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66 The PCB Magazine • April 2015 is a very safe way to minimize the possibility of damage to the wire-bond. Figure 5 shows how easily a wire-bond pad can be damaged. Witness marks are inevitable during electri- cal test in some form or another. Surface finish- es are also an important factor. In today's man- ufacturing arena, the older mindsets of "one setting fits all" for the electrical test machines cannot be used. In many cases the machines, both flying probe and grid test machines, may require adjustments depending on the surface finish. It may not be as critical for compression values when testing the harder finishes such as HASL but when testing the delicate finishes, ex- treme care must be exercised or costly and un- necessary rework may have to be done to the PCBs; in extreme cases, the PCB may have to be scrapped which causes delivery delays, rebuilds and unhappy customers! See you next month and keep reading and Testing Todd! (Your questions are welcome!) PCB Todd kolmodin is the vice president of quality for Gardien Services uSa, and an expert in electrical test and reliability issues. Figure 5: wire-bond damage. realtimewith.com CliCk To View vIDeo IntervIew The HDP user Group engages in a variety of cooperative re- search projects that benefit the industry. I-Connect007 Guest editor Dick Crowe speaks with Facilitator John Davignon, who explains the objectives of the Smooth Copper Signal Integrity project, and invites interested parties to participate John Davignon Discusses HDPUG by Real Time with... IPC APEX EXPO 2015 testIng toDD ELECTRICAL TEST: SURFACE FINISH VS. WATER MARKS continues