Overview

A simple model for testing multi material printing with PLA, PETG and TPU (or you own selection of filaments). The assembly contains interlocking parts and tiny or zero clearance sections designed to be printed with materials that don't stick to each other (PLA and PETG).

An explanation of this model can be found in this video:

Importing and slicing

Import the model as a 3MF to get everything in the right place. Alternatively, import the STL and split to objects.

Assign the materials as follows:

There is no need to turn on support materal. The smallest piece (labelled for PETG) will support the only floating region. Ignore any messages from the slicer about support being needed.

There are no other specific settings that are needed in the slicer.

Post Printing

The following is shown in the video above.

1. Inspect the TPU elbow and make sure it can bend without seperating.
2. Remove the small PETG support block. It should pull right off.
3. Try to toggle the slider. It is likely that due to the extremely tight clearances the junction will not move at this stage. Use a thin blade or other tool to slide between the junction surfaces. There is nothing to cut, you are just clearing any errant extrusions.
4. The slider should now move back and forth, albeit remaining very tight. This is by design and there should be zero wobble or play.

Reasons for failure

• If the TPU pulls free and separates from the PLA pieces either side, your printer may have a TPU feed issue where it is underextruding. The internal structure may be partially missing which weakens the junction.
• If the PETG support piece will not seperate, you may have your flow rate too high. There is a horizontal clearance of 0.2/0.25mm on the sides of this piece, so enough overextrusion to jam the piece in place would have to be dramatic.
• If the sliding junction refuses to budge, flow rate may again need tuning and pressure advance tuning may also assist in creating crisp right angled corners. The slider has a horizontal clearance of 0.1mm and a vertical clearance of 0mm. The joint will always be tight but should be moveable with some force.
• If you are printing through an AMS style system where the PLA and PETG parts are sharing one nozzle and the parts a very weak and brittle, this most likely means the two materials are contaminating with each other in the nozzle. Try increasing the flush volume multiplier to ensure the previous filament is cleared from the nozzle.

General tips for printing with multi material can be found in this video: