Material extrusion
Process description
material extrusion is the most prevalent form of additive manufacturing technology and is probably what most people think of when they hear the words 3d printing.
as the name suggests the basic idea is that material (most often some sort of polymer) is extruded through a heated nozzle built into series a of linear actuators, this allows for the printer to create a part. the printer then “draws“ each layer through the extruding nozzle
strengths
because material extrusion is such a well-established technology it has had the time to develop into an extremely reliable and accessible technology.
- budget-friendly: material extrusion technology has been around long enough that plenty of reasonably priced printers. these will fulfill the needs of people who are interested in getting into printing.
- ease of use: material extrusion has advanced to a point where it is easier to use than some 2d printers. Also, if there is a problem there is an unprecedented amount of free online information to help.
weaknesses
- surface finish: because of the way that parts are created layer lines will almost always be visible. this will especially be an issue anywhere where support is needed.
- need for support: material extrusion can find it difficult to print parts with intense overhangs, so they often need to add extra material to give a stable platform for printing. these can be removed but it does use the material and will affect the surface finish.
- warping: temperature differences can cause uneven contractions in a part while it's printing leaving a warped part. this can be helped with a heated bed and proper enclosure.
| High | Low | |
|---|---|---|
| volume X/Y/Z (mm) | 120/68/150 | 1005/1005/1005 |
| resolution (mm) | .25 | 1 |
| layer height (um) | 20 | 300 |
| price ($) | 200 | 27,475 |
Technologies
There are a number of specific technologies that can vastly change to capabilities of a printer.
Metal replacement (Bound metal deposition/Atomic diffusion)
Metal particles are infused into a thermal plastic. The printed part is put through a secondary process to remove the thermal plastic leaving a smaller metal part in its place.
Continuous fiber reinforcement
A Second print head lays down fiber into the internal structure of a print. This gives the part stronger material properties