In metal processing, it is generally necessary to clamp the workpiece by mechanical, electromagnetic or even freezing methods. Recently, Penn State University engineers developed a new concept clamping technology that uses light to activate the adhesive to clamp the workpiece, which is mainly used in cutting, grinding and other machining situations. Its working principle is to use light-activated adhesive to “clamp” the work piece; and to “loose” the work piece by light and embrittlement adhesive. Penn State University currently has the patent right for this technology, and Master Work-Holding (located in Morganton, North Carolina) has selected this promising new concept product for production and is ready to put it on the market soon .
When Edward De Meter, professor of industrial and manufacturing engineering at Penn State University, introduced this new concept product to people, he said that this new technology can replace the most commonly used mechanical clamping method. The old-style mechanical clamping scheme, the investment cost of automatic fixture is very high, it is easy to cause deformation of the workpiece during clamping, occupy a large space and seriously affect the processing process, and the production efficiency is low. The use of this new method of directly bonding the workpiece to the steel fixture with a very simple structure can well avoid many of the above drawbacks, greatly improve production efficiency, product quality and reduce production costs.
In the new clamping scheme, the workpiece is glued to the steel fixture on the underside of the workpiece. At the key position of the fixture, there are many small diameter cylindrical hole covers made of corundum, a cheap ceramic material. These small hole covers are called clamping pins by Mr. De Meter, which act as lenses or windows to prepare for the penetration of ultraviolet and infrared beams to activate clamping or breaking the adhesive.
To clamp the work piece, apply a sticky adhesive to the upper end surface of the clamping pin, and then place the work piece on it. A beam of low-density ultraviolet light emitted from a UV spotlight quickly penetrates the clamping pin to activate the adhesive to cure it. According to Mr. De Meter, the adhesive is activated and cured to form a cured adhesive layer with a yield strength of up to 6,000psi between the workpiece and the fixture within a few seconds.
When the workpiece is processed, a beam of flickering infrared rays is emitted by the laser, which passes through the clamping pin, embrittles and breaks the adhesive, and relaxes the workpiece.
Embrittlement and broken adhesives do not require heating fixtures and parts, and can be completed in 1 second. Mr. De Meter said that the adhesive is used together with the prototype manufacturing system and can be used for component assembly in the photovoltaic industry. Often add some pigments to the adhesive, so that it can better absorb infrared. After embrittlement and crushing treatment, the original high strength of the adhesive can be reduced to 300 psi.
“The work piece is usually taken out by the operator from the fixture, or using a rubber hammer, tapped lightly, and taken out after loosening.” Mr. De Meter said.