Mold maker blowing smoke at me?

How big is the radius? The .015" flat will probably be strong enough if it
grows quickly. At the very least, it's a hell of an improvement over 0!

Jerry Steiger
Tripod Data Systems
"take the garbage out, dear"

 

The way you have it now - is correct. We always as a rule of thumb used 5
degrees. But when the shut off is not very tall, we made sure that there was
at least .005" angled gap when the shutoff steel was approaching each other
(when the "A" side" met the "B" side.) If we didn't have at least this much,
when the leader pins wore out and if the molding machine was wore out, there
is a chance that the steel will collide and as soon as that happens, the
steel will pickup/gall and you will have a spike of flash in that area
(unless you are running the poly carb or other thicker plastics.)

We actually called out in our mold specs to have this draft. Cheaper corner
cutting toolmakers or a proto-type moldmaker (that wants to be a production
mold maker) would put straight shut-offs (no angle at all, maybe a .001"
clearance) and the tool would run fine for the first shots and the tool
company would get paid. Then after the tool runs for a few thousands shots,
the straight shutoffs would gall and then the flash would start. You would
send the tool back and they would blame the flash on you somehow and you
would pay to fix it.

Anyway, the moral of the story is: always have angled shutoffs....

Dan Bovinich
22 years of moldmaking
www.swcad.com

 

Sporkman,

I looked again, and Black Dragon is correct on both points, eliminate
feather edge and insert the area. You may be able to put a lesser angle
shutoff (no less than .005" top-to-bottom angle) and maybe you can eliminate
the feather edge.

Good eyes Black Dragon....

Dan

 

On Wed, 2 Mar 2005 23:26:05 -0500, "Dan Bovinich" <dittodan-take

With the addition of straight P/L locks, you can get away with much
less than 5°.
We do a lot of extremely small close tolerance multi-cavity medical
molds that you'll never get 5° to work with.

Side Locks, X-Series, Guide Locks,Top Locks and Shuttle Lock sets all
have straight alignment.
My personal favorite is the Guide lock. The female locks can be custom
fitted to pockets that don't match exactly.

Malcontent