Drilling technology encyclopedia, this must be collected _ drill bit Full-time Job

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,mining dth bit, and even breaking the drill bit (such as powdery chips, fan-shaped chips, 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,dth rock bit, 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, which further improves the heat dissipation effect and cutting performance in the processing process. Moreover, because the new chip-rifice 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, so it is better to use a drill with a thick shank and a small edge diameter with a good coaxiality between the blade and the shank. When the regrinding drill is used for machining, the reason for the decrease of hole accuracy is mostly due to the asymmetry of the back shape. Controlling the height difference of the cutting edge can effectively restrain the amount of hole expansion. Roundness of the hole Because of the vibration of the drill bit, the drilled hole shape is easy to be polygonal, and the lines like rifling appear on the hole wall. Common polygonal holes are mostly triangular or pentagonal. The reason for the triangular hole is that the drill bit has two rotary centers during drilling, and they vibrate at the frequency of exchanging once every 600. The main reason for the vibration is that the cutting resistance is unbalanced. When the drill bit rotates for one turn, the resistance is unbalanced during the second turn of cutting due to the poor roundness of the processed hole. The last ill bit and the edge surface of the cutting edge, forming curling or burrs. IV. Processing conditions of f drill life, and feed speed can be selected as the evaluation index of machining efficiency. For high speed steel  life of the drill will be reduced. Because the heat resistance of cemented carbide drill is higher than that of high-speed steel drill, the rotary speed has little effect on the life of the drill, so the method of increasing the rotary speed can be used to improve the processing efficiency of cemented carbide drill and ensure the life of the drill. 2. Reasonable use of cutting fluid The cutting of drill is carried out in the hole with narrow space, so the type of cutting fluid and the way of injection have a great influence on the life of drill and the machining accuracy of the hole. Cutting fluid can be divided into two categories: water-soluble and water-insoluble. The water-insoluble cutting fluid has good lubricity, wettability and adhesion resistance, and also has anti-rust effect. Water-soluble cutting fluid has good cooling property, no smoke and no flammability. For the sake of environmental protection, the amount of water-soluble cutting fluid is large in recent years. However, if the dilution ratio of the water-soluble cutting fluid is improper or the cutting fluid deteriorates, the service life of the tool will be greatly shortened, so attention must be paid in use. Whether it is water-soluble or non-water-soluble cutting fluid, the cutting fluid must fully reach the cutting point in use, and the flow, pressure, nozzle number and cooling mode (internal cooling or external cooling) of the cutting fluid must be strictly controlled. V. Re-sharpening of drill bit Bit regrinding discrimination Criteria for re-sharpening of drill bits are as follows: 1. Cutting edge Wear loss of chisel edge and edge land; 2. Dimensional accuracy and surface roughness of the hole to be machined 3. The color of the swarf , shape; 4. Cutting resistance (Indirect values of spindle current, noise, vibration, etc.); 5. Processing quantity, etc In actual use, accurate and convenient criteria should be determined from the above indicators according to the specific situation. When the wear loss is used as the criterion, the best regrinding period with the best economy should be found out. Because the main grinding parts are the back of the head and the chisel edge, if the wear of the drill bit is too large, the grinding time is too long, the grinding amount is too large, and the number of times of regrinding is reduced (the total service life of the tool = the service life of the tool after regrinding × the number of times of regrinding), which will shorten the total service life; When the dimensional accuracy of the hole to be machined is used as the criterion, the column gauge or limit gauge shall be used to check the cutting expansion and non-straightness of the hole. Once the control value is exceeded, it shall be re-sharpened immediately. When the cutting resistance is used as the criterion, it can be stopped automatically immediately when the set limit value (such as spindle current) is exceeded; When the processing quantity limit management is adopted, the above discrimination contents shall be integrated and the discrimination criteria shall be set. Method for sharpening drill bit When re-sharpening the drill, it is better to use a special machine tool for drill sharpening or a universal tool grinder, which is very important to ensure the service life and machining accuracy of the drill. If the original drill type is in good processing condition, it can be reground according to the original drill type; if the original drill is defective, the rear shape can be properly improved and the chisel edge can be grinded according to the use purpose. Attention shall be paid to the following points during sharpening: 1. Prevent overheating ? Avoid reducing the hardness of the drill bit; 2. Damages on the drill bit shall be (Especially the damage on the edge surface of the blade) is completely removed; 3. The drill pattern shall be symmetrical 4. Be careful not to damage the cutting edge during sharpening. , and remove the burrs after sharpening; 5. For cemented carbide drill bits ? The sharpening shape has a great influence on the performance of the drill. 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. Source: Internet. Note: This picture is reproduced on the Internet,rock drilling tools, the article is the author's independent point of view, does not represent the position of the mechanical community; if there is infringement, please contact to deal with. Return to Sohu to see more Responsible Editor:. wt-dthtools.com