Analysis And Treatment Of Common Problems In Ultrasonic Riveting
The rivet head is inconsistent and the appearance is uneven.
Reason:
◆The riveting cavity is too large or the pin is too short
◆Excessive amplitude leads to material degradation
Solution:
◆Reduce the size of the cavity or increase the height of the pin
◆Reduce the amplitude or use the amplitude step
There are too many flash edges around the rivet head
Reason:
◆The riveting cavity is too small or the pin is too high
◆Mechanical stop setting is too high
◆The pin is not centered in the cavity of the welding head
Solution:
◆Increase the size of the cavity or reduce the height of the pin
◆Reduce mechanical stops
◆Check concentricity
The rivet is formed at the upper pin of the pin; the bottom of the pin melts and begins to shrink
Reason:
◆The sharp corner at the bottom of the pin causes stress concentration
◆The clamping pressure is too high or the amplitude is too small
◆The welding head is too short or the speed is too fast.
Solution:
◆Increase the radius at the bottom of the pin
◆Reduce the pressure too high or increase the amplitude
◆Increase the downstroke or decrease the descending speed
Severe indentation and deformation on the other side of the rivet head
Reason:
◆Improper clamping
◆The clamping pressure is too large
Solution:
◆Test the metal support fixture and reduce the amplitude in the lower part of the riveting area
◆Reduce the clamping pressure and place a metal plate between the pin and the clamp as a heat sink to reduce the indentation
Loose workpiece after riveting
Reason:
◆The molten pin does not completely solidify before the pressure is released.
◆Limit stop or lower limit setting is too high
Solution:
◆Extend the pressure holding time
◆Reduce mechanical stops
The bottom of the pin is broken during the riveting process
Reason:
◆Stress concentration at the sharp corner of the pin
◆The pin and the tip of the horn are not perpendicular
Solution:
◆Increase the bottom radius of the pin
◆Check the alignment
Deformation caused by plastic flow between workpieces during riveting
Reason:
◆The amplitude is too high
◆The gap between the pin and the hole is too large
Solution:
◆Reduce amplitude or purchase amplitude step
◆ Reduce the aperture
◆Use an external or external node plunger for better sealing
Severe indentation and deformation on the other side of the rivet head
Reason:
◆The metal is not properly placed at the bottom of the plastic part
Solution:
◆Increase welding and holding time
◆increase the height of the pin
The rivet head is poorly formed and the pin material sticks to the surface of the horn
Reason:
◆Poor fit between the pin diameter and the through hole
◆Material flows into the gap between the pin and the workpiece
◆ insufficient lubrication of the surface of the welding head
Solution:
◆Slip fit between the pin and the through hole
◆Improve the fit between the pin and the through hole
◆Test weld head coating (such as TiN)
