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Smt pcb assembly unevenness of the whole substrate mounting reason and the solution

1,407 Published by FASTPCBA 10月 22,2019

Smt pcb assembly unevenness of the whole substrate mounting reason and the solution

 

 1.Reason: The BOC mark is not used. In this case, the placement accuracy of each substrate has a non-uniform tendency.

Action: Use the BOC mark. Template matching function is used, when there is no BDC mark on the substrate

2.Reason: The BOC mark is dirty. In this case, the mountingaccuracy of each substrate has a tendency to be inconsistent.

Action: Clean the BOC mark. Also, take appropriate measures to avoid soiling the “BOC mark

 

3.Cause: the “substrate thickness” of the “substrate data” is inputincorrectly . In this case, looseness occurs in the up and down direction, and the substrate moves in the XYZ direction during production. In addition, the mountingelement is detached in the middle of the Z-axis drop.

Confirm and correct the “substrate height” and “substrate thickness” of “substrate data”

 

4.Reason: the support pin is not properly set. Componentsoffset occurs on thin substrates or large substrates

Action: Reset the support pins. In particular, it is important to focus on the support pins of components with high mounting accuracy requirements.

 

5.Cause: The gap between the reference pin and the substrate positioning hole is large, and the substrate moves due to vibration during production.

The measure uses a reference pin that is consistent with the substrate positioning hole. Or change the positioning method to “appearance reference”

 

6.Reason: Due to the fast descending speed of the support table, themounted componentshave been moved when the substrate is clamped off.

Action: In “Setting Group” / “Base Transfer” of “Machine Settings”, set “Descent Acceleration” to “Medium” or “Low”

 

7.Reason: The flatness of the substrate surface is poor.

Action: Rethink the substrate itself. In addition, adjusting the support pin configuration sometimes has some effect

 

8.Cause: The filter on the head of the placementor the air hose is clogged. In this case, when vacuum damage occurs during the smtprocess, the residual vacuum pressure will suck the component up.

Action: Implement “self-calibration” “setting group” / “vacuum calibration. If there is no improvement, replace the filter head or air hose of the placement head.

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