Macaos Gallery 1.4 (August 2016)

"Bed of Nails" test fixture creation

A "bed of nails" test jig is used for in-circuit testing of a PCB with components. Typically, the jig consists of a bottom fixture with many spring-loaded test pins (pogopins) that are placed to make contact with test points on the PCB. An upper fixture presses the board onto the bed of nails so that all of the pins make good contact. A test program may then be run to confirm the operation of the PCB.

A test fixture is a plastic plate with holes drilled at each of the test point positions. Each test point hole will have a base (or receptacle) mounted in it. For each receptacle diameter, a spring-loaded pin head is inserted. You may choose from several different pin head styles, depending on the type of test point the pin will contact.

Test fixture creator module

Open a PCB product in the test fixture creator module and specify the parameters of the fixture plate. Then click on holes to place alignment pins, and click on holes or pads to place test pins. Once all pins have been placed, adjust the position of the press point and then center the PCB under the press point. The published test fixture product includes a drill file for the fixture plate and wiring list documentation.

Top side fixture

Ideally, all of the test points should be on the bottom side of the PCB. However, if necessary, a top side fixture may also be created. If a test fixture already exists for a PCB, then you may choose to use that fixture to specify the placement of the PCB in the new fixture.

Test accessories

Test jigs, test pins and related accessories available for purchase from buy.macaos.com.

Viewer improvements

Lock cursor to axis

Press Alt+X or Alt-Y to lock the cursor position to the current X or Y coordinate. Press Esc to release the lock.