First of all, it must be understood the working principle of the HF machine. It uses high-voltage rectification to stimulate the oscillation of the high-frequency electron tube to generate high-frequency electromagnetic waves. Thus, TPU, EVA, PETG, APET plastics are bonded to achieve the purpose of packaging products. However, in the process of plastic bonding with HF machine, fire will occasionally occur, which will cause plastic burning and damage to the upper and lower molds and the insulation board. There is no need to be panic for high-frequency ignition is a discharge phenomenon caused by friction between the mold and other materials (including dust and impurities in plastic) during high-frequency oscillation.
Ⅰ. When using high-frequency machines and high-frequency machines, there is something that we should do as the following:
1. There is a set of sophisticated high-frequency molds. The situations where there are burrs on the mold, the edges and corners are too sharp, or the material is selected too thin will cause the tip to discharge. This is ignition.
2. Clean working environment. There should be no dust and debris on the work surface of HF machine, especially the parts that touch the upper and lower molds.
3. The purity of the plastic itself. Impurities or metal substances mixed in the workpiece medium are also a hidden danger of fire.
4. The mold is adjusted smoothly. The uneven mold not only cannot produce qualified products, but also easily causes the low side to break down the insulating board and spark when the high-cycle output occurs.
5. Once ignition occurs, please clean the upper and lower molds in time, and the blackened parts must be cleaned (with thinner or alcohol).
6. A certain bonding material must be used under the high-frequency mold, which will effectively prevent high-frequency re-breakdown of required welding products.
7. The capacitor slice should not be adjusted too violently during the adjustment process, and the corresponding range should be adjusted slowly. The edge of the capacitor slice appears to be sparked during the production process. It may be that the edge is not cleaned or has burr on the aluminum plate, which needs to use sandpaper to polish and smooth.
8. The ignition of the oscillating barrel during the production process mainly includes capacitor chips, high-pressure pipe sockets and other flashovers. The processing method is the same as that of the capacitance adjustment piece.
9. HF machine ignition cannot be avoided because it uses the principle of electromagnetic waves. The only thing we can do is to turn frequency of ignition to the lowest point, which is mainly related to the material. If the material is good enough, the ignition will not happen.
10. The HF machine in the production process needs to carry on the oscillating barrel cleaning often, which only needs to use the air compressor.
11. The HF machine selects the corresponding flange material according to the material characteristic in the mold. Common bond materials in the market are bond paper, tetrafluorin, high-temperature cloth, high-temperature tape, silica gel, kraft paper, yellow wax paper and other bond materials.
12. The stability of the high-frequency current is very important during use. The HF machine with unstable current will sparkle frequently during the production process.