A machining method for machining a precise thin-walled part by low-stress clamping and alignment

Abstract

This invention discloses a low-stress clamping and alignment method for machining precision thin-walled parts. By designing special tooling, optimizing process dimensions, and repeating measurements, the turning and grinding of the spherical surface of the part is completed. This method ensures high-precision dimensions for precision parts and is suitable for machining parts with dimensional tolerances within 0.005mm. It does not use hot melt adhesives, as localized heat deformation can affect the accuracy of the final dimensional shape of the part.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, specifically relating to a machining method for precision thin-walled parts using low-stress clamping and alignment. Background Technology

[0002] Thin-walled, low-rigidity parts are widely used in various industries. Some parts require micron-level precision in their surface dimensions due to usage requirements. These parts have poor structural rigidity, and traditional clamping methods (such as internal support, clamping the outer circle, and pressing the end face) can cause localized deformation due to clamping stress, affecting machining accuracy and failing to guarantee the final dimensional tolerances. To address this type of part machining, specialized tooling and enhanced process monitoring have ensured that the final dimensions meet the high-precision design requirements. A search revealed an invention patent (CN108214006A) for a method of clamping thin-walled precision parts using hot melt adhesive bonding, which is similar to this invention patent. The difference lies in that the invention patent emphasizes the convenience of hot melt adhesive bonding for thin-walled precision parts but does not adequately guarantee precision. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a low-stress clamping and alignment method for machining precision thin-walled parts. This method involves designing specialized tooling, optimizing process dimensions, and repeated measurements to complete the turning and grinding of the spherical surface of the part. It is a method to ensure high-precision dimensions for precision parts, suitable for machining parts with dimensional tolerances within 0.005mm. Furthermore, it avoids the use of hot melt adhesives, as localized heat deformation can affect the accuracy of the final dimensional shape of the part.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows:

[0005] Step 1: Bond the product to the tooling and fasten it firmly. The distance between the center of the sphere and the reference surface is the bonding surface. The flatness requirement between the end face of the product and the end face of the tooling is within jmm to ensure that the end faces fit together.

[0006] Step 2: Match the tooling mating surface with the inner cylindrical surface of the product to ensure that the inner and outer cylindrical surfaces fit together and play a supporting role during the processing. Use liquid adhesive to bond the inner circumferential seam. After the liquid adhesive solidifies, connect the tooling to the spindle adapter plate with the pin fixing hole. Clamp the spindle adapter plate on a high-precision CNC lathe or a high-precision CNC grinding machine.

[0007] Step 3: Before product processing, determine the zero point of the tool tip using the large end face of the product and the outer cylindrical surface of the fitting tool. To ensure that the coaxiality between the ball center and the outer cylindrical surface is no greater than k, the cylindricity of the outer cylindrical surface must be within n. To meet the ball center distance tolerance of ±p, determine the ball center coordinates by measuring the distance from the bonding surface to the large end face and subtracting the ball center distance dimension. The flatness of the large end face must be within emm, the flatness of the bonding surface must be within fmm, and the axial inspection error after product clamping must be within g. Sufficient space should be reserved for dimensional adjustment.

[0008] Step 4: Initial machining. Find the outer cylindrical surface of the fitting tool within h to ensure the coaxiality of the spherical center and the outer cylindrical surface. Start machining the spherical surface, ensuring that the entire spherical surface is turned / ground to a smooth finish. Remove the pin and use a coordinate measuring machine to check the relevant dimensions of the spherical surface. Adjust the CNC program according to the spherical radius and the distance between the center and the spherical surface.

[0009] Step 5: Secondary machining. Use pins to fix the product and its tooling to the spindle connecting plate to ensure that the axial and radial positions of the product do not move. Then, turn / grind the entire spherical surface again, leaving machining allowance. Remove the pins and use a coordinate measuring machine to check the relevant dimensions of the spherical surface. Determine whether the adjusted CNC program has been machined to the theoretical value. If it has been machined to the theoretical value, shift the tool tip trajectory towards the center of the sphere and remove all machining allowance. If it has not been machined to the theoretical value, readjust the CNC program and repeat the machining and checking process.

[0010] Step 6: After machining is completed, remove the pin, use a degumming agent to remove the tooling, and check the relevant dimensions of the spherical surface of the product in a free state.

[0011] Preferably, j = 0.005, k = 0.02, n = 0.01, p = 0.023, e = 0.005, f = 0.005, g = 0.01, and h = 0.01.

[0012] A computer program that causes a computer to perform the above-described processing method.

[0013] An electronic device includes: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to cause the electronic device to perform the above-described processing method.

[0014] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described processing method.

[0015] A chip includes a processor for retrieving and running a computer program from a memory, causing a device on which the chip is mounted to perform the above-described processing method.

[0016] A computer program product includes a computer storage medium storing a computer program, the computer program including instructions executable by at least one processor, which, when executed by the at least one processor, implement the above-described processing method.

[0017] The beneficial effects of this invention are as follows:

[0018] 1. The method of the present invention results in low bonding stress in the product and negligible impact of tooling removal on product deformation, making it suitable for machining precision parts;

[0019] 2. The product dimension chain transfer method of the present invention is real and effective, and can be further applied to the processing of ultra-precision parts;

[0020] 3. The method of this invention enables precision machining of spherical parts, forming a complete machining method. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the parts of the present invention;

[0022] Figure 2 This is a schematic diagram of the product clamping of the present invention.

[0023] In the diagram, 1 is the main spindle connecting plate, 2 is the tooling, 3 is the pin, and 4 is the product. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] The problem this invention aims to solve is a high-precision spherical surface machining method for products. Currently, the precision machining datum, bonding clamping, and process inspection for this type of product are all clearly defined, and the product's free-state dimensional inspection has passed.

[0026] To ensure the product's machining accuracy and that the final dimensions meet design requirements, this invention employs a series of methods, including designing specialized tooling, optimizing process dimensions, and repeated measurements, to complete the turning and grinding of the spherical surface of the part.

[0027] by Figure 1 Taking the part as an example, A in the figure represents the spherical surface with the relevant dimensional requirements. B represents the distance between the center of the spheres, which is 73.5 ± 0.023 (based on the end face of the inner step). C represents the product requirement that the coaxiality between the center of the sphere and the reference surface D of the inner cylinder should not exceed 0.02.

[0028] like Figure 2As shown, the product and tooling are bonded and fastened. The center of the sphere is far from the reference surface, which is the bonding surface. The flatness requirement between the end face of the product and the end face of the tooling is within 0.005mm to ensure the end face fit. The mating surface of the tooling fits with the inner cylindrical surface of the product to ensure the inner and outer cylindrical surfaces fit together and play a supporting role during processing. Liquid adhesive is used to bond the inner circumferential seam. After the liquid adhesive solidifies, the tooling and the spindle adapter plate are connected by a pin fixing hole. The spindle adapter plate is then clamped on a high-precision CNC lathe or a high-precision CNC grinding machine. Before product processing, the zero point of the tool tip is determined by the large end face of the product and the outer cylindrical surface of the tooling. To ensure that the coaxiality between the ball center and the outer cylindrical surface is no greater than 0.02, and the cylindricity of the outer cylindrical surface is within 0.01, the ball center distance tolerance is ±0.023. The ball center coordinates are determined by measuring the distance from the bonding surface to the large end face and subtracting the ball center distance dimension. The flatness of the large end face is required to be within 0.005mm, the flatness of the bonding surface is required to be within 0.005mm, and the axial inspection error after product clamping is within 0.01, with sufficient space reserved for dimensional adjustment.

[0029] For the initial machining, ensure the outer cylindrical surface of the fitting tool is within 0.01mm to guarantee the coaxiality of the spherical center and the outer cylindrical surface. Begin machining the spherical surface, ensuring that the entire spherical surface is turned / ground to a smooth finish. Remove the pins and use a coordinate measuring machine to check the relevant dimensions of the spherical surface. Adjust the CNC program according to the spherical radius and the distance between the center and the spherical surface.

[0030] For secondary machining, the product and its fixtures are fixed to the spindle connecting plate using pins to ensure that the axial and radial positions of the product do not move. The entire spherical surface is then turned / ground again, leaving machining allowance. The pins are removed, and the relevant dimensions of the spherical surface are checked using a coordinate measuring machine to determine whether the adjusted CNC program has been machined to the theoretical value. If it has been machined to the theoretical value, the tool tip trajectory is shifted towards the center of the sphere, and all machining allowance is removed. If it has not been machined to the theoretical value, the CNC program is readjusted, and the machining and checking are repeated.

[0031] After machining, remove the pin, use a degumming agent to remove the tooling, and test the relevant dimensions of the spherical surface of the product in a free state.

[0032] Example:

[0033] 1. First, arrange the product and the matching tooling according to... Figure 2 As shown in the assembly diagram, use low-temperature metal adhesive for cold bonding at position M, and fix the spindle connecting plate onto the equipment spindle, aligning the end face of the spindle connecting plate;

[0034] 2. After the product is firmly bonded to the tooling, fix it to the spindle connecting plate with pins and align the outer circle and end face of the product.

[0035] 3. During product processing, the product dimensions are repeatedly checked by removing the pins to ensure that the product processing dimensions meet the design requirements.

Claims

1. A method for machining precision thin-walled parts using low-stress clamping and alignment, characterized in that, Includes the following steps: Step 1: Bond the product to the tooling and fasten it firmly. The distance between the center of the sphere and the reference surface is the bonding surface. The flatness requirement between the end face of the product and the end face of the tooling is within 0.005mm to ensure that the end faces fit together. Step 2: Match the tooling mating surface with the inner cylindrical surface of the product to ensure that the inner and outer cylindrical surfaces fit together and play a supporting role during the processing. Use liquid adhesive to bond the inner circumferential seam. After the liquid adhesive solidifies, connect the tooling to the spindle adapter plate with the pin fixing hole. Clamp the spindle adapter plate on a high-precision CNC lathe or a high-precision CNC grinding machine. Step 3: Before product processing, determine the zero point of the tool tip using the large end face of the product and the outer cylindrical surface of the fitting tool. To ensure that the coaxiality between the ball center and the outer cylindrical surface is no greater than 0.02, the cylindricity of the outer cylindrical surface must be within 0.

01. To ensure that the ball center distance tolerance is ±0.023, determine the ball center coordinates by measuring the distance from the bonding surface to the large end face and subtracting the ball center distance dimension. The flatness of the large end face must be within 0.005mm, the flatness of the bonding surface must be within 0.005mm, and the axial inspection error after product clamping must be within 0.01, with sufficient space reserved for dimensional adjustment. Step 4: Initial machining, ensuring the cylindricity of the outer cylindrical surface of the fitting tool is within 0.01, guaranteeing the coaxiality of the spherical center and the outer cylindrical surface of the product, begin machining the spherical surface, ensuring that the entire spherical surface is turned / ground to a smooth finish, remove the pin, use a coordinate measuring machine to check the relevant dimensions of the spherical surface, and adjust the CNC program according to the spherical radius and the distance between the centers of the spheres; Step 5: Secondary machining. Use pins to fix the product and its tooling to the spindle connecting plate to ensure that the axial and radial positions of the product do not move. Then, turn / grind the entire spherical surface again, leaving machining allowance. Remove the pins and use a coordinate measuring machine to check the relevant dimensions of the spherical surface. Determine whether the adjusted CNC program has been machined to the theoretical value. If it has been machined to the theoretical value, shift the tool tip trajectory towards the center of the sphere and remove all machining allowance. If it has not been machined to the theoretical value, readjust the CNC program and repeat the machining and checking process. Step 6: After machining is completed, remove the pin, use a degumming agent to remove the tooling, and check the relevant dimensions of the spherical surface of the product in a free state.

2. An electronic device, characterized in that, include: Processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to cause the electronic device to perform the method as described in claim 1.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in claim 1.

4. A chip, characterized in that, include: A processor for retrieving and running a computer program from memory, causing a device on which the chip is mounted to perform the method as described in claim 1.

5. A computer program product, characterized in that, The computer program product includes a computer storage medium storing a computer program, the computer program including instructions executable by at least one processor, which, when executed by the at least one processor, implement the method as described in claim 1.

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