A typical drill for drilling
stainless steel is a stainless steel group drill. Stainless steel chip breaking drills and S-shaped carbide drills, four-margin drills and indexable carbide shallow hole drills can also be used. When using a stainless steel chip breaking drill to process martensitic stainless steel 2Crl3, it is only necessary to grind out the chip breaker at E-E; and when drilling lCrl8Ni9Ti austenitic stainless steel, the chip breaker at A-A is also added.
The characteristics of the S-shaped carbide drill are that there is no chisel edge, which can reduce the axial force by about half; the rake angle at the drill core is positive, and the cutting edge is sharp; The liquid hole; the arc-shaped cutting edge and the chip flute are reasonably distributed, which is convenient for chips to be broken into small pieces and discharged. The feature of the indexable carbide shallow hole drill is that the front end of the drill bit is asymmetrically equipped with two convex triangular blades, which divide the chip and cut off different parts of the hole, and can be automatically centered. The straight line performance of the hole is better, and the cutting length is short. ;There are multiple pit-shaped chip breakers on the rake face of the insert, which has good cutting performance, especially reliable chip breaking, and the chips are in consistent broken chips; the internal cooling allows the cutting fluid to be sprayed directly to the drilling surface to improve the cooling effect , Chip removal is very smooth; especially, different grades of cemented carbide inserts can be used according to the workpiece material, the cutting speed can reach 80-120m/min, and the drilling is very brisk.
When drilling stainless steel plates, the drill bit is easy to wear and break, the surface of the hole is rough, and sometimes there are deep grooves that cannot be eliminated; the hole diameter is too large, the hole shape is not round or tilted to one side.
Therefore, the following aspects should be paid attention to during the drilling operation. First, the geometric shape must be sharpened correctly, and the two cutting edges must be kept symmetrical. If the relief angle of the drill bit is too large, the knife will be stuck, causing chatter, making the drilled hole polygonal. The chisel edge should be ground to reduce the axial force of drilling.
Secondly, the drill bit must be installed correctly to ensure that the drill bit is sharp, and it must be sharpened in time after being blunt. Reasonably select the geometric parameters of the drill bit and the amount of drilling. According to the requirements of the drilling depth, the length of the drill bit should be shortened as much as possible, and the thickness of the drill core should be increased to improve the rigidity. When using high-speed steel drills, the cutting speed should not be too high to avoid burning the blade. The feed rate should not be too large, so as to prevent the drill bit from being aggravated or the hole drilling deviated, and the feed rate should be properly adjusted to the lowest point when cutting in and out.
