Rubber injection molding questions
Rubber injection molding questions
(OP)
Currently I run a six hundred ton rubber injection molding press. Mold has six cavities.
How do I go about calculating the tonnage required for a given mold with rubber? Is it the same "projected area" calculation that thermoplastic molding uses? Or are there additional factors I need to be aware of.
Ultimate goal is to refurbish some of our "expired" cavities by re-plating them, re-polishing them and building a new frame to house them. We do not want another 600 ton press, we are thinking 200 or 400 ton.
Ideal situation would be to find out 1 cavity = 100 tons for our application because then we could acquire a new press on the cheap.
How do I go about calculating the tonnage required for a given mold with rubber? Is it the same "projected area" calculation that thermoplastic molding uses? Or are there additional factors I need to be aware of.
Ultimate goal is to refurbish some of our "expired" cavities by re-plating them, re-polishing them and building a new frame to house them. We do not want another 600 ton press, we are thinking 200 or 400 ton.
Ideal situation would be to find out 1 cavity = 100 tons for our application because then we could acquire a new press on the cheap.
----
BFL Dreamworks
"If we don't have an answer we'll get one"





RE: Rubber injection molding questions
I've always used the area at the parting line, which seems to work. We've never independently verified the internal mold pressure, though.
RE: Rubber injection molding questions
Thank you for your help. I suppose if it works it works, eh? :D
I tracked down a few good books on the subject, we'll see what they say.
----
BFL Dreamworks
"If we don't have an answer we'll get one"
RE: Rubber injection molding questions
Let me know what the book says, it's one of those questions I've asked several different rubber mold shops, and can't get a firm answer. I can see where for transfer and compression molds the answer is only pertinent to the mold designer (me); but for injection molding it would start to affect enough different pieces of equipment that it would become important...
RE: Rubber injection molding questions
*laugh*
Seriously it's always great to learn new skills, I'm having a ball. So long as the scrap stays below .5 percent I'm free to experiment.
----
BFL Dreamworks
"If we don't have an answer we'll get one"
RE: Rubber injection molding questions