EVCO Plastics is a custom plastic injection molding company that specializes in providing value-added engineered parts to manufacturers in markets ranging from medical to agriculture. Founded in 1964, the 50-year-plus company attributes its longevity to the many technological advancements it has made to its molding and secondary processes.

One such technology is ultrasonic welding, which EVCO has used for many years. In fact, the company often consults with Herrmann Ultrasonics Inc. to see if ultrasonically welding a specific part is the best option. These meetings also help EVCO engineers identify problem areas related to part design.

In the fall of 2013, both parties met to discuss EVCO’s challenges regarding welding a high volume of large gearboxes for an agricultural equipment manufacturer. The gearboxes come in two styles that require different welding setups. Once welded, the box is inserted into an attachment for seeding equipment.

At the time, EVCO was using a 15-kilohertz welder. Herrmann recommended that EVCO replace it with the HiQ DIALOG 6,200-watt welder for several reasons. First, its 20-kilohertz frequency ensures more efficient welding of a large part. The welder also offers more rigidity, which is essential for repeatable welding.

Another advantage is greater precision. The welder’s controller displays process variables—such as power, force, amplitude and frequency—in data or graphs that visually represent the entire weld cycle. Welding data can be viewed, analyzed, collected and downloaded onsite, or continuously sent to an office offsite for analysis.

In addition, the welder’s composite sonotrode is specially designed using a highly advanced finite element analysis program. This software simulates dynamic performance and material stress to optimize sonotrode geometry that provides even amplitude distribution and extends wear life.

EVCO especially likes that the welder welds warm parts at the molding press and within the molding cycle time; features quick-change stacks and fixtures that allow easy changeover and setup for both styles of gear boxes; and keeps the sonotrode at a consistent distance throughout the welding process, which takes a few seconds. The company’s previous welder had limited success meeting all these requirements.

Two other features that enhance welder performance are the SoftTouch mode and custom stroke selection. Upon contact of the sonotrode with the gearbox, the SoftTouch mode prevents damage to sensitive joint geometries while allowing for maximum stroke speed and movement.

Servo-pneumatic control of the pneumatic drive cylinder enables the operator to customize the start and end positions of the sonotrode for the specific application and plastic part. This shortens welding cycle times and increases productivity.

Since installing the DIALOG welder in December 2013, EVCO has experienced more consistent process control when welding the gearboxes. This has helped the company make products that always meet customer specifications. Equally important, the company is better able to document this process control and verify repeatability for the customer.

Because of these benefits, EVCO is looking to use this welder for other applications in the near future, as well as buying more DIALOG welders whenever the company upgrades its equipment. For more information on ultrasonic welders, call 630-626-1626 or visit www.herrmannultrasonics.com.