Minimizing PCBA Flex
Standard vacuum and pneumatic fixtures can subject the unit under test (UUT) to damaging stress levels if the fixture is not constructed properly. As an example, a test fixture with three thousand 8-ounce spring contacts will push against the board with as much as 1500 pounds of force; Push fingers or vacuum pressure can place additional forces on the board. This may sound like a huge amount of force, but it will actually not harm the UUT in any way, as long as the forces are applied and counterbalanced properly.
Board Stress Analysis (BSA)
BSA has been a useful tool for designers and fixture manufacturers for more than a decade. This tool has allowed designers to minimize induced stresses on the printed circuit board (PCB) under test, and all but eliminate the potential for damage. Board Stress Analysis (BSA) allows for a simulation to be performed before the unit-under-test (UUT) is subjected to potentially damaging forces. Further, once the simulation is run, push fingers, board supports and even probes can be repositioned to reduce flexing and lower stresses placed on the UUT. Typically, the BSA is rerun in an iterative process that successively betters the fixture design until the desired result is achieved.
  • BSA FAQs
  • BSA sample report
  • BSA Article- Adding 3D analysis
  • BSA Article How do you Gage your Test Fixture
Minimizing PCBA Flex with SmartFiles
ECT has invested in the development and implementation of automated software that we use when designing test fixture. Using your CAD data and AVL BOM, we create a virtual PCBA in our computer-aided-fixturing (CAF) software. Our automation software evaluates the quantity, spring-force and location of all test points, locks out all the component areas based on the actual part and pad dimensions, and places the correct quantity of push fingers and hard stops in the best locations to minimize PCBA flex, avoiding any interference with components. It alerts the operator to areas with unacceptable board stress levels so that actions can be taken to reduce the flex in these areas(lower spring force probes, manually add custom fingers or BGA support blocks, etc…)
Strain Gage Testing
Strain gage has become a standard requirement for many PCBA designs. ECT can perform this quality assurance test at any of our global facilities.
  • Defining Strain gage
  • Sample Strain gage Test
  • Strain gage Test Guidelines