Tooling issue in plastic part

[kevin1967]

I need to guidance from tooling experts on this. This is injection moulded plastic part in early design stage. I need to have two snaps and ribs as shown in the image. The snaps can't be pulled in die draw. Pl. share your ideas in pulling the snaps using lifter or slider. The issue is snap side walls can't be drafted and may require two lifters with a split line at the center of snaps. The outboard lifter has travel restrictions due to part geometry. Any suggestions ?

 

[MikeHalloran]

The teeth look a little deep, or their shanks are too short. I'm guessing they'll break on assembly, unless they're still hot from the mold. ... but that's a different issue.

I'm guessing you could pull a couple of angled slides to do the undercuts, maybe even without power. Or you could put slots under them and do the undercut surface from the other side, e.g. with a tang projecting from the mold.. but of course it would leave four slots in the (presumably finished) face that we don't see.

You need to take the drawing to the molder who is most likely to make the part, and seek _his_ advice, the sooner the better.



Mike Halloran
Pembroke Pines, FL, USA

 

[dgowans]

I second Mike's comment about seeking the advice of a molder and toolmaker. I would also suggest that by getting creative with the pull direction of the lifter needed you may still be able to have draft on the snap features without compromising the part design. You might need to relieve the surface that the snaps are protruding from to be able to accomplish this, but it might be possible. What might complicate this is the fact that you have two snaps in such close proximity.

On another note, is the top view truly looking along the line of draw? If so, it appears that the two through holes will have a parting line that walks around the inside of the hole, rather than being entirely on one side of the part. Is this your intent?