ABS molded housing snap fits--side action or bump-offs?

[jbendercp]

Realise this is probably a poor question due to variables (part geometry, intended use). However, trying to design an ABS-plastic injection-molded part and need the two halves of the housing to snap together. As such, been pulling apart every cheap ABS injection-molded part in my house: old phones, cameras, the AC unit controller, and they all see to use cantilevers with undercut (hole) on the moving half, and the peg/hook/"bump" on the fixed half.

Given prevalence & price-point of some of these parts, beginning to wonder if this type of design can be done without use of side action. Tried looking up some guidelines (I'm looking somewhere in the ballpark of a 1/16" wall-thickness ABS part) but haven't been able to get a feel for whether this is doable (as a bump-off) or not.

Not adverse to doing side-action if necessary, but goal is to create an assembly of parts which are all formed from single piece of tooling (like say, a scale model airplane kit) thus would require side action on multiple parts, so trying to avoid this if possible.

My first foray into injection molding, so sorry if this is grossly over-simplified or ignorant. Have tried reading up using various guides (Protomold, etc) but having trouble with this last hurdle.

 

[kjoiner]

Hello,

Depending on how you want the outside of the part to look, it is possible to create undercuts without side actions. Take your hook for example, it is rising out of the floor of your part. If you cut a "window" through the floor then allow a shutoff or blade to come up through the window, it can form the underside of the hook. You will see the rectangular cutout from the outside of the part, but avoid the use of side actions. The window can also function as an access hole for a tool that can be used to unhook the snap so the two halves of your box can be disassembled. Hopefully my verbage is clear I realize a picture would be better.

Kyle

 

[jbendercp]

Kyle--Thanks, I'm familiar with the technique you're talking about. I'll have to see if I it works in the design, as it seems to be a straightforward way to eliminate side actions. Still specifically curious about the cantilever w/ undercut (hole) and fixed hook technique that seems to be utilized on every housing I come across. Are these typically done with side actions? --J