Process method for removing plating layer on surface of part and lathe positioning clamp

Abstract

The invention discloses a process method for removing a plating layer on the surface of a part and a lathe positioning clamp. The clamp comprises a clamp body and a locking nut, one end of the clamp body is provided with a clamping seat formed by splicing fan-shaped blocks, the outer surface of the clamp body is a hyperbolic cylindrical surface, a cone-frustum-shaped groove is formed in the center of the clamp body, heat dissipation grooves are formed between the fan-shaped blocks, and cutter avoiding grooves are formed in the side ends of the fan-shaped blocks. The conical surface of the locking nut is matched with the cone-frustum-shaped groove, and when the locking nut is screwed in, the clamp body can expand in the radial direction to fasten the part. The sealing ring is made of a polytetrafluoroethylene material and has rigidity and wear resistance. During machining, the circular ring type part is clamped and positioned at a time, and the end face, the outer circle face and the other end face are turned through the two tool noses of the special turning tool respectively. And the cutter avoiding groove effectively avoids machining interference. The multi-surface machining clamp is reasonable in structural design, and the coaxiality and clamping efficiency of multi-surface machining of the thin-wall ring part are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a process for removing plating from the surface of parts and a lathe positioning fixture. Background Technology

[0002] To ensure the performance requirements of a certain sealed contactor product, such as Figure 1 and Figure 2 As shown, after the transition ring part is machined and nickel-plated, the plating layer on the specified surfaces of the part must be removed. The commonly used plating removal method can only remove the plating layer on the first end face A and the second end face B by planar grinding and polishing. The plating layer on the third end face C, i.e. the outer cylindrical surface, can only be removed by polishing and grinding after positioning the inner hole with soft jaws on a lathe. The entire plating removal process has the following problems: First, the planar polishing and grinding method is inefficient; second, there are few positioning surfaces on the part, and when positioning with soft jaws on a lathe (based on the inner hole of the part), there are problems such as inaccurate positioning, the surface plating layer falling off due to force during the positioning process, and low processing efficiency. At the same time, because the wall thickness of the part is relatively thin, the clamping force of the soft jaws is too large, which can easily cause the part to deform. Summary of the Invention

[0003] The purpose of this invention is to design and manufacture a further method based on the structure of the transition ring part, in which the part has a machining allowance on each of the three end faces before plating, and the part is machined in one step on a lathe by a lathe fixture after electroplating, so as to remove the surface plating layer while ensuring the final size of the part.

[0004] The technical solution of the present invention: a lathe positioning fixture, comprising a fixture body and a locking nut matching the fixture body; The clamp is disc-shaped, with a clamping seat coaxially arranged on one end face. The clamping seat is composed of multiple sector blocks spliced ​​together. Its outer surface is a hyperboloid cylindrical surface, and a frustum-shaped groove is formed in the center. There are gaps between each sector block to form a heat dissipation groove. A knife avoidance groove with an inward structure is also provided on the side end of the clamping seat.

[0005] Furthermore, the main body of the sector block is distributed in a sector shape, having a lower end face, an upper end face, an outer arc surface connecting the upper and lower end faces, and an inner end face; the outer arc surface is concave arc-shaped, and the inner end face is stepped.

[0006] Furthermore, the locking nut includes a locking thread post and a locking nut tapered surface integrally connected to the locking thread post.

[0007] Furthermore, the inner end face of the sector block is stepped, and multiple sector blocks together form a structure with a threaded hole at the bottom and a truncated cone groove at the top; the conical surface of the locking nut is adapted to the truncated cone groove, and the locking nut is assembled in the threaded hole.

[0008] Furthermore, the lathe positioning fixture is made of polytetrafluoroethylene material.

[0009] Furthermore, a lathe clamping seat is provided on the other end face of the clamping body.

[0010] A method for removing plating from the surface of a part using a lathe positioning fixture includes the following steps: Step 1: Mount the lathe clamping seat of the lathe positioning fixture onto the lathe; Step 2: Fit the part onto the outer ring surface of the clamping base; Step 3: Screw the lock nut into the threaded hole, causing the conical surface of the lock nut to move down along the truncated conical groove, which causes the clamping seat to generate radial expansion force until the part is fastened to the outer ring surface; Step 4: Use a lathe tool to machine the surfaces of the part in sequence.

[0011] Furthermore, the part is a ring, and the upper and lower end faces and the outer circular surface of the ring are all surfaces to be processed. The upper end face is the first end face, the lower end face is the second end face, and the outer circular surface is the third end face.

[0012] Furthermore, when the cutting tool is machining the end face of the part, the tool avoidance groove provides the tool with axial and radial retraction space, and its concave structure ensures that the fixture will not interfere with the tool path during the turning process.

[0013] A special-purpose lathe tool is formed by cutting a cylinder through two planes passing through its central axis, creating an arc-shaped block cutting body with a central angle of 90°. Two main cutting edges, a first main cutting edge and a second main cutting edge, are formed at each end of the cutting body. During machining, the first main cutting edge is used to turn the first end face of the part, and the second main cutting edge is used to turn the second and third end faces of the part, thus achieving machining of all three surfaces of the part in a single setup. The beneficial effects of this invention are: 1. Improved processing efficiency: This invention uses a special turning tool and positioning fixture to continuously complete the turning of three end faces in one clamping, replacing the original low-speed processing methods such as manual or mechanical polishing and grinding, and improving production efficiency by orders of magnitude.

[0014] 2. Ensures machining accuracy: This invention adopts an expansion-type positioning principle based on the inner hole of the part, resulting in high centering accuracy. Simultaneously, the fixture is made of soft materials such as polytetrafluoroethylene (PTFE), which has good toughness. While providing sufficient clamping force, it will not damage or scratch the coating on the surface of the inner hole of the part, effectively protecting the integrity of the coating in non-machined areas.

[0015] 3. The heat dissipation groove of the present invention increases the heat dissipation area, which is conducive to the rapid removal of heat during cutting and machining, and avoids the workpiece size change or thermal deformation caused by heat accumulation in materials with poor thermal conductivity such as titanium alloy, thereby further ensuring machining accuracy.

[0016] 4. The tool avoidance groove of the present invention enables the special turning tool to have an interference-free movement path. In a continuous tool pass, the end face and outer cylindrical surface are machined one after the other without the need to change tools or reclamp in the middle, which greatly saves machining time. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the part to be processed in this invention. Figure 1 ; Figure 2 This is a schematic diagram of the part to be processed in this invention. Figure 2 ; Figure 3 This is a 3D drawing of the lathe positioning fixture of the present invention; Figure 4 This is a three-dimensional front view of the lathe positioning fixture of the present invention; Figure 5 This is a three-dimensional view of the reverse side of the lathe positioning fixture of the present invention; Figure 6 This is a three-dimensional drawing of the locking nut of the lathe positioning fixture of the present invention; Figure 7 This is a schematic diagram of the lathe positioning fixture for clamping parts according to the present invention; Figure 8 This is a schematic diagram of the lathe positioning fixture for clamping and cutting parts according to the present invention; Figure 9 yes Figure 8 A magnified view of a portion of the image; Figure 10 This is a three-dimensional schematic diagram of the special lathe tool of this invention; Figure reference numerals: A-first end face, B-second end face, C-third end face, D-main cutting edge one, E-main cutting edge two, 1-workpiece to be machined, 2-locking nut, 3-clamp body, 4-clamping seat, 5-heat dissipation groove, 6-tool avoidance groove, 7-lathe clamping seat, 8-locking threaded column, 9-locking nut conical surface. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0020] Example 1: Positioning clamp structure, refer to Figures 3-6 , This embodiment describes a lathe positioning fixture specifically designed for transition ring part 1. The core of this fixture lies in its unique expansion positioning mechanism and material selection, which solve the problems of the original clamping method.

[0021] The lathe positioning fixture includes a disc-shaped fixture body 3. One end of the fixture body 3 is equipped with a lathe clamping seat 7 for fixing the entire fixture to the lathe, and the other end is coaxially equipped with a clamping seat 4, which is composed of multiple sector-shaped blocks. Gaps are provided between the sector-shaped blocks, forming heat dissipation grooves 5, which help dissipate heat during the machining of titanium alloy parts and prevent thermal deformation of the workpiece. On the side end of the clamping seat 4, a concave tool-avoiding groove 6 is provided, providing an unrestricted movement path for the special lathe tool used during machining, preventing collision or interference between the tool and the fixture, thereby enabling the continuous machining of multiple surfaces of the part in a single operation.

[0022] The inner end faces of the sector blocks are stepped, and when they are closed together, they form a structure with a threaded hole at the bottom and a frustum-shaped groove at the top. A dedicated locking nut 2 is used to drive the mechanism. The locking nut 2 includes a locking threaded post 8 and a locking nut conical surface 9 integrally connected to it. The locking nut conical surface 9 is adapted to the frustum-shaped groove at the center of the clamping seat 4.

[0023] Principle: By screwing in the locking nut 2, the conical surface 9 of the locking nut and the truncated conical groove of the clamp generate relative movement, converting the axial tightening force into a radial expansion force, causing the clamping seat 4, composed of sector blocks, to expand uniformly outward. The clamp is made of polytetrafluoroethylene (PTFE), which is relatively soft and has good toughness. It can provide sufficient clamping force while effectively avoiding scratching or crushing the fragile coating on the inner surface of the part 1's hole, solving the problem of coating peeling off during positioning. The unique expansion positioning mechanism uses the inner hole of part 1 as a reference, achieving high positioning accuracy and solving the problem of inaccurate positioning by soft jaws. The radially uniform expansion clamping method avoids the problem of deformation of thin-walled parts that may be caused by concentrated force in traditional three-jaw chucks. The design of the heat dissipation groove 5 improves the heat dissipation efficiency during processing, further preventing workpiece deformation. The tool avoidance groove 6 provides an unobstructed machining path for the tool and is one of the key structures for achieving multi-faceted one-time machining. This structure mainly solves the problems of inaccurate part positioning, easy coating peeling, easy deformation during clamping, and provides a foundation for subsequent efficient machining.

[0024] Example 2: Fixture clamping process, refer to Figures 6-9 This embodiment describes the method and process of clamping and disassembling the transition ring part 1 using the lathe positioning fixture described in Embodiment 1. The clamping process includes the following steps: Step 1: The lathe positioning fixture is clamped and fixed on the lathe using its lathe clamping seat 7. Step 2: The electroplated transition ring part 1, with its inner hole as a reference, is fitted onto the outer ring surface of the clamping seat 4 of the fixture body 3. Step 3: The locking nut 2 is screwed into the threaded hole at the bottom of the clamping seat 4. As the locking nut 2 is screwed in, its locking nut conical surface 9 moves downward along the frustum-shaped groove inside the clamping seat 4. Utilizing the principle of conical surface engagement, the clamping seat 4, composed of multiple sector blocks, is forced to generate a uniform radial outward expansion force. Step 4: The expansion force causes the outer surface of the clamping seat 4 to fully contact and tighten with the inner hole surface of the part 1 until the part 1 is firmly fixed, at which point machining can begin.

[0025] Disassembly process: After machining, simply unscrew the locking nut 2 in the reverse direction. The clamping seat 4 loses its expansion force and contracts inward under its own elasticity, disengaging from the inner hole of part 1, allowing part 1 to be easily removed. The conical surface fit converts the linear motion of the axial screw into radial expansion motion, achieving high-precision positioning and clamping based on the inner hole of the part itself. This clamping and disassembly process is simple and quick, significantly improving auxiliary time efficiency. Soft fixtures are used throughout the process to avoid clamping damage. The expansion positioning method ensures extremely high centering accuracy and repeatability. This process mainly solves the problems of cumbersome operation, low efficiency, and inability to guarantee positioning accuracy in the original clamping method.

[0026] Example 3: Part machining process, refer to Figure 10 This embodiment describes a method for machining the three surfaces of part 1 in one operation using a special lathe tool after clamping as described in Embodiment 2. Before electroplating, part 1 has pre-reserved machining allowances on the first end face A, the second end face B, and the third end face C, which require plating removal and whose final dimensions are guaranteed. During machining, a specially designed lathe tool is used. This tool is formed by cutting a cylinder through two planes passing through its central axis, creating an arc-shaped block cutting body with a central angle of 90°. Two main cutting edges are ground at both ends of this cutting body: cutting edge one D and main cutting edge two E.

[0027] The first end face A of part 1 is machined using the main cutting edge D of a dedicated lathe tool. Subsequently, using the same main cutting edge E, the third end face C (outer cylindrical surface) and the second end face B of part 1 are machined through the relative movement of the tool and workpiece. Throughout the machining process, the tool-avoiding groove 6 designed on the fixture provides ample axial and radial retraction space for the movement of the dedicated lathe tool. Its concave structure ensures that the fixture does not interfere with the tool path when the tool changes machining surfaces, thus achieving continuous machining in one go without stopping or changing tools.

[0028] By utilizing the unique geometry of a specialized lathe tool and the tool-avoiding grooves in the fixture, the two cutting tips on a single tool can sequentially reach and machine three different surfaces. With a single clamping, the removal of plating from three end faces and the final dimensional machining can be completed using a single tool, significantly improving machining efficiency and solving the problems of low efficiency in surface polishing and grinding, as well as multi-clamping machining. Completing all machining in a single clamping avoids positioning errors that may occur with multiple clamping operations, ensuring positional accuracy between the three machined surfaces. It reduces tool change time and the number of clamping operations, saving time and lowering production costs. This process primarily solves the core problem of extremely low efficiency in the original plating removal process while simultaneously ensuring the machining quality of the parts.

[0029] The foregoing has provided a detailed description of a process for removing plating from the surface of parts and a lathe positioning fixture provided by the present invention. Specific examples have been used to illustrate the structure and working principle of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A lathe positioning fixture, characterized in that: Includes a clamping body (3) and a locking nut (2) that matches the clamping body (3); The clamping body (3) is disc-shaped, and a clamping seat (4) is coaxially arranged on one end face. The clamping seat (4) is composed of multiple fan-shaped blocks spliced ​​together. Its outer surface is a hyperboloid cylindrical surface, and a frustum-shaped groove is formed in the center. There are gaps between each fan-shaped block to form a heat dissipation groove (5). A concave knife avoidance groove (6) is also provided on the side end of the clamping seat (4).

2. The lathe positioning fixture according to claim 1, characterized in that: The main body of the sector block is distributed in a sector shape, having a lower end face, an upper end face, an outer arc surface connecting the upper and lower end faces, and an inner end face; the outer arc surface is concave arc shape, and the inner end face is stepped.

3. The lathe positioning fixture according to claim 1, characterized in that: The locking nut (2) includes a locking threaded post (8) and a locking nut cone surface (9) integrally connected to the locking threaded post (8).

4. The lathe positioning fixture according to claim 2 or 3, characterized in that: The inner end face of the sector block is stepped. After multiple sector blocks are enclosed, they form a structure with a threaded hole at the bottom and a truncated cone groove at the top. The conical surface (9) of the locking nut is adapted to the truncated cone groove, and the locking nut (2) is assembled in the threaded hole.

5. The lathe positioning fixture according to claim 1, characterized in that: The lathe positioning fixture is made of polytetrafluoroethylene material.

6. The lathe positioning fixture according to claim 1, characterized in that: The other end face of the clamping body (3) is provided with a lathe clamping seat (7).

7. A method for removing plating from the surface of a part using a lathe positioning fixture as described in any one of claims 1-6, characterized in that: Includes the following steps, Step 1: Mount the lathe clamping seat (7) of the lathe positioning fixture onto the lathe; Step 2: Fit the part onto the outer ring surface of the clamping base (4); Step 3: Screw the locking nut (2) into the threaded hole, so that the conical surface (9) of the locking nut moves down along the truncated conical groove, causing the clamping seat (4) to generate radial expansion force until the part is fastened to the outer ring surface; Step 4: Use a lathe tool to process the surface to be processed of the part in sequence.

8. The machining method for removing plating from the surface of a part using a lathe positioning fixture according to claim 7, characterized in that: The part is a ring, and the upper and lower end faces and the outer circular surface of the ring are all surfaces to be machined. The upper end face is the first end face (A), the lower end face is the second end face (B), and the outer circular surface is the third end face (C).

9. The method for removing plating from the surface of a part using a lathe positioning fixture according to claim 7, characterized in that: When the cutting tool processes the end face of the part, the tool avoidance groove (6) provides the tool with axial and radial retraction space, and its concave structure ensures that the fixture will not interfere with the tool path during the turning process.

10. A special turning tool used in claim 7, characterized in that: The special cutting tool is formed by cutting a cylinder through two planes passing through its central axis to form an arc-shaped block cutting body with a central angle of 90°. The two ends of the cutting body are respectively formed with a first main cutting edge (D) and a second main cutting edge (E). During machining, the first end face (A) of the part is machined by the first main cutting edge (D), and the second end face (B) and the third end face (C) of the part are machined by the second main cutting edge (E), so that the machining of the three surfaces of the part can be completed in one clamping.

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