Designing 3D parts, for 3D Printing, Part 2-Threads.

Designing 3D parts for 3D Printing
Image depicting a 3D Printed thread. ©2017 3D Print N Scan Ltd.

Designing 3D parts for 3D Printing

In this latest Blog we will be discussing the production of 3D printed Polyjet Resin threads!
How these threads are produced, what they are used for, and the types of thread that can be produced!
The production of most products, are generally produced by the creation of an assembly, which is the combination of multiple parts, to produce the finished product.
Yes, we all hear! 3D Printers are able to produce complex parts in one go!
But in order to incorporate, for example a PCB (Printed Circuit Board) into the part, or another item that cannot be 3D Printed! You have to have a means of getting the non-printed component into the part.
This is done by means of a body and cover plate.
The speed at which 3D Printing is progressing, has now shown PCB’s can be 3D Printed, and there is a couple of machines on the market which will do this, but for most of us! especially in the production of prototypes, it is still not financially viable, unless you have the need to mass produce PCB’s, and PLA plastic is used unlike conventional fiberglass for the board.
So! How can a conventionally made PCB be incorporated into a product?
One possible solution would be to have hidden clips, so once all your components are in place a lid is pressed onto the body, sealing the components in for life! This is seen on most TV remote controls, as there is no need for the user! to have access to components they can’t fix, unless they are a trained microelectronics expert.
The battery compartment on the other hand, is periodically needed to be accessed, so the user can change old dead batteries for new ones!
But! I hear you say! You can use a molded spring clip on a cover plate, to retain a cover.
This is true, but maybe you as the designer, don’t want a spring clip to retain a cover! Perhaps the aesthetics of the product look better with a screw of two? Or maybe you wish to incorporate Tamper Proof Security Screws, so access is possible to change internal parts with ease.
So, the production of a thread, in a 3D Printed part, gives people the ability to maintain & replace internal parts.
First of all! What type and size of thread do you wish to produce?
All types of thread can be produced with 3D printing! But with Resin 3D Printing you are constrained by the droplet size!
As a standard we don’t suggest trying to print threads below M5 x 0.8, because the flat is at the minimum droplet size of 0.1mm.
To have a properly formed thread produced by resin 3D Printing alone, we suggest not going below M12 x 1.75mm, which has a 0.2mm flat.

Designing 3D parts for 3D Printing

Image depicting thread flat. ©2017 3D Print N Scan Ltd.
That said we have produced custom threads, with large diameters where the pitch is 0.8mm with a flat of 0.1mm successfully!
For this to be possible depends on the resolution you have set, when converting your CAD (Computer Aided Design) file to an STL file, and the material being used to 3D Print your part.
Due to the nature of 3D Printing with PolyJet resin, you will always have a matt finish!
This is because in order to produce any overhangs, support material needs to be laid down to support each subsequent layer built on top. Or you will get a lip wherever the print goes from Matt to Gloss, as shown in the below image.
Designing 3D parts for 3D Printing
Image depicting MATT & GLOSS finish. ©2017 3D Print N Scan Ltd.
For threads below M5 x 0.8mm, the easiest way to produce these, is to design the tapping hole into your design, which can easily be tapped out with a standard hand tap after printing.
With our PolyJet resin we can produce M2 x 0.4mm threaded holes, providing you can get at the hole with a tap!

Designing 3D parts for 3D Printing

If you wish to print a thread in one of your parts? Or you wish to discuss if a particular thread can be printed by us! Please get in touch to discuss your requirements!
Contact us via our contact page, or email us at info@3dprintnscan.co.uk