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Our fixtures are generally built from a
part locating base of machined delrin or baltic birch plywood, depending
on the application and what will be attached to them. Other materials
can be used as necessary. In cases where exceptional durability and/or
significant amounts of concealed wiring are required, aluminum plate,
channel and square/rectangular tubing may be used. Test
fixtures are preferably mounted on a steel chassis box with electrical
connector access or connector-specific openings machined into the box.
Clamping and pre-tensioning is accomplished
with components including spring steel fingers, spring pins and toggle
clamps.
If pogo (miniature spring-loaded) pins
are being used for contact points on test fixtures, they are held in dedicated
receptacles made by the same manufacturer and we strongly recommend designing
a pc board to mate with the pogo receptacles (CAD information is provided)
and to hold any I/O connectors. Loose point-to-point wiring can be used
but such a fixture will be much less durable and probe replacement is
more difficult. If at all possible, center spacing for probe points should
not be less than .039" (1mm).
Fixture cost and lead time are a function
of fixture complexity and durability requirements; fixtures intended for
lab use need less durability features than fixtures intended for use by
skilled workers on the production floor, which in turn require less durability
than fixtures intended to be used with overseas manufacturing. For overseas
use we recommend easily replaced probe subassemblies designed for service
by semi-skilled personnel.
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