Troubleshooting Threaded Insert Installation in Plastics

Insufficient pull-out or torque strength

  • Decrease pressure
  • Increase weld time
  • Imcrease amplitude (change booster)
  • Decrease down speed
  • Increase insert interference
  • Insert is too small or hole is too large
  • Increase hole depth
  • Decrease screw length

Horn heats up

  • Decrease amplitude (change booster)
  • Air cool the horn
  • If possible, contact plastic rather than insert
  • Check coupling between horn, booster and converter

Damage to insert

  • Decrease weld time
  • Decrease amplitude (change booster)
  • Increase pressure
  • Increase down speed

Inserting time is excessive

  • Decrease weld time
  • Decrease hold time
  • Decrease amplitude (change booster)
  • Increase pressure
  • Increase down speed
  • Insert is too large or hole is too small
  • Improper fixturing
  • Power required exceeds capability of power supply

Application is noisy

  • Use sound enclosure or hearing protectors
  • Start the ultrasonics just prior to the horn contacting the insert
  • Decrease amplitude (change booster)
  • Increase pressure
  • Increase down speed
  • If possible, contact plastic rather than insert

Horn wears prematurely

  • Use hardened steel or carbide faced horn
  • Decrease amplitude (change booster)
  • Insert is too large or hole is too small
  • Plastic is too abrasive

Plastic cracks

  • Ensure that ultrasonics is turned on
  • Decrease pressure
  • Walls surrounding hole are too thin
  • Increase weld time
  • Decrease amplitude (change booster)
  • Decrease down speed
  • Enlarge hole diameter

Plastic fills the threaded bore of the insert

  • Increase hole depth
  • Insert is too large or hole is too small
  • Insert is too long

Plastic flows over the top of the insert

  • Adjust positive stop to limit depth of insertion
  • Decrease weld time
  • Insert is too large or hole is too small

Partial insertion

  • Increase pressure
  • Decrease down speed
  • Decrease amplitude (change booster)
  • Increase weld time
  • Increase hole depth
  • Adjust positive stop
  • Check fixturing
  • Horn is at the end of its stroke

Insert does not remain inserted

  • Increase hold time

System overloads

  • Decrease pressure
  • Decrease down speed
  • Decrease amplitude (change booster)
  • Tune power supply
  • Check for loose studs
  • Check coupling between horn and booster
  • Power required exceeds capability of power supply