Ultrasonic Plastic Welding Improves Production Efficiency

2008-01-14 12:26:56

( Business )



Ultrasonic plastic welding helps manufacturers attain their objectives of increasing production, minimizing unacceptable finished product quality, and improving efficiency. This welding method is often employed in industries such as automotive, cosmetics, electrical, house wares, packaging, and toys. You can often find ultrasonic plastic welding used not only to coalesce plastic parts, but also to form plastic rivets, and to put metal fasteners inside some thermoplastic materials. Most industries consider ultrasonic plastic welding as safe, relatively inexpensive, and effective.

There is no need for manufacturers to use glues or solvents, because ultrasonic plastic welding applies vibrations at an ultrasonic frequency to weld the assembly. As a result, there is an increase in temperature produced by friction of surface and intermolecular at the joint. If the temperature rise becomes adequate to melt the resin, the material flows and results in a uniform weld.

Most plastic welding machines work at 20 kHz, which is a frequency beyond the range of what humans are capable of hearing. At this lower frequency, it is easy to obtain the required vibration amplitude and power to melt thermoplastics. The disadvantage of working at this frequency, however, is that it is difficult to control the powerful mechanical vibration, which results in larger tooling. If smaller parts are to be welded, then higher frequencies (between 40 kHz and 60 kHz) must be applied since higher frequencies generate lesser and controllable vibrations.

There are basically two types of ultrasonic plastic welding techniques: the plunge ultrasonic plastic welding and the continuous ultrasonic plastic welding. In plunge welding, you need to place the parts to be welded under a tool (which is called horn). Before welding starts, moderate pressure is then applied to allow the horn to descend to the part. The horn, in a continuous welding method, may either scan or have the parts passed over/under it on a continuous basis.


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