What is the relationship between downstroke distance and absolute distance?
Downstroke distance is the distance the horn travels until the ultrasound trigger point is reached. When this trigger point is reached, the trigger switch closes and ultrasound is “triggered”, or turned on. Typically, this trigger point is where the horn contacts the part being welded. If pre-triggering (i.e., turning on the ultrasound prior to contacting the part) is being used to activate the ultrasound, downstroke distance is then the distance the horn travels until the pretrigger point is reached and not the contact point of the part being welded. Absolute distance is the combination of the downstroke distance, weld distance, and hold distance. The weld distance is the distance the horn moves during the application of ultrasound to create the weld.
