Bonding multimaterials

[thorsenrune 11]

Hi, with our UM5 I work on composite models being partially tough pla partially rubber TPU95.

I try to figure out what is the most efficent and strongest method to make the PLA area bond with TPU area on the same print. Anybody having experiences?

 

[Dim3nsioneer 557]

If you can, change one of the materials. The second table on this page shows you compatible materials. As you can see, PLA and TPU is not a supported combination.

ABS/TPU or PC/TPU should work quite well.

[geert_2 558]

Also try using mechanically interlocking features. Since this is highly recommended for injection moulding in overmoulding, according to the manuals, I think it also applies for 3D-printing. At least, it shouldn't hurt.

 

Think of a dovetail system, or hooks, or chains that interlock. Think of these concepts, but then all melted and squeezed into one solid block.

 

Have a look at how it is done in tooth brushes: most of them also have overmoulding with interlocking features.

 

[thorsenrune 11]

Thanks, great info.

[thorsenrune 11]

I did some tests and this is what I found:

Testpiece

https://cad.onshape.com/documents/d2d908babdc85d50637f9646/w/52297ecc71401cbb8aa29987/e/809910c19b9456f702a47d12

 

Center is TPU and the frame is TOUGH

The test is to see if some anchoring will improve adhesion

Conclusion. 

Use overlap between different materials and let the slicer do the stitching job.

Experiment 3

Half overlap and stitching results in a strong interface between TPU and PLA

link

1 Hour print