PCBA Tech - SMT patch processing fault processing, how to detect?

SMT processing refers to a technological process, mainly for SMT patch processing, which is now a relatively popular technology and process. During SMT patch processing, sometimes there will be certain failures, how do we need to deal with it, the inspection before processing is to ensure the quality

SMT processing refers to a technological process, mainly for SMT patch processing, which is now a relatively popular technology and process. During SMT patch processing, certain failures sometimes occur. What do we need to do? Inspection before processing is an effective way to ensure quality. Today, I will introduce in detail "SMT patch processing troubleshooting, how to detect?"

One, SMT patch processing troubleshooting

1. The equipment has normal performance in operation. Such as: abnormal sound, peculiar smell, motor overheating, etc. You can take the shutdown method and notify the on-line engineer or technician to deal with: (Special attention: when shutting down, first ensure that the produced product has left the area that will cause damage after the shutdown, such as the reflow furnace, the high temperature area of wave soldering)

2. After the equipment fails during operation, there will be no further harm to the product or personnel. If the motor crashes, the normal execution cannot be performed, the moving parts are damaged or impacted, the crimping is abnormal, the control computer crashes, etc., the on-site operator should stop all operations related to the equipment, and immediately notify the line engineer or technician to deal with it after protecting the site .

3. After the equipment fails during operation, it may cause further damage to the product or the human body. For example, the cleaning machine clicks the board, the board enters and exits the board, the ICT line body clicks the board, the automatic container does not stop running, the line body leaks, etc., The on-site operator should press the emergency stop switch (turn off the power), and immediately notify the line engineer or technician to deal with it after protecting the site.

2. SMT patch processing and testing

SMT component inspection:

The main inspection items of components include: solderability, pin coplanarity and usability, which should be sampled by the inspection department. To test the solderability of components, stainless steel tweezers can hold the component body and immerse it in a tin pot at 235±5 degree Celsius or 230±5 degree Celsius, and take it out at 2±0.2S or 3±0.5S. Check the soldering end of the solder under a 20 times microscope, and it is required that more than 90% of the soldering end of the component is soldered.

The patch processing workshop can do the following visual inspections:

1. Visually or with a magnifying glass, check whether the solder ends or pin surfaces of the components are oxidized or have no contaminants.

2. The nominal value, specification, model, accuracy, and external dimensions of the components should be consistent with the product process requirements.

3. The pins of SOT and SOIC cannot be deformed. For multi-lead QFP devices with a lead spacing of less than 0.65MM, the pin coplanarity should be less than 0.1MM (optical inspection by the placement machine).

4. For products that require cleaning, the mark of the components will not fall off after cleaning, and will not affect the performance and reliability of the components (visual inspection after cleaning).

The above is about "SMT patch processing fault processing, how to detect?" detailed introduction