Improving the structure of hard alloy drill bits can enhance the quality of the inner hole.
1. Grind the drill bit into a geometric shape suitable for high-speed drilling. Because high-speed drilling requires the drill bit to have good chip breaking and chip removal performance.
2. Require the grinding to come from a well centered drill bit structure to eliminate the need for center drilling guidance during drilling, while ensuring that there is no drift in the center of the inner hole when adding nuts.
3. The new drill bit breaks the traditional concept and is designed with a triple helix groove structure. According to cutting tests, the hard alloy triple helix groove structure drill bit has the following advantages:
(l) Cutting with three cutting edges can greatly improve the cutting rate compared to ordinary high-speed steel drill bits.
(2) Three spiral grooves increase the chip removal space and greatly enhance the chip removal ability.
(3) The appearance of the third cutting edge can cause the drill bit to advance in a straight line, reducing the deviation of the inner hole.
(4) By reducing the cutting force on each cutting edge and adding a third edge band, the machined inner hole can be polished, thereby reducing the surface roughness of the inner hole.
(5) A three helix groove drill bit with good rigidity can prevent the drill bit from bending or deforming when machining discontinuous surfaces, allowing it to smoothly enter and exit from the discontinuous surface without causing problems such as gnawing or scratching the inner hole surface.
(6) When a large amount of heat and chips are generated in the cutting area during drilling, using two hard alloy drill bits with spiral grooves inserted with cooling lubricant in the middle can reduce cutting heat and smoothly discharge chips. At the same time, due to the addition of two spiral groove oil holes, the drill bit no longer has a transverse edge, which greatly reduces the large axial force generated by the drill bit during processing and ensures that it stores more volume of coolant than the linear coolant hole, thus improving the cooling and lubrication effect of the drill bit. At present, this type of hard alloy drill bit can be used for precision and large parts in small deep holes with sufficient rigidity, horizontal and vertical initial bed drilling, and a hole depth/diameter ratio of 7 or more. The dimensional accuracy and surface roughness of the processed inner hole are better than those of high-speed steel drilling/reaming composite tools and drilling/reaming separately.