Heavy grinding cemented carbide and high speed steel tools and re coating is the common process. Although the cutter regrinding or coating the price is only a small part of the manufacturing cost of new tools, but can prolong tool life. Heavy grinding process is a typical process special tool or expensive tool for tool method. Heavy grinding or re coating including drill, milling cutter, hob and forming tool.
Regrinding of tools
In the drill or milling cutter grinding process, grinding to cutting edge to remove the original coating, so the wheel must have sufficient hardness. The pretreatment of heavy mill cutting edge is very important, not only to ensure that the cutter regrinding after original cutting edge geometry can be completely and accurately preserved, and heavy mill PVD coated tool requirements is “safe” must. Therefore, must avoid unreasonable grinding process (such as: high temperature leads to impaired surface coarse grinding tool or dry grinding).
Before then the tool coating, using chemical methods to remove all of the original coating. Chemical removal method is often used in complex tools (such as hob, broach), tool or multiple coated tool and having problems due to the thickness of the coating method. The chemical removal of the coating is usually limited to high-speed steel cutting tool, because it will damage the hard alloy matrix: removal of coating will be removed from the hard alloy substrate by chemical cobalt, lead to the substrate surface is loose, so it is difficult to produce pores and coating.
In addition, there are some chemical methods for removing PVD coated with a patent. In these chemical methods in coating removal solution and hard alloy chemical reaction only tiny, but these methods have not been widely used. In addition, there are other cleaning coating methods, such as laser machining, abrasive blasting. Chemical removal method the most commonly used, because it can provide good removal of surface coating consistency.
At present, the typical re coating process is to remove the original coating of the tool by regrinding process.