Failure analysis and elimination of ultrasonic welding machine

1. Analysis and elimination of failures in various processing techniques

1.1 Common problems in ultrasonic welding operations

Phenomenon: excessive welding

Reason: too much energy input into the workpiece;

Ultrasonic machine is too powerful

Solution:

1. Reduce work pressure

2. Reduce welding time

3. Use a smaller multiple of the horn to reduce the amplitude

4. Reduce the amplitude of the ultrasonic mold

5. Switch to an horn with a smaller amplitude amplification ratio

Phenomenon: uneven welding
Reasons: 1. Workpiece distortion

2. Uneven weld line

3. Uneven mold amplitude distribution

4. The contact surface of welding head, lower die and workpiece is not flat

5. Side wall bent

6. The workpiece error is too large

Solution:
1. Eliminate large curved workpieces

2. Check whether the workpiece is deformed during the work process and redesign the energy-gathering side to make the height uniform

3. Redesign the ultrasonic mold

4. Ultrasonic machine power is low or unstable

5. Ensure the consistency of the shape and size of the workpiece

6. Adjust the die head and lower die to improve the support effect

7. Thicker plastic product wall thickness

Phenomenon: inconsistent welding results
Reasons: 1. The error of the workpiece is too large

2. The power supply voltage changes

3. Air source pressure fluctuation

4. Mould is wet

5. The proportion of plastic workpiece filler is too high

6. Uneven filler distribution

7. Design error of energy conduction wire

8. Poor welding performance of materials

Solution:
Ensure the consistency of the shape and size of the workpiece

Use a power regulator

Ensure stable output pressure of air source

1. Drying the mold

2. Dry the workpiece and weld immediately

3. Reduce the proportion of filler

4. Improve the quality of the workpiece

5. Redesign the joint surface structure

6. Switch to materials with good welding performance

Phenomenon: Surface damage
Reasons: 1. Ultrasonic mold temperature rise

2. 　The contact surface of the mold and the product does not match

Solution: 1. Check whether the welding head screws are loose

2. Shorten welding time

3. Cool down the mold

4. Ensure that the mold and the horn are well connected

5. Re-engraving the mold