Special Report: Various technologies compete for plastics assembly task

Jan. 1, 2016

When it's time to consider what technology to use for assembly of plastics parts, ultrasonic welding is not the only arrow in the quiver.


Bielomatik Inc., New Hudson, Mich., recently upgraded its camera system for its infrared welding machines. The system, which allows the quality of joined plastic connections to be reliably verified using proprietary software, was introduced in 2014. At Fakuma in October, Bielomatik touted improved software and use of the system for all noncontact welding methods.

Manufacturers increasingly are using noncontact welding methods such as infrared, hot gas and gas convection to assemble engine compartment parts and safety-system components such as chute channels for airbags, according to Bielomatik. However, monitoring quality can be difficult, and these components are subject to documentation requirements. The manufacturer must evaluate the manufacturing process for every safety component and record the results meticulously. "We have to demonstrate that the welding in a noncontact process was executed perfectly," says Tobias Beiss, head of innovation management at parent company Bielomatik Leuze GmbH + Co. KG, Neuffen, Germany. He says that the parameters normally monitored by welding machines are not enough.

The infrared camera system monitors temperatures in certain areas. Shortly before joining parts, the machine operator uses a camera to determine whether the heat distribution is correct. The quality-assurance control system can store key data about every component, along with the thermal image, machine parameters, production date and time stamp or bar code.

The company also has developed new technology for natural gas-based convection welding. Bielomatik has applied for a patent for an innovation that allows the user to regulate the supply of gas separately for different zones and set it precisely by adjusting a nozzle. The ability to set the temperature distribution makes the process a good choice for joining glass-fiber-reinforced engine compartment components or other complex parts made of high-temperature plastics.


Extol Inc., Zeeland, Mich., recently introduced the Compact Fusion, a precise hot-plate welder designed for clean rooms and applications with limited space. Hot-plate welding is appropriate for products with contoured surfaces or internal walls that must be sealed, Extol says.

The new welder produces strong, hermetic seals and offers excellent flash control, while preserving the appearance of the parts it handles. It is easy to automate applications involving the Compact Fusion, which features an Allen-Bradley control system and 6.5-inch color touch screen interface, the company says.

Using servo-driven actuation on the upper and lower press platens, the high-strength, aluminum welder achieves a high degree of control over force, distance and acceleration/deceleration; good weld strength; and cycle time efficiency. It features electric doors on the side and front, so that users have flexibility in setting up their work cells. It also has quick-change tooling.

Extol offers several Compact Fusion options, including a clean-room model, a 12-inch screen, integrated load cells, integrated linear scales and a back-up power supply. It also offers the          ErgoStation, a heavy-duty machine base that can be adjusted by the operator. Extol's other products include infrared staking and spin-welding machines.


Kamweld Technologies Inc., Norwood, Mass., provides hot gas (heated-tool) welders, industrial hot air guns, plastic sheet bending devices and accessories. The company's 40 Series welders, which are its biggest sellers and most versatile welders, apply localized heat to fuse thermoplastic parts together. The pressure, rate and area of heating are precisely controlled to provide strong, tight bonds, says Len Alter, product manager.

All of Kamweld's welders perform three basic types of welding: tack welding, hand welding and hand high-speed welding. Tack welding produces a temporary bond with enough tensile strength to hold the work pieces together, pending permanent welding. This operation does not require a plastic welding rod, Alter says. Hand welding and hand high-speed welding use a plastic welding rod, which is a strip of thermoplastic material that must be the same material as the part.

"All of our welders can do all [these] types of welding. The major difference in all those welders is speed," Alter says. Furthermore, all of the company's welding tips fit all its welders. "We've got about 25 tips; they all fit. You could have a 50-year-old Kamweld welder, and all the tips would fit it."

The most important application for Kamweld's hot-gas welders is for making products that require corrosion resistance, such as housings for blowers, barrels and tanks for plating and acid storage, and chemical processing equipment.


Herrmann Ultrasonics Inc., Bartlett, Ill., has recently upgraded its equipment for one-step punching and sealing of plastic components with integrated membranes.

The company says the demand for components with integrated membranes is growing. Such membranes are used in the automotive industry to protect against water condensation and balance out pressure changes. They are also used in medical components.

The Modular Punch Weld (MPW) machine is capable of simultaneously punching and welding. It operates using a membrane tape with widths between 8mm and 20mm, replacing pre-cut single membranes. In a single step, the unit moves the membrane tape, punches the membrane contour and performs an ultrasonic weld. The cycle time is less than 2 seconds, a considerable improvement over alternative processes.

Herrmann recently improved the color recognition capability of the MPW's splice sensor, adopted a new adjustment concept to improve tool settings and increased the size of the touch screen to 8.4 inches.

Merle R. Snyder, senior correspondent

[email protected]


Bielomatik, 248-264-7142, www.bielomatik.us

Extol Inc., 616-748-9955, www.extolinc.com

Herrmann Ultrasonics, 630-626-1626, www.herrmannultrasonics.com

Kamweld Technologies Inc., 781-762-6922, www.kamweld.com