“The tool coating is particularly beneficial for the processing of hard-to-machine materials.” Those harder materials contain large amounts of nickel and cobalt, which usually require processing with a coating tool. “However, for other materials it can not be so Say.
“It is certainly not necessary or necessary to force the use of the coating when cutting aluminum or plastic, and cutting aluminum with uncoated cutting tools has become a practice.” But there are exceptions, that is, the production workshop that wants to minimize the tool change. In this case, the use of PVD deposition of ZrN or TiB2 coating is more appropriate.
Coating systems and service providers also agree that the TiB2 coating is suitable for cutting aluminum alloys, but only for workpiece materials with a silicon content of less than 10%. He said that when the silicon content in the aluminum alloy is higher than 10%, TiB2 coating is difficult to effectively prevent the workpiece material and tool material bonding and transfer. Therefore, when the silicon content is higher than 10%, in view of the abrasive material of the workpiece, should be used CVD diamond coating tool.
Most coating companies apply cathodic arc deposition technology to a variety of coatings because they can evaporate and deposit more than 90% of the target onto the tool, compared to other methods, Liu said. Material waste is rare. “In addition, the kinetic energy associated with the process gives the coating a good adhesion.”
The disadvantage of the cathodic arc deposition process is that coarse particles are produced when the smooth coating is deposited. Liu described the coarse particles as “molten droplets”, which is a commonly used coating element, titanium. It’s almost like a little bit of splashing droplets. This droplet may not hinder the chip control of the larger tool, but when the tool size is getting smaller, its negative effect becomes more and more obvious, at this time, the tool coating business needs to adjust the process. Minimize droplet size or avoid droplets. Liu added that there is also a choice, that is, after coating to maintain the integrity of the coating under the premise of removing the droplets.
Liu said that if these coarse particles maintain the same basic size, the surface texture of the tool will become smooth, it is possible to catch the chips and squeeze the chips together.