Efficient cutting bits typically use one of four drill tip geometries. Among them, the tetrahedral drill tip with chisel edge is easy to grind and easy to control the grinding tolerance, but its center clearance is small. When the feed amount is large, the flank face will contact with the bottom of the hole, thus affecting the feed rate. Improvement. The other is a tapered drill tip, which has a larger center clearance than a tetrahedral drill tip, so the axial thrust generated during drilling is small, but the geometry of the drill tip is complex and it is not easy to guarantee tool manufacturing. Consistency with management. In addition to the above two types of drill tip types, there are also auger tips, which are divided into two different types: the traditional auger tip has a flute, and the chips can be discharged from the center; the new auger The tip also grinds the flute and the flank to eliminate the drilling steps and further improve the chip flow. Because the center clearance of these two drill tip designs is greater than several other drill tip geometries, it has a high feed capacity. In addition, the new auger tip has high-speed cutting capability and can be drilled with less axial thrust. The only disadvantage of this drill tip geometry is the complex grinding process required to make the drill bit. Previous Next Manual Sanitary Butterfly Valve Manual Sanitary Butterfly Valve,Clamp Butterfly Valve,Manual Butterfly Valve,Stainless Steel Butterfly Valve WENZHOU FOREVER CLASSIC TECHNOLOGY CO.,LTD , https://www.fosicvalve.com
In addition to tool life and processing speed, another major factor to consider when selecting a drill bit is the quality of the hole. In recent years, how to reduce burrs has become the focus of attention. Deburring is a typical manual process that is costly and can cause serious problems if not handled properly.
Solid carbide drills place a lot of pressure on the workpiece material during high-speed rotation and feed. Therefore, when a conventional drill type design or a drill tip angle is used, a large burr is generated at the exit of the through hole. To solve this problem, the easiest way is to increase the drill angle to 135° to 145°. The drill with the drill angle in this range can produce a disc at the exit of the hole and keep the workpiece material at all times. Under tensile stress, the material is easy to cut and not just push it out of the workpiece. Cutting edge preparation, top chamfering and other geometrical parameter optimization measures can also play a significant role in reducing burrs.
A completely different problem arises when drilling grey cast iron and ductile cast iron. These materials are more brittle and are more prone to material collapse at the exit of the through hole than burrs. Material breakage not only affects the quality of the workpiece, but can also cause damage to the drill bit. The top chamfering designed for cast iron machining allows the drill to drill the workpiece in a very smooth manner and keep cutting until the last revolution, helping to avoid material breakage.
The tip design needs to be continually adjusted based on the geometry of the flute. The number of cutting edges, the thickness of the chisel edge, the width of the flutes, and the width of the land are all factors to consider when designing the drill tip. In addition, the influence of the workpiece material cannot be ignored.
Two-slot twist drills are often the best tool choice when drilling holes in steel. This drill is easy to use, easy to regrind, and extremely fault tolerant enough to minimize runout errors and tolerate machine and workpiece instability.
A drill bit with more than 2 flutes has a performance advantage when drilling large length to diameter holes or drilling holes in workpiece materials with internal stresses such as cast steel. The three-slot drill has better guiding and self-centering capabilities during drilling due to its three belts and three cutting edges. However, since such drills cannot withstand too much torque, they are only recommended for the processing of grey cast iron and non-ferrous materials. A drill with 2 cutting edges and 4 cutting edges is also available as an optional tooling solution (especially where in-tool cooling is required).