The important thing to take note when designing for 3D printing is the digital design has to be printable. In the digital world, every design is possible but not everything can be 3D printed. The projected image of 3D printing ever since it launched is 3D printing can print anything that traditional molding cannot produce. Yes, 3D printing has the ability to produce the impossible design possible but there is still some design consideration that we need to take note.
Overhangs and Supports
Bear in mind that 3D printing builds parts layer-by-layer, therefore material cannot build in the air; each layer must be printed on top of some underline material.
If your design required to build the part in the air (also known as overhang), there are 2 ways of printing them. One is to print the layer partially over the layer below or print the design with the help of the support material if the slope is greater than 45 degree. The disadvantage of printing over support is the surface finish is usually rougher.
It’s a good practice to design the models with lesser support. It’s because if the product required lots of supports, more materials needed to print the supports and it will also take a longer time to print the model as well as the extra time needed to remove the supports.
Alternate workaround to reduce support is to orient the model during printing.
Wall thickness plays an important role in a product that will affect the warpage and fragile of the product. If the wall thickness is too thin, it may not be able to print or it will break easily. If the wall thickness is too thick, it will increase the weight of the product, more materials will be used and also increase the printing time.
Some recommended guidelines for different 3D printing technologies:
- FDM Printing – minimum of 0.5mm
- SLS Printing – minimum of 0.7mm (for Nylon 12) to 2.00mm (for Carbon-filled Polyamide)
- SLA Printing – minimum of 0.4mm with supporting walls; 0.6mm for unsupported walls
- Binder Jetting Printing – minimum of 2.0mm with supporting walls; 0.3mm for unsupported walls
Due to the materials’ physical change during the process of printing (melted, sintered, scanned with the laser and solidified), the heating and cooling of the materials can cause the parts to warp.
Material selection plays a role in causing the warping of the printed part; the good practice is to always check for the physical properties of the material and adjust the printer’s setting to suit the material.
Another 2 other good practices when designing the model is to avoid large flat surface as this tends to warp more and adding fillets to the corners of the model also help to reduce warpage.
Embossed and Engraved Profile
For some reasons, we might need to add text on the products for branding purposes. In order to ensure that these small details are visible during printing, we need to apply some of the rules:
- FDM Printing – minimum height and depth of 0.5mm
- SLS Printing – minimum height and depth of 1.0mm
- SLA Printing – minimum height of 0.1mm for embossed profile; 0.4mm width and depth for engraved profile
- Binder Jetting Printing – minimum height and depth of 0.5mm
3D Printing allows you to think out of the box and do not be constraint by the traditional design concept. Design the impossible yet with the thumb of rule in mind.