on the filament, regardless of its diameter, by using a spring. However, not all extruder tensioners have this feature and will not guard you against gross diameter deviations.

Typically, when looking at filament tolerance, the gold standard across the industry is 0.05 mm. Working extensively with many extrusion lines and partners, we’ve found that it’s very hard to go lower than that and maintain consistency across the full length of a spool. When you purchase a new spool, you can use a micrometer to measure the diameter at several places and ensure that it meets the advertised tolerance.

When making contact with the extruder wheel, the filament will always suffer some compression due to the extruder wheel gripping the plastic. This will, in fact, reduce the roundness of the filament, but is also consistent across the entire spool, so it will not really affect print quality.

That being said, the consistency of filament roundness across the entire length of the spool is still important. This is because filament that suddenly loses its perfect round shape and becomes oval-shaped can lead to extruder failure in the same way that increasing or decreasing the filament diameter does.

Spool form factor is a highly debated topic across the 3D printing world. Several standards currently exist and different parties consistently attempt to standardize spool dimensions. The key dimensions in any spool are the flange diameter, the mounting diameter, the inner coil diameter and the width of the spool. These dimensions can affect the mounting compatibility of your filament since certain 3D printer manufacturers attempt to lock consumers into purchasing only their filament by creating enclosed mounting systems that can only receive a single spool form factor (almost like a key hole). Others have gone so far as to include technological protection measures (TPMs), such as chips and bar codes, to further restrict your choices.

If you are buying filament, it’s because you intend to use it all and chances are you’ll be looking for the best quality at a reasonable price. We’ve tried filament from many different suppliers and came across many different types of spools. We found that some spool designs actually compromise the usability of the material. When using spools where the inner coil diameter is relatively small (< 80 mm), we found that the tightly wound plastic becomes harder to unspool. The temperature of the plastic can affect this when it is spooled by the manufacturer; good manufacturers ensure that the plastic is cooled before winding it onto to the spool to minimize shape-memory deformation.

Nonetheless, it’s important to remember that most extruder designs require the extruder to pull the filament off the spool. As such, when you reach the end of a tightly coiled spool where the plastic retained the shape of the coil, the filament becomes harder to unspool and the extruder gear can start to slip and/or strip your filament.

This situation can usually be avoided by increasing the extruder tension, but with too much tension, the roundness of the filament can start to become compromised and the slightest variation may overpower the extruder’s power rating.

To maintain a constant setup and minimize extruder strain, we recommend a spool with an inner coil diameter greater than 80 mm. Of course, you don’t want to have a spool with an inner coil diameter that is too large, as it is more expensive to ship and store. Each supplier has its own design policy aimed at optimizing cost and spool volume, but spool inner coil diameter is of utmost interest when considering plastic filament purchases for 3D printing.

If you are going to purchase high-quality filament and properly calibrate your machine for a high-quality result, filament storage is as important. The problem with most plastics (regardless of quality) is that over time they absorb moisture, which creates small water bubbles in the filament itself. These small bubbles, when heated at the tip of your extruder, reach the boiling point and explode violently. This dramatically reduces the quality of your prints, as the plastic is spewed out randomly, instead of being carefully laid down. At Boots Industries, we recommend two simple strategies to store your 3D printing filament and avoid the accumulation of moisture. You can store individual filament spools in a sealed Ziploc bag with a small silica gel desiccant pouch (all our spools ship vacuum-sealed with a desiccant pouch and we include a Ziploc bag). For bulk storage, one technique is to use plastic bins and a bucket of uncooked rice as a natural desiccant. This is very effective for keeping the filament bone dry and is also quite accessible and inexpensive.

Filament is susceptible to the environment and should always be shipped in sealed packaging with desiccant. Great manufacturers go to extreme lengths to produce filament in a highly controlled environment and won’t spare any expense to preserve its integrity during shipping. We offer best-in-class vacuum-sealed protection for all spools we ship, including a humidity indicator to ensure that the product arrives in perfect condition.

PLA filament is manufactured from PLA pellets, which come from various producers and have many applications outside of 3D printing. NatureWorks is the foremost producer of PLA in the world, but many other companies in the Netherlands and in China also manufacture it. When purchasing PLA filament for 3D printing, it’s very important to buy from a supplier with extensive 3D-printing experience. The main reason is that many PLA filaments are extruded from PLA pellets that are not designed for 3D printing. A lot of PLAs is manufactured specifically to create food packaging, cups and other items that are not manufactured through an extrusion process (i.e. injection molding, film and sheet casting, spinning etc.). These PLA blends are not designed to be reheated and extruded for a third time (i.e. 3D printed). These generic PLA variants often work for 3D printing, but are far from optimal for this application. The resulting materials are hard to extrude, warp, have low adhesion and have low heat deflection points. At Boots Industries, we use the very best PLA formulation, Ingeo 3D850, which is specifically designed for 3D printers and produced by NatureWorks in the United States. All our filament blends use 100% new PLA pellets (no recycled materials) that have only undergone one melting cycle (when extruding it into 1.75 mm filament). Most competitors use lower quality blends, such as 4043D, 2003D and perhaps even cheaper alternatives.

This is a very important factor in 3D printer filament, which is why we only sell products that are 100% made in North America with top-quality materials. We strongly advise against filaments made in China, which are increasingly flooding the market.

We’ve discussed some important parameters to consider when buying plastic filament for 3D printing. We hope to have successfully demonstrated our understanding of 3D printing materials and convinced you that our PLA filaments are designed to meet the highest quality standards. Our Super Premium Series PLA was formulated to be the best filament for 3D printing:

• Sourced from corn in a sustainable way and 100% biodegradable
• Super Premium Series PLA has a heat deflection point of 144 °C!
• Excellent adhesion characteristics
• Sharp melting behavior for accurate extrusion profiles
• Excellent material stability – virtually no warping
• Does not require a heat bed
• Very low emissions and no odor
• Post-annealing in the range of 80-130°C can be used to promote crystallization and improve the heat deflection temperature of the 3D printed part.

We hope you’ve enjoyed our article and will consider trying our world-class materials, but should you choose to purchase from another source, we recommend following these simple rules:

1. Only buy filament where a tolerance is advertised (0.05 mm and lower seems to be the gold standard).
2. Only buy filament that features excellent roundness (usually this comes with excellent tolerance as well).
3. If the spool used has a very small inner coil diameter, beware of material usability issues. We recommend spools with an inner coil greater than 80 mm.
4. Only buy filament that is properly packaged to protect its properties.
5. Make sure that the person selling the filament has experience with 3D printing. Some people are only re-sellers and don’t fully understand or test their product. Take the time to ask the sellers questions and do not settle for vague or incomplete answers.