Design Best Practices for Fused Deposition Modeling (FDM)

Fused deposition modeling (FDM) is the most common type of additive manufacturing. When you hear people talking about 3D printing, more often than not they’re referring to FDM. 

FDM has the potential to change our technological landscape and improve people’s lives in countless ways—but only if it’s leveraged correctly. With the right design approach, FDM is an inexpensive, fast, and reliable manufacturing method that yields high-quality parts. However, if designers and manufacturers aren’t careful, FDM products can be weak in composition or sloppy in appearance. 

At Alchemy Industrial, we want you to have all the information you need to produce the best 3D printed parts. We even developed an entire eBook dedicated to design tips for FDM. We’ll dive into a couple best practices in today’s blog, but you’ll have to download the eBook for the rest of them! 

Design Tips for Fused Deposition Modeling

There are several ways to ensure your FDM parts are cost-effective and functional. Here are two tips that are crucial for the best outcome:

1. Choose the right infill density

FDM parts have two components: the outer walls and the infill (i.e. the structure printed inside the part). The default infill option is a solid infill, which yields the greatest possible strength. The downside of a solid infill is that it’s time-consuming and requires maximum material, two factors that can add cost to a project. 

Alchemy Industrial offers three different infill options to meet the needs of various applications:

• Ultralight: Ultralight infill is the  least expensive option. This method involves printing a single cross-hatch pattern throughout the part.
  
• Light: If your part needs to retain considerable strength, but you’d still like to keep costs low, light infill is usually the right choice. This method involves printing a double cross-hatch pattern throughout the part.
  
• Solid: Solid infill is the strongest and densest option, producing a completely filled interior.

2. Orient parts correctly

The orientation—horizontal or vertical—of a part is critical to its outcome during FDM printing. The FDM printing process involves building a part by adding one layer of filament at a time. The layers build upward or outward depending on the orientation. 

A part’s orientation contributes directly to its overall strength and appearance, especially if the part has fine and concentric features. Designing a part so that fragile and concentric features grow in the same direction will help determine the best print orientation for a part. 

Here are a few key considerations for orienting parts: 

• Concentric features and fine features, such as tabs, resolve best and are strongest when the layers print parallel to the XY-axis.
• Long surfaces print more time- and cost-efficiently if the cross-sections orient parallel to the XY-plane.
  
• Printing a part from the bottom up will yield weak vertical tabs that may break off between layers. However, concentric features will be more resolved and have no layer stepping. Printing the same part on its side will yield stronger tabs, but the concentric features will have significant stepping.

Want to learn more FDM design best practices? Download our eBook here. You’ll find plenty of quick tips to improve your next FDM designs and get better 3D printed parts from your outsourced manufacturing partner. If you’d like to leverage FDM printing for your part, contact Alchemy Industrial today.