Welding & assembly.

Vibration welders led the major new technology developments in thermoplastic bonding and assembly equipment at NPE '94. Two firms introduced new lines of vibration welders, while another company launched a new series of controls for its ultrasonic welding models.

VIBRATION WELDERS MAKE WAVES

Forward Technology Industries Inc., Minneapolis, brought out its new high-accuracy linear vibration welder with a work envelope up to 10 x 12 in., which incorporates an automated pallet transfer assembly system.

The model LVW1012 features an adjustable mechanical amplitude that maintains a constant amplitude level (a range of 0.25 to 2.5 mm), unlike standard electromagnetic systems, according to company executives. The unit operates via a high-speed, electromechanical spindle powered by a servo-drive motor. The spindle's circular motion is mechanically converted into linear motion through a steel spring system.

The welder has an accuracy of [+ or -] 0.002 in. for start and stop positioning. It has a frequency range of 100-200 Hz, which can be programmed by the operator. In addition, it features automatic frequency control.

The LVW1012 offers a multiple-pressure system that provides eight adjustable pressures during the weld cycle. This enables an operator to initiate the welding process at higher pressures, gradually decreasing pressure through the welding and cooling phases. The unit features a modular C-frame design and has a base price of $58,000.

Branson Ultrasonics Corp., Danbury, Conn., introduced its new "Hi-Line" series of linear vibration welders, which feature electromechanical vibration drive and a new digital drive controller for enhanced accuracy of the bonding process.

The first unit being rolled out in the Hi-Line series is the VW-4H; additional new models are expected to follow later this year. Branson offers the vibration welder with an optional touch-screen control system based on its EPIC (Enhanced Processing Industrial Computer) technology. EPIC is a microprocessor-based control system that performs on-line monitoring of all welding parameters.

The VW-4H utilizes a hydraulic lift and clamping system that includes two proportional valves that control the speed of the lift table and the clamp force applied to parts. This capability enables operators to input up to eight weld forces of meltdown velocity and up to three hold forces during the cooling cycle. The unit has a self-tuning frequency program that automatically finds and stores the resonant frequency of the upper tooling mass. Frequency range is variable between 160-240 Hz. Base price is about $80,000.

ULTRASONIC CONTROLS

Dukane Ultrasonics, St. Charles, Ill., launched its new DPC (Dynamic Process Control) system, which incorporates its MMI (Man-Machine Interface) touch-screen controller pad for ultrasonic welders.

The DPC is a 32-bit RISC microprocessor-based unit that offers a range of programmable welding control variables, such as pulse-width modulation, linear-ramp soft start, and "AutoTrac" tuning. The MMI touch-screen provides an on-line graphical display of ultrasonic welding distance and power parameters.

Bill Lynch, v.p. sales and marketing, said the DPC and MMI package will be the control technology for all new Dukane ultrasonic welders, but can also can be retrofitted onto existing Dukane models. The technology incorporates a new package of software and hardware, and is available for 350- and 700-watt welders (at 40 kHz), as well as 500-, 1000-, 1500-, and 2000-watt welders (20 kHz). Pricing for the control package was not available.

In addition, Dukane introduced a new line of narrow-profile 20- and 40-kHz "Thruster Systems," which allow operators to incorporate ultrasonic systems into multi- or single-head welding applications, where standard column mounting isn't preferred or used.