Failure Analysis of Ultrasonic Plastic Spot Welding Machine
1. Ultrasonic mold heating
Ultrasonic molds will have a certain degree of heat during work, which is caused by the mechanical loss of the material itself and the heat conduction of the weldment. Whether the welding head heat is normal or not is that when there is no load (that is, not touching the workpiece), the ultrasonic wave should be continuously emitted for more than half an hour, and the temperature should not exceed 50-70°C. If heat is experienced, it proves that the welding head is damaged or the material is unqualified. Need to be replaced.
2. Ultrasonic mold whistle
When whistling occurs when the ultrasonic mold is working, the following reasons should be analyzed:
①Whether the installation screws are loose
②Whether the welding head has cracks
③Whether the welding head is in contact with objects that should not be in contact.
3. Ultrasonic generator shows overload
When the generator sends out an overload alarm, it should be checked as follows:
No-load test, if the working current is normal, it may be that the ultrasonic mold is in contact with objects that should not be touched or the parameter adjustment between the welding head and the welding seat has failed.
When the no-load test is abnormal, first observe whether the welding head has cracks and whether the installation is firm, then remove the welding head and perform no-load test to rule out whether there is a problem with the transducer + horn, and eliminate it step by step. After eliminating the possibility of failure of the transducer + horn, replace the new ultrasonic mold for judgment.
Sometimes the no-load test is normal, but not working normally. It may be that the internal sound energy components such as ultrasonic molds have changed, resulting in poor sound energy transmission. Here is a relatively simple judgment method: hand touch method. The amplitude of the normal working welding head or horn surface is very uniform when it is working, and the hand feels velvety smooth. When the sound energy is not transmitted smoothly, the hand feels shaking or shaking feeling, then it is necessary to use it. Elimination method to eliminate problematic parts. When the ultrasonic generator is abnormal, the same situation can occur, because normally, the input waveform of the transducer should be a smooth sine wave. This phenomenon can also occur when there are spikes or abnormal waveforms on the sine wave. At this time, you can replace it with another pruning acoustic energy component for judgment.