I had a lot of trial and error and wanted to share my findings
Step 1: First Print
I wanted to create a simple dove tail snap to connect pieces to one and other. PLA doesn't do well with shear stress and they kept shearing right off.
Step 2: Re-design
The simple snap in step one kept shearing off. So I then added extra material to the cross sectional area as shown in my part file. You can see the difference between the thin and thicker snaps.
Step 3: Something in Between
I also tried something that added to the cross sectional area but wasn't as clunky. This can see as the snap on top in the photo.
Step 4: Printing the Changes
I then used a type A machine to do the prints. I did the two new snaps side by side to see how they compared.
Step 5: Other Design Change
I added a chamfer to the other side if the snap. This allowed for it to slowly deform and stretch. Without it the snaps were shearing off. It made the process more gradual when attaching.
Side note: I put 0.25mm clearance between the snaps to give room for shrinkage, etc. for the plastic.
Step 6: Final Design
Through all my trials and tribulations I got a nice snap fit that allowed my parts to click snuggly together with out breaking off.
I hope all of this helps. It was all done at the TechShop. Their website is TechShop.ws