How To Choose Plastic Welding Equipment

There are two general methods of plastic connection: bonding and welding. Generally speaking, the bonding process has low production efficiency, is not beautiful, and the adhesive has certain toxicity; while the welding process is relatively high in production efficiency, beautiful welding parts, and high welding strength, so the plastic welding process has been getting more and more Wide application. Welding equipment supplier shares with you:

Adopt appropriate welding methods according to the type of material, product shape, and cost. According to the different heating and softening methods used, plastic welding can be divided into several types such as softening by external heating sources, mechanical movement and electromagnetic action.

Welding technology softened by external heating source:

Welding Equipment

1. Hot plate welding

Hot plate welding is a welding method that uses a flat electric heating plate to melt and soften the two planes to be welded, quickly removes the hot plate, combines the two planes, and applies force to cooling. It is suitable for ultrasonic refractory non-rotating or large plastic workpiece This method has high welding strength, and the shape design of the welded parts is relatively easy, such as products such as car water tanks, car tool boxes, car combination lights, and washing machine balance rings.

2. Hot air welding

When the hot air current is blown directly to the joint area, the filler wire and the joint area of the same material as the base material are melted, and the filler material and the welded plastic are melted together to form a weld seam. The advantage of this welding method is that the welding equipment is lightweight and portable, but the welding skills of the operator are relatively high.

3.Hot rod and pulse welding

These two technologies are mainly used for welding of thinner plastic films. And these two methods are similar, both are to press two pieces of film tightly together, and use the instantaneous heat generated by a hot rod or nichrome wire to complete the welding.

Second, the method of completing welding by mechanical movement softening:

Mechanical kinematic welding is a fully automatic welding process that uses the heat generated during the friction between two workpieces under pressure to melt the plastic on the contact surface, and aligns it until it solidifies. Special welding equipment is required. Once the correct welding parameters are determined, the operator can stabilize production. Its advantages are: fast, flexible, stable welding process, no flux or shielding gas is required, no harmful gas or slag is produced, and the welding quality of the product is guaranteed. According to the movement track, it can be divided into straight type and rotary type: straight type can be used for welding of straight and flat welds, and rotary type can be used for welding of circular welds.

1.Ultrasonic welding

Ultrasonic welding uses a signal generator to generate a high-frequency sine wave signal, which is converted into high-frequency mechanical vibration energy by a transducer, and then the amplified vibration is coupled to the welded plastic part through a horn and a welding head. High-frequency friction causes the plastic contact surface to instantly melt at high temperatures. After the ultrasonic wave stops, the two plastic parts are welded together after a brief holding and cooling. The welding process generally takes less than one second. The welding strength is comparable to the body and is widely used Used in electronics, auto parts, packaging, plastic toys, stationery, daily necessities, crafts and other industries. When welding plastic products, do not add any adhesives, fillers or fluxes, nor consume a large amount of heat source. It has the advantages of easy operation, fast welding speed, high welding strength, beautiful welding parts and high production efficiency. In addition, the ultrasonic welding process can also achieve riveting of plastic and metal parts. Therefore, welding equipment is widely used.

2.Rotary friction welding

The mechanical energy is converted into thermal energy by the relatively high-speed rotating friction of the workpiece, so that the contact surface of the welding chuck is frictionally heated, melted and pressurized, thereby welding together. Compared with ultrasonic welding, this process is not limited by the size and material of the workpiece, and the welding strength is higher than other plastic welding processes, which is almost close to the strength of the plastic body. It is suitable for welding of rotating parts such as filter element, plastic cup, float ball, toy ball, shower head and so on.

Third, the welding method to soften the surface by electromagnetic action:

1. High frequency welding

High-frequency welding is based on the principle of electromagnetic induction and high-frequency induction heating technology. It penetrates plastic products to inductively heat the induction body or magnetic plastic buried inside the plastic part, so that the welded plastic generates heat in the fast alternating electric field and makes it to be welded The part quickly softens and melts, then fills the interface gap, and is complemented by perfect mechanical devices to achieve perfect welding. Suitable for welding stationery clips, inflatables, waterproof clothing and blood bags.

2.Infrared welding

This technology is similar to electric hot plate welding. The two parts to be welded are fixed close to the electric hot plate but not in contact with the electric hot plate. Under the action of heat radiation, the connecting part is melted, then the heat source is removed, the two parts are butted together and pressed together to complete the welding. This method does not produce welding slag, pollution-free, and has strong welding strength. It is mainly used for welding of piping systems with high accuracy such as PVDF and PP.

3.Laser welding

The principle is that the light beam generated by the laser is passed through an optical path system composed of a mirror, a lens or an optical fiber, and is focused on the area to be welded to form a thermally active area. The plastic in the thermally active area is softened and melted. In the subsequent solidification process, it has melted. The material is used to form a joint, and the parts to be welded are connected. It is usually used for welding of light-transmitting materials such as PMMA, PC, ABS, LDPE, HDPE, PVC, PA6, PA66, PS, etc., and carbon black is added in the heat action zone Isoabsorbents enhance the endothermic effect. Plastic laser welding has many advantages: fast welding speed and high precision; automation and precision numerical control are easy to implement. Therefore, plastic laser welding technology has been widely used in automotive, medical equipment, packaging and other fields.