3D printer filament

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Draft

1 Introduction

This article should list the major 3D printer filaments that are available for 3D printing machines

For each plastic, slicer settings must be adapted. In addition, adjustments should be made for the kind (or the kind of the object part) In particular general parameters like:

  • Extrusion height (related to z-axis movement, typically between 0.1 and 0.5 mm).
  • Extrusion width (related to feed and flow rates)
  • Temperature
  • Feed rate (speed of print head)
  • Flow rate (amount of plastic extruded)

In addition, other parameters like the following must be adapted.

  • Wall thickness
  • filling (density and pattern)
  • horizontal floors
  • first layers

For the moment, this page doesn't include too many details. Also, information about some filaments I did not try out may be wrong. I do report some concrete experiences in other articles, e.g. as of Jan 2016 the Felix Pro 1 3D printer - 19:03, 17 February 2016 (CET)

2 Physical properties of printing materials

Printing materials (filament) can be characterized in various ways. Below is a list of general properties that may be of interest to hobby 3D printers.

General properties
Property name Comments Testing method Units
Processing temperature Typical filaments are processed between 180 and 260 degrees, often in a range of 30 degs. E.g. PLA prints from 180 to 220.
Melt flow index How well it floats at typical processing temperature ASTM D-1238 (ISO1133)
Thermal expansion Material expands when heated (or not) and shrinks when cooling. Expansion makes printing difficult. E.g. ABS does expand and warp. To print ABS, it's a good idea to use heated chamber (that will inhibit the plastic to cool down too much).
Recommended print speed Recommended print speed depends on the quality you want to achieve, layer thickness, nozzle size and the plastic itself. PLA, for example can be printed very fast, whereas NinjaFlex or PETG should be printed at much lower speed. mm/s
Density How heavy it is. mg/m3
Odor Smells good or bad (related to fumes)
Toxicity of fumes Fumes can be dangerous: Some are not problematic (PLA), others somewhat or rather dangerous (ABS). However, while PLA can be considered to be safe, the colors and other additives used in the PLA may not be safe !
Size Most printers either use 1.75mm or 3mm filament
Size variation Filament should have little variation in either diameter (< 1mm) or roundness (< 0.5mm). Larger knots can block the filament and too thin filament can loosen the grip. This implies that you should buy from a reliable vendor (or at least keep track of what you bought).
Water absorbtion Most filaments absorb Water. When full with water printing quality will decrease since water bubbles with explode, sometimes a lot, e.g. in the cas of Nylon. Therefore it is recommended to keep the filament in a sealed plastic bag or even preheat in an oven.
Solvability Most plastic are soluble with respect to some chemical. E.g. HIPS will dissolve in Water, ABS and PLA in Acetone.
Food safe Most plastic is not food safe, i.e. can fusion with food molecules. PET(G) is food safe and water proof in addition.
Surface gloss ABS for example is fairly glossy, PET is very glossy, PLA is less. In addition, one can play with temperature and coating. ABS is more glossy when printed very hot and with a ''small'' amount of Acetone paint.
Colors From none (natural) to many. Some plastics also allow for "glow in the dark".
Translucency From totally opaque to very translucent. Some plastics have both kinds, e.g. PLA exists in opaque, semi-opaque and translucent form.
Adherence between layers This important property tells how much hot filament will bond to each other
Adherence to print bed Depends on the type of coating of the bed (Metal, Kapton, Blue tape, etc.), the bed temperature and the interaction with the plastic. Different materials require different bed coatings and different temperatures.
Strength and flexibility See below. One of the strongest materials is Nylon (but printing is a bit more difficult and the result looks ugly, i.e. needs some processing). The weakest ones or HIPS (disolvable) and laybrick. Some flexible ones are also quite weak. ABS, PETG and PLA are in the middle. Elasticity
Durability How long does it last (some plastic degrade much faster when exposed to use, light, water, etc.)

There are several formal standards with respect to strength testing

ISO created in 2011 the ‘Technical Committee 261 Additive Manufacturing’ (ISO/TC 261) to develop standards for Additive Manufacturing. Tasks of this committee are terminology, file standards, and quality standards.

  • ISO 527 defines tensile strength for all sorts of materials (not just Additive manufacturing). "ISO 527-1:2012 specifies the general principles for determining the tensile properties of plastics and plastic composites under defined conditions. Several different types of test specimen are defined to suit different types of material which are detailed in subsequent parts of ISO 527. The methods are used to investigate the tensile behaviour of the test specimens and for determining the tensile strength, tensile modulus and other aspects of the tensile stress/strain relationship under the conditions defined." (retrieved feb 2017)
  • ISO 178 defines flexural properties of plastics. "ISO 178:2010 specifies a method for determining the flexural properties of rigid and semi-rigid plastics under defined conditions. A standard test specimen is defined, but parameters are included for alternative specimen sizes for use where appropriate. A range of test speeds is included." (retrieved feb 2017)
  • ISO 179 defines impact properties, i.e. a way of defining toughness and brittleness. In technical terms it measures the "Charpy impact strength" of plastics under defined conditions. It has two parts. Part 1 defines how to test it generally. Part 2 defines e.g. what happens when you hammer on it in a precise location.

The American manufacturing association (ASTM) has two sub-committees related to additive manufacturing technology: F42 for Additive Manufacturing Technologies and F42.05 for materials and processes.

Aaron M. Forster from NIST (the US standards agency) provided an interesting overview of standard testing methods: Tension, flexure, compression, shear, creep, fatigue, fracture toughness and impact.

Below is table that includes some of testing categories. For each testing category some standard material form plus some precise testing method is defined. Testing methods do not seem to take into account how a piece was printed (i.e. in which direction the strings of filament point).

Filament strength properties
Property name Comments Testing Methods Measure
Tensile modulus, (Young’s elastic modulus) Measures the stiffness of a material (how much can you pull it or compress it before breaking). According to Wikipedia: The Young's modulus enables the calculation of the change in the dimension of a bar made of an isotropic elastic material under tensile or compressive loads. For instance, it predicts how much a material sample extends under tension or shortens under compression. ASTM D638 (ISO 527, GB/T 1040) MPa
Tensile strength The capacity of a material or structure to withstand loads tending to elongate, as opposed to compressive strength, which withstands loads tending to reduce size. (wikipedia) ASTM D638 (ISO527, GB/T 1040) MPa
Elongation at break How far can you pull before it breaks ? Also known as fracture strain or ''elongation to break'', it is measured as ratio between the changed length when it breaks and the original length. ASTM D638 (ISO527, GB/T 1040) %
Bending modulus Also known as ''bending stiffness'' or ''flexural modulus'' it defines the resistance to bending deformation. Bending and beam theory can be very complex... ASTM D790 (ISO 178, GB/T 9341) MPa
Bending (flexural) strength ASTM D790 (ISO 178, GB/T 9341) MPa
Fracture toughness Does it break completely or not.
(Izod) Impact strength How easily does it break on impact in vertical position ? E.g PLA is fairly brittle compared to ABS. ASTM D256 (ISO 180, GB/T 1043) kJ/m2
Charpy impact strength How easily does it break on impact in horizontal position ? ASTM D256 (ISO 179, GB/T 1043)
(Vicat) Softening temperature Temperature when it becomes soft (e.g. ABS between 90 and 130, PLA at ?? degs) ASTM D-1525 (ISO306B)

Strength and elasticity are very important properties. It can be defined in terms of pulling, bending and shock.

Interestingly, 3D hobby printers can perform as well as industrial machines. Tymrak et al. (2014) in their Mechanical properties of components fabricated with open-source 3-D printers under realistic environmental conditions article [1] “The results show that the average tensile strength of RepRap printed parts are 28.5 MPa for ABS and 56.6 MPa for PLA with average elastic moduli of 1807 MPa for ABS and 3368 MPa for PLA. These results indicate that the 3-D printed components from RepRaps are comparable in tensile strength and elastic modulus to the parts printed on commercial 3-D printing systems.”

3 Rigid polymers and co-polymers

3.1 ABS

  • ABS ((Acrylonitrile Butadiene Styrene) is used for Legos and car parts for example. It is solid, but warps when printed a room temperature. I.e. it is difficult to print objects that have a larger than 4cm footprint. When hobby 3D printers emerged, ABS was the material of choice. As of 2015, it is still popular, but there are other similar alternatives.
  • Temperature: 220 - 260 (temperature depends on both type of ABS plastic and the kind of object your print).
  • Bed temperature: 65

3.2 Nylon

  • Nylon is a very strong material but more difficult to print than PLA. It doesn't stick well to Glass or Aluminum platforms surfaces and may warp. You can try printing on wood. It sticks very well to Polymide tape (Kapton), i.e. removing the part can pull off the Kapton tape.

Various variants exist. At the time of writing, Taulman 645 seems to be popular. Since it is fairly expensive, you also can consider the Bridge filament which is not as strong, but cheaper and easier to use. It does work fairly nicely with a modern printer such as the Felix Pro 1, i.e. am "open air" design with a 0.35mm hotend.

Printing tips for Bridge Nylon

  • Print slowly
  • Print larger layers (e.g. 0.2 to 0.3)
  • Fan = off (50% for small objects)
  • Temperature = 255C
  • Bed temperature = 45C or more (e.g. I use 65)

Problems:

  • Nylon warps a lot or a bit in the case of Bridge Nylon. Use the same strategies as for ABS.
  • Nylon soaks up water from the air (within a few days) and then will sputter and make your prints uglier. Some people will heat it in the oven at low temperatures. I put a halogen lamp on top of the roll.

3.3 PLA

  • PLA (polylactic acid) is made of starch (i.e. plants). It doesn't warp, but it's not very solid and starts deforming (melting) at relatively low temperature. PLA is probably the most popular filament.
  • Temperature: 180 - 220
  • Bed temperature: 55

3.4 PolyMax PLA

  • Polymax PLA is the commercial name of a new PLA that is much stronger (up to 9 times the impact resistance of normal PLA). I also claims better overall mechanical properties than ABS.
  • FactSheet

3.5 PLA/PHA

  • PLA/PHA is a PLA / PHA (polyhydroxyalkanoate) mix from Colorfabb. It is stronger and more bendable than ordinatry PLA. As strong as weak ABS and as easy to print as PLA it seems.

3.6 PET(G/T)

  • PETG is a combination of PET (polyethylene terephthalate) aka polyester and different concentrations of glycol (G). PETG is a strong filament similar to ABS in strength, but it prints more like PLA.

Properties of PET (The "G" or "T" will modify this)

  • Is the most recycled plastic (e.g. softdrink bottles). It is not biodegrable like PLA, but recyclable.
  • No shrinking or warping
  • No smell
  • It does not degrade in water or absorb water, also since it bonds very well, objects should be watertight. That is at least the case with T-glase
  • It is US FDA approved for food contact
  • Unlike PLA, it is not brittle and it is a bit more flexible than either PLA or ABS

General print properties:

  • Temperature: 210 - 260
  • Bed temperature: 55

There are very different variants, e.g. see the T-glase below.

  • Amphora™ 3D Polymer, made by Eastman and Helian Polymers. A popular brand is XT sold by Colorfabb, a Dutch company
  • T-glase made by Taulman (see below)
  • PET+ by MadeSolid

3.7 T-glase

T-Glase is a co-polymer very similar to PETG. T-glase is polyethylene-co-trimethylene terephthalate (PETT)

This pretty plastic made is somewhat translucid, has a rather good surface finish, and it shimmers. T-glase (aka "Tough Glass") can be used as replacement for ABS. It's stronger and it does not warp or split while printing. This article by Mike Adams (March 11, 2015,) makes a good case for t-glase: It's solid, safe for (cold) food, watertight, both rigid and flexible, etc.

  • It seems to have low shrinkage and no warping.
  • It sticks to acrylic, glass, and Kapton.
  • Unlike ABS, bonding between layers is very good (i.e. makes cups watertight).
  • It doesn't produce fumes or smells when printing.
  • Material density: ?
  • Bending temperature: 78 C

Parameters below were taken from here and here

  • Print temp = 240 (maybe 250)
  • Nozzle = any size, but maybe more than usual extrusion ?
  • Extrusion width = about 90% of the Nozzle diameter, e.g. 0.315 mm for a 0.35mm nozzle
  • Print speed, about half speed of ABS
  • Retraction = .5mm/.1mm nozzle or for a .5mm nozzle = 2.5mm
  • Print bed = glass with a PVA coat, Kapton,
  • Print bed temperature: 45C

This worked for me on a Felix Pro 1 printer, but I probably have to optimize some stuff.

Other tips:

  • To reduce glass breakage, don't cool the bed before removing the part (have it at least at 35 C).
  • When you forcibly remove it, a shattered piece can reach your eye

3.8 Carbon Fiber

Carbon Fiber allows to create tough and lightweight objects. It seems to require a lot of infill (delamination problems ?) . Not tested yet.

4 Solubles

These are great for printing support structures with a dual head printer.

4.1 PVA

  • PVA (Polyvinyl Alcohol) can dissolve in water

4.2 High Impact Polystyrene (HIPS)

HIPS has similar structural properties as ABS, but warps less during printing. According to a Lulzbot tutorial, “the most practical characteristic of HIPS is its ability to be sanded, glued, primed and painted with acrylic paints once the print is completed.For anyone printing scale-models, miniatures, and even cosplay items, this is a outstanding feature of an inexpensive material. HIPS is also very light-weight, making it even more ideal for wearable objects. ” (Feb 2016).

Some properties:

  • HIPS is like ABS, a petrochemical synthetic polymer and not biodegradable
  • It is often used to pack food, i.e. it is not toxic. Examples are styrofoam or yogurt containers.
  • Although it is a fairly strong polymer, it is often used for support of ABS prints, since it is very easily dissolved in limonene (a strong but easily available chemical).

Printing tips (not tested): Print temperature: 220 to 240 Bed temperature: 100 to 120

Limenene can be a by-product from the citrus juice industry, since it can be extracted from the rind of lemons and oranges. It can replace more aggressive solvants like turbentine. Read more at BioChemcorp. It can be bought from on-line stores like this offer from Amazon. We didn't try using Limene. There are conflict reports about its use, e.g. read this challenge by DBrowny3 (2015).

From what I understand, using HIPS as support is ok if one can remove most of it by breaking it out, then use d-limone to remove the rest. To do so, use gloves and do it outside !

5 Flexible

5.1 Soft PLA

Is a kind of PLA that is flexible (does that really exist ?)

  • Temperature: 220-230
  • Bed temperature: ?

5.2 Thermoplastic elastomer (TPE)

There are several variants of TPE. As a general rule, TPE must be printed with less speed than PLA (e.g. 20-30 mm/second). It is also important to have a strong extruder that does not heat in the upper part. Bowden extruders will not work, since one cannot push very flexible filament over a long distance.

Well known variants of Thermoplastic elastomers are:

5.2.1 Arnitel

  • Arnitel is a flexible filament that produces very strong prints (e.g. bracelets for watches are made with this), but difficult to print since it doesn't stick well and since it warps like ABS. Use it to print mechanical parts that must resist to high temperatures and strain.
  • Temperature: 220-230
  • Bed temperature: 65

5.2.2 NinjaFlex

  • NinjaFlex is a thermoplastic polyurethane
  • Similar to Arnitel, maybe not as strong and more reactive to solvants, but easier to use
  • Print temperature 245 °C at low speed (e.g. 30 mm/s)

5.2.3 NinjaSemiFlex

  • Harder (less elastic) than NijaFlex (not tested)

5.2.4 3D Prima TPE

3D Prima TPE is a flexible filament that produces "rubber" like objects (if you print with little fill you can create "squeezy" things)

  • Much cheaper than NinjaFlex.
  • It is a easy to print, if your extruder can handle it (see next item). The result looks good enough and feels great.
  • This filament is very easy to print, if you can manage to extrude. I believe that you need a hotend that is only hot near the exit area. Since the filament is really flexible (before printing), pushing through the extruder can be tricky. Works OK with my Felix 2 and Felix Pro printers. With the Felix 2.0, only works if the hot-end doesn't have any "PLA balls" (rests) inside. It cannot push these down. Extruding some ABS before inserting the Prima TPE does help.
  • Prints between 190 and 240 degs., Print bed at 50-80, low speed. I used 220, 55 and a speed of 10 up to 45mm/s .... however I don't have enough experience to provide any solid information.
  • Since the plastic is flexible and takes time to cools down, you may encounter problems if you use larger structures with little infill (e.g. 10%). The fill may drop and contact with the filament may break, i.e. there wont't be enough pull from the deposited plastic. To avoid this:
  • do something to cool down the print by printing something aside, e.g. use the "auxiliary structure" in Felix Builder)
  • Use some extra extrusion for infill, e.g. 120%
  • Use more infill or add some internal structure, e.g. a few sticks.

5.2.5 Plasticized Copolyamide TPE (PCTPE)

Nylon-based TPE, made by Taulman sold by 3D Prima, also available on amazon.fr (not yet tested).

5.2.6 FilaFlex

  •  ?

5.2.7 Nunus TPE

  • Nunus Flexible Rubber Filament
  • Temperature 210 - 230° C
  • Platform temperature: 20 - 50 °. For my first successful prints I added glue plus a raft - Daniel K. Schneider (talk) 14:05, 7 September 2015 (CEST)
  • Speed 30 mm / s. Maybe you could print faster, but it's important that the plastics bonds when hot. Otherwise the object will be brittle, e.g. the infill will be weak, layers will not stick together.
  • This filament is by no means like rubber. It just feels much more flexible than PLA, i.e. you can bend but not stretch this. Unlike Arnitel, you also have to use some "decent" fill (5% fill will not bond IMHO).

6 Composites

Composites are often based on PLA or ABS (e.g. 80%) plus other ingredients (e.g. 20%) like metal particles or wood fibers.

Over the last two years (2014/2015) the most creative inventor of composite filaments has been Kai Parthy. He invented laywood, laybrick, laywood flex, bendlay and so forth. A full list of these is available here.

In the meantime, other manufacturers offer their own blends, in particular combinations with wood.

6.1 Laybrick

Laybrick, according to Simon J. Oliver is a thermoplastic with fine-milled chalk as a filler, and so it prints with a decidedly ceramic look and feel, and an off-white putty color. In his blog post (2013), he writes that laybrick is an “easy-to-work-with and forgiving material that has a striking but neutral appearance that easily hides the tell-tale layering that mars many 3D prints, without needing to resort to ultra-fine layers. I’ve found that the attractive texture and warm feel work well for sculptures and bowls that invite handling, and also for printing 3D scans of people, where the ability to hold detail and yet not look overly layered is a great combination. Architectural models are another area where I expect to see a lot of potential. LayBrick is clearly not designed for harsh environments of high temperature, solvent exposure, or mechanical wear, so its applications will be mostly aesthetic and artistic – but for those, it opens up whole new vistas compared to traditional plastics.”

Properties:

  • A mixure of sandstone (milled chalk) and binding polymer (PLA??)
  • Printed at 195°C it should have a fairly realistic sandstone effect (after cooling down for at least 2 hours!)
  • No warping
  • The result is fairly brittle, e.g. Lego walls easily break.

Print considerations:

  • No heated print bed is needed it seems (however, I use the same as for PLA)
  • Print speed should be low, e.g. about 40mm/second.
  • Use large layers, e.g. 0.25mm or more. Maybe, add some extra-extrusion factor if you got a 0.35mm nozzle.
  • Print temperature: 165 - 220 ?. Best is probably between 180 and 200. Changing the print temperature changes the results. With higher temperatures one can print faster, but with lower temperatures one gets better quality, in particular with overhangs. In addition, the look of the object changes, lower temperature will make it smoother in theory. In practice, I suggest printing at least at 190 with a 0.35mm nozzle. Most web sites report that up to 195 C, the skin should be smooth. This is not the case with our 0.35mm nozzle printer. Printing at 170 to 180 C gives rough results, probably due to bad plastic flow.
  • Since the filament can break, it's probably not a good idea to print it with a Bowden extruder (motor far away from the hotend)

Other tips:

  • Laybrick breaks easily and cannot be re-spooled since it may break. You could use a flat wide spooler or hang it "as is" on a chemistry stand. The inventor of this filament has a picture on his website of a new spooler that one probably will be able to buy (Y_COIL-PACK-HOLDER)
  • If the object has fragile parts (e.g. walls, feet, etc.) do not remove it from the print bed before it is hardened, e.g. wait for 2-4 hours ! However, you also should be aware that laybrick can stick fairly well once cooled down, so there may be a tradeoff.
  • Keep it inside a plastic bag
  • Make sure that the filament does not run out. Even a printer that waits printing after the filaments stops coming and allows you to reinsert filament cannot prevent an ugly missing layer.

6.2 Laywood

Laywood is a wood-polymer composite made from 40% recycled wood particles mixed with binding polymers, i.e. the principle as laybrick.

(to do)

6.3 Bendlay

Bendlay is also made by Kai Parthy who invented Laywood and Laybrick.

7 Feeding and keeping filament

7.1 Reels and spoolers

Most 3D printers do not come with an acceptable spooler and for two reasons: They offer too much resistance and there is a high chance that some rolls will not fit.

  • Mount hole diameters range from 19 to 74 mm. Frequent ones are 31mm, 39mm and 52mm.
  • Outersize diameter ranges from 12.5cm (e.g. Taulman T-glase) to 30cm
  • Inner coil diameter is 5cm to 8cm
  • Typical outer width if from 6cm to 12.5cm.

The best and easiest solution I found is to use a chemistry stand and then print adapters. However, in that case some systems that filter the dust are no longer there (e.g. on the Felix Pro 1 it's on the side) and you would have to come up with another solution.

Read Universal 3D printing filament spool standard 2014, One spool to rule them all... by Richard Horne, 2014.

7.2 Storing and reusing filament

Moisture

Some plastics are extremely sensitive to moisture. Prints fail or print not as nicely as they could if there is too much humidity in the filament.

  • Very sensitive: PVA and Nylons
  • Somewhat sensitive: PLA (you still can print with 2-year old PLA left in the open, but the results are not as good) and Bridge Nylon.
  • Not very sensitive: ABS
  • Not sensitive: T-glase

Therefore it is crucial to store both Nylons and PVA in an airtight bag or container that includes Silica Gel. Better in a vacuum bag (but then you need equipment for that). This must be done immediately after printing

It is possible to dry most plastics again by putting them into an oven at low temperature (e.g. 50C) for a few hours.

Particles

Polymers attract dust and when dust gets in the hotend, the filament will not flow as well as it should. Therefore it's a good idea to pass the filament through some felt (or similar) before it enters the extruder. Otherwise, clean the dust from the surface of the roll.

One can "clean" a hotend by extruding a plastic like ABS at fairly high temperatures (e.g. 155 C). One reason to buy a printer where the platforms moves in the z-axis is the possibility to force the plastic down a bit. Using ABS is also a good method to open an extruder that is clogged with PLA or other low temperature plastics (heat for a while before you attempt to do this). Using a drill is more delicate. Try acupuncture needles first. A last solution is buy some "cleaning filament" (not tested).

8 Links

8.1 Principles

8.2 Filament makers and suppliers

See:

The ones below are randomly chosen as examples, no endorsements here !)

Suppliers for Switzerland

We don't have time to compare shops, but we are satisfied with the ones below. Both deliver via regular postal service.

Tip: If you buy a printer with institutional money, e.g. for a school, include filament in the printer "package". This way it will be financed by "investment" money which is always easier to get at than money for buying smaller supplies. Most often, the company selling printers offers a decent enough choice of plastics...

8.3 Filament comparisons, introductions, etc.

Specific
  • What Material Should I Use For 3D Printing? – Advanced Materials Review #1 – BendLay, Laywoo-D3 and LayBrick]. This web site has other nice introductions, see [http://3dprintingforbeginners.com/category/materials/ materials]

9 Bibliographie et référence

Bibliographie

  • Aaron M. Forster, Materials Testing Standards for Additive Manufacturing of Polymer Materials: State of the Art and Standards Applicability, NISTIR 8059, http://dx.doi.org/10.6028/NIST.IR.8059

9.1 Citations

  1. B.M. Tymrak, M. Kreiger, J. M. Pea rce, Mechanical properties of components fabricated w ith open-sour ce 3-D printers under realistic environmental conditions, Materials & Design, 58, pp. 242-246 (2014). http://dx.doi.org/10.1016/j.matdes.2014.02.038.