PCB Flying Probe Testing Technology (1)

When talking about PCB Flying Probe Test, what is Flying Probe Test? Flying probe test is one of the methods to check the electrical function of PCB (open and short circuit test). A flight tester is a system for testing PCBs in a manufacturing environment. Instead of using all the traditional bed-of-nails interfaces found on traditional in-circuit test machines, flying probe testing uses four to eight independently controlled probes that move to the component under test. The unit under test (UUT) is transported into the testing machine by means of a belt or other UUT conveying system. Then fixed, the probes of the tester contact the test pads and vias to test the individual components of the unit under test (UUT). Test probes are connected to drivers (signal generators, power supplies, etc.) and sensors (digital multimeters, frequency counters, etc.) through a multiplexing system to test components on the UUT. While one element is being tested, other elements on the UUT are electrically shielded by the prober to prevent reading interference.

The steps of making the flying probe test program:

Method One

1: Import the layer file, check, arrange, align, etc., and then rename the two outer layers to fronrear. Rename the inner layer to ily02, ily03, ily04neg (if it is a negative film), rear, rearmneg.

2: Add three layers, copy the two solder mask layers and the drilling layer respectively to the added three layers, and change the names to fronmneg, rearmneg, mehole. Those with blind buried holes can be named met01-02.,met02- 05, met05-06, etc.

3: Change the two layers of the copied fronmneg and rearmneg to the round of 8mil. We call fronmneg the front layer test point and rearmneg the back test point.

4: Delete the NPTH hole, find the via hole according to the circuit, and define the unmeasured hole.

5: Change fron and mehole as the reference layer, change the fronmneg layer to on, and check to see if the test points are all at the window opening of the front layer circuit. Test points in holes larger than 100 mil should be moved to the solder ring for testing. The test points at the BGA that are too dense should be misplaced. Some redundant intermediate test points can be appropriately deleted. The back layer operates the same.

6: Copy the sorted test point fronmneg to the fron layer, and copy the rearmneg to the rear layer.

7: Activate all layers and move to 10,10mm.

8: The output gerber files are named fron, ily02, ily03, ily04neg, ilyo5neg, rear, fronmneg, rearmneg, mehole, met01-02, met02-09, met09-met10 layers.

Then use Ediapv software.

1: Import all gerber files such as fron, ily02, ily03, ily04neg, ilyo5neg, rear, fronnmneg, rearmneg, mehole, met01-02, met02-09, met09-met10 layers.

2: Generative network. Net annotation of artwork button.

3: Generate the test file. Make test programs button, enter the D code of the test hole.

4: Save.

5:Set the reference point and done. Then take it to the flying probe machine and test it.

A. Using this method to make test files often make many test points, and the intermediate points cannot be automatically deleted.

B. The test of the hole is not well grasped. Looking at the generated connectivity (open circuit) test points in ediapv, there are no test points for individual holes. Another example, there is a line on one side of the hole, but there is no line on the other side. It is reasonable to test the hole on the side without the line. However, the test points generated by ediapv conversion are random.

C. If there is no window for the REAR surface solder mask, the name of the REAR layer can be named as another name, so that the measurement point will not be inexplicably run out of the EDIAPV.

4. If there is a MEHOLE with only one window on both sides, but there are test points on both sides, you can press the make test programs button again. It should be noted that the cursor can be placed above the MEHOLE layer. In this way, the measuring points on the holes without windows for solder mask can be deleted.

5. The names of the above layers must not be wrong, otherwise you will be in trouble later.