The Structure And Maintenance Of Drill Bits

   A drill bit comprises a shank (1) with one or two cutting inserts (5, 5') located on a main plane (C-C). The cutting inserts (5, 5') feature short central cutting edges oriented on a common second plane (E-E). These cutting edges form a point-like central cutting edge for entering the workpiece and thereby centering the drill bit. On the shank, two chip flutes (6, 6') are provided, extending from the shank to its bottom end. On any cross-section along the shank, the chip flutes are located diametrically opposite each other in a tube plane, which extends at 90° to a common flute plane (F-F) of two flute bands on both sides of the tube. The shank exhibits maximum rigidity in this plane. The orientation of the second plane (E-E) of the central cutting edge is approximately at a 90° angle to the flute plane or the main rigidity direction (F-F) of the shank's bottom end.
A drill bit that can mitigate sudden changes in drilling conditions during drilling operations on concrete and other materials, ensuring stable drilling operations and preventing a decrease in drilling efficiency even when large chips are generated.
The cutting edge portion, which is arranged in a generally radial configuration, comprises at least two main cutting edge portions, and at least two auxiliary cutting edge portions arranged in the circumferential direction between the main cutting edge portions. The main cutting edge portion features a main cutting edge as its cutting edge, with its inner end located at the center of rotation and its outer end located at the outer edge of the rotational trajectory of the cutting edge portion
     How should a drill bit be maintained?
1. When drilling steel parts, please ensure sufficient cooling and use metal cutting fluid.
2. Good rigidity of the drill rod and clearance between the guide rails can improve the accuracy of drilling and extend the lifespan of the drill bit
3. Please ensure the flatness and cleanliness between the magnetic base and the workpiece.
4. When drilling thin plates, the workpiece should be reinforced. When drilling large workpieces, please ensure the stability of the workpiece.
5. At the beginning and end of drilling, the feed rate should be reduced by 1/3.
6. For materials that generate a large amount of fine powder during drilling, such as cast iron and cast copper, compressed air can be used to assist in chip removal instead of using cooling fluid.
7. Please promptly remove the iron chips entangled on the drill body to ensure smooth chip evacuation.
use
1. The drill bit should be placed in a specially made packaging box to avoid vibration and collision.
When in use, the drill bit taken out of the packaging box should be immediately installed into the spring chuck of the spindle or placed into the tool magazine for automatic drill bit replacement. After use, it should be promptly returned to the packaging box.
3. To measure the diameter of the drill bit, use non-contact measuring instruments such as tool microscopes to avoid damage to the cutting edge due to contact with mechanical measuring instruments.
4. Some CNC drilling machines use locating rings, while others do not. For those that use locating rings, the depth positioning of the drill bit during installation must be accurate. For those that do not use locating rings, the extension length of the drill bit when mounted on the spindle must be adjusted consistently. This is especially important for multi-spindle drilling machines, where the drilling depth of each spindle must be consistent. If it is not consistent, the drill bit may drill into the table or fail to drill through the circuit board, resulting in scrap.
5. Normally, a 40x stereo microscope can be used to inspect the wear of the cutting edge of the drill bit.
6. It is necessary to regularly check the concentricity of the spindle and the spring chuck, as well as the clamping force of the spring chuck. Poor concentricity can lead to issues such as drill breakage in small diameter drills and oversized hole diameters. Insufficient clamping force can result in a mismatch between the actual and set rotational speeds, as well as slippage between the chuck and the drill bit.
7. The clamping length of the fixed shank drill bit on the spring chuck should be 4 to 5 times the diameter of the drill shank to ensure a secure grip.
8. Regularly check the spindle presser foot. The contact surface of the presser foot should be horizontal and perpendicular to the spindle, without any wobbling, to prevent drill breakage and hole deviation during drilling.
9. The dust collection effect of the drill press should be good. The dust suction can reduce the temperature of the drill bit and simultaneously remove dust, thereby reducing the high temperatures caused by friction.
10. The substrate stack, including the upper and lower backing plates, should be securely positioned and leveled on the workbench of the drilling machine using a one-hole-one-slot positioning system. When using adhesive tape, care should be taken to prevent the drill bit from drilling through the tape, causing the drill bit to adhere to the chips and making it difficult to remove the chips and resulting in drill breakage.