The vast array of 3D printing options out on the market today creates an issue when talking about the technology. The issue lies in the fact that no one type of printer can do it all. Each technology has its own strengths and weaknesses and no one printer excels at everything. This is especially true at the consumer level. However, understanding the basic types of printers and technology can help you make a decision on what printer to buy or even what printer you need access to have print your designs. In this this post I’ll cover some of the main types of printers currently on the market and cover some of the strengths and weaknesses of each printer.
Because of the powder based printers ability to print in full color, TLB decided to purchase a ProJet 660 Pro. It will print to resolutions of 100 microns in millions of colors. It does this by laying down a bed of powder and using bonding agents, clear and colored to bind the powder together. As it prints, it colors the model using inkjet print heads. Upon completion, the model is retrieved by vacuuming out the loose powder and taking the model over to clean of the fine particles. Finally, the model is coated with a choice of bonding agents that increase the strength and help bring the color to life. Due to the nature of the technology, the models can fragile depending on what bonding agent is used, the axis it is printed on, and the alignment of layers.
Fused Deposition Modeling (FDM):
FDM is the most prevalent home based printing technology. Essentially, a FDM printers melt and extrude a plastic on a X, Y, and Z axis. There are numerous designs on the market and the differences lie in the resolutions, speeds, and ease of use. For example, the Mega Prusa which we purchased uses a single extruder head of various diameters, from .2mm to .7mm, to melt either ABS or PLA plastics. In the Mega Prusa design, the platform and extruder heads move in conjunction to create the model. Each layer builds upon the next to create the model. Here is an excellent time lapse video of a Maker Bot in action. You can see the extruder head moving to print each layer and upon the layer completion, the platform drops in order that the next layer can be added.
One of the main strengths of this technology is that the materials are cheap and as you are printing in plastic, the overall model resilience is good. Using our Mega Prusa, I printed a number of robots for my five year old and they were able to handle his use and abuse. The printers can print in color if you use a color plastic or a multi-extruder head set up where the printer can choose from different color spools to print from. This does not equate to full color printing but does give the user some color choices.
Stereolithography Printing (SLA)
SLA printing has been around since 1986 when it was patented by Charles Hull. The machines cure a liquid resin using a light system to bond materials together. The parts are strong and can be machined or used to create mold. However, up until recently, the printers themselves cost tens of thousands of dollars and the liquid resin ran around $100, or more, a liter. There are a number of home use platforms being developed with the Pegasus Kickstarter which offered four liters of resin for $400 and a printer for $2500 donation. As you can see from the photos, the ability to print at high resolutions is one of the great strengths of these printers. I think we will see more and more of these types of printers as costs continue to drop.
Due to the nature of the printers, the disruption of production that some people have been alluding to might be farther off then people think. However large scale printing in concrete is closer than you think and could alter the way we build homes and buildings. Leaving aside what this would do to the construction industry, the technology itself is amazing. Take a look at this article to get a concept of how this works. It essentially is a large printer similar to the FDM style; it just extrudes concrete as opposed to plastic. One interesting application, as the article points out, might be the launching of such a printer to the Moon or Mars and preprinting structures for people to man when they got there. They're already starting to print pre-fabricated sections in China.
This is a groundbreaking technology that has interesting implications and uses. As opposed to creating a casting, you could just print any part you need. Jay Leno is already doing this with some of his car parts, but in the Popular Mechanics article he is still doing them in plastic. However, being able to reproduce the parts in metal would allow people to open up all sorts of one of and rapid prototyping avenues. Extremetech posted a fantastic article covering metal printing that includes some great videos on how the various metal printers work. I encourage you to check it out.
The printers I have outlined only cover a few of the avenues out there. We are also seeing :
As you can see there are a wide variety of options and capabilities. The challenge for the person new to the technology is seeing what is out there, thinking of how they will use a printer, and then picking one out. Happy Printing!