Original Title: Drilling Technology Encyclopedia, This Must Be Collected! Drill, as the most common tool in hole processing, is widely used in mechanical manufacturing, especially in the processing of holes in cooling devices, tubesheets of power generation equipment and steam generators. I. Characteristics of drilling Drills usually have two main cutting edges, and when machining, the drill cuts while rotating. The rake angle of the drill is getting larger and larger from the central axis to the outer edge, the cutting speed of the drill is getting higher and higher when it is closer to the outer circle, and the cutting speed decreases to the center, and the cutting speed of the rotary center is zero. The chisel edge of the drill is located near the central axis of rotation. The chisel edge has a large secondary rake angle, no chip space and low cutting speed, so it will produce a large axial resistance. If the chisel edge is ground to Type A or Type C in DIN1414 and the cutting edge near the central axis has a positive rake angle, the cutting resistance can be reduced and the cutting performance can be significantly improved. According to the shape, material, structure and function of the workpiece, the drill bit can be divided into many types, such as high-speed steel drill bit (twist drill, group drill, flat drill), solid carbide drill bit, indexable shallow hole drill, deep hole drill, trepanning drill and interchangeable head drill bit. 2. Chip breaking and chip removal The cutting of the drill is carried out in a narrow hole, and the chips must be discharged through the drill edge groove, so the chip shape has a great influence on the cutting performance of the drill. Common chip shapes include flaky chips, tubular chips, acicular chips, conical spiral chips, ribbon chips, fan-shaped chips and powdery chips. Key Chip Control in Drilling When the chip shape is not appropriate, the following problems will arise: ① Fine chips block the cutting edge groove, affecting the drilling accuracy, reducing the life of the drill bit, and even breaking the drill bit (such as powdery chips, fan-shaped chips,dth rock bit, etc.); ② Long chips entangle the drill bit, which hinders the operation, causing the drill bit to break or preventing the cutting fluid from entering the hole (such as spiral chips, ribbon chips, etc.). How to solve the problem of improper chip shape: ① The chip breaking and chip removal effects can be improved by increasing the feed rate, intermittent feed, grinding the chisel edge, installing the chip breaker and other methods respectively or in combination, so as to eliminate the problems caused by chips. ② Professional chip-breaking drill can be used for drilling. For example, the addition of a designed chip breaker in the groove of the drill breaks the chips into more easily removed chips. The debris is smoothly discharged along the groove, and the phenomenon of blockage in the groove does not occur. Therefore, the new chip-breaking drill obtains a much smoother cutting effect than the traditional drill. At the same time, the short scrap iron makes the coolant flow to the drill tip more easily,DHD Drill bit, which further improves the heat dissipation effect and cutting performance in the processing process. Moreover, because the new chip-breaking edge penetrates the whole groove of the drill bit, it can still maintain its shape and function after many times of grinding. In addition to the above functional improvements, it is worth mentioning that the design strengthens the rigidity of the drill body and significantly increases the number of holes drilled before a single grinding. III. Drilling accuracy The accuracy of the hole is mainly composed of the hole size, position accuracy, coaxiality, roundness, surface roughness and hole burr. Factors affecting the accuracy of the hole to be machined during drilling: Expand the full text ① Bit clamping accuracy and cutting conditions, such as tool holder, cutting speed, feed rate, cutting fluid, etc.; ② Drill size and shape, such as drill length, blade shape, drill core shape, etc.; ③ Workpiece shape, such as orifice side shape, orifice shape, thickness, clamping state, etc. Reaming Reaming is caused by the oscillation of the drill during machining. The swing of the tool holder has a great influence on the hole diameter and the positioning accuracy of the hole, so when the tool holder is worn seriously, it should be replaced with a new one in time. When drilling a small hole, dhd drill bit ,dth drill bits, it is difficult to measure and adjust the swing, The drill shape when leaving the factory is the best drill shape obtained through scientific design and repeated tests. Therefore, the original edge shape should be maintained when re-sharpening. This article is from Momo's WeChat public account [UG NC Programming]. You can get the tutorial after paying attention to it. Return to Sohu to see more Responsible Editor:. wt-dthtools.com