Choosing the right wall thickness is perhaps one of the most important decisions when designing parts for 3D printing. If the walls of your parts are too thick, your part will cost more to produce, take longer to print, and may even wind up cracking. If your walls are too thin, the part may not be functional, may warp during printing, or, once again, cost more to produce because you’ll have to go back and rework the design.
Understanding the minimum wall thickness for 3D printing will set you up for design success and lower your production costs.
What Is Minimum Wall Thickness?
Minimum wall thickness is the smallest possible thickness a structure can have while maintaining functionality. This minimum is impacted by several factors, including the type of 3D printing process you are using to print, constant physical forces (such as gravity), and how much pressure the structure you’re creating will be under during use.
Think of a graphite pencil. The thinner the point and the farther the shaft extends, the less pressure the graphite can withstand. The precise breaking point varies with each user as the precise pressure is unique to the person wielding the pencil. This is also the case for 3D printed structures.
Supported vs. Unsupported Walls
An unsupported wall is one that connects with a second wall on only one side (or edge). A supported wall is one that connects with two or more walls (on two or more sides).
Wires are round as opposed to walls, which are flat surfaces. Due to their different physical shape, their minimum thickness is expressed as a minimum wire diameter. For a pillar or vertical wire, you’ll need to calculate the minimum vertical wire diameter (or thickness at the widest point in your circle).
Embossed vs. Engraved Details
When it comes to calculating the minimum and maximum thickness for intricate details, it’s important to understand the difference between embossing and engraving. Embossed details are those that protrude outward from a design, and engraved details are those that recede inward, or are concave.
Minimum Wall Thickness by 3D Printing Process
Minimum wall thickness varies based on the type of 3D printer. In many cases, the manufacturer of the 3D printer or the 3D printing service provider offers a design guide with wall thickness recommendations based on testing performed on the specific printer model.
In general, SLA 3D printers can create the thinnest walls of all 3D printing technologies, but there are differences from machine to machine. For example, Formlabs’ own Form 3 SLA printer offers more design freedom than its predecessor, the Form 2, because it uses a flexible resin tank to significantly reduce peel forces during printing.
If you are printing with an FDM 3D printer, recommended wall thickness can also change based on the size of the nozzle you are using. For example, if you are using a 0.4 mm nozzle, your minimum wall thickness should be divisible by 0.4, so instead of the 1 mm recommended minimum thickness in the table, you’ll likely get better results with 1.2 mm thick walls or by switching to a thinner nozzle.