A new type of drill bit which can overcome the dev

2022-07-25
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A new type of drill bit that can overcome the "Deviation" phenomenon

all drill bits will have the "Deviation" phenomenon during processing. Although this harmful phenomenon is more typical on high-speed steel bits, it will also affect the roundness, straightness and cylindricity of the hole (although to a lesser extent) due to "Deviation" when using integral cemented carbide bits. The same force that causes "Deviation" of the drill bit will also shorten the service life of the tool, especially when drilling and machining difficult to machine materials, special materials and valuable workpiece materials (such as Inconel alloy, Waspaloy high temperature nickel base alloy, duplex stainless steel, etc.) used to manufacture parts and components in aviation, energy and other industries. Rapid wear accelerates the tool breaking, and the drill bit will suddenly fail to drill 1 ~ 2 holes after the tool breaking, resulting in the shutdown of the machine tool and prolonging the processing time of key parts

due to the high cost of materials, labor and machine tools, aviation, energy and other important industries urgently need enterprises that can ensure processing safety and tool life to produce plastic products with life consistency (including new drill bits and polished drill bits) and the quality of processed holes. The new y-tech drill bit developed by Kenner metals can meet this demand. The company has re weighed the technical performance of the integral cemented carbide bit and adopted a unique drill type design - the cutting edge with asymmetric angle and three arrises

the basic idea of designing this new type of drill bit is that the conventional drill bit with two symmetrical cutting edges and two arrises will produce a certain degree of "Deviation" when drilling into the workpiece. Although the cross edge drill point has the function of centering the drill bit, it is still difficult to avoid the occurrence of "Deviation". The main geometric factors that affect the correct alignment of the drill bit can rest assured that you can understand the knowledge of all the experimental machines of our company Jinan new era assaying Instrument Co., Ltd., including the inclination angle of the horizontal edge, the grinding of the horizontal edge and the drilling sharp angle, as well as the grinding accuracy when finishing the drill bit

during drilling, the cutting speed at the center of the drill point is zero, and the cutting speed along the length of the transverse edge is also very low. Therefore, the drill point pushes the workpiece material away until the main cutting edge cuts into the workpiece. Although precise adjustment of the drill tip geometry can improve the bit alignment, the cost is to reduce the transverse edge strength. On the contrary, the horizontal edge with high strength has poor alignment and large axial thrust, but can withstand high feed rate

recent research by the Institute of production management technology and processing technology (PTW) of the University of Darmstadt in Germany shows that when the cross edge is drilled into the workpiece, it will form a concave ellipse, which will make the drill bit swing in a way similar to the pendulum motion. The drill bit will drill a triangular hole; As the drill bit continues to swing caused by the cross edge, a triangular drill point will be formed at the top of the drill bit

this cutting motion, coupled with the feed rate, is slightly similar to spiral interpolation. During the whole drilling process, the edge band of the drill usually follows the guidance of the transverse edge. As a result, the hole circularity and cylindricity are very poor, and sometimes deviate significantly from the center line

since the cutting forces of each cutting edge are not equal, when they swing with the drill, each cutting edge is on a slightly different plane. Geometric deviation (such as unequal passivation degree of cutting edge and symmetry error) produced in the grinding process of drill bit will also cause asymmetric cutting force

workpiece materials with high tensile strength will make the above problems more serious. However, the aerospace, energy, food processing and medical industries are in great need of components made of these materials. When cutting such materials, the machine operator must reduce the feed rate, thus extending the time for the cross edge to push the workpiece materials away before the main cutting edge of the drill bit cuts into the workpiece. This further aggravates the wear of the horizontal edge, and this severe wear of the horizontal edge further weakens the centering ability of the drill bit in the subsequent processing, which will continuously increase the swing of the drill bit

when machining workpiece materials with high tensile strength, cold work hardening and material elasticity will increase the cutting force, thus increasing the risk of "Deviation" of the drill bit. As a result, the roundness error of holes machined on such materials becomes larger

when drilling high tensile strength workpiece materials, typical tool wear forms include horizontal edge collapse, cutting edge collapse (usually occurs when the drill bit retreats) and edge band collapse under the cutting edge. All these wear will reduce the regrinding times of the bit, shorten the life of the bit and reduce the total value of the tool

other factors affecting drilling quality include the clamping of drill bit, the rigidity of machine tool and the performance of clamp. However, these factors are difficult to correct the error caused by the horizontal edge

balance refers to a state of equilibrium. Although the conventional drill adopts symmetrical design, it is easy to generate and maintain uncontrollable non-equilibrium cutting force in cutting. The controllable function of y-tech bit from aesthetic design to drilling process redefines the concept of balance

this new bit adopts an asymmetric design. The angle of one of the two cutting edges above the centerline of the drill bit is asymmetric. This slightly advanced cutting edge creates an overloaded unidirectional cutting force. What counteracts all these cutting forces is a guide rib behind the leading cutting edge. The direction of this controlled cutting force is precisely aligned with the reaction force of the guide rib, thus ensuring that the drill bit maintains the same tool diameter throughout the cutting process. Any potential lateral cutting force is borne by two edges set in the traditional way

in order to minimize the phenomenon of "Deviation" and swing, the horizontal edge of y-tech bit can effectively achieve self centering, and the transition time from the horizontal edge to the cutting edge is relatively short. In addition, this kind of drill is very suitable for the low feed rate usually used in machining high-temperature alloys. Among them, 3D printing and sensors related to the third industrial revolution bear the brunt of drilling, because the cutting edge with mild or moderate passivation treatment can ensure that the drill will not cause cold work hardening during cutting

because the y-tech bit eliminates the oscillation phenomenon, it not only improves the quality of the hole, but also reduces the wear of the transverse edge, cutting edge and the top of the bit, thus significantly improving the tool life. When a turbine generator manufacturer uses this drill to cut ASTM A 681 D3 (DIN x210cr12) workpiece materials, the tool life is increased by 60%, and the drill tool withdrawal damage caused by hole shape errors (such as spiral shape and top edge collapse) is eliminated

the drill bit has the tendency of "Deviation" when drilling into the workpiece. However, through the innovation of the traditional technical concept, the drilling quality of the drill bit can be significantly improved (see the table below), which is very important for the drilling of key parts

table performance comparison of drill bits for drilling double refined stainless steel under test conditions

performance indicators - y-tech drill bits - conventional solid carbide drill bits

Roundness - 13 μ m-52 μ M

cylindricity - 19 μ m-117 μ M

straightness - 20 μ m-23 μ M

parallelism - 20 μ m-36 μ M

inclination - 4 μ m-33 μ m(end)

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