Re: Reg-Injection moulding

Feb 13, 2006 4 Replies

Bo,



I thought what you described was called compression molding!?!?



I always thought that 2-Stage clamping was simply the definition of the platens full motion, split up to 2 separate set of parameters. My understanding is this:



  1. The first stage was a high-speed, low pressure motion, using a mold protect feature, to get the mold to within a predetermined distance from fully closed. Its only function is to reduce processing time, essentially.
  2. Stage two was low speed, high pressure for applying clamping tonnage.

Am I wrong on this???


You could indeed say this is a "Hybrid Injection Compression" process.

I believe Arburg has this "coining" option available specifically for producing optical lenses, as I recall discussing this with the Arburg guys a couple years ago.

In lenses, you need to get away from miniscule flow lines and apparently a small amount of coining does the trick, to get better lenses.

I personally haven't molded these types of parts, though.

Bo

Seth,

That was my understanding too - but Bo's description also sounds possible although I've never seen/heard of it - but then again we've not done any tooling for lenses yet.

Kev

Seth Renigar wrote:

My boss and I quoted a mold that uses the exact process as Bo describes (didn't get it). It was not a lens though. I can't remember exactly what it was either. Anyway, the customer called it compression molding. That is where my information was derived from. I had never had any dealings with this process before myself. So I can't say for certain that Bo is in any way wrong either. I agree, it sounds plausible...

"Seth Renigar" wrote in message news:r_1If.20104$ snipped-for-privacy@tornado.southeast.rr.com...

I can't remember what it is called, but it isn't compression molding as I know it (used for molding rubber parts, where you put a slug of thermoset material in a mold, then close the mold over it, forcing the material into the mold shape, with lots of flash and often overflows). I think the process Bo described was developed for making CDs and DVDs.

That's my understanding as well, but I'm a plastic part designer, not a tool designer.

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

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