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How to choose the right material for 3D Printer

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15 thg 4 2020

Once you have chosen a 3D printer, you don’t get to sit back and wait for cool stuff to pop out of it. You first need to select some additional things to compliment your printer, beginning with the filament material shown in Figure 1-16.

Figure 1-16. Assorted filament on spools

Filament is like the ink or toner in a traditional printer except that it’s, well, plastic. It is available in a variety of diameters, colors, and types of material, sold in long lengths, coils, or spools. There are some important things to consider in your filament buying decision, so let’s look at some of the possibilities.

Filament Materials

Regarding the choice of filament materials, there are two very popular types of plastic in common use today: PLA and ABS. ABS, or acrylonitrile butadiene styrene, is essentially the same stuff that LEGO bricks are made of. It is a very durable thermoplastic that is slightly flexible and suitable for many purposes. It can be sanded, painted, and glues very well with plastic glue made for ABS; and it is dissolvable in the household chemical acetone (think fingernail polish remover). It is impact resistant and has a relatively high resistance to heat, extruding at temperatures around 210°C. When printing with ABS, a heated printbed covered in polyimide tape set to about 110°C is a near absolute necessity or otherwise the parts will curl as they cool and might even crack with larger prints. ABS has been the long-standing favorite material of the personal 3D-printer community, although the recent increase in the availability of PLA has changed that somewhat.

PLA, or polylactic acid, is a biopolymer plastic derived from cornstarch or sugar cane. It is not easily recyclable, but it is biodegradable in the right circumstances. PLA is a more environmentally friendly alternative to petrochemical plastics and it smells a little like maple syrup while extruding. It is a tough plastic when cooled, albeit a little on the brittle side, and it has a lower threshold for high temperatures than ABS, extruding at a temperature around

180°C. A heated printbed is not absolutely necessary; however, if you have one, printing with the printbed set to 60°C helps with the quality of the print. PLA can even be printed on a clean glass print surface as long as the surface is heated.

This plastic is slow to cool, though, so having a secondary fan pointed at the recently extruded filament will make for better prints. Many suppliers of PLA filament offer PLA in very pleasing colors that range from bright semitranslucent to very dense and opaque.

Other, more exotic thermoplastics have had mixed results on most DIY 3D printers—including polycarbonate, high-density polyethylene (HDPE), and polyvinyl alcohol (PVA)—although the community continues to experiment with these plastics.

When choosing the right material, consider the environment that your 3D printer will be placed in. If you have an open place for your printer that is well ventilated, then ABS extrudes in most printers very well and gives you a lot of flexibility with the material after your object has been printed. On the other hand, if your 3D printer lives in a closed office or classroom, then PLA is a better choice for producing less toxic fumes, and the material contributes to more renewable green material practices. As a general rule of thumb, if your printer supports PLA, I recommend this material about 95 percent of the time.

Filament Diameter

Once you have chosen a material, you might need to decide on the diameter of the filament to use in your printer. Nearly half of the printers discussed in this chapter have moved to extruders that exclusively support 1.75mm diameter filament. Proponents of the smaller filament argue that it is easier to design filament drivers and hot ends because it requires less material to heat and is easier to feed into the extruder. Filament in 3mm diameter had been the de facto standard of the RepRap printers from the beginning. Proponents argue that it is easier to keep a steady extrusion with the larger filament and it is still possible to create really fine layer heights even with the larger filament.

Regardless of the theoretical views of which filament is best, you might not have much option in the filament that you choose depending on the 3D printer that you settle on. Instead, all you need to do is to choose the correct filament for the extruder of your printer. For example, the MakerGear Mosaic is exclusively a 1.75mm filament printer, while the Ultimaker uses only 3mm filament. It’s not so much that one is better than the other, only that the designer decided on one size over the other and built their extruders to fit.

Buying Filament

For the most part, filament has been sold increasingly on 1kg or even 2.2kg spools (roughly 2 to 5 pounds) for easy feeding into your printer. All you need to do is make, print, or cobble together some form of spindle holder, and you will never need to worry about your filament again. Some suppliers, however, prefer to offer their filament in loose coils or sell it by the meter. While this might be less convenient than filament on spools, it is usually cheaper and gives you more options for exploring many different colors.

Whatever you do, buy from reputable suppliers of filament that have a proven track record as evidenced by positive comments by the community in forums, message groups, and web chat. Research any new supplier before blindly throwing money at them because not all filament is the same and it might cost you more in the long run. Some suppliers sell filament that is of inconsistent diameters over the length of the filament, or filament that is oval instead of round. Either of these conditions will jam your extruder in mid-print, causing unnecessary maintenance, repairs, and frustration. Some filament has even been reported with grainy, sand-like material inside of it that can destroy parts of your extruder, which will then need to be replaced. Other filament simply never prints very well, leaving you to think you have a bad printer when really it’s just poor- quality filament.

Remember: choosing the right filament is at least as important as choosing the right printer. The following are a few vendors that have had very good track records of providing excellent-quality filament:

MakerBot Industries (http://store.makerbot.com/plastic.html)

Ultimaker (https://shop.ultimaker.com/en/...

ProtoParadigm (https://www.protoparadigm.com/products- page)

Faberdashery (www.faberdashery.co.uk)

Once you have received your filament, don’t leave it exposed to air and

moisture for longer than is absolutely necessary. Instead, keep unused filament in sealed plastic bags, and if you have them around somewhere, toss in a small bag of desiccant to keep your filament dry.

Basic Tools and Supplies

Even if you are buying a fully assembled kit, there are a handful of tools and supplies that are essential to successful 3D printing. While some printers might require an exhaustive tool list, in this section we will look at just the bare essentials that you should have on hand regardless of the complexity of your 3D printer.

Hand Tools

If you bought a kit, then all you need to build and operate your 3D printer are some simple hand tools, as shown in Figure 1-17. If you are sourcing your own printer, then you will also need tools to cut steel rod and plywood.

Figure 1-17. Some basic hand tools

Figure 1-17 shows the following tools (remember, this is not a definitive list but rather a good cross section of tools that are helpful to have on hand):

Small, battery-powered hand drill (10.8V drill shown) Assorted drill bits

Precision dial indicator

Torpedo or spirit level

Set of precision screwdrivers

Set of metric hex keys, including 1.5mm, 2.5mm, and 3mm

Metric wrenches, including 10mm and 13mm

Adjustable wrench Flat and needle files Hobby knife

Metric ruler

Digital calipers

Square

Needle-nose pliers Slip-joint pliers Scissors

When cleaning the printed parts of your printer, you will probably use a drill and drill bits to clean out holes and the files, and a hobby knife to smooth edges. To build the printer’s frame, you will need the ruler to ensure correct spacing, and the square and torpedo level to make things level and square. Wrenches, pliers, and hex keys are useful for tightening all the nuts and bolts, while scissors are useful for cutting any tape you use to attach to the hot end. Finally, the digital calipers and (though not entirely necessary) the dial indicator are used to calibrate your finished printer and will come in handy later for designing some of our projects.

Electronics Toolkit

If your electronics come preassembled, then you might not have much of an urgent need for these tools; but inevitably you will need to fix something, so having the tools shown in Figure 1-18 is just as helpful as having a good toolbox.

Figure 1-18. A sample electronics toolkit

Figure 1-18 shows the following equipment:

Soldering iron

Solder

Digital multimeter

Heat gun Flush cutters Wire strippers Crimping tool

The soldering iron and solder are useful for assembling the controller electronics, endstops, wires, and other electrical components. A wire stripper is the best tool for cleanly removing the wire insulation before soldering. Flush cutters are useful for tripping wires and the legs of electrical components, and wire crimpers might be used for connecting plugs on the ends of the wires. A

heat gun or other heat source is useful for applying heat shrink to bare wires, and the digital multimeter comes in handy when troubleshooting your electronics.

Printing Supplies

Once you have your printer up and running, you will still need a few tools and supplies around (see Figure 1-19) to help with making good prints and to fix

little problems that pop up. The necessity of some of these supplies, like acetone, will depend on the type of plastic you predominately use.

Figure 1-19. Assorted printing tools and supplies

Figure 1-19 shows the following tools and supplies:

135mm or wider polyimide tape

20mm or narrower polyimide tape

Acetone or nail polish remover

Oil or silicone lube

Tweezers

Spatula or putty knife

Clean, cloth rags

The necessity of polyimide tape, also known as Kapton tape, depends somewhat on the filament you are using. It is an essential surface for the build platform if printing in ABS, although it also works great for PLA. When covering your printbed, it is easiest to use tape that is as large as your printbed. I usually apply it with some soapy water and a small card or squeegee to spread the tape smoothly over the build surface, as discussed in Appendix A. Smaller polyimide tape can be pretty handy for general attaching and repairing. It is generally a good idea to clean the print surface daily with acetone on a clean rag to remove any dust or grease and ensure the plastic sticks when printing. While printing, tweezers are helpful for removing stray bits of plastic. The spatula or putty knife (preferably rounded and smooth) can help remove the finished print. Finally, it’s a good idea to periodically grease your smooth rods with a lightweight oil or grease.



Info from book: 
Practical 3D Printers_ The Science and Art of 3D Printing 

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