Rigid Pin Fixture also called Tilt Probe Fixtures

Rigid pin fixtures are test fixtures allowing to contact very find pitch structures on the PCBs!

The underlying technology is used since years in the wafer or bare pcb test. Between the DUT with very small structures/testpoint distances and the 'base grid' containing standard-sized pogo-pins a rigid pin cassette is introduced. This cassette contains tilt / rigid (wire-only) pins which translate between the fine pitch on DUT size and the pogo-pins in the base grid.

This allows to contact fine-pitch test points with a very high probing accuracy using 'normal' spring forces.  

Pros:

• very high probing accuracy
• allows higher spring forces than ordinary fine pitch pogo-pins
• reliable as only spring loaded probes/pogo pins with large sizes (typically 100mil) are used
• more cost effective compared to a 'normal' interface with a large number of fine-pitch probes

Cons:

• Higher test fixture due to the additional rigid pin cassette
• High complexity to calculate the optimum positions of the rigid pins (containing enough clearances to prevent short circuits)
• Additional electrical contact between the rigid pin and the pogo-pin in the base-grid
• Requires a lot of know-how and experience to choose the best materials and foresee optimum clearance between the rigid probes and the guiding plates in the cassette
• Not each topology can be contacted with rigid pins. If there are zones with a very high density of fine-pitch probes the grid can't be widened enough
• In zones with a high density of rigid pins, a very high force might be applied by the probes to the PCB. This force needs to be compensated by pushers on the opposite side of the PCB

Using our own rigid pin software we can assign the optimum positions of the rigid pins in the cassette and output the drill files for the plates as well as converting the PCB data to allow a 'normal' generation of a test program where the 3070 software will generate the drill and wiring files of the base grid (fixture).