Advantages of plastic seam welder
There are generally two methods of plastic connection: bonding and welding. Generally speaking, the bonding process has low production efficiency, is not aesthetically pleasing, and the adhesive has a certain degree of toxicity; However, welding technology has relatively high production efficiency, beautiful welding parts, and high welding strength, so plastic welding technology has been increasingly widely used.
Choose appropriate welding methods based on the type of material and the shape and cost of the product. According to the different heating and softening methods used, plastic welding can be divided into several types, including "external heat source", "mechanical motion", and "electromagnetic softening".
1、 Welding technology softened by an external heat source
1: Hot plate welding
Hot plate welding is a welding method in which two flat surfaces to be welded are melted and softened using a flat electric heating plate, and then the electric heating plate is quickly moved away to combine the two surfaces and force cooling. Suitable for welding ultrasonic refractory non rotating workpieces or large plastic workpieces. This method has high welding strength and relatively easy shape design of welded parts, such as car water tanks, car toolboxes, car combination lights, washing machine balance rings, and other products.
2. Hot air welding
When the hot air flow directly blows towards the seam area, the filler wire and seam area of the same material as the base material are melted, and the filler material and the welded plastic melt together to form a weld seam. The advantage of this welding method is that the welding equipment is lightweight and easy to carry, but it requires high welding skills from the operator.
3. Hot rod and pulse welding
These two technologies are mainly used for welding plastic films. And these two methods are similar, both of which press two thin films tightly together and use the instantaneous heat generated by the hot rod or nickel chromium wire to complete the welding.
2、 Method of completing welding through mechanical motion softening
Mechanical motion welding is a fully automatic welding process that utilizes the heat generated by friction between two workpieces under pressure to melt the plastic on the contact surface, aligning and fixing it until it solidifies, requiring specialized welding equipment. Once the correct welding parameters are determined, the operator can stabilize production.
Its advantages are: fast, flexible, stable welding process without the need for flux or protective gas, and without the generation of harmful gases or slag, ensuring the quality of product welding. According to the motion trajectory, it can be divided into linear and rotary types: linear type can be used for welding linear and planar welds, while rotary type can be used for welding circular welds.
1. Ultrasonic welding
Ultrasonic welding is a process in which a high-frequency sine wave signal is generated by a signal generator and converted into high-frequency mechanical vibration energy through a transducer. The amplified vibration is coupled to the welded plastic part through a variable amplitude rod and welding head. The high-frequency friction under high pressure causes the plastic contact surface to instantly produce high temperature melting. After the ultrasonic stops, the two plastic parts are welded together after a brief pressure maintaining cooling, and the welding process generally does not exceed one second, The welding strength can be comparable to the body and is widely used in various industries such as electronics, automotive parts, packaging, plastic toys, stationery, daily necessities, handicrafts, etc. When welding plastic products, there is no need to add any adhesive, filler or flux, and a large amount of heat source is not consumed. It has the advantages of simple operation, fast welding speed, high welding strength, beautiful welding parts, and high production efficiency. In addition, ultrasonic welding technology can also achieve riveting of plastic and metal parts. Therefore, ultrasonic welding technology has been increasingly widely used.
2. Rotary friction welding
The mechanical energy is converted into thermal energy through the relatively high-speed rotation friction of the workpiece, causing the contact surface of the welded workpiece to heat up through friction, melt, and then pressurize, thus welding together. Compared to 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, almost close to the strength of the plastic body. Suitable for welding rotating parts such as filter cartridges, plastic cups, floating balls, toy balls, lotus heads, etc.
3、 Welding method for softening the surface through electromagnetic action
1. High-frequency welding
High frequency welding is a high-frequency induction heating technology based on the principle of electromagnetic induction. By penetrating plastic products, induction heating is generated on sensors or magnetic plastics buried inside the plastic parts, causing the plastic to be welded to generate heat in a fast alternating electric field, quickly softening and melting the parts to be welded, and then filling the interface gap. Perfect mechanical devices are used to achieve perfect welding. Suitable for welding stationery clips, inflatable items, waterproof clothing, and blood bags.
2. Infrared welding
This technology is similar to electric heating plate welding, where the two parts that need to be welded are fixed close to the electric heating plate but not in contact with it. Under the action of thermal radiation, the connecting part is melted, and then the heat source is removed. The two parts are docked and pressed together to complete the welding. This method does not produce welding slag, has no pollution, and has high welding strength. It is mainly used for welding pipeline systems with high precision requirements such as PVDF and PP.
3. Laser welding
The principle is to focus the light beam generated by the laser through a reflective mirror, lens, or optical fiber system, focusing on the area to be welded, forming a thermal action zone. The plastic in the thermal action zone is softened and melted. In the subsequent solidification process, the melted material forms a joint, and the components to be welded are connected. It is usually used for welding materials with good transparency such as PMMA, PC, ABS, LDPE, HDPE, PVC, PA6, PA66, PS, etc, Adding absorbents such as carbon black to the heat affected zone enhances the heat absorption effect. There are many advantages of plastic laser welding: fast welding speed and high accuracy; Automation and precision CNC are easy to achieve. Therefore, plastic laser welding technology has been widely applied in fields such as automobiles, medical devices, packaging, etc.
