What is the Reason for the PCB Open and Short Circuit?

Why is the PCB open and short circuited? How can we improve in this situation?

PCB open and short circuit problems are encountered almost every day in PCB Bare Board Manufacturers, and such problems have always plagued production and quality management personnel. It caused replenishment, overdue delivery, and overdue delivery due to insufficient shipments. Customer complaints are more difficult for people in the industry to solve. We first summarize the main causes of PCB open circuit into the following aspects:

The reasons for the above phenomenon and the improvement methods are listed as follows:

Open circuit caused by exposed substrate:

1. There are scratches before the copper clad laminate enters the warehouse;

2. The copper clad laminate was scratched during the cutting process;

3. The copper clad laminate is scratched by the drill tip when drilling;

4. The copper clad laminate was scratched during the transfer process;

5. The copper foil on the surface was bumped due to improper operation when stacking the boards after copper sinking;

6. The copper foil on the surface of the production board is scratched when it passes through the leveling machine.

Improve methods:

1. IQC must conduct random inspections before the copper clad laminates enter the warehouse to check whether there are scratches and exposed substrates on the surface of the copper clad laminates. If any, contact the supplier in time and make appropriate treatments based on the actual situation.

2. The copper clad laminate is scratched during the cutting process, mainly because there are hard sharp objects on the cutting machine table. The friction between the copper clad laminate and the sharp objects during cutting causes the copper foil to scratch and expose the substrate. The countertop must be carefully cleaned before feeding to ensure that the countertop is smooth and free of hard and sharp objects.

3. The copper clad laminate was scratched by the drill nozzle during drilling. The main reason was that the spindle clamp nozzle was worn out, or there was debris in the clamp nozzle that was not cleaned, the PCB proofing could not grasp the drill nozzle firmly, and the drill nozzle did not reach the top. , Slightly longer than the set length of the drill tip, the height of the lifting is not enough when drilling, and the tip of the drill tip scratches the copper foil when the machine is moving, causing the phenomenon of exposed substrate.

a. The chuck can be replaced by the number of times recorded by the knife or according to the degree of wear of the chuck;

b. Clean the clamp nozzle regularly according to the operating regulations to ensure that there is no debris in the clamp nozzle.

4. The board is scratched during the transfer process:

a. The amount of the board lifted by the carrier at one time is too large and the weight is too large during the transportation. The board is not lifted when being transported, but dragged up, causing the board corners and the board surface to rub against the board surface;

b. Since the board was not placed neatly when the board was put down, the board was pushed hard in order to rearrange it, causing friction between the circuit board and the board and scratching the board surface.

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