Cutter for machining small deep hole and machining method

Abstract

The invention provides a cutter for machining a small deep hole, which can reduce the appearance problems of cutter vibration lines, built-up edges, redeposition of materials and the like on the inner wall of the deep hole, is better in rigidity and improves the reliability. The tool comprises a tool body, the tool body comprises a tail handle, a middle handle and a tool bit, the tail handle, the middle handle and the tool bit are of an integrally-formed structure, the diameter of the middle handle is smaller than the outer diameter of a circle where the outer edge of the tool bit is located, two cutting edges are arranged at the two ends of the tool bit and distributed in a rotationally symmetrical mode, and a chip groove is formed in the tool bit and located between the two cutting edges. The chip groove extends to the lower end of the handle body of the middle handle in the axial direction.

Description

Technical Field

[0001] The invention relates to the technical field of boring cutters, in particular to a tool and a processing method for processing small deep holes. Background Art

[0002] In the field of aerospace, parts made of titanium alloy are one of the important accessories. Since such parts have to bear high loads and fatigue life, especially engine parts, the surface finish and appearance requirements are more stringent, and usually require that the surface is not allowed to have appearance defects such as chatter marks, built-up edge and redeposited materials. At present, when titanium alloy parts are processed with special tools for processing small deep holes, due to the excessive length of the cutting edge of the tool, during the processing, after the front blade of the tool is processed, the rear blade still rubs and squeezes with the deep hole wall, resulting in appearance problems such as chatter marks, built-up edge, and redeposited materials on the inner wall surface of the deep hole, making the appearance of the hole after processing not meet the standard. At the same time, the chip groove of the cutting edge of the tool is too deep and too long, which also leads to poor rigidity of the tool. Summary of the invention

[0003] In view of the problem that existing cutting tools for processing small deep holes of titanium alloy parts are prone to cause appearance problems such as chatter marks, built-up edge, and redeposited material on the inner wall of the deep holes, and the cutting tools have poor rigidity, the present invention provides a cutting tool for processing small deep holes, which can reduce the appearance problems such as chatter marks, built-up edge, and redeposited material on the inner wall of the deep holes, and at the same time has better rigidity and improved reliability.

[0004] The technical solution is as follows: a tool for processing small deep holes, comprising a tool body, characterized in that the tool body comprises a tail shank, an intermediate shank and a cutter head, the tail shank, the intermediate shank and the cutter head are an integrally formed structure, the diameter of the intermediate shank is smaller than the outer diameter of the circle where the outer edge of the cutter head is located, two cutting edges are provided at both ends of the cutter head, the two cutting edges are rotationally symmetrically distributed, there is a chip groove on the cutter head and between the two cutting edges, the chip groove extends along the axial direction to the lower end of the shank body of the intermediate shank.

[0005] The further feature is that the cutting edge comprises two side edges, the angle between the two side edges and the horizontal direction is 18° to 32°, the two side edges are connected by an arc transition, and the radius of the arc is 0.3mm to 0.8mm; The rake angle of the cutting edge to the horizontal direction is 10°~14°, and the clearance angle of the cutting edge to the vertical direction is 8°~12°; The outer diameter of the circle where the outer edge of the cutter head is located is the same as the diameter of the hole to be processed, the length of the cutter head is 2~5mm, the length of the chip groove is 5~9mm, and the diameter of the middle handle is 0.65~0.8 times the outer diameter of the circle where the outer edge of the cutter head is located; A method for machining small deep holes using the above-mentioned tool is characterized in that: The method comprises the following steps: S1, rough machining, using a drill or a milling cutter to rough-machine a small deep hole on the part to be machined, and the single-side allowance after machining is 0.02-0.07 mm; S2, finishing, use the tool to rotate clockwise at a fixed speed and reciprocate once along the axial direction of the processed hole at a fixed feed. The fixed speed of the tool is 400~900r / min and the feed is 25~100mm / min to complete the finishing.

[0006] After adopting the above structure, since the diameter of the middle handle is smaller than the diameter of the cutter head, a larger chip space can be provided during deep hole processing to avoid extrusion and friction between the chips and the hole wall. At the same time, the two cutting edges of the front end cutter head are rotationally symmetrically distributed, which can offset the radial cutting force during cutting and avoid the tool vibration phenomenon, thereby reducing the appearance problems such as tool vibration marks, built-up edges, and redeposited materials on the inner wall of the deep hole. At the same time, it adopts an integrated molding structure, and the chip groove is short and shallow, so that the tool of the present invention has better rigidity and improved reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is the front view of the overall structure of the present invention; Figure 3 It is a schematic diagram of the structure of the cutter head of the present invention; Figure 4 It is a bottom view of the cutter head structure of the present invention. DETAILED DESCRIPTION

[0008] like Figure 1 , Figure 2 As shown, a tool for processing small deep holes includes a tool body, the tool body includes a tail handle 1 at the rear end, an intermediate handle 2 in the middle, and a cutter head 3 at the front end, the tail handle 1, the intermediate handle 2, and the cutter head 3 are an integrally formed structure, thereby increasing the rigidity of the tool. The outer diameter of the circle where the outer edge of the cutter head 3 at the front end is located (i.e., the maximum cutting outer diameter of the cutter head 3) is equal to the diameter of the processed hole, the length of the cutter head part is about 2~5mm, wherein the diameter of the intermediate handle 2 is smaller than the outer diameter of the circle where the outer edge of the cutter head 3 is located, and the diameter of the intermediate handle 2 is 0.65~0.8 times the outer diameter of the circle where the outer edge of the front end cutter head 3 is located, two cutting edges are arranged at both ends of the cutter head 3, and the two cutting edges are distributed in rotational symmetry, and there is a chip groove 8 on the cutter head 3 and between the two cutting edges, and the chip groove 8 extends along the axial direction to the lower end of the handle body of the intermediate handle 2, the diameter of the tail handle 1 is not limited, and is generally equal to the mounting hole diameter of the commonly used tool handle, and the tail handle 1 can be installed on the machine tool through a traditional heat shrink tool handle or a cold press tool handle.

[0009] Further, such as Figure 3As shown, the cutting edge includes two upper and lower side edges, the angle 4 between the two side edges and the horizontal direction is 18°~32°, and the two side edges are connected by an arc transition, and the radius of the arc is 0.3mm~0.8mm.

[0010] Further, such as Figure 4 As shown, the front angle 6 of the cutting edge to the horizontal direction is 10°~14°, and the back angle of the cutting edge to the vertical direction is 8°~12°.

[0011] The method for machining a small deep hole using the tool of the present invention comprises the following steps: S1, rough machining, use a drill or milling cutter to rough-machine small deep holes on the parts to be machined, and the single-side allowance after machining is 0.02~0.07mm; S2, finishing, use the tool to rotate clockwise at a fixed speed and reciprocate once along the axial direction of the processed hole at a fixed feed. The fixed speed of the tool is 400~900r / min and the feed is 25~100mm / min to complete the finishing.

[0012] For the tool of the present invention, since the diameter of the middle shank 2 is 0.65~0.8 times the diameter of the front end cutter head 3, a larger chip space can be provided during deep hole processing to avoid squeezing and friction between the chips and the hole wall. At the same time, the two cutting edges of the front end cutter head 3 are rotationally symmetrically distributed, which can offset the radial cutting force during cutting and avoid tool vibration. After actual implementation testing, this implementation case can avoid the appearance problems such as tool vibration marks, built-up edges, and redeposited materials when finishing small deep holes in titanium alloys, improve the surface finish of the holes, and enable the parts to withstand higher fatigue loads. At the same time, compared with the traditional process of rough machining the holes first and then manually polishing, the present invention can greatly reduce the cost of deep hole finishing.

[0013] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by anyone familiar with the technology within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A tool for machining small deep holes, comprising a tool body, characterized in that: The tool body includes a tail shank, an intermediate shank and a cutter head. The tail shank, the intermediate shank and the cutter head are an integrally formed structure. The diameter of the intermediate shank is smaller than the outer diameter of the circle where the outer edge of the cutter head is located. Two cutting edges are provided at both ends of the cutter head. The two cutting edges are rotationally symmetrically distributed. There is a chip groove on the cutter head and between the two cutting edges. The chip groove extends along the axial direction to the lower end of the handle body of the intermediate shank.

2. A tool for machining small deep holes according to claim 1, characterized in that: The cutting edge includes two upper and lower side edges, the angle between the two side edges and the horizontal direction is 18°~32°, and the two side edges are connected by an arc transition, and the radius of the arc is 0.3mm~0.8mm.

3. A tool for machining small deep holes according to claim 2, characterized in that: The rake angle of the cutting edge to the horizontal direction is 10°~14°, and the back angle of the cutting edge to the vertical direction is 8°~12°.

4. A tool for machining small deep holes according to claim 3, characterized in that: The outer diameter of the circle where the outer edge of the cutter head is located is the same as the diameter of the hole to be processed, the length of the cutter head is 2~5mm, the length of the chip groove is 5~9mm, and the diameter of the middle handle is 0.65~0.8 times the outer diameter of the circle where the outer edge of the cutter head is located.

5. The method for machining a small deep hole with a tool according to claim 1, characterized in that: The method comprises the following steps: S1, rough machining, using a drill or a milling cutter to rough-machine a small deep hole on the part to be machined, and the single-side allowance after machining is 0.02-0.07 mm; S2, finishing, use the tool to rotate clockwise at a fixed speed and reciprocate once along the axial direction of the processed hole at a fixed feed. The fixed speed of the tool is 400~900r / min and the feed is 25~100mm / min to complete the finishing.

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