Brief introduction of masking tape for thermal spraying and sand blowing masking

       Currently used masking tapes can be divided into sandblasting tapes, spray process tapes and sandblasting and spraying one-step tapes. The sandblasting tape has strong sand impact resistance, high viscosity, and does not pollute the sprayed workpiece. However, it is not resistant to high temperature, easy to burn at high temperature, and cannot be used for substrate protection in the spraying process. Commonly used protective tape for spraying process is made of non-combustible glass cloth or aluminum foil coated with heat-resistant adhesive, pressure-sensitive tape that can withstand normal spraying temperature. The tape used must not run or contaminate the parts at high spray temperatures. This method is suitable for parts with complex shapes and difficult to make fixtures, and the protection part and the spraying part are on the same surface. When the sprayed layer is thick, the coating deposited on the protective tape should be cleaned frequently during the spraying process to prevent the sprayed layer from accumulating on the tape, to avoid difficulty in tape removal and damage to the edges of the coating.



Only silicone and Teflon (polytetrafluoroethylene) can be used both as a masking protection before roughening treatment and as a masking protection before spraying. However, during the thermal spraying process, special attention should be paid to keeping the surface of the part at a lower temperature, especially when silicone resin and Teflon (polytetrafluoroethylene) are used for shielding protection, and the surface temperature of the substrate should be carefully controlled to prevent shielding. The material overheats and even burns, thereby contaminating the coating. Masking before spraying Protective masking tapes block spray particles from forming a coating on non-roughened surfaces and can be easily removed after spraying is complete.



At present, when spraying some heterogeneous parts, sandblasting and spraying "one-step" masking tapes are often used abroad for the protection of non-sprayed surfaces (which can be used for sandblasting protection or spray masking), but the price is high. In China, when spraying heterogeneous parts, the "two-step method" tape is used for shielding protection. When sandblasting, first use sandblasting tape containing glass fiber with good particle impact resistance; when spraying, use aluminum foil or silicon with better temperature resistance effect. Rubber spray tape, this masking process is relatively cumbersome, and it is easy to contaminate the sandblasted surface when the spray tape is pasted.



In response to these situations, in recent years, some domestic tape manufacturers have also developed sandblasting and spraying "one-step" tapes with relatively low prices. This tape is made of special high-elasticity silicone rubber and glass fiber composite modification. A high-elasticity anti-wear surface layer is compounded on the high-strength and high-temperature resistant substrate, which can not only withstand the erosion and wear of sand particles, but also resist the impact of high-temperature and high-speed spray particles, and realize the shielding and protection of non-spraying surfaces of heterogeneous parts. . The test results of supersonic plasma spraying and supersonic flame spraying show that the performance is comparable to that of similar foreign products. The adhesive tape has strong bonding ability, leaving no glue residue after removal.