One of the most common methods of joining plastics is ultrasonic welding. This method uses high-frequency vibrational energy to melt plastic, forming a weld.
Can be performed successfully using shear-type joints. Shear joints produce strong, hermetic bonds. In some limited situations, energy directors may work satisfactorily; but in most situations, the bond will not retain enough toughness for the application.
Many medical devices use this type joining method.
Advantages of Using Ultrasonic Welding
- Environmental friendliness; no chemicals are used.
- Good joint appearance.
- Improved product uniformity.
- Fast bonding, which gives high productivity
- Low energy consumption
- And it’s a computer-controlled process suitable for SPC
Typical Ultrasonic Welding Set-up Conditions
| Horn Type |
Aluminum or titanium |
| Booster Type |
Green (1:1) |
| Welder Power |
1,000 watts (typical) |
| Frequency |
20 KHz |
| Fixture/nest |
Rigid or semirigid |
| Options |
Collapse control, constant weld-energy, computer control |
Typical Ultrasonic Welding Conditions
| Welding Time |
0.5 - 1.0 s |
| Hold Time |
1.0 s (min.) |
| Welding Pressure |
0.207-0.345 MPa (30-50 psig) |
| Trigger Pressure |
Minimize |
| Downspeed |
Minimize |