During the use of the mold, it is inevitable that the mold will be polluted by the comprehensive deposition of rubber, compounding agents and release agents used in the vulcanization process (the main pollutants are sulfides, inorganic oxides, silicone oil, carbon black, etc.). Repeated use will cause some dead areas of pattern pollution. Therefore, the mold must be cleaned regularly to ensure the cleanliness of its surface in order to ensure the quality of the tire and the life of the mold.
Mechanical cleaning method
Manual sandpaper or steel wire physical grinding and dry sandblasting are used, and different combinations of cleaning can be selected according to needs. Mechanical cleaning method is a mature technology and is widely used in the tire industry. This method has the advantages of being simple and easy to operate, and not requiring high equipment and tools, but it also has insurmountable defects: it will cause mechanical damage to the mold and shorten the life of the mold; sandblasting treatment is easy to block the exhaust holes of the mold, and the workload of unblocking the exhaust holes after sandblasting is very large. The mold must be disassembled, resulting in high labor intensity and long cleaning cycle.
Chemical cleaning method
Chemical cleaning methods mainly include: organic solvent method, melting method, acid cleaning method, alkali cleaning method, etc. These methods are easy to use and low cost. However, long-term use of the above methods will cause mold corrosion, which will directly affect the appearance and quality of the product; at the same time, these pharmaceutical raw materials pollute the environment and harm the health of operators, so there must be complete labor protection measures and pollutant treatment equipment.
Dry ice cleaning method
Dry ice cleaning, also known as cold spraying, uses compressed air as the power and carrier, and uses dry ice particles as accelerated particles. It is sprayed onto the mold surface through a special spray cleaning machine, and uses the momentum change, sublimation, melting and other energy conversion of high-speed solid dry ice particles to quickly freeze the dirt, oil, residual impurities on the mold surface, thereby condensing, embrittlement, and being peeled off, and at the same time removed with the airflow. It will not cause any damage to the mold surface, nor will it affect the finish of the metal surface. However, due to noise, operating costs and relatively harsh online working environment, dry ice cleaning will be gradually eliminated in some tire companies.
Laser cleaning method
Laser cleaning technology refers to the use of high-energy laser beams to irradiate the surface of the workpiece, causing the dirt, rust or coating on the surface to evaporate or peel off instantly, and quickly and effectively remove the surface attachments or surface coatings of the cleaning object, thereby achieving a clean process. Specifically used for tire mold cleaning, the mold absorbs lasers of a specific wavelength, the energy is extremely small, and will not cause damage. The dirt on the mold surface (sulfide, inorganic oxide, silicone oil, carbon black, etc.) absorbs a large amount of energy, is instantly expanded, vaporized and evaporated, and taken away from the mold surface, thereby achieving the cleaning effect. However, the one-time investment cost is relatively large at present, and it has not yet been widely popularized.
Finally, under the condition of doing a good job of basic assembly and lubrication maintenance, the surface cleaning of the pattern blocks and the upper and lower side panels directly affects the appearance quality and production efficiency of the tire. In the future, non-destructive and efficient cleaning technology will replace the old method, and the comprehensive solution of laser cleaning + automation will meet the online or offline application scenarios of tire companies.
