Causes and solutions of SMT placement offset

2022-05-07 20

1. What are the causes and solutions for the offset of the whole substrate?


Cause measures

① The X and Y coordinates of "Patch Data" are input incorrectly. ① Reset "Patch Data" (confirm CAD coordinates or re-teach, etc.).

② The position of BOC mark is offset or dirty. Especially when it is dirty, the tendency of patch deviation is very likely to be unfixed. ② Confirm and reset BOC mark. In addition, appropriate measures should be taken to avoid fouling BOC marks.

③ When making data, teach the patch coordinates without BOC calibration. ③ After making the "substrate data", be sure to implement "BOC calibration", and then teach the "patch data".

④ When using CAD data, there is an error in the patch coordinates of CAD data or the coordinates of BOC mark. ④ Confirm the CAD data, and if there is an error, re-teach all the patch data. Among them, when the whole is biased towards a fixed direction, the BOC coordinates of the substrate data are moved (for example, when the X direction is offset by 0.1mm, the X coordinates of all BOC marks are reduced by 0.1mm) to correct the offset.

2. What are the causes and solutions for the offset of the substrate?


Cause measures

① The X and Y coordinates of "Patch Data" are input incorrectly. ① Reset "Patch Data" (confirm CAD coordinates or re-teach, etc.).

② When using CAD data, there are errors in CAD patch coordinates or part of BOC marks. If the coordinates of BOC mark in a certain place move, the offset of patches around it will increase. ② Confirm the CAD data, and when there is an error, reset the patch coordinates or BOC mark coordinates of this part.

③ BOC mark is dirty. ③ Clean BOC mark. In addition, appropriate measures should be taken to avoid fouling BOC marks.

④ The input of "substrate thickness" in "substrate data" is wrong. In this case, due to the looseness of the substrate in the up-down direction, the patch may sometimes shift in a certain area. Patch offset is usually uneven. ④ Confirm and correct "substrate height" and "substrate thickness" of "substrate data".

⑤ Poor setting of support pin. When the substrate is thin or large, it is easy to offset the patch. ⑤ Mainly set the support pin under the part where the patch is offset.

⑥ Because of the fast descending speed of the support table, when the clamping of the substrate is released, a part of the components that have been pasted will move. ⑥ Set "Setting Group"/"Substrate Transfer" in "Machine Settings" to "Medium" or "Low"

⑦ The flatness of the substrate surface is poor. ⑦ The substrate itself needs to be reconsidered. In addition, by adjusting the configuration of support pins, some effects can sometimes be achieved.



3. What are the causes and solutions for the offset of specific components?


Cause measures

① The "laser height" of the "expansion" of "component data" or the selection of suction nozzle is wrong. ① Stabilize the component and set the centering height to the laser height. In addition, stabilize the suction nozzle that the suction nozzle can suck.

② The setting of "Patch Pressing Amount" in "Additional Information" of "Component Data" is wrong. ② Re-set the appropriate "patch pressing amount".

③ The position of IC mark is offset or dirty. ③ Reset the IC mark coordinates (in case of teaching, the coordinates must be confirmed).

④ Poor setting of support pins. When the substrate is thin or large, it is easy to offset the patch. Usually, the patch offset occurs in a certain area. ④ Reset the support pin. Especially under the components with offset of the patch.

⑤ Because of the fast descending speed of the support table, when the clamping of the substrate is released, a part of the components that have been pasted will move. Especially when the adhesive force of solder paste is low, compared with the weight of electrolytic capacitors and other components, components with small grounding area are easy to occur. ⑤ In the "Setup Group"/"Substrate Transfer" of "Machine Setup", set the "Descending Acceleration" to "Medium" or "Low".



4. Causes and solutions of uneven patches of the whole substrate (each substrate has different offset ways)?


Cause measures

① BOC mark is not used. In this case, the mounting accuracy of each substrate tends to be non-uniform. ① use BOC mark. When there is no BOC mark on the substrate, the template matching function is used.

② BOC mark is dirty. In this case, the mounting accuracy of each substrate tends to be non-uniform. ② Clean BOC mark. In addition, take appropriate measures to avoid fouling BOC marks.

③ The input of "substrate thickness" in "substrate data" is wrong. In this case, looseness occurs in the vertical direction, and the substrate moves in XYZ direction during the production process. In addition, the patch element falls off halfway down the Z axis. ③ Confirm and correct the "substrate height" and "substrate thickness" of "substrate data".

④ Poor setting of support pins. When the substrate is thin or large, it is easy to offset the patch. ④ Reset the support pin. Especially, it is important to set the support pins of the components with high precision of the patch.

⑤ The gap between the reference pin and the positioning hole of the substrate is large, and the substrate moves due to the vibration in the production process. ⑤ Use the reference pin consistent with the positioning hole of the substrate. Or change the positioning method to "shape reference".

⑥ Because of the fast descending speed of the support table, the components that have completed the pasting will move when the clamping of the substrate is released. ⑥ In the "Setup Group"/"Substrate Transfer" of "Machine Setup", set the "Descending Acceleration" to "Medium" or "Low"

⑦ Poor flatness of substrate surface. ⑦ Reconsider the substrate itself. In addition, by adjusting the configuration of support pins, some effects can sometimes be achieved.

⑧ The filter or air hose at the head of the patch is blocked. In this case, when vacuum failure occurs in the process of pasting, the residual vacuum pressure will suck up the components. ⑧ Implement "set group"/"vacuum calibration" of "self-calibration". If there is no improvement, replace the filter or air hose at the head of the patch.



5. The causes and solutions of the angle deviation of the patch?


Cause measures

① The patch angle of "Patch Data" is input incorrectly. ① Re-enter the angle of the patch.

② The input of "Component Supply Angle" in "Component Data" is wrong. The mounting angle in production is based on the shape of supplied components, and becomes "component supply angle ("component data "+mounting angle (mounting data)". ② Reset the component supply angle in "Form" of "Component Data".

③ Wrong nozzle selection. In this case, due to unstable suction, the patch angle and the patch coordinates tend to be inconsistent. ③ Re-select the suction nozzle. Select the suction nozzle that can stabilize the suction element. Usually, based on the area of the suction surface of the component, a large suction nozzle is selected from the suction nozzles.

④ In the case of a long connector, the θ rotation speed is higher than the suction area of the suction nozzle. In this case, too, due to unstable suction, the patch angle and patch coordinates tend to be inconsistent. ④ Consider using a special suction nozzle. Or in "Expansion" of "Component Data", set "θ Speed" to "Medium Speed" or "Low Speed".


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