How to design for 3D printing
- What-Plan out what you want to design (pencil and paper is still useful) and what you want it to do. With this clear in your mind it will be easier to make the design trade-offs required later on.
- Uniqueness-Consider how to take advantage of what 3D printers can do compared to other manufacturing methods. For example if you are making a jewelry box instead of making it square (that you could make with wood or metal straight edges) why not design in several curves and multi dimensional contours that couldn’t be made any other way.
- Build volume-If you have a 3D printer or know which ones you are going to use make sure you know the maximum build volume and stay inside this volume (unless you want a large object and you will have to print it in several pieces).
- Print orientation-During the design phase make sure you consider that the object will be made in layers and so the print orientation will have an important effect on strength, number of supports required and final appearance of your design.
- Supports-If you can design an object so that no support is needed then this is best for appearance and print time but sometimes that is not possible. Try to minimise supports to reduce time and material used. If the object is being designed with aesthetics in mind try and place support structures in locations that won’t be visible on the final object (when supports are removed they can leave a rough surface finish and marks).
- Tolerances-If the object has multiple parts or even two sections that are close together you will need to consider the tolerances that your printer can handle. It varies from printer to printer but a good rule of thumb is to leave space between parts/sections that is 2 times your layer height. For example if your layer height was 0.2mm then by leaving 0.4mm between two components will ensure that they do not fuse together.
Specific guidelines or ‘rules of thumb’
- Wall thickness-Use a minimum wall thickness of 2mm to stop flex and warpage from too thin walls (obviously the longer the wall length the thicker it needs to be)
- Small edges-Avoid having parts that terminate in very small edges/corners as the printer won’t physically be able to print this or it will be extremely weak
- Avoid sharp corners-If a part is load bearing and connects to other sections of the part make sure that corners have fillets otherwise the sharp corner will act as a stress raiser and make the part much weaker
- Shrinkage-Parts will shrink after cooling so if you are designing a part to fit an existing object remember to take this into account. Shrinkage rates will vary depending on materials but can be up to 3% for some ABS blends. If you are designing parts to fit with other 3D printed parts then this will be less important because all the parts should shrink by the same percentage leaving your tolerance ratios the same.
This page is currently under construction, check back soon for tips (with images) on how to design specifically for 3D printing.