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Basics of drill bits.

1. The drill bit should be installed in a special packaging box to prevent the vibration from hitting each other.
2. When applying, remove the drill bit from the packaging box, and immediately put it into the machine tool spindle spring clip or the tool magazine system for automatic drill replacement. Immediately after application, put it in the box.
3. Use a tool microscope and other non-contact testing instruments to accurately measure the diameter of the drill bit to prevent the cutting edge from being injured by touching the mechanical equipment detector.
4. Some CNC drills use a precision positioning ring. Some CNC drills do not use a precision positioning ring. For example, if the precision positioning ring is used to install the deep precision positioning, it must be accurate. To keep this in mind, make every machine spindle drill the same depth. If not, there is a good chance that the drill bit will dig into the table or not into the circuit board, causing damage.
5. The damage of the drilling edge of the drill bit can be checked with a 40 times stereo microscope.
6. Always check the coaxiality of the machine tool spindle and the collet and the clamping force of the collet. Too low coaxiality will cause small diameter drills to break and large diameters. Weak clamping force will cause inconsistency between specific efficiency and setting rate, and misalignment between the collet and the drill bit.
7. The clamping length of the spring chuck on the spring chuck is 4~5 times the diameter of the drill shank.
8. Always check the presser foot of the machine tool spindle. The contact area of ​​the presser foot should be level, and it should not be shaken vertically with the machine tool spindle to avoid punching cracks and errors.
9. The dust removal effect of the planer is very good. The dust removal wind reduces the temperature of the drill bit, and friends take away the dust, reduce friction, and cause high temperature.
10. The substrate layer comprises a top layer. The lower block should be firmly and accurately positioned in the hole and groove mobile phone positioning system on the table during the planer operation. Leveling. When applying the tape, the drill bit should be avoided to drill on the tape, so that the drill bit will stick to the cutting, resulting in difficult milling and drill breakage.
11. When purchasing drill bits from manufacturers, check whether 4% of them meet the regulations. Check 100% of vacancies, wounds and cracks with a 10-15x optical microscope.
12. Regrinding the drill bit immediately can increase the application and regrinding frequency of the drill bit, increase the service life of the drill bit, and reduce the product cost and cost. Measured with a special tool microscope. Within the total length of the two main cutting edges, the damage depth should be less than 0.2mm. When regrinding, 0.25mm should be removed. Generally, the fixed shank bit can be reground 3 times, and the undercut bit can be reground 2 times. Excessive cutting reduces hole quality and precision, resulting in damage to the finished circuit board. The actual effect of excessive cutting outweighs the gain.
13. When the damage diameter is reduced by 2% compared with the original, the drill bit is damaged.
14. The basic parameters of the drill bit Under normal circumstances, the manufacturer gives the processing plant a table of drilling rate and speed parameters of the drill bit. The main parameters are only for reference. The specific processing technology staff will use the main parameters of the drill bit speed and efficiency. Usually, the main parameters are specified. It is not the same as referring to the main parameters, but the difference is not big.
Drill grinding method.
1. The cutting edge should be level with the surface of the grinding wheel.
Before grinding the drill bit, first place the main cutting edge of the drill bit and the surface of the grinding wheel on the same level surface, that is, to ensure that when the blade touches the surface of the grinding wheel, all the blades should be damaged. This is also the first step in the relative position of the drill bit and the grinding wheel, and then gradually leaning against the surface of the grinding wheel.
2. The axis of the drill bit should be inclined 60° to the surface of the grinding wheel.
This angle of view is the declination angle of the drill. At this time, if the viewing angle is incorrect, the size of the top angle of the drill bit, the shape of the main cutting edge and the inclination angle of the chisel edge will be affected at the same time. This also refers to the positional relationship between the centerline of the drill bit and the middle of the grinding wheel surface. Take 60°. This angle of view is usually clearer. Here, you need to pay attention to the relative level and angle of view of the drill bit before grinding. Both should be considered comprehensively. You don’t have to ignore the leveling angle for a better level of the blade, and you don’t have to ignore the leveling blade for a better level of the angle of view.
3. Grind from the edge to the back.
After the blade touches the grinding wheel, it cuts backward from the main cutting blade, that is, the blade of the drill gradually touches the grinding wheel, and then slowly cuts down along all the rear blades. When the drill is cutting, lightly touch the grinding wheel, grind a small amount of blades first, pay attention to the uniformity of the flame, adjust the hand clamp immediately, pay attention to the cooling of the drill, do not grind too much, causing the blade to fade, until the blade is quenched. When the blade temperature is found to be high, the drill should be refrigerated immediately.
4. The cutting edge of the drill should sway from side to side, and the tail end of the drill should not expand or shrink.
This is also the normative posture for drill cutting. The main cutting edge should sway left and right on the grinding wheel, that is, hold the hand on the front side of the drill bit and shake the drill bit on the surface of the grinding wheel evenly. However, the hand of a part of the gun stock should not be shaken, and the rear handle should be inclined upward, that is, the tail end of the drill bit should not be higher than the axis of the level of the grinding wheel, otherwise the cutting edge will be blunt and cannot be cut. This is also the most important step. How well the drill is ground has a lot to do with it. In the case of similar grinding, gradually and gently rub the front corner from the edge of the blade to make the rear edge of the blade smoother.
5. Ensure that the blade tip is aligned with the axis, and the symmetry on both sides is gradually repaired.
After grinding the cutting edge on one side of the drill, grind the cutting edge on the other side. Be sure to ensure that the cutting edge is in the middle of the drill shaft, and the cutting edges on both sides should be symmetrical. A seasoned expert will observe the symmetry of the drill bit in bright light and grind it gradually. The rake angle of the cutting edge of the drill is generally 10°-14°, the rear angle is relatively large, the cutting edge is too thin, the punching vibration is serious, the hole is trilateral or pentagon, and the cutting is needle-shaped; the rake angle is small, the shaft The axial force is relatively large, it is not easy to cut, the cutting force increases, the temperature rises, the heating of the drill bit is serious, and even drilling is not possible. The front angle grinding is suitable, sharp centering, two-edge symmetry, light drilling, no vibration, and the diameter is not easy to expand.
6. After the two are well ground, the drill bit with a relatively large hole diameter is cut.
After the drill is ground, there will be a plan at the tip of the two edges, which will endanger the precise positioning of the core of the drill. You will need to pour the lower corners behind the blade and grind the plan of the tip of the blade as small as possible. The way to do this is to firm up the drill bit, point to the view of the grinding wheel, at the root behind the blade, and pour a small groove on the tip of the blade. This is also a key component of the drill’s immobilized core and light cutting. It must be noted that when repairing the rounded corner of the tip of the blade, do not wear it on the main cutting blade, which will increase the off-angle of the main cutting blade and immediately endanger the punching.
Maintenance of drill bits.
1. When milling iron castings, please ensure sufficient cooling capacity and apply metal cutting fluid.
2. Excellent drill rigidity and slide rail clearance can improve the precision and service life of the drill bit.
3. Ensure the neatness and cleaning between the magnetic base and the product workpiece.
4. When drilling the plate, the product workpiece should be structurally reinforced. When drilling large and medium-sized parts, please ensure the reliability of the product workpiece.
5. At the beginning and end of drilling, the cutting speed should be reduced by 1/3.
6. Use air compression to assist milling, instead of using refrigerant to assist the small powdery raw materials that occur in the whole process of drilling, such as pig iron, copper casting, etc.
7. Immediately remove the iron pin coiled on the drill body to ensure smooth milling.


Post time: Feb-19-2022