RE: [rp-ml] Prototyping: Conductive Rubber Switchpads on the west coast?

From: Carl Dekker (
Date: Wed Mar 02 2005 - 16:55:30 EET

This can be done in a few ways.
As you may already know, they can be installed in the prototype after
the build is completed. The problem with this is the material options
are limited.
Another way would be to make a cast tool (Silicone, Urethane, etc) then
place the pieces in their respective location and fill the cavity. This
can yield a nice part in respect to material and finish. Drawbacks are
that a pattern must be created, finished, and a tool made resulting in
more time and cost. Additionally, should the pieces move in the casting
process the parts is lost and removing the pads could damage them.
And another is to make a tool off of the CAD data where the pads can be
inserted and a casting done to encapsulate them. The tools are hard to
finish but the lead time is shorter and the total investment may be
Should you consider one of the casting processes, you will need to
determine a way to hold the pads in place. Sometimes a simple vacuum
lock caused when the pads are inserted after a release agent is applied
is enough. This will probably be one of the more difficult aspects to
resolve in your application.
Good luck. I hope this helps,
Carl Dekker
Met-l-flo Inc.


From: [] On
Behalf Of Alex Do
Sent: Tuesday, March 01, 2005 7:02 PM
Subject: [rp-ml] Prototyping: Conductive Rubber Switchpads on the west

For any of you prototyping bureaus out there, as part of a full product
prototyping process (I'm talking PCB and everything) do you ever find
the need to get low volume conductive rubber switchpads?
These are the rubber buttons with the black dots inside that when
depressed against a contact area on PCB shorts a connection - pretty
standard for remote controls, cell phones, cordless phones, etc. I do
"product prototyping" (in quotations because it's on an academic level)
and rather than making FDM buttons I'd like to emulate the look, feel,
and operation of a real device where conductive rubber switchpads are
well applied. Plus it makes the PCB prototyping fairly simple.
Alexander Do
Research Assistant
Ford Prototyping Studio
University of California, Berkeley <>
2117 Etcheverry Hall
Berkeley, CA 94720-1750
(510) 643 9486

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