A method for cutting grooves of thin-walled guide sleeves

Abstract

The invention provides a method for cutting a groove of a thin-walled guide sleeve, which is processed by a special tool. The special tool comprises a tool body and a cutting part, the head of the cutting part is provided with an open groove and two cutting edges, and the cutting part is provided with two convex edges, a first chip breaking groove and two second chip breaking grooves on the side where the front cutting faces of the two cutting edges are located, comprising the following steps: roughly turning the groove of the thin-walled guide sleeve, leaving a processing allowance of 0.2mm-0.25mm; the cutting part feeds from the first groove wall of the groove to ensure that the cutting part is perpendicular to the groove bottom, and finely turns the first groove wall until the cutting edge moves to the groove bottom, and a boss is formed in the open groove; retracting the tool; the cutting part feeds from the second groove wall of the groove to ensure that the cutting part is perpendicular to the groove bottom, and finely turns the second groove wall until the cutting edge moves to the groove bottom; transversely cutting the cutting part from the bottom end of the second groove wall to the bottom end of the first groove wall; and using high-pressure water to flush the cut iron chips during cutting.

Description

Technical Field

[0001] The invention relates to the field of guide sleeve processing, in particular to a method for cutting a groove of a thin-wall guide sleeve. Background Art

[0002] With the development of coal mine machinery manufacturing industry, the support height of hydraulic supports is getting higher and higher, and the size of hydraulic cylinders is constantly enriched, which puts forward higher requirements on the processing accuracy and quality stability of thin-walled guide sleeves. Compared with ordinary guide sleeves, the groove structure design of the inner and outer walls of thin-walled guide sleeves is relatively compact. In order to ensure the reliability of the seal, especially for large-diameter thin-walled guide sleeves, the groove design size is deeper and the groove wall thickness is thinner. During the processing, it is easily affected by cutting and vibration. At the same time, because the overall thickness of the thin-walled guide sleeve is compared with the radial and axial dimensions, its specific gravity is very different, resulting in the thin-walled guide sleeve. The rigidity is weak and it is easy to deform, which makes the traditional tool unable to meet the processing accuracy requirements of the thin-walled guide sleeve.

[0003] After analysis, it is found that it is difficult to ensure the machining accuracy of the groove wall and groove bottom of the thin-walled guide sleeve groove. The main reasons are as follows: (1) The cutting edge of the tool is wide, and the contact area is large when machining the groove bottom. The tool is prone to vibration, resulting in poor groove bottom roughness. At the same time, tool vibration is also likely to cause groove depth or width deviations and guide sleeve roundness deviations. (2) Traditional tools are not easy to automatically break chips when machining grooves, and long strips of iron chips are generated. They are entangled on the tool or workpiece, easily scratching the workpiece and causing tool damage, thereby affecting the automatic cycle of the machine tool and even destroying the normal operation of the entire automation line.

[0004] In view of the problems of low machining accuracy, low machining efficiency, and difficulty in chip breaking in the fine turning of thin-walled guide sleeve grooves, it is urgent to explore an automatic chip breaking tool and cutting method for fine turning of thin-walled guide sleeve grooves to improve machining efficiency, reduce tool vibration, effectively control chips, realize automatic chip breaking, and achieve a machining accuracy of roughness ≤Ra1.6. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the prior art and thereby provide a thin-wall guide sleeve groove cutting method which has scientific design, high machining accuracy, high machining efficiency and automatic chip breaking.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a method for cutting a groove of a thin-walled guide sleeve, which is processed by a special tool. The special tool comprises a tool body and a cutting part, the root of the cutting part is connected to the end of the tool body, the head of the cutting part is provided with an open groove and two cutting edges, the groove bottom of the open groove is recessed toward the root of the cutting part, and the two cutting edges are symmetrically arranged at the two side ends of the open groove; the main cutting edges of the two cutting edges are located on the end face of the head of the cutting part, and the open groove is located in the direction of the secondary back cutting faces of the two cutting edges, and the cutting part is provided with two convex ridges, a first chip breaking groove and two second chip breaking grooves on the side faces where the front cutting faces of the two cutting edges are located, the two convex ridges are arranged in a one-to-one correspondence with the two cutting edges, the convex ridges extend from the tip of the cutting edge to the root of the cutting part, and are connected as a whole at the root to form a convex ridge platform, the two convex ridges are arranged around the outside of the first chip breaking groove, and the outside of the convex ridge and the tip of the cutting edge form the second chip breaking groove;

[0007] The following steps are involved:

[0008] Step S1: Rough turning the groove of the thin-walled guide sleeve, leaving a machining allowance of 0.2mm-0.25mm;

[0009] Step S2: the cutting part feeds from the first groove wall of the groove to ensure that the cutting part is perpendicular to the groove bottom, and fine turning the first groove wall until the cutting edge moves to the groove bottom, and a boss is formed in the open groove;

[0010] Step S3: retract the knife;

[0011] Step S4: the cutting part feeds from the second groove wall of the groove to ensure that the cutting part is perpendicular to the groove bottom, and finish turning the second groove wall until the cutting edge reaches the groove bottom;

[0012] Step S5: cutting the cutting portion transversely from the bottom end of the second groove wall to the bottom end of the second groove wall;

[0013] Among them, in step S2, step S4 and step S5, high-pressure water is used to flush the cut iron chips.

[0014] Based on the above, the tool tip adopts a wiper blade, and the wiper blade is composed of 3-6 arcs with different radii, and the radius Rn of each arc is between 0.1mm and 0.2mm.

[0015] Based on the above, in step S2, step S4 and step S5, the cutting speed is 2500 mm / min-3500 mm / min, the machining feed is 0.1 mm-0.2 mm, and the cutting depth is 0.15 mm-0.25 mm.

[0016] Based on the above, the machining allowance in step S1 is 0.2 mm, and in steps S2, S4 and S5, the cutting speed is 2500 mm / min-3000 mm / min, the machining feed is 0.1 mm-0.15 mm, and the cutting depth is 0.15 mm-0.2 mm.

[0017] Based on the above, the machining allowance in step S1 is 0.25 mm, and in steps S2, S4 and S5, the cutting speed is 3000 mm / min-3500 mm / min, the machining feed is 0.15 mm-0.2 mm, and the cutting depth is 0.2 mm-0.25 mm.

[0018] Based on the above, in step S2, step S4 and step S5, the tool does not rotate but the guide sleeve rotates to maintain continuous cutting.

[0019] Based on the above, the width L1 of the cutting edge is 0.6 mm-0.8 mm.

[0020] Based on the above, the width Lc of the second chip breaking groove at the tool tip is 0.18 mm-0.4 mm.

[0021] Based on the above, the included angle γ between the rake face and the base surface of the cutting edge is 15°-20°, the main cutting edge of the cutting edge is passivated at 0.05mm-0.1mm, and the chamfer angle η at the tip of the cutting edge is 3°-6°.

[0022] Based on the above, the overall blade width L of the cutting portion is 4 mm.

[0023] The present invention has outstanding substantive features and significant progress compared to the prior art. Specifically, the present invention has the following advantages:

[0024] (1) The two cutting edges are separated by the open groove, which can reduce the width of a single cutting edge, thereby reducing the width of the iron chips cut off and making the iron chips easier to break; when the groove wall of the guide sleeve groove is precision-turned, it can be turned from the groove mouth to the groove bottom, and the iron chips cut off are mainly blocked by the convex ridges and curled toward the second chip breaking groove, thereby playing an auxiliary chip breaking role; when the groove bottom of the guide sleeve groove is precision-turned, the tool can be moved from the bottom end of one side of the groove wall to the bottom end of the other side of the groove wall, and at the starting position of precision-turning the groove bottom, part of the groove bottom that has not been precision-turned will fall into the groove bottom. In the open groove, this part of the groove bottom is cut by the inner side of the cutting edge, and is mainly blocked by the convex ridge, curling toward the first chip breaking groove, producing threaded iron chips narrower than the width of the cutting edge, which plays an auxiliary chip breaking role. The remaining groove bottom is cut by the outer side of the cutting edge, and is mainly blocked by the convex ridge, curling toward the second chip breaking groove, which plays an auxiliary chip breaking role. During the processing, with the impact of high-pressure water, the iron chips can be broken in time to avoid the formation of long strips of iron chips, thereby ensuring the chip breaking effect and protecting the workpiece surface from being scratched and the tool from being entangled and damaged.

[0025] (2) The width of a single cutting edge is reduced, and the contact area is smaller when machining the groove bottom, so that the vibration amplitude of the tool is also smaller, thereby improving the smoothness of the machined surface and avoiding excessive tolerances in the depth, width, and roundness of the groove of the thin-walled guide sleeve.

[0026] (3) Due to the good chip breaking effect and small vibration amplitude, this tool can maintain smooth and continuous cutting when finishing the groove of the thin-walled guide sleeve, thereby improving the processing efficiency; the normal speed can achieve a processing accuracy of roughness ≤Ra1.2, and further increase the processing speed, it can also achieve a processing accuracy of roughness ≤Ra1.6.

[0027] (4) The setting of the convex ridge platform can improve the strength of the cutting part. The width of the cutting edge is suitable, which can not only reduce the width of the iron chips, but also maintain a certain strength to avoid being easily broken. The open groove cooperates with the cutting edge to alleviate the impact of the tool at the moment of cutting in, improve the shockproof performance, and make the tip of the tool not easy to break.

[0028] (5) The open groove is a V-shaped groove, which is better in force bearing, easier to produce, and reduces manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a stereoscopic view of the thin-wall guide sleeve groove automatic chip breaking cutting tool of the present invention.

[0030] Figure 2 It is a top view of the thin-wall guide sleeve groove automatic chip breaking cutting tool of the present invention.

[0031] Figure 3It is a schematic diagram of the cutting edge in the present invention.

[0032] Figure 4 It is a schematic diagram of the wiper blade in the present invention.

[0033] Figure 5 It is a schematic structural diagram of the thin-wall guide sleeve processed in the present invention.

[0034] Figure 6 It is a schematic diagram of the thin-walled guide sleeve groove being processed by the thin-walled guide sleeve groove automatic chip breaking cutting tool in the present invention.

[0035] In the figure: 1. tool body; 2. cutting part; 3. V-shaped groove; 4. cutting edge; 5. convex ridge; 6. first chip breaking groove; 7. second chip breaking groove; 8. convex ridge platform; 9. heat dissipation groove; 10. guide sleeve; 11. groove. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0037] Example 1

[0038] like Figure 1-4 As shown, a thin-wall guide sleeve groove automatic chip breaking cutting tool includes a tool body 1 and two cutting parts 2, the roots of the two cutting parts 2 are connected to the ends of the tool body 1, and the tool body 1 and the cutting parts 2 are integrally formed and made of cemented carbide.

[0039] The head of the cutting part 2 is provided with an open V-shaped groove 3 and two cutting edges 4. The bottom of the open V-shaped groove 3 is recessed toward the root of the cutting part 2. The two cutting edges 4 are symmetrically arranged at the two side ends of the open V-shaped groove 3, so that a gap is formed between the two cutting edges 4, so that the width of a single cutting edge 4 becomes narrower. On the one hand, the cutting width can be reduced, and the iron chips become narrower and easier to break; on the other hand, the contact area between the two can be reduced when processing the bottom of the groove, thereby reducing the vibration amplitude of the tool and improving the processing accuracy; in addition, the open V-shaped groove 3 and the cutting edge 3 cooperate with each other, and can also alleviate the impact of the tool at the moment of cutting in (the gap in the middle makes the cutting edge 3 have a certain elasticity), improve the shockproof performance, and make the tip of the tool not easy to break.

[0040] The main cutting edges of the two cutting edges 4 are located on the head end face of the cutting part 2, and the open V-shaped groove 3 is located in the direction of the secondary back cutting edge of the two cutting edges 4. The cutting part 2 is provided with two ridges 5, a first chip breaking groove 6 and two second chip breaking grooves 7 on the side where the front cutting edges of the two cutting edges 4 are located. The two ridges 5 are arranged one by one with the two cutting edges 4. The ridges 5 extend from the tip of the cutting edge 4 to the root of the cutting part 2 and are connected at the root to form a ridge platform 8. The two ridges 5 are surrounded by the outside of the first chip breaking groove 6, and the outside of the ridges 5 and the tip of the cutting edge 2 form the second chip breaking groove 7; the ridges 5 can guide the direction of the iron chips during the cutting process of the cutting edge 2, and use the first chip breaking groove 6 and the second chip breaking groove 7 to play an auxiliary chip breaking role. The setting of the ridge platform 8 improves the strength of the cutting part 4.

[0041] Among them, the width L1 of the cutting edge 4 is 0.6mm-0.8mm. After experiments, when the width of the cutting edge 4 exceeds 0.8mm, the iron chips become wider and less easy to break, and the ideal chip breaking effect cannot be achieved. When the width of the cutting edge 4 is less than 0.6mm, the strength becomes weaker and it is easy to be broken during the cutting process.

[0042] The width Lc of the second chip breaking groove 7 at the blade tip is 0.18-0.4 mm. Within this range, the guiding direction of the iron chips is better and the iron chips are easier to break.

[0043] The overall blade width L of the cutting portion 2 is 4 mm, and the angle α between the two side walls of the open V-shaped groove 3 is 100°-120°.

[0044] The included angle γ between the rake face and the base surface of the cutting edge 4 is 15°-20°, the main cutting edge of the cutting edge 4 is passivated at 0.05mm-0.1mm, and the chamfer angle η at the tip of the cutting edge 4 is 3°-6°.

[0045] The tool tip adopts a wiper blade, which is composed of 3-6 arcs of different radii, and the radius Rn of each arc is between 0.1mm and 0.2mm. The wiper blade can further improve the processing efficiency and processing accuracy. Specifically, when the tool tip does not adopt a wiper blade, the processing feed of 0.07mm-0.1mm can ensure that the roughness of the groove wall and the groove bottom is ≤Ra1.6. When the tool tip adopts a wiper blade, the roughness can be guaranteed to be ≤Ra1.2 under the premise of processing feed of 0.1mm-0.15mm, and the roughness can be guaranteed to be ≤Ra1.6 under the premise of processing feed of 0.15mm-0.2mm.

[0046] The first chip breaking groove 6 is semi-elliptical, with a semi-major axis La of 2 mm and a semi-minor axis Lb of 1 mm; the second chip breaking groove 7 extends along the trajectory of the convex ridge 5 to the root of the convex ridge platform 8 .

[0047] The shape of the open V-shaped groove 3 is not limited to a V-shape, and as long as it is an open groove, a certain cutting effect can be achieved. However, the open V-shaped groove 3 has better mechanical properties and is simpler to manufacture.

[0048] The tool body 1 is provided with positioning V-shaped grooves 9 on two opposite sides respectively; the positioning V-shaped grooves 9 can play a role in tool installation and positioning, and can also introduce coolant into the cutting position to play a role in cooling the working surface.

[0049] Through the precise cooperation of the open V-shaped groove 3, the finishing edge, the cutting edge 4, the convex edge 5, the first chip-breaking groove 6 and the second chip-breaking groove 7, the tool can break the chips with a width of 1mm-2mm and a length of 17mm-23mm under the premise of ensuring the processing accuracy of the roughness ≤Ra1.2. Especially in the process of processing the groove bottom, the technical problem of difficult chip breaking can be solved under the premise of ensuring the processing accuracy, so that the processing efficiency, processing accuracy and cutting control are comprehensively improved, and it performs excellently in the groove processing of thin-walled guide grooves.

[0050] Working principle:

[0051] When the groove wall of the guide sleeve groove is precision-turned, it can be turned from the groove mouth to the groove bottom, and the iron chips cut off are mainly blocked by the convex ridge 5 and curled toward the second chip breaking groove 7, thereby playing an auxiliary chip breaking role; when the groove bottom of the guide sleeve groove is precision-turned, the tool can be moved from the bottom end of one side groove wall to the bottom end of the other side groove wall. At the starting position of precision-turning the groove bottom, part of the groove bottom that has not been precision-turned will fall into the open V-shaped groove 3. This part of the groove bottom is cut by the inner side of the cutting edge 4 and is mainly blocked by the convex ridge 5 and curled toward the second chip breaking groove 7, thereby playing an auxiliary chip breaking role. The first chip breaking groove 6 is curled to produce threaded iron chips narrower than the width of the cutting edge 4, which plays an auxiliary chip breaking role. The remaining groove bottom is cut by the outer side of the cutting edge 4, mainly blocked by the convex ridge 5, and curled to the second chip breaking groove 7, which plays an auxiliary chip breaking role. Because the width of the iron chips is reduced, in the actual processing process, with the impact of high-pressure water, the iron chips can be broken in time to avoid the formation of long iron chips, ensure the chip breaking effect, protect the workpiece surface from being scratched, and protect the tool from being entangled and damaged. The width of a single cutting edge 4 is reduced, and the contact area is smaller when processing the groove bottom, so the vibration amplitude of the tool is also smaller. Due to the good chip breaking effect and small vibration amplitude, the tool can maintain stable and continuous cutting when fine turning the groove of the thin-walled guide sleeve, thereby improving the processing efficiency. The normal speed can achieve a processing accuracy of roughness ≤ Ra1.2. After further increasing the processing speed, it can also achieve a processing accuracy of roughness ≤ Ra1.6.

[0052] Example 2

[0053] like Figure 5 and Figure 6 As shown, a method for cutting a groove of a thin-walled guide sleeve is provided, wherein the cutting tool in Example 1 is used for cutting, and the cutting process comprises the following steps:

[0054] Step S1: Rough turning the groove 11 of the thin-walled guide sleeve 10, leaving a machining allowance of 0.2 mm;

[0055] Step S2: the cutting part 2 is fed from the first groove wall of the groove 11 to ensure that the cutting part 2 is perpendicular to the groove bottom, and the first groove wall is precision-turned until the cutting edge 4 moves to the groove bottom, and a boss is formed in the open groove;

[0056] Step S3: retract the knife;

[0057] Step S4: the cutting portion 2 is fed from the second groove wall of the groove 11 to ensure that the cutting portion 2 is perpendicular to the groove bottom, and the second groove wall is precision-turned until the cutting edge 4 reaches the groove bottom;

[0058] Step S5: cutting the cutting portion 2 transversely from the bottom end of the second groove wall to the bottom end of the first groove wall.

[0059] Among them, in step S2, step S4 and step S5, the tool does not rotate, the guide sleeve 10 rotates, and high-pressure water is used to flush the cut iron chips. The cutting speed is 2500 mm / min-3000 mm / min, the processing feed is 0.1mm-0.15mm, the cutting depth is 0.15mm-0.2mm, and continuous cutting is maintained.

[0060] The finished product outer diameter of the processed guide sleeve 10 is 80mm-650mm, the wall thickness is 7mm-15mm, the groove 11 is 6mm-12mm deep, the width of the broken chip iron chips is 1-2mm, and the length is 17-23mm.

[0061] After the processing is completed by this processing method, the roughness and roundness are detected by using a roughness meter and a three-dimensional coordinate measuring instrument. The roughness of the groove 11 is ≤Ra1.2, and the roundness of the guide sleeve 10 is ≤0.05mm.

[0062] Example 3

[0063] The difference between this embodiment and embodiment 2 is that the machining allowance in step S1 is 0.25 mm; in steps S2, S4 and S5, the cutting speed is 3000 mm / min-3500 mm / min, the machining feed is 0.15 mm-0.2 mm, and the cutting depth is 0.2-0.25 mm.

[0064] The processing efficiency of this processing method is 1.2-1.3 times that of Example 2. After the processing is completed, the roughness and roundness are detected using a roughness meter and a three-coordinate measuring instrument. The groove roughness is ≤Ra1.6, and the guide sleeve roundness is ≤0.06mm.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A method for cutting a groove of a thin-walled guide sleeve, characterized in that: A special tool is used for processing, and the special tool comprises a tool body and a cutting part, the root of the cutting part is connected to the end of the tool body, the head of the cutting part is provided with an open groove and two cutting edges, the groove bottom of the open groove is recessed toward the root of the cutting part, and the two cutting edges are symmetrically arranged at the two side ends of the open groove; the main cutting edges of the two cutting edges are located on the end face of the head of the cutting part, and the open groove is located in the direction of the secondary back cutting faces of the two cutting edges. The cutting part is provided with two ridges, a first chip breaking groove and two second chip breaking grooves on the side faces where the front cutting faces of the two cutting edges are located, and the two ridges are arranged in a one-to-one correspondence with the two cutting edges, the ridges extend from the tip of the cutting edge to the root of the cutting part, and are connected as a whole at the root to form a ridge platform, the two ridges are arranged around the outside of the first chip breaking groove, and the outside of the ridges and the tip of the cutting edge form the second chip breaking groove; The following steps are involved: Step S1: Rough turning the groove of the thin-walled guide sleeve, leaving a machining allowance of 0.2mm-0.25mm; Step S2: the cutting part feeds from the first groove wall of the groove to ensure that the cutting part is perpendicular to the groove bottom, and fine turning the first groove wall until the cutting edge moves to the groove bottom, and a boss is formed in the open groove; Step S3: retract the knife; Step S4: the cutting part feeds from the second groove wall of the groove to ensure that the cutting part is perpendicular to the groove bottom, and finish turning the second groove wall until the cutting edge reaches the groove bottom; Step S5: cutting the cutting portion transversely from the bottom end of the second groove wall to the bottom end of the first groove wall; Among them, in step S2, step S4 and step S5, high-pressure water is used to flush the cut iron chips.

2. The method for cutting a groove of a thin-walled guide sleeve according to claim 1, characterized in that: The tool tip adopts a wiper blade, which is composed of 3-6 arcs with different radii, and the radius Rn of each arc is between 0.1mm and 0.2mm.

3. The method for cutting a groove of a thin-walled guide sleeve according to claim 2, characterized in that: In step S2, step S4 and step S5, the cutting speed is 2500 mm / min-3500 mm / min, the machining feed is 0.1 mm-0.2 mm, and the cutting depth is 0.15 mm-0.25 mm.

4. The method for cutting a groove of a thin-walled guide sleeve according to claim 3, characterized in that: The machining allowance in step S1 is 0.2 mm, and in steps S2, S4 and S5, the cutting speed is 2500 mm / min-3000 mm / min, the machining feed is 0.1 mm-0.15 mm, and the cutting depth is 0.15 mm-0.2 mm.

5. The method for cutting a groove of a thin-walled guide sleeve according to claim 3, characterized in that: The machining allowance in step S1 is 0.25 mm, and in steps S2, S4 and S5, the cutting speed is 3000 mm / min-3500 mm / min, the machining feed is 0.15 mm-0.2 mm, and the cutting depth is 0.2 mm-0.25 mm.

6. The method for cutting a groove of a thin-walled guide sleeve according to any one of claims 1 to 5, characterized in that: In step S2, step S4 and step S5, the tool does not rotate but the guide sleeve rotates to maintain continuous cutting.

7. The method for cutting a groove of a thin-walled guide sleeve according to claim 6, characterized in that: The width L1 of the cutting edge is 0.6 mm-0.8 mm.

8. The method for cutting a groove of a thin-walled guide sleeve according to claim 7, characterized in that: The width Lc of the second chip breaking groove at the tool tip is 0.18 mm-0.4 mm.

9. The method for cutting a groove of a thin-walled guide sleeve according to claim 8, characterized in that: The included angle γ between the rake face and the base surface of the cutting edge is 15°-20°, the main cutting edge of the cutting edge is passivated at 0.05mm-0.1mm, and the chamfer angle η at the tip of the cutting edge is 3°-6°.

10. The method for cutting a groove of a thin-walled guide sleeve according to any one of claims 7 to 9, characterized in that: The overall blade width L of the cutting portion is 4 mm.

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