3D Printers
FDM vs. SLA Printing
Fused deposition modeling (FDM) and stereolithography (SLA) are two methods of 3D printing an object. FDM printing is the type of printing described on the homepage, where a nozzle heats up a material and then extrudes the molten plastic onto a bed using a motor. In SLA printing, a bed sits above a vat of resin. This resin is then selectively cured using a precise laser, which causes it to harden into a plastic. The bed is then moved up, and the process is repeated. SLA printing is known for its higher print resloutions and intricate details, due to the use of light on resin instead of heated plastic. Any information detailed on this site will refer to FDM printing.
Bowden vs. Direct Drive
In a bowden system, the filament is fed through extruding gears mounted off to the side of the printer and into a flexible tube (bowden tube). These gears then push the filament down the tube and into the hot end, where it gets melted down and extruded. In a direct drive system, the gears are mounted directly above the hot end of the printer. The filament travels along a much shorter distance before getting melted. If you plan on using a wide variety of materials and colors, you might want to pick a direct drive system. If you don't plan on printing with a lot of flexible filament, you might want to choose a bowden system for higher speed and accuracy.
Other Info
3D printers move in three axes. The X and Y axes are the lateral directions; the Z axis is the vertical direction. The way these axes are utilized varies by printer. Some have the bed moving along the Z axis, and the nozzle moves along the X and Y axes. Some printers have the nozzle take the Z axis and the Y axis, and the bed handles the X axis. Each printer may have a different bed size (dictates the maximum size it can print) or a different maximum temperature.
Filament
Filament Types:
Filament is the material that is used in FDM printing machines. Filament comes in a wide range of colors and types. Each type of filament has different properties (strength, flexibility, durability, etc.) and different melting points. Here is an overview of some of the most common types:
- PLA: Polylactic acid (PLA) is the most common type of filament in the world of consumer 3D printing. It is easy to print with, has a low printing temperature, and gives off low amounts of toxic fumes. PLA fumes can give headaches and eye strain if one has too much exposure to it, so be sure to print with PLA in a well-ventilated area. It is also more environmentally friendly than other filaments, being made from renewable resources like fermented plant starches (from corn, cassava, sugarcane, beet pulp, etc.).
- ABS: Acrylonitrile butadiene styrene (ABS) is the second most popular 3D printer filament. Although being more difficult to print with, ABS's material properites are moderately superior to PLA. Products such as LEGO bricks are made of ABS. ABS has high durability and higher temperatures, but it tends to warp during cooling. ABS also emits harmful fumes, so printing in a ventilated area or an enclosing around the printer is ideal.
- PETG: Polyethylene trephthalate gylcol-modified (PETG) is a popular filament type that is known for its flexability and durability. It is a varient of polyethylene trephthalate (PET), the most commonly used plastic in the world (used for bottling and packaging). It is in the middle of PLA and ABS, being more flexible and durable than PLA but being easier to print with than ABS. PETG is the safest filament available in regards to fumes emitted during the printing process.
- TPE: Thermoplastic elastomers (TPE) are rubber-like palstics, which have high durability and flexibility. TPE is a non-specific term for flexible filament, and is a broad class of plastics that are used to label different types of filaments. Printing can be difficult, as it is not as easy to extrude as other filaments.
- TPU: Thermoplastic polyurethane (TPU) is a variety of TPE. It is slightly more rigid than TPE, which makes it easier to print. It is better resistant to cold temperatures, meaning prints better retain elasticity, as well as having a higher durability than TPE.
- TPC: Thermolactic copolyester (TPC) is an additional variety of TPE that is used in 3D printing (although it is less common). It is more resistant to high temperatures as well as chemical and UV exposure.
- Nylon: Nylon has many industrial applications outside of 3D printing. It is the most flexible, most durable, and strongest filament on the list. There are many grades of nylon, the most common for 3D printing being 618 and 645.
- PP: Polypropylene (PP) has a broad range of applications, such as engineering fabrics, food packaging, textiles, and bank notes. It is tough, light, flexible, food-safe, and chemically resistant. However, PP is extremely difficult to print with and often has many issues with warping and adhesion. Fumes produced from PP are very toxic, and they can cause respiratory irritation, pulmonary edema, and a possible asthma-like response.
| Filament Type | Print Difficulty | Strength | Flexibility | Durability | Nozzle Temp. | Bed Temp. |
|---|---|---|---|---|---|---|
| PLA | Low | High | Low | Medium | 180°C – 230°C | 20°C – 60°C |
| ABS | High | High | Medium | High | 210°C – 250°C | 80°C – 110°C |
| PETG | Medium | High | Medium | High | 220°C – 250°C | 50°C – 75°C |
| TPE | Medium | Medium | Very High | Very High | 210°C – 230°C | 30°C – 60°C |
| TPU | Low | Medium | Very High | Very High | 210°C – 230°C | 30°C – 60°C |
| TPC | Medium | Medium | Very High | Very High | 210°C – 230°C | 30°C – 60°C |
| Nylon | High | High | High | High | 240°C – 260°C | 70°C – 100°C |
| PP | Very High | High | High | High | 230°C – 260°C | 60°C – 110°C |
Choosing a Filament Type
If you are starting out with 3D printing, it is recommended to start with PLA. It is easy to print with and comes in many different colors and types. Once you get the hang of printing with PLA, you can start moving into different types, such as PETG and TPU.