Posted by Alex R English on June 14, 2012
This is intended to be a very basic Personal 3D Printer filament buyer’s guide for new 3D Printer users. Every single point presented here is worth a lengthy post, but this should serve as a top-level summary that might help you determine what plastic filaments will best suit your needs.
Additionally, see What Plastic Filament does my 3D Printer Use.
For corrections or ideas of other factors worth considering, share them with us at content AT protoparadigm DOT com.
There are two common diameters of 3D Printer plastic filament, 1.75mm and 3mm. Your Personal 3D Printer is likely to use one of these. Each printer (or to be more specific, each extruder) is designed to work with one diameter of plastic filament and will not work with the other. Check your printers listed specifications or documentation to see which it uses. If you can’t find any indications of the diameter in those places check forums and user groups for the information, or ask there if you still can’t find it. If your printer came with some filament, you can also measure the filament to determine which of the two it is.
Some printers may use proprietary diameters that are slightly different from above. As above, read up to make sure your printer can use filament from suppliers other than your printer manufacturer. Likewise, if you’re shopping for a printer right now, make sure to buy one that uses standard materials so you have more choice when it comes to suppliers (which also gives you access to more materials, colors, etc.), or at least make sure there is a good technical reason for the proprietary diameter besides just locking you into the brand.Here are diameters for some of the more predominant printers. Please email us any additions or corrections at content AT protoparadigm DOT com .
|Company||Printer or Extruder||Diameter|
|Bits From Bytes|
|Mk 5 and Earlier||3mm|
|Mk 6||3mm default, 1.75mm supported|
|Mk 7 and later||1.75mm|
|Mosaic||1.75mm (3mm extruder available)|
|M2||1.75mm (3mm extruder available)|
|Prusa||1.75mm or 3mm, buyer selectable|
|LulzBot Budaschnozzle 1.1||3mm default, 1.75mm supported|
Filament diameters will vary slightly from supplier to supplier, and possibly from product to product (different colors or different plastics), though filaments coming from the same supplier should be fairly close. There is a slight discrepancy between the nominal diameters for each size. For 3mm, the maximum diameter of the filament should not exceed 3mm. Our nominal, and that of many others is 2.88mm. This is in contrast to 1.75mm where the nominal diameter IS 1.75mm and not a maximum. This is one reason this smaller size is sometimes referenced as 1.8mm.
Filament can also have lumps (short sections where the diameter is larger than tolerances allow, usually only a few cm long), and neck-downs (short sections where the diameter is smaller than tolerances allow, again, usually only a few cm long). These will often cause jamming or stripping, but should be rare from a quality supplier. These are usually unrelated to the tolerances of the filament.
There are several materials available to print with. In general, the question for a new user usually comes down to ABS vs PLA. These are the two most common materials used in Personal 3D Printers. Each have distinct characteristics. The main deciding factor between ABS and PLA is probably going to be personal preference, though there are some limiting factors on each printer that may make one preferable to use over the other.Here is a quick reference table of some of the differences between ABS and PLA. The details of each of these points can be found later in this post.
|Extrude at ~225°C||Extrude at ~180-200°C|
|Requires heated bed||Benefits from heated bed|
|Works reasonably well without cooling||Benefits greatly from cooling while printing|
|Adheres best to polyimide tape||Adheres well to a variety of surfaces|
|Filament tolerances are usually tighter||Finer feature detail possible on a well calibrated machine|
|Prone to cracking, delamination, and warping||Prone to curling of corners and overhangs|
|More flexible||More brittle|
|Can be bonded using adhesives or solvents (Acetone or MEK)||Can be bonded using adhesives|
|Fumes are unpleasant in enclosed areas||More pleasant smell when extruded|
|Oil Based||Plant Based|
There are other materials, in particular Polycarbonate and PVA that are used for printing, but which are outside the scope of this buyer’s guide. Here you can find more information about printing with Polycarbonate. You may also come across blends of materials, such as a polycarbonate/ABS blend or polystyrene blends, but these too are outside the scope of this post.
Each different kind of plastic can come in different grades. Different grades may have different properties like melt temperature, flexibility, viscosity when melted, stickiness when melted, etc. These can all affect both your ability to print with them and the quality of your prints or the difficulty of calibration.
The Personal 3D Printing community has adopted 4043D and 2003D as the standard PLA grades, and PA-747 as the standard ABS grade. These grades are generally going to be the best for new users, as they are what other people have the most experience with; the community support for working with these materials is much better. Make sure to buy from a supplier that specifies the grade they sell, and make sure to either buy one of these standard grades or make an informed decision about why you're choosing a different grade.
Generally speaking, it is easier for manufacturers to attain better tolerances with ABS than with PLA. However, the extrusion characteristics of PLA will allow for finer feature detail on a well tuned machine.
While many people will claim that ABS is stronger than PLA, we haven't found them to be substantially different. PLA is more brittle than ABS and will tend to splinter and break where ABS may tend to bend, but similar force is required for either to fail. It is more likely that you will find your print settings to be a bigger contributor to the strength of printed objects than the plastic you're using (at least between PLA and ABS). Insufficient infill density, too few shells, delamination (layers pulling apart), and related problems may make your object weak even though the material itself is relatively strong. If your objects feel too flimsy or break too easily try upping infill, adding shells (perimeters), and tweaking your temperature and speed (to try to get better adhesion between layers) before you write off your plastic.
Does your printer have a heated bed? Is the bed capable of reaching temperatures over 100 degrees celsius? ABS tends to warp and peel, and often won’t stick well to an unheated, or under-heated print-bed. If you have an unheated bed, or one that doesn’t get hot enough, you’ll probably want to stick with PLA.
Does your printer have a cooling fan blowing directly at the print area near the end of the nozzle? If it does, you’re probably good to go with either material, but if it doesn’t, ABS may be a better choice. PLA has a tendency to curl at corners and overhangs, a tendency that can be minimized with proper cooling. While good cooling will help either, ABS may fare better without a fan.
ABS adheres best when printed onto a bed covered with Polyimide Tape (you will also see references to Kapton, which is a trademarked name for a brand of Polyimide Tape). PLA is a little more lenient and works great on Kapton, but also works well on blue painter’s tape. Polyimide Tape is more expensive than painter’s tape, but it goes a long way and can be replaced a little less frequently. Some people have luck printing PLA directly onto freshly cleaned glass (be careful not to drive your nozzle into your bed though).
ABS softens at a higher temperature than PLA, which makes parts printed in ABS more resistant to warping under higher temperatures. Keep in mind, we’re not talking about a huge difference; you’re still going to have a bad time if you print an oven rack accessory in ABS. For more moderate temperature situations, the difference may be important to you, it depends entirely on how you plan to use your printed object.
Fumes can also play a factor. If you are operating your printer in a poorly ventilated environment, or where people will congregate, such as a classroom or your living room, you may find the fumes from long prints with ABS a bit overwhelming. PLA has a much more organic, less “plastic” smell to it. As was pointed out in the comments by Madox, the strength or offensiveness of fumes can vary by grade as well.
The temperature of your environment can make a difference too. If your 3D Printer is open to the air and you’re printing in an environment with relatively cold air, you’re much more likely to experience cracking and warping with ABS than with PLA. When the ambient air temperature is very cold, such as in a basement or shop during the winter, layers of ABS will have more of a tendency to come apart and peel away from each other.
After a print, you may need to join parts together, or clean up the surfaces to make them look nicer. Both PLA and ABS may be sanded, and both can be painted with acrylic paints. Parts printed in PLA and ABS can both be joined with adhesives (those that advertise they adhere to plastic) (we like super-glue for its strength, ease of use, and quick drying time). ABS parts can also be joined with MEK (methyl ethyl ketone) or Acetone (especially in the form of ABS Glue, as we’ve detailed before), and can to some extent also be polished with these to create glossy surfaces. Common solvents for PLA (chemicals you would use like MEK or Acetone are used with ABS) tend to be very dangerous, expensive, and hard to acquire.
Like many other plastics, ABS is a petroleum product. PLA is made from vegetable waste (primarily from corn, but also from sugar beets and sugar cain). This is important to some people. Likewise, consider where your plastic is coming from. Supporting domestic retailers who use domestic suppliers helps reduce the energy used to transport goods, and also helps the domestic or local economy.
Natural, whether natural ABS with its creamy white appearance, or transparent Natural PLA, are great colors to keep stocked. For one, they tend to be less expensive because there is no pigment expense, which makes them great for test prints and prototypes where color doesn’t matter. Natural ABS and PLA also tend to minimize the appearance of flaws, which is great for finished prints, but actually makes it more difficult to diagnose calibration issues while you are getting your printer settings dialed in.
Colored filaments print slightly differently, and are also easier to diagnose with. We recommend calibrating your settings and printer to print well with a colored filament, which will generally give you good results with other colors, and with natural filaments. Selecting colors is completely subjective and is based entirely on personal taste and the kinds of items you wish to print. As you’re stocking up, think about how you’ll be using your printer and what colors you imagine you’d like the printed items to be.
Also note that some plastics are translucent or transparent where others are opaque. Generally speaking, ABS is opaque, with the exception of natural ABS which has a milky, slightly (very slightly) translucent appearance. For the most part, any color of PLA may be offered as transparent, translucent, or opaque.
Some people like coils, others like spools. There are pros and cons to each.
Spools (also called reels) are the easiest to work with. They store and travel neatly, dispense easily and evenly, mount conveniently, and look nice while helping avoid tangles. There are many accessories out there for mounting spools on your printer (or above it, or next to it, or under it...) or dispensing from spools set along side your printer on the desktop. The biggest down side to spools is the weight. When buying 1kg of plastic on a plastic spool, almost a third of the shipping weight can be the spool itself.
Coils (sometimes called "Air Spooled", which seems a bit hokey and misleading to us) are cheaper as you don't have to pay for the spool, and they weigh less, so shipping costs should be reduced. If you've got a spool with a removable flange that you can drop your coil onto, it can be just as easy to work with as buying spools; if not, you'll need some way to dispense it. Coils are also more practical for smaller quantities of plastic filament, anything greater than a pound becomes unwieldy very quickly.
Make sure you are buying from a good supplier. While we feel we’re a great supplier, we recognize that there are other good suppliers out there. We suggest considering the following factors when selecting suppliers.
Keep in mind that when using plastic filament from different suppliers, you may need to recalibrate your 3D Printer. This isn’t necessarily difficult, but it does take time and effort. Keep this in mind when shopping around.
Of course, price is a major factor for most people, but keep in mind not only the price tag of the plastic itself, but also the cost of shipping (we now have free shipping, by the way...). Buy multiple spools or coils at a time to reduce per pound shipping costs. Also make sure to find information about any deals or promotions a supplier is offering.
Keep in mind that if you buy cheap filament and wind up throwing portions of it out (whether throwing out the filament or failed prints from it), you may not come out ahead (that stuff you're trashing cost money).
Make sure your supplier advertises good tolerances and guarantees them. Poor tolerances can cause problems ranging from poor surface finish to failed prints (which also mean wasted plastic, see Price above). See our post about the importance of filament tolerances for more information.
Make sure you select a supplier that is responsive to customers, has reasonable guarantees and return policies, and stands behind and understands their products.
As with everything, you will need to prioritize and decide which considerations are important to you when buying filament.
Hopefully this is helpful to you. If you have any suggestions for points we didn't hit on, please let us know at content AT protoparadigm DOT com. Likewise, if there are any questions you have about buying filament that you didn't feel were addressed here, let us know about that too.