multi cavity moulds
multi cavity moulds
(OP)
We have a new product consisting of 20 different components of various sizes. We wanted to produce individual moulds with 4 cavities but it turns out they are more expensive than we though. We have a quote for making 2 family moulds but we are afraid it will not work irrespectively of the toolmaker assurance. Any good ideas of how to bypass this problem and test all components effectively handling also low production demands?






RE: multi cavity moulds
Consider starting with single- cavity soft molds, e.g., aluminum,
OR with single cavities sunk in mold bases big enough for four cavities. Add cavities as production ramps up, after the part design stabilizes.
Mike Halloran
Pembroke Pines, FL, USA
RE: multi cavity moulds
How I agree with Mike!!
As a moulder, we do not use "family" moulds - I tell our customers who have these bright ideas that it is more accurately called a "dysfunctional family" tool.
If the customer insists, then they are welcome to find some other moulder who is willing to waste time and money!
btw - never believe a toolmaker!! - talk to the moulder (or should that be "molder"?!)
Rgds
Harry
RE: multi cavity moulds
http://www.beaumontinc.com/news/pr/05-03.html
Dave
RE: multi cavity moulds
Also an excess of rejects on one cavity only gives an excess of other parts.
Family moulds work very well on mirror images where an otherwise identical left and right hand part are required.
They are especially problematic where there is a considerable variation in part weight, flow length or section thickness between the cavities.
10 parts in each family mould sounds like a horror story to me. About 7 moulds with about 3 parts each or 5 moulds with 4 parts each sounds maybe doable, depending on part geometry.
Please discuss this in detail with your moulder and the raw materials supplier rather than a toolmaker or at least in addition to the toolmaker. Toolmaking is a highly skilled profession, but does not necessarily indicate a good understanding of the entire moulding process.
Talk to each together to get a consensus, but also individually to get a more frank opinion of each others input. Remember the others all have overlapping relationships on other projects as well as yours.
Regards
eng-tips, by professional engineers for professional engineers
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RE: multi cavity moulds
I thought of adding flow restrictors/valves (if there are such things) so that in the worst case senario by which the flow can not be balanced, we can at least produce the parts individually for further tests and sampling. Is this possible, or would the problems still exist?
RE: multi cavity moulds
There is more than just balancing the flow. That can be done by tuning gate size. For example, different fill speeds, different pack conditions to control size, finish warping etc can also be problems.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: multi cavity moulds
RE: multi cavity moulds
Regards
RE: multi cavity moulds
Bite the bullet, buy multi cavity individual dies.
The days of hit and miss with tooling are gone with the latest Cad/Cam software around these days, you can get very good quality and workable dies requiring little mods if they don't mould exactly right from word go.
Good luck with it anyway.
RE: multi cavity moulds