Hey Bill,
How many do you need?
The down and dirty molds I used to make were out of RTV but it doesn't sound
like that would work here.
Can't remember if I ever worked with 2651-40.
What's the working life of the stuff?
Prone to entrapped volatiles?
Do you specify the material or are you building to drawing. If you could
change the catalyst (assuming an alternative exists) then you could shorten
your cycle time to 20 - 30 minutes.
What kind of shrinkage do you see during cure?
<Stating the obvious>
We'd route bare laminate into the ring shape a couple of times. (Ah, the
advantages of a turn key shop.)
Caulk the compound into the mold. (With or without a top cover.)
If it's low volume you could get away with a Dremel or razor blade touch up.
We tried injection molding on some stuff but it caused more trouble with
entrapped air.
Hans
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
Process Engineer
Toppan Electronics, Inc.
770 Miramar Road
San Diego, CA 92126
(858) 695 - 2222 ext. 241
(858) 695 - 6823 fax
[log in to unmask]
-----Original Message-----
From: Kasprzak, Bill (sys) USX [mailto:[log in to unmask]]
Sent: Monday, July 16, 2001 8:51 AM
To: [log in to unmask]
Subject: [TN] Recommendations for developing a mold
Hello all,
I am involved with a project that requires that I encapsulate a pc board in
mold so that when completed, it will be a ring with an ID of 1.37" and an OD
of 1.64". The ring will be .13" thick and .35" tall. There will be six, 28
AWG wires exiting the finished potted assembly. The potting compound will be
Emerson & Cumings 2651-40 with Catalyst 11.
I have a basic 3 piece mold that works OK, but the pieces only
reflect what the final product should look like. It takes a little work to
get the mold apart even though mold release is used. The cure for the
potting is 8 - 16 hours at 180 deg F
What I'm looking for is any tricks and hints that should be incorporated
into the mold design that would facilitate easy processing. What I mean is
to make it easier to pour the material, easy to assemble into the mold, easy
to take apart, etc. etc. Right now the whole process just seems to be crude
and messy. Maybe, that's just the nature of the beast.
Any and all responses appreciated. Thanks.
Bill Kasprzak
Moog Inc., Electronic Assembly Engineering
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