According to the processing characteristics of the materials, has the following characteristics: drill bit hardness must be greater than the workpiece hardness;tusngten carbide drill bit under great torsion and axial force on the workpiece, therefore must have sufficient strength and toughness; because the processed material has good toughness, when the cutting blade is sharp enough to ask. Therefore the tool material must have sufficient wear resistance, so as to reduce the hardening of the workpiece; because the chemical properties must be high, so the requirement of tool material and titanium alloy affinity to poor, in order to avoid stroke diffusion caused by sticking to the knife and broken drill.

At present, there are many kinds of materials which are suitable for cutting tools, such as tool steel, hard alloy, super hard material and so on.

At first, try to use ordinary high-speed tungsten carbide drill coating test, ordinary high speed steel bit low price, when using coating technology, can significantly reduce the friction coefficient of the tool and the workpiece, improve the tool life. But because of the high speed machine tool, the drill bit breaking strength is not enough, cause in the process, the effect is not ideal.

Cemented carbide is the latest development of a cutting tool material,suitable for most of the rough material processing, including steel, cast iron, special materials and plastics

The main auxiliary plane of twist drill: the main auxiliary plane of twist drill is base plane,cutting plane, middle section and column section

If the auxiliary movement is not considered,the base surface of any point on the main cutting edge of the twist drill is changed.

The cutting plane at any point on the main cutting edge, is the point of cutting speed and cutting direction in the plane surface of the processing. The cutting plane and the vertical plane, and the main cutting edge of each point on the cutting plane are not the same. The column section at any point of the main cutting edge on the cylindrical surface by this point and to the bit center line to the center line and the column section,the main cutting edge on different radius of the cylindrical surface.

Select main geometric parameters of tungsten carbide drill bit.the main geometric parameters of drill bit selection including drill bit cutting edge angle, before and after angle selection, drill helix angle effect on the drill life analysis and edge processing.

The bit angle determine chip width and bit angle.When the diameter of carbide drill bit and certain amount of feed, increase the angle, then iron narrows, unit load on the cutting edge. Reduce angle have great impact on rake angle, the corresponding increase in angle to improve the cutting condition of a vertex. Influence of chip flow direction according to the relevant data. The tool design, combined with the processing of product hardness is not high, but the viscous characteristics, select the bit angle for 140 degrees.

Posted by: hannahgwendolyn at 09:04 AM | No Comments | Add Comment
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