Management method for the ultrasonic welding process of the enclosure

AC/DC Power Adapter enclosure is assembled using ultrasonic welding. On this page, we introduce part of our thorough management methods for the ultrasonic welding process.

By ensuring that ultrasonic welding is properly performed, it is possible to prevent accidents in which live electrical parts become exposed from the enclosure.

1. Preparation Before Production Start

The production engineering personnel shall install and adjust the horn of the ultrasonic welding equipment and set and adjust the ultrasonic welding conditions in accordance with the work instructions.
After adjustments are completed, insert a dummy board into the enclosure and perform welding on one unit.
After welding, the IPQC (In Process Quality Control) personnel shall conduct a drop test in compliance with safety standards.
After the drop test, visually confirm that the ultrasonic welded area of the enclosure is not cracked.
Using a dedicated tool, open the enclosure and check the ultrasonic welded surface to confirm that at least 75% of the welded area is securely fused.

After confirming the above, production will begin.

2. After Production Start

1. Production Line

To prevent skipping the ultrasonic welding process, a checkpoint shall be installed between the ultrasonic welding process and the next process.
After ultrasonic welding, the operator in the ultrasonic welding process shall visually inspect all welded areas.
In the subsequent automatic electrical characteristics inspection process, before connecting the enclosure to the inspection equipment, strike the enclosure against the workbench to confirm for all units that the welded area does not open.

2. IPQC

Once every two hours, the IPQC personnel shall conduct the following patrol sampling inspection from the production line.

After adjustments are completed, insert a dummy board into the enclosure and perform welding on one unit.
After welding, the IPQC personnel shall conduct a drop test in compliance with safety standards.
After the drop test, open the enclosure and check the welded surface to confirm that at least 75% of the welded area is securely fused.

After confirming the above, if any abnormality is found in items 2) or 3), actions will be taken in accordance with our ISO nonconformance control procedures, tracing back to the point of the previous IPQC patrol inspection and performing 100% rework.

3. OQC (Outgoing Quality Control)

Five units will be randomly selected from the shipment lot, and the gap between the upper and lower enclosures at the ultrasonic welded area will be measured with a thickness gauge to confirm that it is within the specified standard range.

For 5W-class USB types with particularly short ultrasonic welding lines, the impact applied to the enclosure during a drop test compliant with safety standards is relatively small. Therefore, even if there is a latent defect in the ultrasonic welding, it may not become apparent. To apply a greater impact force to the enclosure than in the drop test, as an inspection similar to a steel ball drop test, a cable with a weight attached will be connected to the enclosure, and the weight will be freely dropped from a height specified in internal regulations. The IPQC personnel will confirm once every two hours that there is no damage to the ultrasonic welded area.