An ever increasing proportion of plastic components have integrated membranes. These membranes are used as pressure compensating elements (PCEs). A newly developed machine can punch and weld PCE membranes in a single cycle. This reduces the cycle time to less than two seconds.
Pressure compensating elements (PCEs or pressure vents) protect electronic housings, lamps, headlamps and sensitive electronic components from dust, dirt and moisture. They provide continuous pressure compensation relieving strain on seals and preventing leaks as well as allowing moisture to escape from the casing.
Until now two steps were needed to process the membranes. Firstly the previously assembled membranes had to be removed from a carrier belt by means of vacuum handling and supplied to the ultrasonic welding tool (sonotrode) to then be welded onto the plastic component via the pneumatic sealing stroke.
The HiQ MPW (Modular Punch Weld) machine, a new technical development from ultrasonic specialist Herrmann Ultrasonics, can punch and weld at the same time. A cheaper membrane material belt of 5 – 22 mm can therefore be used as the membrane does not have to be tailored in advance.
In one single step, the unit:
- Shapes the membrane contour by punching
- Transports the membrane belt by conveyor to welding site
- Ultrasonically welds the membrane
- Winds the membrane tape on
This saves material and reduces the cycle time to less than 2 seconds per weld cycle which translates into a major improvement in OEE (Overall Equipment Efficiency).
Targeted application of energy and defined melt formation ensure that the membrane is not damaged. Following ultrasonic welding the membrane is immediately able to support loads and processing of the part can continue without any interruption. Additional materials such as adhesives or mechanical fasteners are not required.
The standard optical quality control previously undertaken downstream is not needed because the MPW system has a vacuum monitor to reliably check whether the membrane is correctly punched and positioned. The machine control also features gentle conveyor transport with a splice check which reduces other sources of error and therefore potential production downtime. A special position measuring system for high cycle rates is wear-free. The Herrmann MPW unit can be flexibly integrated into automation lines or supplied as a manual work station.
The fully integrated work station will be shown at the PLAST-EX (booth # 2139) in Toronto, Canada.
For more information, visit www.herrmannultrasonics.com.