Qualitative Layer Adhesion Test

This is a qualitative layer adhesion test. 

If your trying  to get the best layer adhesion in your prints, you can use this model to look at the failure mode of your layers. Ideally, you are looking for a cohesive failure where the part doesn't break evenly along a layer line. 

You can find a more detailed description on my website, bcarvercreatives.com 

Print Instructions: 

Snapper: You will need two of these. 

Print at 100% infill.

No supports needed, but you will need to cut away a little drooping inside the cavity. you could also use tree supports if desired. 

Print laying flat. Note only one side of the model will let the round handle rest on the print bed. 

Cylinder: 

Print standing on end so that the layer lines are being stressed when you break the cylinder. 

Try tweaking your settings and compare the fracture surface for different settings 

Use: 

 1) Hold one snapper in each hand 

2) slide the cylinder into each snapper until it is pressed up against the internal wall of the snapper. make sure the z seam is facing upward. If it is facing away from or toward you, it will be experiencing the peak stress and have more influence on your results. 

3) place you thumbs on the flats of he snapper (as seen in the photo) 

4) press away from you until the part snaps. For best results, try and be consistent with the rate you apply pressure.  

5) Examine the fracture surface. The photo of the part in my hand is a example of a fairly poor fracture mode (adhesive failure). The part standing on its own is a example of cohesive failure, which implies much better layer adhesion 

Have fun getting strong prints without a expensive Universal Testing Machine!

I will be releasing some of my research on how to improve layer adhesion, like seen in the photo, in the next few days.