3D Printed 7mm Scale Gearbox

Thermochromic PLA Gearbox

This was an idea we had as we had some thermochromic PLA at hand. The thermochromic PLA changes colour with an change in temperature. In this case the PLA changes from a dark green to a yellow/green when it is warmed above 32 degrees C. The lefthand image shows the gearbox at room temperature and the righthand image shows an increase in temperature around one of the gearbox bearings, by a change in colour, this change could be due to the bearing running hot for some reason.

 

It should be noted that the bearing in the righthand image was artifically heated to show what would happen if the bearing was to get hot.

7mm Scale prototype Gearbox

This is the prototype gearbox and motor adaptors, as supplied to the customer for testing, for a commissioned production run of 40-off.

 

The main gearbox case is 3D printed and is fitted with single row radial ball bearings and the box like tube design adds rigidity to the case. The motor adaptor plates are laser cut from 3mm acrylic sheet. The gears are ones supplied by the customer who commissioned the gearbox and uses a combination of crossed helicals and spur gears. This also makes the gearbox, depending on the motor fitted, reversable. The gearbox also needed to be able to accept four different motors, so the adaptor plates have been designed so these four motors can be fitted to the gearbox using the same standard fitting for all.

Using a combination of both 3D printing and laser cutting to produce this gearbox has made it much easier to design, prototype and produce the 40-off required.

7mm Scale production Gearbox

The final product will be finished using both black PLA and black Acrylic sheet.