When designing lots of different parts for a single product, it’s important to consider how they are all going to be connected together. On most designs, it is generally acceptable to use self-tapping screws inserted into holes with a slightly smaller diameter. However, if you need to remove the screen from the 3D print multiple times, this method will quickly rip out the thread you’ve created in the plastic.
A better approach can be to introduce brass threaded inserts into the design of your parts. This reduces the chance of your parts coming loose and allows your products to be taken apart and put back together, indefinitely! At Prodpoint we’re introducing heat set threaded inserts for 3D prints. This method is very simple to design in and can quickly increase the durability, and perceived value to your parts
Heat Set Threaded Inserts
Heat set threaded inserts consist of small brass part that have a threaded interior and an exterior surface covered in knurls and ridges. To install these brass parts, they are placed over undersized holes in the 3D printed part and are then gradually heated up. When the brass insert is hot enough to melt the surrounding plastic, the insert is pushed down until it is flush with the top of the hole. As the plastic flows around the knurls, it forms a tight bound that can resist both torque and pull out forces.
When adapting your CAD model to allow these brass parts to be inserted, it is very important to read the specification of each insert you plan to include. In general, the 3D printed hole should be around 80 – 90% of the diameter of the insert and about 1.5 times its height. These values are only approximate, and to get the best result you should use the dimensions quoted by the manufacturer. However, if you’d rather leave it to the professionals, the Design and Development Service at Prodpoint can make the adaptations to your model for you. We can also install the inserts onsite, so all the parts come to you ready for assembly. Just inquire about threaded inserts when asking for a quote.