Meaning
Diagnostic profiling of the vibrational displacement across the face of an ultrasonic horn is a prerequisite for ensuring uniform energy delivery in plastic assembly. Executing horn amplitude mapping reveals localized variations in acoustic output that can cause uneven welding or cosmetic damage to the plastic parts. This procedure involves measuring the physical excursion of the welding tool at multiple points using non-contact sensors.
The resulting profile helps toolmakers adjust the horn geometry to achieve a balanced output.
Diagnostic Method
Non-contact measurements are typically gathered across the active surface of the tool under dry-run conditions. Through horn amplitude mapping, technicians can identify dead zones where the amplitude drops below the threshold required to melt the polymer. If these low-energy regions align with the joint line of the molded part, they produce weak welds and incomplete hermetic seals.
This diagnostic action is performed prior to production to prevent the generation of scrap.
Tooling Wear
Structural degradation of the titanium or steel horn over thousands of cycles alters its natural frequency and acoustic distribution. Inconsistent amplitude across the face indicates that horn amplitude mapping must be repeated to verify the tool integrity. Cracks or erosion from hard filler fibers, such as glass, will cause the profile to drift, requiring tool replacement or re-machining.
Process Stability
Maintenance of a uniform vibrational output ensures that the welding cycle remains highly repeatable. Consistent horn amplitude mapping results correlate with stable melt initiation and shorter weld times during high-volume production.
