WO2020253818A1

WO2020253818A1 - Machining process for large-diameter thin-walled part

Info

Publication number: WO2020253818A1
Application number: PCT/CN2020/097053
Authority: WO
Inventors: 陈少峰; 肜建森
Original assignee: 苏州市意可机电有限公司
Priority date: 2019-06-20
Filing date: 2020-06-19
Publication date: 2020-12-24
Also published as: GB202108394D0; GB2594182B; GB2594182A9; CN110102988A; CN110102988B; GB2594182A

Abstract

A machining process for a large-diameter thin-walled part. The machining process comprises the steps of: S1. selecting a raw material having an appropriate size; S2, machining an inner hole (5); S3. performing shaping; S4. performing aging heat treatment; S5. semi-finishing the inner hole (5) and part of the shape; S6. semi-finishing part of the shape; S7. performing natural aging treatment; S8. finishing the inner hole (5) and a second end (8); S9. finishing a second outer circle (2) and a process step (6); S10. finishing a first outer circle (1); S11. machining and forming a flange (3); and S12. machining and forming multiple protrusions (4). According to the machining process, a stable process route is designed to control deformation, reduce the number of times of positioning and clamping, shorten the machining time, improve machining efficiency and ensure product quality; the one-time machining of all features is implemented by means of the positioning of the inner hole (5), ensuring that product deformation is within a controllable range; reasonable process parameters are used to achieve accurate production guidance work, get rid of the limitation of special person and special machine, and well implement automated production.

Description

A processing technology for large diameter thin-walled parts

Technical field

The invention relates to the field of mechanical processing and manufacturing, in particular to a processing technology of a large-diameter and thin-walled part of an aviation avionics kitchen and bathroom system.

Background technique

The structure of the large thin-walled pipeline of the aviation avionics kitchen and bathroom system is relatively complex, with a maximum diameter of 360mm, a total length of 560mm, and a minimum wall thickness of 1.3mm. At the same time, the position of the hole on the flange surface of the workpiece is required to be higher than the inner hole of the workpiece. , The part structure is asymmetrical, there are gaps, and it is easy to deform during the cutting process. The part material is selected as stainless steel 17-4PH. The material has high high-temperature strength and high-temperature hardness. The cutting force generated during the machining process, the surface work hardening, the chip is difficult to break, the sticking of the tool, accelerates the tool wear, and the cutting temperature is high. The structure is a thin-walled part, and the machining process is greatly affected by cutting force, clamping force, cutting temperature, etc., which will affect the dimensional accuracy and surface quality of the parts, resulting in large deformation and processing difficulties. The machining of this part, especially for milling, needs to be processed in multiple processes, which cannot be completed at the same time under one clamping. This will increase the clamping time, and will also generate cumulative errors, which will affect the product accuracy and increase Machining time, product process efficiency is low.

Summary of the invention

technical problem

The solution to the problem

Technical solutions

The technical problem to be solved by the present invention is to provide a process for processing large-diameter and thin-walled parts with convenient processing and improved accuracy.

The technical solution adopted by the present invention to solve the above-mentioned problems is: a processing technology of a large-diameter thin-walled part, the large-diameter thin-walled part includes an axial inner hole, an outer circle on the outside, a flange on the outer circle, and Close to a plurality of bosses in the radial direction of the flange, the plurality of bosses and flanges divide the outer circle into a first outer circle and a second outer circle. The processing steps are as follows:

S1. Select raw materials of appropriate size;

S2. The inner hole is processed by wire cutting on the raw material, and a machining allowance of 2～3mm is left on one side of the inner hole;

S3. Perform rough machining in the axial and radial directions on the outside of the raw material to form a first outer circle, a second outer circle, a process step between the first outer circle and the second outer circle, and two ends, both Leave a machining allowance of 2～3mm;

S4. Perform aging heat treatment on the semi-finished product obtained in step S3;

S5. Fix the first end of the semi-finished product, semi-finish the inner hole, the second outer circle, the process step and the second end, and leave a machining allowance of 0.5-0.8mm;

S6. Fix the second end of the semi-finished product, semi-finish the first outer circle and the first end, and leave a machining allowance of 0.5-0.8mm;

S7. Naturally aging the semi-finished product, the processing time is 7-8 hours;

S8. Fix the first end of the semi-finished product, and finish machining the inner hole and the second end to reach the required size;

S9. Insert a disc into the inner holes of the two ends of the semi-finished product respectively, fix the first end of the semi-finished product, locate the second end of the semi-finished product by a thimble, and finish machining the second outer circle and process steps to the requirements size;

S10. Turn the semi-finished product over and fix the second end of the semi-finished product. The first end is positioned by the thimble, and the first outer circle is finished to the required size;

S11. With the first end of the semi-finished product facing downwards, the inner hole is fixed by a hydraulic clamping fixture, and a pressure of 1.0-1.2Mpa is applied for clamping, and holes and positioning surfaces are processed on the process steps to form a flange;

S12. The positioning surface in step S11 is downward, the inner hole is fixed by a hydraulic clamping fixture, and a pressure of 1.0-1.2Mpa is applied for clamping, and the process bosses are processed to form a plurality of bosses.

More specifically, the hardness of the aging heat treatment in the step S4 is controlled at HRC 34-42.

More specifically, the position of the first outer circle close to the first end, the position of the second outer circle close to the second end, and the process step close to the first end by turning between the steps S4 and S5 The position of the part is processed to the light for clamping.

More specifically, in step S5, step S6, step S8, step S9, and step S10, a center frame is used to support the process steps.

More specifically, the pressure release is completed within 30 minutes after the processing in step S11 and step S12 is completed.

More specifically, the load of the main shaft in the processing process is controlled within 5.5 KW.

More specifically, the large-diameter thin-walled part is made of 17-4PH stainless steel.

More specifically, one of the two discs in the step S9 is provided with a tapered hole at its center, and the tapered hole is matched with a thimble.

The beneficial effects of the invention

Beneficial effect

The beneficial effects of the present invention are: design a stable process route to control deformation, reduce the number of clamping, shorten the processing time, thereby improve the processing efficiency and ensure the product quality; through the inner hole positioning to complete all features on the basis of the specified clamping force The one-time processing ensures that the product deformation is within the controllable range; the use of reasonable process parameters to achieve accurate production guidance work, get rid of the limitations of special personnel and special machines, and better complete automated production; improve product process efficiency and product quality.

Brief description of the drawings

Description of the drawings

Figure 1 is a flowchart of the present invention;

Figure 2 is a schematic structural view of the finished product of the large-diameter thin-walled part of the present invention;

Fig. 3 is a structural schematic diagram of an intermediate state of the large-diameter thin-walled part of the present invention.

In the figure: 1. the first outer circle; 2. the second outer circle; 3. the flange; 4. the boss; 5. the inner hole; 6. the process step; 7. the first end; 8. the second end .

Invention embodiment

Embodiments of the invention

The present invention will be described in detail below in conjunction with the drawings.

As shown in Figure 1 and Figure 2, a large-diameter thin-walled part processing technology, the large-diameter thin-walled part includes an axial inner hole 5, an outer circle on the outside, a flange 3 on the outer circle, and a proximity method A plurality of bosses 4 in the radial direction of the flange 3, the plurality of bosses 4 and flanges 3 divide the outer circle into a first outer circle 1 and a second outer circle 2. The processing steps are as follows:

S1. Select raw materials of appropriate size, and select 17-4PH stainless steel material, which has a cylindrical structure with a diameter of 400mm and a length of 600mm.

S2. First, the inner hole 5 is processed by wire cutting on the stainless steel material, and processed to the required size according to the actual size of the inner hole 5. Considering the heat treatment deformation and subsequent finishing, the inner hole 5 is left with 2~ 3mm machining allowance, this machining is rough machining.

S3. Rough machining in the axial and radial directions on the outside of the stainless steel material to form a first outer circle 1, a second outer circle 2, a process step 6 between the first outer circle 1 and the second outer circle 2, and The shape of the two ends is shown in Figure 3, and the above-mentioned structural dimensions are left with a machining allowance of 2 to 3 mm.

S4. Perform aging heat treatment on the semi-finished product obtained in step S3, so that the hardness of the semi-finished product reaches HRC34-42.

S5. In order to remove the heat treatment deformation, position accurately and facilitate clamping, the position of the first outer circle 1 close to the first end 7 and the position of the second outer circle 2 close to the second end 8 and the process steps are adjusted by turning. 6 The position close to the first end 7 is processed until the light is seen. The light is to remove the skin of the semi-finished product. Here, the deformation is mainly removed; the light-visible area of the first outer circle 1 is clamped by a three-jaw chuck to realize the fixation of the semi-finished product. At the same time, the first end 7 is held by the center frame for auxiliary support on the process step 6, and the visible area of the second outer circle 2 and the visible area of the process step 6 are verified by a dial indicator to ensure its roundness The runout is within 0.1mm. At this time, the inner hole 5, the second outer circle 2, the process step 6 and the second end 8 are semi-finished, and a machining allowance of 0.5-0.8mm is left.

S6. Fix the second end 8 of the semi-finished product by clamping the visible area of the second outer circle 2 by the three-jaw chuck, and at the same time, use the center frame to clamp the process step 6 for auxiliary support, and use the dial indicator to check the first The visible area of the outer circle 1 and the visible area of the process step 6 are checked to ensure that the circle runout is within 0.1mm. At this time, the first outer circle 1 and the first end 7 are semi-finished, and left There is a machining allowance of 0.5～0.8mm;

S7. The semi-finished product is treated with natural aging, and the treatment time is 7-8 hours.

S8. The first end 7 of the semi-finished product is fixed by clamping the visible area of the first outer circle 1 by a three-jaw chuck, and at the same time, auxiliary support is provided on the process step 6 of the center frame clamping process, and the second outer circle Check the visible area on circle 2 to ensure that its circle runout is within 0.08mm. At this time, finish machining the inner hole 5 and the second end 8 to meet the dimensions required by the drawing.

S9. Insert a disc into each of the inner holes 5 at both ends of the semi-finished product. One of the two discs has a tapered hole in the center to facilitate matching with the thimble; insert the disc without a tapered hole into the first end In order to prevent the clamping deformation from occurring, the inner hole of the part 7 is clamped by the three-jaw chuck to clamp the visible area of the first outer circle 1 to realize the fixing of the first end 7 of the semi-finished product; due to the long and heavy workpiece, the workpiece The other end has a supporting function. Insert the disc with the tapered hole into the inner hole of the second end 8, insert the thimble into the tapered hole of the disc with the tapered hole to achieve positioning, and clamp the process step 6 by the center frame. Perform auxiliary support on the upper surface, check the second outer circle 2 with a dial indicator to ensure that the circle runout is within 0.08mm, and finish machining the second outer circle 2 and the process step 6 to the required size.

S10. Turn the semi-finished product over, insert a disc without a tapered hole into the inner hole of the second end 8, and insert a disc with a tapered hole into the inner hole of the first end 7. The fixing method and verification method are as in step S9 , The second end 8 of the semi-finished product and the auxiliary support are fixed, and the first outer circle 1 is finished to the required size.

S11. With the first end 7 of the semi-finished product facing downwards, the inner hole 5 is fixed by a hydraulic clamping fixture, and a 0.05mm plug is used to check whether the first end 7 and the bonding surface of the hydraulic clamping fixture fit in place. After the fitting is in place, the hydraulic clamping fixture applies a pressure of 1.0～1.2Mpa to clamp, and then the end surface of the second end 8 is tested by a dial indicator to ensure that the runout is controlled within 0.1mm, and a hole is processed on the process step 6. And the positioning surface to form the flange 3; after finishing the processing, the pressure needs to be released in the hydraulic clamping fixture within 30 minutes.

S12. Place the positioning surface in step S11 downwards, the inner hole 5 is fixed by a hydraulic clamping fixture, and use a 0.05mm plug to check whether the second end 8 and the bonding surface of the hydraulic clamping fixture fit in place. After being in place, the hydraulic clamping fixture applies a pressure of 1.0～1.2Mpa to clamp, and then uses a dial indicator to detect the end surface and circumferential direction of the second end 8 to ensure that the runout is controlled within 0.1mm, and the process step 6 is processed , Forming multiple bosses 4 and flanges 3 to the required size; after finishing processing, it is necessary to release the pressure within 30 minutes of the hydraulic clamping fixture.

The spindle load of the whole machining process mentioned above is controlled within 25%, that is, within 5.5KW.

In summary, by analyzing the processing performance of stainless steel 17-4PH material and the structural characteristics of the thin-walled parts of the aviation kitchen and bathroom piping system, a stable process route was designed and invented to control deformation, reduce the number of clamping times, shorten processing time, and improve processing efficiency And to ensure product quality; use reasonable process parameters to achieve accurate production guidance, get rid of the limitations of special personnel and special machines, and better complete automated production.

It should be emphasized that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are all It still falls within the scope of the technical solution of the present invention.

Claims

A process for processing a large-diameter thin-walled part, the large-diameter thin-walled part includes an axial inner hole, an outer circle on the outside, a flange on the outer circle, and a plurality of bosses in the radial direction close to the flange. Each of the bosses and flanges divides the outer circle into a first outer circle and a second outer circle, and is characterized in that the processing steps include:

S1. Select raw materials of appropriate size;

S2. The inner hole is processed by wire cutting on the raw material, and a machining allowance of 2～3mm is left on one side of the inner hole;

S3. Perform rough machining in the axial and radial directions on the outside of the raw material to form a first outer circle, a second outer circle, a process step between the first outer circle and the second outer circle, and two ends, both Leave a machining allowance of 2～3mm;

S4. Perform aging heat treatment on the semi-finished product obtained in step S3;

S5. Fix the first end of the semi-finished product, semi-finish the inner hole, the second outer circle, the process step and the second end, and leave a machining allowance of 0.5-0.8mm;

S6. Fix the second end of the semi-finished product, semi-finish the first outer circle and the first end, and leave a machining allowance of 0.5-0.8mm;

S7. Naturally aging the semi-finished product, the processing time is 7-8 hours;

S8. Fix the first end of the semi-finished product, and finish machining the inner hole and the second end to reach the required size;

S9. Insert a disc into the inner holes of the two ends of the semi-finished product respectively, fix the first end of the semi-finished product, locate the second end of the semi-finished product by a thimble, and finish machining the second outer circle and process steps to the requirements size;

S10. Turn the semi-finished product over and fix the second end of the semi-finished product. The first end is positioned by the thimble, and the first outer circle is finished to the required size;

S11. With the first end of the semi-finished product facing downwards, the inner hole is fixed by a hydraulic clamping fixture, and a pressure of 1.0-1.2Mpa is applied for clamping, and holes and positioning surfaces are processed on the process steps to form a flange;

S12. With the positioning surface in step S11 facing down, the inner hole is fixed by a hydraulic clamping fixture, and a pressure of 1.0-1.2Mpa is applied for clamping, and the process bosses are processed to form multiple bosses.
The process for processing large-diameter thin-walled parts according to claim 1, wherein the hardness of the aging heat treatment in the step S4 is controlled at HRC34-42.
The machining process of a large-diameter thin-walled part according to claim 1, characterized in that, between said step S4 and step S5, the position of the first outer circle near the first end and the second The position of the outer circle near the second end and the position of the process step near the first end are processed to be exposed to light for clamping.
The processing process of large-diameter thin-walled parts according to claim 1 or 3, characterized in that, in the steps S5, S6, S8, S9, and S10, a center frame is used to support the process steps.
The processing technology of a large-diameter thin-walled part according to claim 1, characterized in that the pressure release is completed within 30 minutes after processing in the step S11 and the step S12.
The machining process of large-diameter thin-walled parts according to claim 1, wherein the load of the spindle is controlled within 5.5 KW in the machining process.
The processing technology of the large-diameter thin-walled part according to claim 1, wherein the large-diameter thin-walled part is processed by using 17-4PH stainless steel material.
The processing technology of the large-diameter thin-walled part according to claim 1, wherein one of the two discs in the step S9 is provided with a tapered hole in its center position, and the tapered hole and the thimble Cooperate.