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[How can a carbide drill bit be used to its full potential?]
Release date:[2019/9/30] Is reading[77]次

The material of the cemented carbide drill bit is one of the commonly used alloy materials, which is characterized by high hardness and wear resistance. In terms of composition, the cemented carbide is mainly composed of one or more refractory carbides, such as tungsten carbide, titanium carbide, and the like, and a metal powder such as cobalt, nickel, or the like as a binder is added. An alloy material made of metallurgy. Cemented carbide is commonly used in the manufacture of cutting tools, cold work dies, and high wear parts. Cemented carbide has an extremely high hardness and wear resistance. At room temperature, its hardness can reach 69 to 81HRC, and the wear resistance is also quite good. Therefore, the cutting speed of the tool can be 4 to 7 times faster than that of the high speed steel tool. The service life is not lower than the latter, but it is 5 to 80 times longer than the high speed steel tool and can be used for cutting hardness up to 50HRC. High hardness material.

Cemented carbide has good corrosion resistance, oxidation resistance and high temperature resistance. Carbide-made tools are generally resistant to corrosion caused by the atmosphere, acids, alkalis, etc., are not susceptible to oxidation, and can be kept hard at temperatures between 900 and 1000 degrees. Carbide materials can be used to make various types of tools such as turning tools, milling cutters, planers, drill bits, etc., suitable for different types of machining processes and workpiece materials. Among them, tungsten-cobalt cemented carbide is suitable for the processing of short chips of ferrous metals and metallic metals and the processing of non-metallic materials; tungsten-titanium-cobalt hard alloys are more suitable for long-chip processing of ferrous metals such as steel. In the same kind of alloy, if the cobalt content is too much, it is more suitable for rough processing; the cobalt content is less, which is more suitable for finishing.

In the past, it has been thought that drilling must be carried out at lower feed rates and cutting speeds, a view that was once correct under the processing conditions of a conventional drill bit. Today, with the advent of carbide drills, the concept of drilling has changed. In fact, by properly selecting the right carbide drill bit, the drilling productivity can be greatly improved and the processing cost per hole can be reduced.

Because the price of cemented carbide drill bit is relatively high, it is the responsibility of every machining practitioner to use the carbide drill bit correctly and make the best use of it. How to properly use carbide drills mainly includes the following aspects:

One: choose the right machine tool

Carbide drills can be used in CNC machine tools, machining centers and other high-power, steel-good machine tools, and should ensure that the tool tip jumps TIR < 0.02. The machine tools such as rocker drill and universal milling have low power and poor spindle precision, which may lead to early collapse of cemented carbide drills and should be avoided as much as possible.

Two: choose the right handle

The spring chuck, the side pressure shank, the hydraulic shank, the hot shank, etc. can be used, but the clamping force of the quick-change drill chuck is not easy enough to cause the cemented carbide drill to slip and fail, and should be eliminated.

Three: correct cooling

1. The external cooling should pay attention to the combination of cooling directions, form the upper and lower steps, and reduce the angle with the tool as much as possible.

2. The inner cold alloy drill bit should pay attention to the pressure and flow, and should prevent the coolant leakage from affecting the cooling effect.

Four: the correct drilling process

1. When the surface angle of the drill is >8-10°, it cannot be drilled. When <8-10°, the feed should be reduced to 1/2-1/3 of normal;

2. When the inclination angle of the drilled surface is >5°, the feed should be reduced to 1/2-1/3 of normal;

3. When drilling cross holes (orthogonal holes or oblique holes), the carbide drill bit feed should be reduced to 1/2-1/3 of normal;

4. Blade alloy drill bits shall not be reamed.