CN112775468A - Novel hard alloy inner-cooling deep hole twist drill - Google Patents
Novel hard alloy inner-cooling deep hole twist drill Download PDFInfo
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- CN112775468A CN112775468A CN202110143055.8A CN202110143055A CN112775468A CN 112775468 A CN112775468 A CN 112775468A CN 202110143055 A CN202110143055 A CN 202110143055A CN 112775468 A CN112775468 A CN 112775468A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B51/00—Tools for drilling machines
- B23B51/02—Twist drills
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B51/00—Tools for drilling machines
- B23B51/06—Drills with lubricating or cooling equipment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2251/00—Details of tools for drilling machines
- B23B2251/40—Flutes, i.e. chip conveying grooves
- B23B2251/408—Spiral grooves
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- Engineering & Computer Science (AREA)
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- Drilling Tools (AREA)
Abstract
The invention discloses a novel hard alloy inner-cooling deep hole twist drill which comprises a cylindrical handle part and a cutter body arranged on the cylindrical handle part, wherein the cutter body comprises a cutting edge part and a transition neck part connecting the cylindrical handle part and the cutting edge part, the cutting edge part is provided with a chip groove, the cutting edge part adopts the design of front inverted cone and back parallel core thickness, the chip groove is intersected with the solid part of the cutter body to form two cutting auxiliary edges and two blade sections, the cutting edge part is provided with two rear cutter faces and two chip grooves, the two rear cutter faces are intersected to form a chisel edge, the two rear cutter faces are respectively intersected with the two chip grooves to form two main cutting edges, the two rear cutter faces are respectively intersected with the two chip grooves to form two cutting inner edges, and the cutting front angles of the main cutting edges. The novel hard alloy inner-cooling deep hole twist drill provided by the invention solves the problems of cutter abrasion, cutting edge breakage, drill rod breakage and the like caused by high cutting temperature, unsmooth chip removal, poor cutter rigidity and easy vibration and deflection in drilling.
Description
Technical Field
The invention belongs to the technical field of deep-hole twist drills, and particularly relates to a novel hard alloy inner-cooling deep-hole twist drill.
Background
In metal cutting, the hole drilling process accounts for about 40-50% of the total cutting process, especially more in the aerospace and automobile industries, and the production of drill bits accounts for about 60% of the total cutter production. Among them, the twist drill is one of the most common hole drilling tools and is also one of the tools with the largest loss amount in the mechanical cutting process, and the deep hole twist drill is used for deep hole processing in which the ratio of the drilling depth to the drilling diameter is not less than 12.
Hole drilling is a processing mode in a semi-closed state, and due to the semi-closed state, friction between a cutter and a workpiece is large and cutting temperature is high in the drilling process. Compared with the common twist drilling, the deep hole drilling and chip removal distance is longer, when the cooling liquid pressure is insufficient, the chips can not rapidly take away the heat generated in the cutting process, so that the cutting edge of the drill bit can be subjected to plastic deformation abrasion caused by high cutting temperature, and simultaneously, the chips are easy to block, so that the chips are blocked or the tipping of the drill bit is caused, and even the drill bit is broken due to too large torque.
In addition, because the deep-hole twist drill has large overhang amount and poor process system rigidity, vibration is easy to generate in the drilling process, so that the cutting positioning precision is poor, a drill hole is easy to deflect, and even a drill bit is broken when the drill hole is serious, and the processing precision and the production efficiency are influenced. Therefore, a novel hard alloy inner-cooling deep hole twist drill needs to be designed to solve the problems of high cutting temperature, unsmooth chip removal, poor cutter rigidity, easy vibration and deflection of drilling, cutter abrasion, cutting edge breakage, drill rod breakage and the like in deep hole machining.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide a novel hard alloy inner-cooling deep hole twist drill.
In order to achieve the purpose and achieve the technical effect, the invention adopts the technical scheme that:
a novel hard alloy inner-cooling deep hole twist drill comprises a cylindrical handle part and a cutter body arranged on the cylindrical handle part, wherein the cutter body comprises a cutting edge part and a transition neck part used for connecting the cylindrical handle part and the cutting edge part; the cutting edge part is provided with two symmetrical spiral chip grooves along the axis of the cutter body, and the chip grooves and the solid part of the cutter body are intersected to form two cutting auxiliary edges and two blade sections; the outer diameter of the cutting edge part is provided with an inverted cone, the front part of the core thickness of the cutting edge part is provided with a front core thickness, and the rear part of the core thickness of the cutting edge part is provided with a rear core thickness; the cutting edge part is provided with two rear cutter faces and two chip grooves, the two rear cutter faces are intersected to form a chisel edge, the two rear cutter faces and the two chip grooves are respectively intersected to form two main cutting edges, and the two rear cutter faces and the two chip grooves are respectively intersected to form two cutting inner edges; the main cutting edge, the cutting inner edge and the arc transition edge for connecting the main cutting edge and the cutting inner edge are connected to form a cutting edge, and the cutting rake angles of the main cutting edge and the cutting inner edge are different; the intersection of the cutting edge and the cutting auxiliary edge is provided with a tool nose chamfer, and the included angle of the two cutting edges forms a vertex angle.
Further, the cutter body material is selected from 10 percent of cobalt and K with fracture toughnessIC10.2 to 10.5MPa m1/2The submicron crystal grain hard alloy inner-cooling bar stock.
Further, the diameter d of the cylindrical shank1Is greater than or equal to the diameter d of the cutting edge part2Minimum even number of (d), diameter of cutting edge part d2Greater than the diameter d of the transition neck3Diameter d of cutting edge2Is 3 mm-10 mm.
Further, the diameter d of the cutting edge portion2Is provided with an inverted cone with a length lo8-10 mm and the back taper value BT of 0.35/100 mm.
Furthermore, the end section groove shape of the chip groove is formed by tangency of a plurality of sections of arcs with different radiuses (R1 ≠ R2 ≠ R3) and straight line sections (l), and the groove surface is in smooth transition.
Further, the front core thickness d of the cutting edge portiono1Is the diameter d of the cutting edge20.30-0.35 times, the thickness of the front core decreases from front to right along the central axis of the diameter, and the thickness d of the rear coreo2Is the diameter d of the cutting edge20.25-0.30 times of the thickness of the back core, the thickness of the back core is the thickness of the parallel core, and the thickness of the back core is not increased by the thickness of the core.
Further, the length l of the cutting edge part1Is the diameter d of the cutting edge26-10 times of the length of the chip groove2Is the diameter d of the cutting edge212-30 times of the total weight of the powder.
Further, the land ratio (l) of the cutting edge portion3/l4) Is 9:10, the helical angle beta of the cutter body is 28-35 degrees.
Further, a cutting rake angle γ of the main cutting edgeoIs 4 to 6 degrees, and the cutting rake angle of the cutting inner edge is 0 degree.
Furthermore, the cutting edge comprises an edge back and an edge zone, the edge zone of the cutting edge part is provided with two edge zones, and the second edge zone is arranged in the middle of the edge back.
Further, the flank face of the cutting edge part is of a four-plane blade shape, the cutting edge of the cutting edge part is a straight edge, the distance between the two flank faces of the cutting edge part is 0.05 mm-0.15 mm, and the first relief angle alpha of the flank face1Is 8 to 10 degrees and a second relief angle alpha2The angle is 20 to 23 degrees, and the vertex angle of the cutting edge part
Is 135-140 degrees.
Furthermore, passivation treatment is adopted before the cutter body coating, and a titanium aluminum nitride coating is arranged on the cutting edge part.
Compared with the prior art, the invention has the beneficial effects that:
1) the spiral chip removal groove formed by tangency of the multi-section circular arc and the straight line segment is designed, rigidity and chip removal performance are considered, and the durability and cutting efficiency of the cutter are improved;
2) the design of the double-edged strip enhances the guidance and supporting functions of drilling processing, ensures the straightness and position degree of a drilled hole, and improves the smoothness of the hole wall;
3) the design of a large internal cooling hole of the drill bit is matched with the reasonable selection of the groove-back ratio, so that the cutting cooling, lubricating and chip removal performances are improved;
4) the main cutting edge and the cutting inner edge adopt different cutting rake angles, so that the chips are shunted and additional strain is generated, and the cutting chip breaking performance of the drill bit is improved;
5) the design of combining the four-plane edge type with the straight cutting edge enhances the cutting edge strength and cutting sharpness while improving the cutting centering precision.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a cross-sectional view of a core of the cutting edge of the present invention;
FIG. 3 is a schematic view of a partial structure of the cutting edge portion of the present invention;
FIG. 4 is an end cross-sectional view of a flute of the present invention;
FIG. 5 is a schematic end view of a cutting edge portion of the present invention;
FIG. 6 is a schematic view of the cutting rake angle of the main cutting edge of the present invention;
the cutting edge comprises a cylindrical handle part 1, a cutting edge part 2, a transition neck part 3, a chip groove 4, a cutting auxiliary edge 5, a cutting edge lobe 6, a blade ridge 601, a blade back 602, a blade band 7, a rear cutter face 8, a chip groove 9, a cross edge 10, a main cutting edge 11, a cutting inner edge 12, an arc transition edge 13, a cutting edge 14 and a cutter tip chamfer.
Detailed Description
The following detailed description of the embodiments of the present invention is provided to enable those skilled in the art to more easily understand the advantages and features of the present invention, and to clearly and clearly define the scope of the present invention.
As shown in fig. 1-6, a novel hard alloy inner-cooling deep hole twist drill comprises a cylindrical handle portion 1 and a cutter body arranged on the cylindrical handle portion 1, wherein the cutter body comprises a cutting edge portion 2 and a transition neck portion 3 used for connecting the cylindrical handle portion 1 and the cutting edge portion 2; the cutter body material is selected from 10 percent of cobalt and K with fracture toughnessICHigher submicron-grain hard alloy inner-cooling bar stock; diameter d of the cylindrical shank 11Is greater than or equal to the diameter d of the cutting edge part 22Minimum even number of (d), diameter d of cutting edge part 22Is 3 mm-10 mm.
As shown in fig. 2, because the deep-hole twist drill has a long overhang, in order to reduce the friction between the tool and the hole wall during drilling, the outer diameter (the maximum diameter of the twist drill) of the cutting edge portion 2 is provided with a back taper, and the length l of the back taper is equal to the length of the back tapero8-10 mm, and the back taper value BT is 0.35/100mm, namely every 100mm, the back taper gradual reduction of the cutter is 0.35 mm; meanwhile, the transition neck 3 adopts a clearance design, and the diameter d of the cutting edge part 22Greater than the diameter d of the transition neck 33。
As shown in fig. 3-4, the cutting edge part 2 is provided with two symmetrical helical chip grooves 4 along the axis of the cutter body, the end section groove shape of the chip groove 4 is formed by tangency of a plurality of circular arcs with unequal radiuses (R1 ≠ R2 ≠ R3) and a straight line segment (l), and the groove surface is in smooth transition.
The cross section shape of the chip removal groove 4 of the deep hole twist drill not only influences the rigidity and chip containing space of the tool body, but also influences the formation and discharge of chips and the inflow and discharge of cutting fluid, and in addition, influences the shape and strength of a main cutting edge, adopts the forming design of the spiral chip removal groove 4, gives consideration to the rigidity and the chip removal performance, and improves the durability and the cutting efficiency of the tool. The common twist drill can also be provided with a drill core increment to improve the rigidity of the cutter, but for the deep-hole twist drill, the drill core increment can cause the space of a chip groove of the cutter to be gradually reduced, so the core thickness of the cutting edge part 2 adopts the design of front inverted cone and back parallel core thickness, the front part of the core thickness of the cutting edge part 2 is provided with a front core thickness, the diameter of the front core thickness is gradually reduced from front to right along the direction of a central axis, and the front core thickness do1Is a diameter d20.30-0.35 times, the rear part of the core thickness of the cutting edge part 2 is provided with a rear core thickness which is parallel to the core thickness and has no core thickness increment, and the rear core thickness do2Is a diameter d20.25 to 0.30 times of the amount of the active ingredient.
The chip groove 4 and the solid body part of the cutter body are intersected to form two cutting auxiliary edges 5 and two blade lands 6, each blade land 6 comprises a blade back 601 and a blade zone, the blade land 6 of the cutting edge part 2 is provided with two blade zones, and the blade zone in the middle of the blade back 601 in the two blade zones is called as a second blade zone 602; the cutting edge 602 of the deep-hole twist drill plays a role in guiding and correcting when used for drilling a cutter so as to ensure the straightness and the position degree of a drilled hole, and simultaneously, the double-edged ribbon drill bit is used for reducing the friction between the cutter body and the processed hole wall, so that the guiding property can be further enhanced, and the smoothness of the hole wall is improved. Edge length l of cutting edge part 21Is a diameter d26-10 times of the length of the chip groove 42Is a diameter d212-30 times of the total weight of the powder.
Generally, larger inner cooling holes of the tool can pass more cooling medium in the same unit time, so that chip removal is facilitated, but the rigidity and strength of the drill bit are weakened by the large-diameter inner cooling holes. While the flute-to-back ratio of the drill bitThe relationship between the rigidity of the drill bit and the chip containing and discharging is visually reflected. Within a certain range, the reasonable groove-back ratio can effectively improve the chip removal performance of the cutter while ensuring the rigidity of the cutter. The deep hole twist drill adopts the design of large internal cooling hole and the groove-back ratio (l) of the cutting edge part 23/l4) Is 9:10, and the value range of the helical angle beta of the cutter body is 28-35 degrees.
As shown in fig. 5-6, the cutting edge portion 2 is provided with two flank faces 7 and chip flutes 8, the two flank faces 7 intersect to form a chisel edge 9, the two flank faces 7 intersect with the two chip flutes 4 to form two main cutting edges 10, and the two flank faces 7 intersect with the two chip flutes 8 to form two cutting inner edges 11; the cutting tool comprises a main cutting edge 10, a cutting inner edge 11 and an arc transition edge 12 for connecting the main cutting edge 10 and the cutting inner edge 11, which are connected to form a cutting edge 13; since the cutting rake angles of the main cutting edge 10 and the cutting inner edge 11 are also different, the chip flow directions are also different, so that the internal stress between two sections of chips is changed, and the chips generate additional strain, and the chips are easier to break. Cutting rake angle γ of the main cutting edge 10oIs 4 DEG to 6 DEG, and the cutting rake angle of the cutting inner edge 11 is 0 deg.
The rear cutter face of the cutting edge part 2 forms a four-plane blade shape, and the cutting edge is a straight edge; compared with the existing double-cambered-surface edge type, the four-plane edge type structure is simpler, the chip containing space is larger, the requirement on blade grinding is low, the cutting centering precision is high, and the strength and cutting sharpness of the cutting edge are greatly improved by combining the design of a straight cutting edge. However, since the chisel edge of the four-plane-edge type is short, the chisel edge length is usually adjusted by controlling the distance between the back lines of the two flank faces, and the distance between the back lines of the two flank faces 7 of the cutting edge part 2 is 0.05 to 0.15 mm. Meanwhile, in order to increase the clearance between the flank of the drill and the machined surface of the bottom of the hole and reduce frictional resistance, the first relief angle α of the flank 7 of the cutting edge1Is 8 to 10 degrees and a second relief angle alpha2Is 20-23 degrees.
A tool nose chamfered edge 14 is arranged at the intersection of the cutting edge 13 and the cutting auxiliary edge 5, the tool nose chamfered edge 14 can effectively improve the strength of the tool nose and eliminate or avoid the occurrence of tipping, damage or plastic deformation abrasion of the tool nose caused by the concentration of cutting stress; clamping of two cutting edges 13The angle forms a vertex angle, the vertex angle of the cutting edge part 2
Is 135-140 degrees.
The drill bit can effectively improve the finish degree of the surface of the groove of the cutter through the polishing treatment of the grinding wheel, but the cutting edge of the drill bit still has microscopic gaps with different degrees, so that the cutting edge can be smoothened by passivating with a nylon wheel brush or a manual file before the coating of the drill bit, the defect of tipping is reduced, but the passivation amount of the drill bit cannot be too large or too small, and the passivation amount is too small, so that the tipping of the cutting edge is easy to realize; the passivation amount is too large, and the front angle of the cutting edge is a negative value, so that the cutting resistance is increased. The cutter passivation amount of the invention is about 1/2 of the feed amount, and simultaneously, the cutter is immersed into walnut powder by a vertical passivation machine for rotary passivation, thereby realizing uniform polishing of the cutter groove, improving the surface quality of the cutter groove and enhancing the adhesive force of the cutter coating.
After the drill bit is passivated, the surface (the cutting edge part 2) of the drill bit is coated in a Physical Vapor Deposition (PVD) mode and is combined with an aluminum titanium nitride (AlTiN) coating. The AlTiN coating has good chemical stability, high hot hardness, small friction coefficient, high wear resistance and strong film-base binding force; meanwhile, because the Al concentration in the film layer is higher, a layer of extremely thin amorphous Al can be generated on the surface of the cutter during cutting processing2O3And a hard inert protective film is formed to play a role of a thermal barrier, so that the high-temperature oxidation resistance of the surface of the cutter is effectively improved. In addition, AlTi can effectively improve the lubricity of the surface of the cutter groove.
The parts of the invention not specifically described can be realized by adopting the prior art, and the details are not described herein.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A novel hard alloy inner-cooling deep hole twist drill is characterized by comprising a cylindrical handle part and a cutter body arranged on the cylindrical handle part, wherein the cutter body comprises a cutting edge part and a transition neck part used for connecting the cylindrical handle part and the cutting edge part, the cutting edge part is provided with a spiral chip groove, the outer diameter of the cutting edge part is provided with an inverted cone, the front part of the core thickness of the cutting edge part is provided with a front core thickness, the rear part of the core thickness of the cutting edge part is provided with a rear core thickness, the chip groove and the solid part of the cutter body are intersected to form two cutting auxiliary blades and two blade sections, the cutting edge part is provided with two rear cutter faces and two chip grooves, the two rear cutter faces are intersected to form a cross blade, the two rear cutter faces and the two chip grooves are respectively intersected to form two cutting inner blades, and the main cutting blades, the cutting inner blades and the arc transition blade used for connecting the main, the cutting rake angles of the main cutting edge and the cutting inner edge are different, a tool nose chamfer is arranged at the intersection of the cutting edge and the cutting auxiliary edge, and the included angle of the two cutting edges forms a vertex angle.
2. The novel hard alloy inner-cooling deep hole twist drill as claimed in claim 1, wherein the end section groove shape of the chip groove is formed by tangency of a plurality of sections of circular arcs with unequal radii and straight line sections, and the groove surface is in smooth transition.
3. The novel hard alloy inner-cooling deep-hole twist drill as claimed in claim 1, wherein the front core thickness of the cutting edge part is 0.30-0.35 times of the diameter of the cutting edge part, and the diameter of the front core thickness decreases progressively from front to right along the central axis direction.
4. The novel hard alloy inner-cooling deep-hole twist drill as claimed in claim 1, wherein the rear core thickness of the cutting edge part is 0.25-0.30 times of the diameter of the cutting edge part, and the rear core thickness is parallel core thickness.
5. The novel hard alloy inner-cooling deep hole twist drill according to claim 1, wherein the land comprises a land and a land, and the land in the middle of the land is the second land.
6. The novel hard alloy inner-cooling deep-hole twist drill as claimed in claim 1, wherein the flank face of the cutting edge portion is of a four-plane-edge type, the cutting edge is in a straight edge form, and the distance between the two flank faces of the cutting edge portion is 0.05 mm-0.15 mm.
7. The novel hard alloy inner-cooling deep-hole twist drill as claimed in claim 1, wherein the diameter of the cylindrical shank is not less than the minimum even value of the diameter of the cutting edge part, the diameter of the cutting edge part is greater than the diameter of the transition neck part, the edge length of the cutting edge part is 6-10 times of the diameter of the cutting edge part, the groove length of the chip groove is 12-30 times of the diameter of the cutting edge part, and the diameter of the cutting edge part is 3-10 mm.
8. The novel hard alloy inner-cooling deep-hole twist drill as claimed in claim 1, wherein the length of the back taper is 8 mm-10 mm, and the back taper value is 0.35/100 mm.
9. The novel hard alloy inner-cooling deep-hole twist drill as claimed in claim 1, wherein the flute back ratio of the cutting edge portion is 9:10, the helix angle is 28 degrees to 35 degrees, and the apex angle is 135 degrees to 140 degrees.
10. The novel hard alloy inner-cooling deep hole twist drill as claimed in claim 1, wherein the cutting rake angle of the main cutting edge is 4-6 °, and the cutting rake angle of the cutting inner edge is 0 °.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110143055.8A CN112775468A (en) | 2021-02-02 | 2021-02-02 | Novel hard alloy inner-cooling deep hole twist drill |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110143055.8A CN112775468A (en) | 2021-02-02 | 2021-02-02 | Novel hard alloy inner-cooling deep hole twist drill |
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| CN112775468A true CN112775468A (en) | 2021-05-11 |
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| CN202110143055.8A Pending CN112775468A (en) | 2021-02-02 | 2021-02-02 | Novel hard alloy inner-cooling deep hole twist drill |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115770902A (en) * | 2022-12-20 | 2023-03-10 | 一汽丰田发动机(长春)有限公司 | Honing workbench for negative chamfer of main cutting edge of drill bit and application |
-
2021
- 2021-02-02 CN CN202110143055.8A patent/CN112775468A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115770902A (en) * | 2022-12-20 | 2023-03-10 | 一汽丰田发动机(长春)有限公司 | Honing workbench for negative chamfer of main cutting edge of drill bit and application |
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