Adding value with welding option

Welding and related technologies enhance a processor’s capabilities and make a company more competitive for new work. Custom injection molder Plastic Molding Concepts Inc. (Eagle, WI) offers welding and joining services to include every type of welding except vibration welding, says Bill Aalto, VP. There are many ways to weld plastics including contact welding, hot-plate welding, high-frequency welding, ultrasonic welding, vibration or friction welding, spin welding, laser welding, and solvent welding. “We’re a job shop so we try to do value added services for everyone, and we do it because others can’t or won’t,” Aalto says, living up to the firm’s motto “Crazy jobs that no one else will do.”

Providing extensive welding services is a matter of convenience as well. “One customer is a union shop and they like to buy fewer components or parts numbers,” Aalto says. “We do the molding, weld the parts into the assemblies and put them in a box. The customer then buys one part number instead of six different part numbers, which saves them money in the long run.”

Sylvio Mainolfi, worldwide product manager for Branson Ultrasonics Corp. (Danbury, CT), notes that over the past three decades, as plastics have evolved, so too have joining technologies. Today, his company offers seven different assembly technologies, with ultrasonics being one of those. When customers contact Branson, the primary focus is on the application. “We have a series of questions we ask them such as what it the material? What is the size of the part? What are the requirements of the product? Do you need a structural weld? A water tight or airtight weld?” explains Mainolfi. Also taken into consideration are volume, desired cycle time, and more. “A lot goes into the mix when determining the right type of joining technology,” Mainolfi adds. “Once we get enough input, we try to guide the customer into the best assembly technique.”

Electromagnetic welding/bonding is the specialty of Emabond (Norwood, NJ). It’s an uncommon joining technique but one that has its place, explains Steve Chookazian, general manager for Emabond. “When you need a reliable robust bond in a product where the cost of failure is high, electromagnetic bonding is ideal,” he says.  “The most common materials for this process are the olefins and more common engineering thermoplastics such as nylon, ABS, PC, and highly filled thermoplastics.”

Emabond provides complete turnkey systems that include assisting with the design of the product to be welded, and then designing and building the equipment for the customer. “Much of our expertise is in electromagnetic bonding of high-pressure vessels that have to reliably contain a fluid or gas,” Chookazian says. “This is a good technology for demanding structural, leak-proof products in markets such as plumbing, building and construction, and transportation industries.”

At Plastec West in Anaheim earlier this year, Dukane (St. Charles, IL) introduced an all-electric ultrasonic press, the iQ Servo Welder. Mike Johnston, national sales and marketing manager for Dukane, said this ultrasonic welding unit offers better repeatability than a pneumatic press, “just as all-electric injection molding machines are [more precise over time] versus pneumatic molding presses,” he says. “It’s also easier for people to validate and calibrate.” Dukane has three patents on this device, and a fourth patent is filed, with a provisional patent in process of filing.

Optimizing the collapse speed during the weld and hold phase created stronger pull test results during development of the iQ Servo Welder, says Johnston. “Collapsing too slow allows for material degradation. Collapsing too fast may cause cold forming. Matching the collapse speed during the melt phase of the process is critical to producing superior bond strength.” The iQ Servo Welder can either stop or continue to collapse a specified distance and speed during the hold phase.

During the same event, Branson introduced a number of new welding systems including its Radiance Laser welder, billed as a cost-effective solution to plastics joining, given that laser welding is becoming one of the most important methods for welding plastics. The Radiance 3G and 3I are the company’s newest additions to its laser welding line. According to Branson, its Radiance systems offer “cleaner” welds through reduced flash; faster welding cycle times; no movement required between parts; no adhesives or consumables; and quiet operation and uniform melt on both halves by achieving collapse. Materials that have been welded successfully to date include ABS, acrylics, elastomers, PC, PP, PS, HDPE, LDPE, polyethylene, PET, and nylon, according to the company. —[email protected]