I'm looking for ideas on how to obtain undercuts on the A side of an existing mold. I would like to add some sort of "mushroom" features that would key into a slot on the mating part to hold them together. The part is approximately 18" square and I would like to add 4 such features at the perimeter of the part. If you have any ideas on how this could be done, I'd like to hear about it.

Thanks,
Matt Sommerfield

You could do this by floating either the
a or b plates. While they float you will
need mechanical action to pull the slides/
lifers or what ever is forming the undercuts.
This action is tied into a stationary plate.

Also hydraulic cylinders are an option

I think a collapsing core may work for you. Check our a company called Roeher in Hudson, MA. DME also has some of these on their website.

If you can stand a hole in the part, you can undercut the cavity with an angled shutoff going back to the part. How much undercut depends on how much taper in the wall. Once you have the shutoff, you can add molding on the top portion of the shutoff, to achieve a straight draw. Just a thought.