Your priority was likely finding the right 3D printer to match your requirements and budget. But what often gets less attention is the filament you feed through it. After all, plastic is just plastic, right? So it would make sense to just find something that’s cheapish and prints OK.
This is how most people approach buying and using 3D printer filament. Which is understandable. After all, unless you’ve been in the industry for years and have seen first-hand the good, the bad and the outright dangerous ‘tricks of the trade’ that go on in the relatively ‘sleepy industry’ of 3D printer consumables, you’d be forgiven for believing otherwise.
My name’s Ed, I’m the founder of a 3D filament company here in the UK called rigid.ink. This article is an expansion of our detailed filament comparison guide. But don’t worry, I’m not here to push our product.
I just want to save you from the tears, hassle and despair that comes with trying to use bad filament. From this I’ll explain what to really look for to take out the guesswork when choosing 3D filament.
You see there are a few obvious factors to consider when buying filament, like price or strength. Then there are the little-known considerations, the stuff people don’t tend to think about. Like why you should print with a hardened nozzle if you use glow in the dark filament (hint: Strontium aluminate is abrasive).
I’m going to interchange the words ‘cheap’ and ‘poor’ throughout this guide because the two words are nearly perfectly interchangeable when discussing 3D printer filament. Not that I’m going to disregard budget, but this is an industry where you definitely get what you pay for.
Buying cheap filament, especially from eBay, Amazon and unknown websites, is fraught with problems. Now don’t get me wrong, there are many reputable filament suppliers out there and I’m not here to badmouth any brands. It is possible to get reasonably performing filament for an acceptable price, but there’s always a trade-off.
Most of these super-budget ‘makes’ are just white labelled products or worse, don’t have a discernible brand name. This means it’s easy for sellers to change the supplier often and without warning, depending on which factory is cheapest at the time.
This means you might get lucky with a spool that prints OK, only to reorder what you think is the same filament, but it’s actually been produced in a different factory and it prints completely different the second time around. You’re using the same settings but all of a sudden you’re getting different results. Read the reviews, you’ll often see many people stating the quality varies a lot.
When talking about PLA for example, this is an expensive raw material. There’s no way to get around this ethically. So naturally, it seems many poor filament manufacturers get their business acumen from drug dealers. Because any time you see cheap PLA, it will likely have been ‘cut’ with much cheaper filler materials, or is a significantly lower grade of PLA to begin with. Not always, but this is a much higher likelihood.
The rest is ‘filler’ which can be a mixture of returned material at best, and usually other non-natural plastics. Sawdust is a popular filler and is prone to clumping (in your extruder), while Calcium Carbonate is commonly mixed with ABS, making it feel harder but also making it unnaturally brittle and ‘crumbly’. Not to mention excessively wearing nozzles and extruder gears.
One issue with filler is besides you not getting what you’ve paid for; it’s packed with foreign particles of varying melting temperatures lurking, ready to block your nozzle. Often just to get it to print, you need to heat your PLA to over 220°C+ (425°F +), and certainly our PLA should never really need to be printed over 210°C (410°F), maybe 215°C if you’re going really fast. Some performance grade PLAs need to be printed hotter, but ‘regular’ PLAs shouldn’t need this increased temperature.
It’s not just printing consistency that suffers from using cheap filaments. While all 3D printing should only ever be done in a well-ventilated environment, it still doesn’t excuse using unregulated raw materials, like pigments containing Cadmium (highly toxic) in yellow and orange filaments, for example.
Many people seem to assume they’re playing it safe, just printing with PLA and so they don’t need to worry that there are unnatural or unsafe components in the mix. It’s just not safe to assume PLA is all natural and doesn’t need to be treated with the same considerations as other filaments.
There are many cheap filament manufacturers from various countries that take no regard to the hazardous materials they put in them and the health risks posed to their customers. Is saving a bit of cash worth a potentially shorter life expectancy in the long run?
It’s not just health issues and the frustration of nozzle blockages you’ve got to worry about with bad filament. Other aspects you need to look out for include varying tolerances, leading to less than optimal layer aesthetics and poor pigments in colours, resulting in your parts looking washed out after printing.
Another sneaky trick is some suppliers will claim to offer 1KG (or 2.2lb) spools, when in reality that’s the whole weight of the filament AND the empty spool. The average empty spool weighs ~250g, so you realise you’re only actually getting about 750g of filament.
When the manufacturing process is rushed, you’ll also end up with oval filament, air pockets and dust on the filament. All these sound fairly innocent, but each has the opportunity to ruin your print.
Some manufacturers use water quenching to stabilise the dimensions of the filament after it leaves the die. If this filament is not dried properly before spooling, then it can retain considerable moisture, leading to a poor finish quality, or some instances popping in the extruder.
If good looking, consistently coloured prints, that actually finish printing are important to you, then you’ll likely want to pay a bit more attention to the filament you use.
So now you understand the importance of using good filament, how do you spot it, and what should you print with?
- Look for a company with plenty of information about their filament upfront. You’re looking for specifics. Specifics about their filament usually hold them more accountable, because it’s easy for them to hide behind vague promises or claims. Tighter than average tolerances (say 0.03mm +/-) are a good starting point, but don’t necessarily guarantee quality of the material. If you’re looking for strength or hardness, compare Mohs or Rockwell hardness figures from the hopefully easy-to-find datasheets.
- Order samples – companies that don’t have anything to hide will usually let you order a sample, sometimes for free if they’re confident. That way you can do the following advised tests before committing to large spools.
- Your filament supplier should offer clear and easy-to-understand printing settings. Not just nozzle temperature; but bed surface, fan speed and any material specific considerations. Clear instructions will save you time dialling in the settings, and give you a reference point when contacting their customer service if anything isn’t right.
- Expect good packaging. That’s not just to look nice, but all filaments should come in sealed bags with desiccant at a minimum. Some suppliers will even supply in metallic vac sealed bags. This isn’t just to make it look like space food; it keeps it fresh, cooler and away from degrading UV light.
- Test your samples. Now these vary depending on materials, but the following advice is generally true for most:
- Bend your filament until it snaps. Was it easy to snap or brittle? If PLA, that means it might be stale (or just not very good to begin with), if ABS snaps, it’s likely high in filler. You should be able to bend the filament sample back on itself 180°C at least once without it easily breaking.
- Print a small object with the sample. It should print easily within the advised parameters from the supplier.
- There should be no popping or steam from the nozzle. This means your filament is dry. Wet filament makes for poor finish quality on your prints.
- There shouldn’t be any dust on the filament. Mostly one or two specks of dust is harmless, but some on a whole roll can build up and clog your nozzle.
- Measure the diameter with calipers if you have them, is it within the tolerances they promise? If it isn’t, this can happen but your supplier should be happy enough to replace the spool. Varying tolerances don’t sound too big a deal, but they can affect the finish quality of your prints.
- Did everything go to plan? Great, sounds like you’ve found a good filament supplier. But if the finish quality isn’t spot on, or you have other issues – don’t be afraid to give their customer support a test. If they’re worth their salt, they’ll advise you or offer replacements where necessary.
Way too many people settle for average results. Get all those settings dialled in right, and you can have some seriously impressive results from some very average 3D printers.
While a full material comparison is beyond the scope of this buyer’s guide, I’m going to give you a brief insight into the most popular filament materials. With this list I’m assuming you have a 3D printer with a heated bed, and a nozzle capable of reaching usual printing temperatures of around 260°C. If you don’t have a heated bed, you’re really just limited to printing with PLA, TPU and PETG with adhesion assistance.
If you’re not sure what you should be printing with, more often than not there’s no reason to stray from the good ol’ trusty PLA. It’s the easiest to print with, all naturally based (very long-term biodegradable) and if you get a good grade, surprisingly strong.
So in a lot of instances it’s good for end-use parts that don’t go through too demanding use. The great thing with PLA filament is you can get an absolutely perfect finish quality with minimal tinkering.
For many, they only ever print with PLA – and that’s fine. For a wide range of uses it’s a great material. For other applications though, you might want to try out some more versatile materials.
A now very popular material is PETG filament. Think PET plastic bottles, but Glycol modified for extra durability. We say extra, what I really mean is it’s nearly unbreakable. PETG is a strong material with a good amount of flex to it, without being flexible.
Like PLA, PETG is also very easy to print with, with no warp and strong layer adhesion. If you’re looking for a long lasting, ultra durable print, this is worth serious consideration.
Now ABS is well-known, but less common is its newer sister, Acrylic Styrene Acrylonitrile or ASA filament. This shares many of the same properties of ABS so it’s excellent for functional end-use parts, but is slightly more durable and has a very smooth finish quality.
It also prints well with very little or no cooling fan, so if your part cooling is a little sketchy, you’re in luck with ASA.
The key difference though, is that ASA will withstand extended periods in direct sunlight, exposed to UV light. Where other materials would soon degrade in strong sunlight, ASA is the material of choice for outdoor prints.
One of the most underrated materials is Nylon. Or more specifically, Nylon grade 12. It has a bad reputation as being tricky to print, but you just need to use the right settings and the right bed adhesion.
Pro-tip: we recommend a layer of Wolfbite Nitro on your bed to keep it stuck down solid until the end of the print. We also advise to print in a heated chamber, when possible.
Without trying to over-hype Nylon 12 as the perfect all-round wonder material, it is in fact the perfect all-round wonder material.
It’s thermo and chemically stable, which means it won’t change shape much in extreme low and high temperatures, or degrade with most chemicals. It’s extremely durable, and even flexible when printed thin. And it’s got a very low friction coefficient among other benefits, which is why it’s often used for plastic gears in RC cars.
The grade 12 also absorbs less moisture than other grades, still it’s advisable with any type of Nylon to dry it before each use, just to make sure.
I trust this article has been eye opening for you with the importance of selecting the right filament for your needs at a price that makes sense. Hopefully this knowledge has made choosing your trusted filament supplier and next favourite materials a little less daunting, whilst giving you a clearer picture of what to avoid.
This should save you a lot of time and frustration. Don’t forget to comment below with any experiences you’ve had, good or bad. Especially fun horror stories or the little things that have really made the difference to you and your printing.