Browse Prior Art Database

High-Speed Opens And Shorts Substrate Tester

IP.com Disclosure Number: IPCOM000120584D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 9 page(s) / 520K

Publishing Venue

IBM

Related People

Bird, K: AUTHOR [+8]

Abstract

Described is an assembly of custom-designed ceramic substrate handlers and fixtures which are combined with commercial devices to test substrates for electrical opens and shorts at a high speed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 17% of the total text.

High-Speed Opens And Shorts Substrate Tester

      Described is an assembly of custom-designed ceramic
substrate handlers and fixtures which are combined with commercial
devices to test substrates for electrical opens and shorts at a high
speed.

      In prior art, the testing of substrates for opens and shorts,
as used in circuit boards and cards, required manual loading and
unloading one part at a time and test probes were positioned
manually.  The concept described herein eliminates the prior-art
manual effort and provides automatic handling and testing operations
of the substrates. This not only speeds the testing operations, but
improves the reliability of the tests.  The five figures show the
various functional mechanisms which make up the assembly. Fig. 1
shows the overall substrate tester.  Fig. 2 shows an exploded view of
the first section of the tester and Fig. 3 shows an exploded view
(section A-A of Fig. 2) of typical probe testing station 16.  Fig. 4
shows an exploded view of the output handler and Fig. 5 shows the
details of the transfer mechanisms.

      The overall substrate tester, as shown in Fig. 1, includes
input handler 1, which comprises of two input elevator drawers 4,
input robot 2, and input conveyor belt 3, also shown in Fig. 2.  To
load parts, the operator slides out drawer 4 enabling wire basket 5,
which is full of trays, to be loaded into the inside section of
drawer 4.  Wire basket 5 can hold up to ten trays and each tray can
hold up to twenty-five substrates.  An empty wire basket 5 is loaded
into the outside section of drawer 4.  Once the loading operation is
completed, the operator slides drawer 4 back into the machine and
repeats the loading operation with the other drawer.  The input of
the tester has now been loaded with a maximum of 500 substrates.

      Handler control computer 6 operates under software control from
sensors when input drawers 4 are closed. Handler control computer 6
turns on a pair of solenoids (not shown) which pressurizes two pairs
of cylinders (not shown) which move up through closed drawers 4 and
lifts up two full stacks of trays from wire basket 5.  The stack of
trays are stopped by a set of tray clamping fingers (not shown) above
each drawer 4.  In this way the top tray of substrates is accurately
positioned against a top surface as well as in the X/Y plane for
robotic loading into the rest of the tester.

      Input robot 2 picks five substrates at a time from the tray and
places them into pockets of input conveyor belt 3. Belt 3 is indexed
forward until a substrate is sensed by a sensor located at shuttle 10
(Figs. 1 and 2).  Input conveyor belt 3 then waits for shuttle 10 to
"rake" the substrate off input conveyor belt 3 and into a mid-tool
shuttle track (not shown).  After input conveyor belt 3 has indexed
five times, input robot 2 will do another pick-and-place cycle.
After five pick-and-place cycles, the top tray in drawer 4 will be
empty...