On management method of ultrasonic welding process of housing

By performing ultrasonic welding surely, it is possible to prevent accidents such as exposing the live parts from the casing in advance.

1. Preparation before starting production

  1. According to the instruction manual of production engineering, we adjust the attachment of ultrasonic welding equipment horn and adjust the setting of ultrasonic welding conditions.
  2. After completing the adjustment, place the dummy board in the chassis and perform one welding.
  3. After the welding, a person in charge in the IPQC (In Process Quality Control) division conducts a drop test conforming to safety standards.
  4. After carrying out the drop test, confirm that the ultrasonic weld of the housing is not broken by visual inspection.
  5. Open the enclosure with a special tool, check the ultrasonic weld surface, and confirm that 75% or more of the welded part is reliably fused.

2. After production start

2.1 Production line

  1. Ultrasonic welding process in order to prevent skipping, a part is set up between the ultrasonic welding process and the next process.
  2. After ultrasonic welding, the operator in the ultrasonic welding process visually checks all ultrasonic welds.
  3. Before connecting the chassis to the inspection facility in the automatic process of inspection of the electrical characteristics of the next process, confirm the total number that the welded part does not open by hitting the housing against the workbench.

2.2 IPQC

Once every two hours, from the production line IPQC personnel will carry out the following sampling inspection.

  1. After completing the adjustment, place the dummy board in the chassis and perform one welding.
  2. After the welding, IPQC staff will perform a drop test conforming to safety standards.
  3. After carrying out the drop test, open the case, check the weld surface, and confirm that 75% or more of the welded part is reliably fused.

If the above is confirmed and an abnormality is found in the 2) and 3) above, we follow the abnormality treatment regulation of our company's ISO and go back to the IPQC patrol inspection point immediately before that and carry out the total rework treatment.

2.3 OQC (Out-going Quality Control)

Pull out 5 units from the shipping lot and check the clearance between the upper and lower casing of the ultrasonic weld with the thickness gauge to confirm that it is within the range of the standard value.

In the case of a 5 W class ultrasonic welding wire having a particularly short USB type, the impact applied to the housing is small in the drop test in conformity with the safety standards, so even if there is a potential defect in ultrasonic welding, it becomes apparent.  Therefore, in order to increase the impact force applied to the enclosure more than the drop test, as a test similar to the steel ball drop test, connect the weighted cables to the enclosure and connect them to the inside of the company.  The IPQC staff will confirm one unit every two hours that the ultrasonic weld is not damaged by letting the weight fall freely from the prescribed height.

You can get the product catalog in PDF.

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