Wednesday, May 6, 2015

Servo driven Ultrasonic Welding technology provides sophisticated results in assembling Mini Medical Device

A leading medical device manufacturer uses Dukane’s iQ Series Servo Ultrasonic Welding System to produce high-quality results in assembling small, delicate Test Strips.  These Test Strips are used to measure a person’s Total Cholesterol, HDL, Glucose and Triglycerides.  Assembling small medical devices, like these Test Strips, requires precise, repeatable and consistent process control.  The Test Strips are made of two thin layers of Polyethylene Terephthalate (PET) film.  Between the two PET layers is a mesh membrane infused with the diagnostic chemical.  

Prior to investing in Dukane’s iQ Servo Ultrasonic Welder technology, the biggest challenge for this manufacturer was misalignment of the thin PET films during the assembly process.  Scrap rate was more than 30%.  The iQ Series Servo Ultrasonic Welding System with patented Melt-Match® technology solved the assembly alignment problems and provided accurate, repeatable and reliable process.  By using the digital process control from the iQ Series Servo Ultrasonic Welders, they have produced 20+ million Test Strip assemblies in less than three years while reducing their scrap rate to less than 5%.  

iQ Series Servo Ultrasonic Welding System
Multiple parameters are available for defining the weld cycle sequence for iQ Servo systems.  For this application, the iQ Servo system is programmed to trigger the weld cycle using minimal force.  As each weld cycle is initiated, the ultrasonic horn descends towards the assembly at a fast rate of speed.  Then, approximately 1.0 mm above the assembly, the horn slows down to a programmed, controlled speed prior to coming in contact with the Test Strip.  This is when the iQ Series Servo Melt-Match® feature is initiated.  This is best described as when the system reaches the programmed trigger force value on the Test Strip, the horn’s downward movement stops and the ultrasonics start vibrating the horn to soften the PET material.  Next, the system’s load cell detects a programmed drop in force, indicating that parts have begun to melt.  At that point the weld cycle downward motion re-initiates to further compress the parts.  Part welding continues for a programmed distance or energy value at a determined collapse speed.  With the weld speed precisely controlled in addition to using Melt-Detect™, unnecessary force is reduced on the thin film that would otherwise distort it.  This, in turn, results in improved weld quality.

In the final stage of the weld cycle, the iQ Servo system also gives the flexibility to program Dynamic and/or Static Hold.  Dynamic Hold will have the horn further compress the parts after the ultrasonics has been turned off.  Static Hold has the weld horn hold its final end-of-weld position for a given amount of time.  In this application, Static Hold has been programmed.  This gives the materials enough time to solidify without misalignment.  Once the Static Hold time has been completed, the horn then returns to its home (or Top of Stroke) position ready for the next weld cycle. This was the most helpful feature for these thin PET Test Strips.

Another major advantage of using iQ Servo system is the ability to duplicate a known process on multiple iQ Servo Systems without any variation in weld results. In this application, this feature was of major benefit for the manufacturing company. They were able to install multiple iQ Servo Systems for their growing need without investing extra time or effort in fine-tuning the process for each welder.

Dukane’s extensive product line of servo-driven technology and our professional sales and engineering team will collaboratively work with customers to provide the best solution for their given application. For more information on iQ Series Servo Ultrasonic Welder and other Ultrasonic Welding products visit http://www.dukane.com/us/ or call 630-797-4900.