Printing Colors: FDM Thermoplastics

By Kelly Judson on

FDM parts are probably the most popular type of 3D printed parts. The FDM (fused deposition modeling) process is “melting” a solid thermoplastic filament, like a hot glue gun. If you plan on testing your parts in a strenuous process, FDM may be the best choice. These materials specialize in high tensile strength and resistance to high temperatures.

Color for FDM parts are available in a relatively wide range of colors in the most common materials like ABS and ASA. And if you can’t get the exact color directly from the filament you’re using, there are a variety of other methods you can use. 

Fused Deposition Modeling (FDM)

The FDM process allows for 3D printing with the most commonly used thermoplastics, such as ABS, polycarbonate, a variety of blends, as well as engineered thermoplastics for aerospace, medical, automotive, electronic and other specialty applications.



When printing on an FDM machine you tend to get stronger parts since you are working with thermal plastics, but color accuracy is usually not the main reason you would use this approach. 

Different Options

If you want a part in a particular color, you would typically select the color that is closest to the end result color that you want, ie. red, blue, black, grey, etc. So you can have yellow, but not Dandelion or Goldenrod initially.

Print and assemble

FDM assembled part

This is an example that looks really appealing at first, but since FDM can only print one color at a time, this assembly is printed at different times with different colors and then assembled. But the advantages of FDM from a material characteristics standpoint outweighs the extra work of printing these parts separately.

Switch colors in a single print

FDM layered printYou are able to print “multi colored” parts with an FDM printer; you have to use the Pause command inside of either Catalyst or Insight and then switch out the color of the material and Resume the print job. One item to keep in mind is that the Pause will stop at the start of the print layer and then that layer and every other layer will be the new replaced color. This is doable, but maybe not as user friendly as one might hope because a material color change takes about 3-5 minutes. Also, you can only switch color, you can’t switch type of material.

>> Read our related article How to Make Multi-Colored Prints with FDM for a walk-thru of the steps to do this in GrabCAD Print


Post-Processing options

A nice benefit of FDM parts is that they can be secondarily post-processed. The most common of secondary post processing would be painting, but FDM materials can handle being sanded, bonded, epoxied, anodized, smoothed, machined and a host of other techniques to make the part look different than how it was printed. 

>> Read our related article: 5 Easy Steps For Painting FDM Printed Parts

Another common approach to secondarily post processing FDM parts could be mass finishing, like a tumbler. The advantages of a tumbler is that many parts can be finished at the same time and a tumbler has the flexibility to work on pretty much any FDM material, you would just change the media in the tumbler for the different materials.


Color is usually a secondary consideration for FDM parts as their shining characteristics are the material properties. You don’t have to worry about the limited color options for FDM, because you’ll have an awesome part or prototype at its core and have the option to make it better with multiple coloring and finishing techniques.

Do you want to learn more about FDM materials? Click below to download our white paper, Thermoplastics: The Strongest Choice for 3D Printing.