Much the same as moulded components, a 3D printed part’s functionality can be improved through the inclusion of threads and metallic inserts. As manufactures utilising functional materials for structural and end use applications, we have listed below the different thread and insert types to assist your design process.
Self-tapping screws – Fit and forget: A blind or thru-hole can be printed as per the specification of the self-tapping screw you desire. We recommend that the holes are drilled prior to assembly to ensure the hole size is to specification, this design is perfect for assemblies that are not going to be taken apart. Best practice is to ensure the surrounding material has a diameter two times greater than the external thread diameter of the screw.
Tapped Threads – Low load re-usability: Conventional tapping tools can be used to create male and female threads, threads greater than M8 can be modelled directly into the part. Cutting a thread will always give a sharper definition so this is always recommended, but printing the thread directly gives you the flexibility to design custom threads and features. The thread only has the strength of the base material so we advise that it is used for low load and limited re-usability.
Helicoils – Low load & high re-usability: Thread repair Helicoils can be inserted into our materials creating a thread that has the re-usability of a metal but still retaining the strength of the substrate material. Ideal for low assembly forces where confidence in the thread’s reusability is required.
Threaded Inserts – High load & re-usability: There are a number of products that work in the category, all providing a reusable thread with significantly increased pull out force.
- Tapped: These inserts have a male thread on the outside and are tapped into the substrate material using conventional tools as mentioned above
- Self-tapping: External self-tapping threads allow these to be assembled to drilled holes
- Heat-staked: The combination of external knurling and assembly at temperature allows these inserts to be press fit into a hole and the substrate material flow around the knurl, giving superb pull out strength.
These inserts come in a number of material types (brass, steel, aluminium etc.), we have found and can recommend Tappex Inserts for use with our materials.
For a full range of Tappex inserts and design guides please get in touch with sales@graphite-am.co.uk
Compression Limiters: When thru bolting your assembly you need to ensure that the substrate is not over clamped and damaged. We can fit all types of compression limiters, from knurled press fit to spring so please get in touch with your requirements.
