Welding plastics -electromagnetic

Welding plastics - electromagnetic radiation A BUXTON IR microwave, high frequency, etc. 

The next generation electrical contact materials based on bismuth-silver compositions are suitable for automobile sectors, since they do not weld or arc under heavy loads. The unique conduction properties of bismuth have led to the production of plastics with a built-in shielding protection against electromagnetic or radio-frequency interferences and electrostatic discharge which create serious disturbance to the electronic equipment around us. 

The use of plastics and their composites is rapidly increasing in numerous areas. However, the final assembly of products is often limited by the capability of existing joining techniques. The ability of ICPs, especially polyaniUnes, to absorb electromagnetic radiation and convert it into heat introduces another application in the welding of thermoplastics and thermosets [210]. 

High-frequency (1892) n. Pertaining to the part of the electromagnetic spectrum between 3 and 200 MHz, employed in plastics welding, sealing and preheating operations. Frequencies of 30 MHz and below are the most used. 

Sensors Electromagnetic shielding Electrochromic screens or windows Lithography Conductive textiles Microwave welding of plastics Electrolytic capacitors... 

Plastics that are readily bonded with induction methods include aU grades of ABS, nylon, polyester, polyethylene, polypropylene, and polystyrene, as well as those materials often considered more difficult to bond such as acetals, modified polyphenylene oxide, and polycarbonate. Reinforced thermoplastics with filler levels up to 65 percent have been joined successfully. Many combinations of dissimilar materials can be bonded with induction welding processes. Table 8.5 shows compatible plastic combinations for electromagnetic adhesives. Thermoset and other nonmetallic substrates can also be elec-tromagnetically bonded. In these applications the bonding agent acts as a hot-melt adhesive. 

Infrared radiation, i.e. radiated electromagnetic energy in the wavelength range of 780 qm to 1 nun, has been used as a heating source in industrial applications for decades. Previously it was used mainly in large scale industrial processes recently more applications in smaller scale plastic welding have been developed. 

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