When designing a model for 3D printing there’s a list of things to keep in mind, regardless of the technology that you will be printing with.

 

Different 3D printing processes have different capabilities and different design restrictions. The design software you use to create your 3D model doesn’t matter, the most important thing to remember when designing for 3D printing is the fact that your digital design will become a physical object. In the digital design environment, there are no laws of physics to adhere to, such as gravity. This means that anything can be drawn in 3D on a digital canvas, but not everything can be 3D printed. Each 3D printing process has its own limitations and these include:

 

Overhangs

All 3D printing processes build parts layer by layer. Material cannot be deposited onto thin air, so every layer must be printed over some underline material.

 

Overhangs are areas of a model that are either partially supported by the layer below or not supported at all. There is a limit on the angle every printer can produce without the need of support material. For FDM and SLA this angle is approx. 45° degrees.

 

It’s good practice to limit the overhangs of a model, as layers printed over support usually have a rougher finish.

 

Wall thickness

When designing a part to be 3D printed it’s important to keep in mind the wall thickness. Every 3D printing process can produce accurate features that are thin up to a certain point.

 

As good practice, you should always add thickness to your models and walls with a thickness greater than 0.8mm can be printed successfully with all processes.

 

Warping

Something that is often easily overlooked when designing a 3D model is the fact that materials used for 3D printing undertake physical change, they are melted, sintered or scanned with a laser and solidified. The heating and cooling of materials can cause the parts to warp while printing.

 

Particularly large, flat surfaces can be especially prone to warping and warping can typically be avoided by using the correct machine calibration and having adequate surface adhesion between your part and the print bed.

 

A good practice is to avoid large flat surfaces and add rounded corners to your 3D models.

 

Level of detail 

When you are creating a 3D model with intricate details, it’s important to keep in mind what is the minimum feature size each 3D printing process can produce. The minimum level of detail is connected to the capabilities and mechanics of each 3D printing process and to the selected layer height.

 

The process and materials used will have an impact on the speed and cost of your print, so determining whether smaller details are critical to your model is an important design decision.

 

Key points

- Avoid overhangs in your design when possible, by using angles smaller than 45°
- Add at least 0.8mm wall thickness to your models
- Avoid large flat surfaces and use rounded corners to avoid warping.
- Decide what is the minimum level of detail your models require and choose a 3D printing process accordingly