Plastic welding, hot plate machine, rotary melting machine according to the different heating softening methods used, plastic welding methods can be divided into softening through the addition of heat, softening through mechanical movement, and softening through electromagnetic action of several kinds. The use of an external heat source way to soften the welding technology: hot plate welding, hot air welding, hot rod and pulse welding;
1. Hot plate welding may be the simplest plastic welding technology, but this way is particularly suitable for the need for a large area of the welding surface of the welding of large-scale plastic parts, generally a plane of the electric heating plate will need to be welded to the two planes of the melting soften the rapid removal of the electric heating plate to merge the two planes and add force to the cooling. This method of welding device is simple, high welding strength, products, welding part of the shape design is relatively easy. However, due to the heat generated by the hot plate to soften the product, the cycle is longer; molten resin will adhere to the hot plate and is not easy to clean up (hot plate surface coated with F4 can alleviate this phenomenon), the formation of impurities affect the adhesive strength over time; the need to strictly control the pressure and time to ensure that the appropriate amount of molten; when the different types of resins or metals and resins into the bonding, there will be a lack of strength of the phenomenon.
2. Hot air welding when the hot air flow blowing directly to the seam area, resulting in the seam area and the base material of the same material filler wire melting. Through the filler material and the welded plastic melted together to form a weld. This welding method welding equipment is lightweight and easy to carry, but the operator's welding skills are more demanding.
3. Hot rod and pulse welding these two techniques are mainly used to connect the welding of small thickness of plastic film. And these two methods are similar, are two pieces of film tightly pressed together, the use of hot rod or nichrome wire generated by the instantaneous heat to complete the welding. Welding technology using mechanical movement to soften the way: friction welding, ultrasonic welding;
1. Friction welding: according to the movement of the track can be divided into linear and rotary; linear can be used for straight weld welding and plane welding welding, rotary can be used for round weld welding. In the use of pressure under the two parts in the friction process of friction heat generated by the contact part of the plastic melting and softening, right fixed until the condensation of solid.
2. Ultrasonic welding: the use of high-frequency mechanical energy to soften or melt the thermoplastic at the joint. Be connected to the part of the pressure under the action of fixed together, and then after the frequency is usually 20 or 40 kHz ultrasonic vibration, transducer to the high-power vibration signal, converted to the corresponding mechanical energy, applied to the need to weld the plastic parts of the contact interface, weldments joints violently rubbing instantaneous generation of high heat, which makes the molecules alternately fused, so as to achieve the welding effect. Ultrasonic welding process is very fast, welding time is less than a second, and it is easy to realize automation, in electronics, electrical appliances, automotive parts, plastic toys, stationery, daily necessities, handicrafts, cosmetics and other industries are widely used. Motion mode welding is an automated welding process, all of which require specialized welding equipment. Once the correct welding parameters are determined, the operator can stabilize production. Its advantages are: fast, flexible, welding over a short stable and do not need flux or protective gas, and does not produce harmful gases or slag, product welding quality is guaranteed. Electromagnetic effect of softening the welding technology: high-frequency welding, infrared welding, laser welding;
1. High-frequency welding: the use of electromagnetic induction principle of high-frequency induction heating technology, penetrate the plastic products buried inside the plastic parts of the inductor or magnetic plastic to produce inductive heating, the plastic being welded in the rapid alternating electric field can produce heat and make the welding parts to be welded to rapidly soften and melt, followed by the filling of interfaces Gap, and with the perfect mechanical device to achieve perfect welding. The most common method of generating high-frequency induction is to utilize high-frequency current through the coil, thus obtaining a strong high-frequency magnetic field. The inductor (i.e., the heat generator) is generally made of iron, aluminum, stainless steel, etc., but magnetic composite plastics processed by adding magnetic substances are also used. Products made by welding in this way include stationery clips, inflatable items, waterproof clothing and blood bags.
2. Infrared welding: This technique is similar to hot plate welding in that the two parts to be welded are fixed in close proximity to, but not in contact with, the hot plate. Under the action of heat radiation, the connecting part is melted, and then remove the heat source, the two parts of the butt, pressed together to complete the welding. This method does not produce welding slag, no pollution, welding strength, mainly used for PVDF, PP and other high precision requirements for the connection of piping systems.
3. Laser welding: the 1970s, the laser began to be applied to plastic welding. It is the principle of the laser beam (usually present in the infrared region of the electromagnetic spectrum of the cluster of strong radiation waves) through the reflector, lens or fiber optic optical system, focusing on the area to be welded, the formation of the thermal zone, the plastic in the thermal zone is softened and melted, in the subsequent solidification process, has been melted material to form a joint, to be welded parts that are connected, usually used for PMMA, PC, ABS, LDPE, PP, etc. precision requirements of piping system connection, and so on. Usually used for PMMA, PC, ABS, LDPE, HDPE, PVC, PA6, PA66, PS and other light transmittance of good materials, in the heat of the action area to add carbon black and other absorbents to enhance the heat absorption effect. Plastic laser welding has more advantages: fast welding speed, high precision; automation, precision numerical control is easy to realize; relatively low cost. Therefore, plastic laser welding technology in the automotive, medical equipment, packaging and other fields have been more widely used.