What is "Infill" ?

Fused Deposition Modeling (FDM) is a 3D printing technology that builds a part layer by layer by depositing heated thermoplastic along an extrusion path. In this process, there are several different ways the solid areas of a part can be interpreted when the part is built. Infill describes how the solid areas of a part should be filled in. Xometry offers 3 types of infill options, each with their own properties. When quoting a part to be made in the FDM process, you will see these options listed under "Material Options".



Selecting infill options for a part on the Xometry instant quote page

Xometry offers Solid, Light, and UltraLight infill options. The best option will be determined by your personal needs and desired characteristics for the part. For example if you are looking to reduce the part weight as much as possible, then you may want to consider the UltraLight infill option. If you are looking to get a part that is as strong and dense as possible, the Solid infill option would be most appropriate. The Light infill option offers a happy medium between weight and rigidity of the part. 


Photo Example Comparing Different Infill Options

This part was duplicated with different infill options and built simultaneously. We paused the build mid-way to produce this cross-section example. Seen from left to right is the Solid, Light, and UltraLight infill options.

If you are still unsure of which infill option to select, you may want to explore how each option influences the final price of the part. Overall geometry and complexity of a part will determine how the infill is calculated. For some parts changing the infill may result in negligible cost differences. For other parts, the infill pattern can dramatically influence the price. When in doubt if part strength, durability and mechanical functionality supersedes other concerns, then the Solid infill choice is usually the safest bet. 


For more information on infill options and other information about the FDM 3D printing process, be sure to check out our FDM Design Guide!  


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