CN121339841A

CN121339841A - Precision machining process for metal part

Info

Publication number: CN121339841A
Application number: CN202511698816.0A
Authority: CN
Inventors: 刘志东; 朱金勇
Original assignee: Danyang Puhe Precision Machining Co ltd
Current assignee: Danyang Puhe Precision Machining Co ltd
Priority date: 2025-11-19
Filing date: 2025-11-19
Publication date: 2026-01-16

Abstract

The invention relates to the technical field of metal processing and discloses a precise processing technology of a metal part, which comprises the following steps of S1, raw material screening and pretreatment, S2, rough processing and stress relief, cutting processing based on pretreatment blank size data of S1 to obtain a rough workpiece, then, heat treatment of the rough workpiece, obtaining the stress relief part after the internal stress relief effect reaches the standard, S3, semi-finishing and surface pretreatment, S4, precise grinding and finished product detection, S5, machine tool precise processing, S6, and finished product post-treatment. By adopting the procedure linkage verification and closed loop detection and defining the implementation precondition and feedback mechanism of each processing step, each procedure is ensured to be carried out based on the preface qualified workpiece, the technical effects of controllable processing errors and advanced avoidance of defects are achieved, and compared with the technical scheme that each processing step is directly connected and precondition verification is lacking in the prior art, the defects of unstable quality of finished products caused by error accumulation and defect transmission are overcome.

Description

Precision machining process for metal part

Technical Field

The invention relates to the technical field of metal processing, in particular to a precise processing technology of a metal piece.

Background

The precision metal piece is used as a core basic component in the fields of aerospace, high-end equipment, precision instruments and the like, and the dimensional precision, the surface quality and the structural stability of the precision metal piece directly determine the operation precision and the service life of the terminal equipment. The metal parts are usually molded step by step through a plurality of processing procedures, and balance among material characteristics, processing efficiency and finished product precision is considered in the processing procedure, so that the metal parts are key processing links of intensive technology in the modern manufacturing industry, and the requirements on the scientificity and the rigor of the processing technology are extremely high.

In the existing metal part precision machining process, most schemes adopt a mode that all machining steps are directly connected, and a clear process implementation precondition verification and closed loop feedback mechanism is lacked. The processing defects of the preceding procedure are not recognized in time and then enter subsequent processing, so that errors are accumulated continuously, the defects are transmitted continuously, and finally, the finished product has large fluctuation of dimensional accuracy and poor quality stability, and the severe requirements of high-end scenes on precise metal parts are difficult to meet. The processing mode lacking linkage verification becomes a core bottleneck for limiting the improvement of the qualification rate and the quality stability of finished products of precise metal parts.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a precision machining process for metal parts, which solves the technical problems of direct connection of all machining steps and lack of precondition verification in the prior art, and solves the problems of unstable quality of finished products caused by error accumulation and defect transmission.

In order to achieve the purpose, the invention is realized by the following technical scheme that the metal part precision machining process comprises the following steps:

S1, raw material screening and pretreatment, namely selecting a metal blank meeting the requirement of preset components, adopting flaw detection and initial size calibration, and obtaining a pretreated blank when no internal defects exist and the initial size deviation meets the preset range;

S2, rough machining and stress relief, namely cutting the blank based on the pretreatment blank size data of the S1 to obtain a rough machined part;

s3, semi-finishing and surface pretreatment, namely milling and boring the stress relief piece to obtain a semi-finished piece, and then sequentially deburring, ultrasonic cleaning and drying to obtain a clean workpiece;

S4, precisely grinding and detecting a finished product, namely grinding the key surface of the clean workpiece by adopting a superhard abrasive grinding wheel, and matching cooling and lubricating measures in the grinding process to obtain a ground workpiece;

s5, machine tool precision machining, namely boring a grinding workpiece by using a boring machine;

s6, post-processing of finished products, namely performing rust prevention treatment and sealing packaging on the qualified detected workpiece to obtain the finished metal piece.

Preferably, the boring machine comprises a frame body, the lateral wall of frame body is provided with boring assembly, the lateral wall fixedly connected with mounting bracket of frame body, the lateral wall of mounting bracket is provided with fixed subassembly, fixed subassembly is including:

the end face of the fixing rod is fixedly connected with a fixing plate, and the side wall of the fixing plate is connected with a bolt in a threaded manner;

The movable plate I is fixedly connected with a connecting rod on the side wall of the movable plate I, a limiting plate is sleeved on the side wall of the connecting rod, and a movable plate II is sleeved on the side wall of the fixed rod;

and the side wall of the sliding frame is rotationally connected with a cam.

The boring assembly comprises a driving motor fixedly connected to the side wall of the frame body, the output end of the driving motor is fixedly connected with a bidirectional screw rod, the side wall of the bidirectional screw rod is in threaded connection with a mounting seat, and the side wall of the mounting seat is fixedly connected with a boring device;

The fixing rod is fixedly connected to the side wall of the mounting frame, the end face of the bolt is fixedly connected with a knob, the bolt is rotationally connected with the limiting plate, and the bolt is rotated to change the transverse position of the limiting plate;

the side wall cover of connecting rod is equipped with the spring, the quantity of spring is provided with a plurality of groups, spring and carriage looks butt, spring and fly leaf two looks butt, spring and limiting plate looks butt, the spring promotes the carriage and centers.

The sliding frame is sleeved with the connecting rod, the cam is movably connected with the second movable plate, and the cam is movably connected with the fixed plate;

the outer wall of the cam is fixedly connected with a handle, and the movable plate I is sleeved with the fixed rod;

The movable plate I and the movable plate II are fixedly connected with a hinge bracket on the side wall, an arc-shaped block is hinged to the end face of the hinge bracket, a torsion spring is sleeved on the side wall of the arc-shaped block, one end of the torsion spring is abutted to the hinge bracket, and the other end of the torsion spring is abutted to the arc-shaped block.

Preferably, in the step S1, the flaw detection adopts an ultrasonic flaw detection mode, the metal blank is any one of stainless steel, aluminum alloy or titanium alloy, and the initial size deviation is less than or equal to +/-0.5 mm.

Preferably, in the step S2, numerical control cutting equipment is adopted for cutting, the cutting speed is 80-120m/min, the feeding amount is 0.1-0.3mm/r, and the dimensional tolerance of the rough workpiece is controlled to be +/-0.1-0.3 mm.

Preferably, in the step S2, the heat treatment is vacuum heat treatment, the treatment temperature is 850-950 ℃, the heat preservation time is 2-4h, the cooling rate is less than or equal to 50 ℃ per hour, and the internal stress elimination rate is more than or equal to 90%.

Preferably, in the step S3, the milling speed is 100-150m/min, the coaxiality error of the boring is less than or equal to 0.01mm, the surface roughness Ra of the semi-finished product is less than or equal to 1.6 mu m, and the finish grinding allowance of 0.05-0.1mm is reserved.

Preferably, in the step S3, deionized water is used as a medium for ultrasonic cleaning, the cleaning temperature is 40-60 ℃, and the cleaning time is 10-20min;

The drying treatment is hot air drying, the drying temperature is 80-120 ℃, and the drying time is 30-60min.

Preferably, in the step S4, the superhard abrasive grinding wheel is a cubic boron nitride grinding wheel or a diamond grinding wheel, the grinding speed is 30-50m/S, the grinding depth is 0.001-0.003 mm/time, and the cooling and lubricating measures are that oil-based cutting fluid is adopted.

Preferably, in the step S4, the dimensional tolerance of the ground workpiece is less than or equal to +/-0.005 mm, and the surface roughness Ra is less than or equal to 0.2 mu m;

The regrinding times are less than or equal to 2 times, and the special detection equipment comprises a three-coordinate measuring instrument, a laser interferometer and a roughness meter.

Preferably, in the step S6, the rust-preventing treatment is passivation treatment or coating of rust-preventing oil;

Wherein the passivation treatment time is 15-30min, and the coating thickness of the rust preventive oil is 5-10 mu m.

Preferably, the step S2 takes the pretreated blank of the step S1 as a unique processing reference;

S3, taking the internal stress elimination rate of S2 as the only implementation precondition;

s4, taking the finish grinding allowance of S3 meets the requirement, and the clean workpiece has no burr and greasy dirt residue as execution conditions;

And if the regrinding times in the step S4 exceeds 2 times and is still unqualified, returning to the step S3 to conduct regrinding, and adjusting the fine grinding allowance after regrinding to be 0.08-0.12mm.

The invention provides a precision machining process for a metal part. The beneficial effects are as follows:

1. According to the invention, through working procedure linkage verification and closed loop detection, and through defining the implementation precondition and feedback mechanism of each processing step, each working procedure is ensured to be carried out based on the preface qualified workpiece, so that the technical effects of controllable processing errors and advanced avoidance of defects are achieved.

2. The invention adopts the combination of vacuum heat treatment, a superhard abrasive grinding wheel and special cooling lubrication, combines the design thought of accurate adaptation of material characteristics, achieves the technical effects of full release of internal stress of a metal part, excellent surface quality and strong structural stability, and solves the problems of deformation, easy surface burn or scratch caused by residual internal stress compared with the technical proposal of adopting common heat treatment, a general grinding wheel or a single cooling mode in the prior art.

3. The invention adopts the optimization procedure logic and scene technology adjustment, and by reasonably planning the processing sequence and customizing the process details aiming at different use scenes, the technical effects of wide processing adaptability and strong finished product working condition adaptation capability are achieved, and compared with the technical scheme that the procedure sequence is fixed and disordered and the scene-specific design is lacked in the prior art, the invention solves the defects that secondary pollution is easy to generate and the use requirements of special working conditions are difficult to meet.

4. According to the boring machine, the first movable plate and the second movable plate move oppositely to clamp the workpiece, the workpiece is clamped simultaneously from two sides, the clamping force is uniform, deviation or inclination cannot be generated, machining precision is guaranteed, the cam has self-locking characteristics, the cam cannot easily reverse after the cam is rotated to be positioned, when one side of the workpiece is required to be bored, the workpiece is placed in a deviation mode, the workpiece is close to one side of one group of boring devices, the transverse position of the limiting plates is changed by rotating the bolts, the initial distance between the movable plates is changed, the clamping space can be flexibly adjusted no matter how large the workpiece is, the application range of the equipment is improved, the first movable plate and the second movable plate can be more attached to two sides of the workpiece after adjustment, the gap is reduced, the workpiece positioning accuracy is guaranteed, the clamping force is uniform, and the workpiece deviation caused by overlarge or overlarge distance is avoided.

Drawings

FIG. 1 is a schematic flow chart of the process of the present invention;

FIG. 2 is a schematic diagram of the main structure of the present invention;

FIG. 3 is a schematic view of the structure of the area A in FIG. 2 according to the present invention;

FIG. 4 is a schematic view of a fixing assembly according to the present invention;

FIG. 5 is a schematic view of a movable plate according to the present invention;

FIG. 6 is a schematic view of the structure of the area B in FIG. 5 according to the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made more apparent and fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Examples

Referring to fig. 1, an embodiment of the present invention provides a precision machining process for a metal part, including the following steps:

wherein, the flaw detection adopts an ultrasonic flaw detection mode, the metal blank is any one of stainless steel, aluminum alloy or titanium alloy, and the initial size deviation is less than or equal to +/-0.5 mm;

Wherein, the cutting processing adopts numerical control cutting equipment, the cutting speed is 80-120m/min, the feeding amount is 0.1-0.3mm/r, and the dimensional tolerance of the rough workpiece is controlled to be +/-0.1-0.3 mm;

The heat treatment is vacuum heat treatment, the treatment temperature is 850-950 ℃, the heat preservation time is 2-4h, the cooling rate is less than or equal to 50 ℃ per hour, and the internal stress elimination rate is more than or equal to 90%;

wherein the milling speed is 100-150m/min, the coaxiality error of boring is less than or equal to 0.01mm, the surface roughness Ra of the semi-finished product is less than or equal to 1.6 mu m, and the fine grinding allowance of 0.05-0.1mm is reserved;

Ultrasonic cleaning is carried out by taking deionized water as a medium, wherein the cleaning temperature is 40-60 ℃ and the cleaning time is 10-20min;

the drying treatment is hot air drying, the drying temperature is 80-120 ℃, and the drying time is 30-60min;

Wherein the superhard abrasive grinding wheel is a cubic boron nitride grinding wheel or a diamond grinding wheel, the grinding speed is 30-50m/s, the grinding depth is 0.001-0.003 mm/time, and the cooling and lubricating measures are that oil-based cutting fluid is adopted;

The dimensional tolerance of the ground workpiece is less than or equal to +/-0.005 mm, and the surface roughness Ra is less than or equal to 0.2 mu m;

the number of times of regrinding is less than or equal to 2, and the special detection equipment comprises a three-coordinate measuring instrument, a laser interferometer and a roughness meter;

The boring machine comprises a frame body 1, boring components are arranged on the side wall of the frame body 1, a mounting frame 6 is fixedly connected to the side wall of the frame body 1, a fixing component 7 is arranged on the side wall of the mounting frame 6, the fixing component 7 comprises a fixing rod 701, a movable plate one 702, a connecting rod 703, a limiting plate 704, a movable plate two 705, a fixing plate 706, bolts 707, a sliding frame 708, a spring 709, a cam 710, a sliding frame one's body and a sliding frame one's body,

In one embodiment, the fixing rod 701 is fixedly connected to the side wall of the mounting frame 6, the end surface of the fixing rod 701 is fixedly connected with the fixing plate 706, the side wall of the fixing plate 706 is in threaded connection with the bolt 707, and the end surface of the bolt 707 is fixedly connected with the knob;

The movable plate I702 is sleeved with the fixed rod 701, the side wall of the movable plate I702 is fixedly connected with the connecting rod 703, the side wall of the connecting rod 703 is sleeved with the limiting plate 704, the bolt 707 is rotationally connected with the limiting plate 704, the bolt 707 is rotated, the transverse position of the limiting plate 704 is changed, the side wall of the fixed rod 701 is sleeved with the movable plate II 705, the side wall of the connecting rod 703 is sleeved with the springs 709, the number of the springs 709 is provided with a plurality of groups, the springs 709 are abutted with the sliding frame 708, the springs 709 are abutted with the movable plate II 705, the springs 709 are abutted with the limiting plate 704, and the springs 709 push the sliding frame 708 to be centered.

The sliding frame 708 is sleeved with the connecting rod 703, the side wall of the sliding frame 708 is rotatably connected with a cam 710, the cam 710 is movably connected with the movable plate II 705, the cam 710 is movably connected with the fixed plate 706, and the outer wall of the cam 710 is fixedly connected with a handle.

The boring assembly comprises a driving motor 2 fixedly connected to the side wall of the frame body 1, the output end of the driving motor 2 is fixedly connected with a bidirectional screw rod 3, the side wall of the bidirectional screw rod 3 is in threaded connection with a mounting seat 4, the side wall of the mounting seat 4 is fixedly connected with a boring device 5, the boring device 5 comprises a boring rod and a boring cutter, the specific structures and principles of the boring rod and the boring cutter are common in the prior art, and the boring rod and the boring cutter are not described in detail, and the boring assembly is also embodied in fig. 3.

The workpiece is placed between the first movable plate 702 and the second movable plate 705, the cam 710 is rotated, the cam 710 pushes the second movable plate 705 and the limiting plate 704, the limiting plate 704 moves towards the direction close to the fixed plate 706, the first movable plate 702 is driven to move through the connecting rod 703, the first movable plate 702 and the second movable plate 705 move oppositely, the workpiece is fixedly clamped, the workpiece is clamped simultaneously from two sides, the clamping force is uniform, deflection or inclination cannot be generated, the machining precision is guaranteed, the cam 710 has a self-locking characteristic, and the cam is not easy to reverse after being rotated to be positioned.

The boring device 5 is provided with two groups, two sides of a workpiece can be bored synchronously, when one side of the workpiece is required to be bored, the workpiece is placed in an offset mode, the workpiece is close to one side of one group of boring devices 5, then after the workpiece is clamped, the two-way screw 3 can be driven to rotate through the driving motor 2, the mounting seat 4 and the boring device 5 can move transversely, and the boring device 5 bores the workpiece.

The transverse position of the limiting plate 704 is changed by rotating the bolt 707, at this time, the distance between the first movable plate 702 and the second movable plate 705 is reduced, the initial distance between the movable plates is changed, the clamping space can be flexibly adjusted no matter the size of the workpiece, the application range of the device is improved, after adjustment, the first movable plate 702 and the second movable plate 705 can be more attached to two sides of the workpiece, gaps are reduced, the workpiece is accurately positioned, the clamping force is uniform, and the workpiece deflection caused by overlarge or overlarge distance is avoided.

In addition, fly leaf 702 and fly leaf 705's lateral wall fixedly connected with articulated frame 8, articulated frame 8's terminal surface articulates there is arc piece 9, torsional spring 10 has been cup jointed to arc piece 9's lateral wall, torsional spring 10's one end and articulated frame 8 looks butt, torsional spring 10's the other end and arc piece 9 looks butt, arc piece 9 takes place to rotate along the surface of work piece, make arc piece 9 laminating work piece's surface, even if there is certain camber in work piece surface, arc piece 9 also can laminate automatically, adapt to different overall dimensions work pieces, the commonality is strong, improve the clamping effect, arc piece 9 is hugged closely work piece surface, contact area is big, the atress is more even, the work piece is difficult for becoming flexible or skidding when processing, reinforcing clamping stability, after unclamping the centre gripping, the operator need not to adjust clamp angle or position repeatedly, arc piece 9 can the automatic alignment under torsional spring 10 effect.

When the boring device is used, a workpiece is placed between the first movable plate 702 and the second movable plate 705, the cam 710 is rotated, the cam 710 pushes the second movable plate 705 and the limiting plate 704, the limiting plate 704 moves towards the direction close to the fixed plate 706, the first movable plate 702 is further driven to move in the same direction through the connecting rod 703, the first movable plate 702 and the second movable plate 705 move in opposite directions, the workpiece is fixedly clamped, the workpiece is placed in an offset mode, the workpiece is close to one side of one group of boring devices 5, and after the workpiece is clamped, the two-way screw 3 can be driven to rotate through the driving motor 2, so that the mounting seat 4 and the boring device 5 move transversely, and the boring device 5 bores the workpiece.

S6, post-processing of finished products, namely performing rust prevention treatment and sealing packaging on the grinding workpiece which is qualified in detection to obtain a finished metal piece;

Wherein, the rust-proof treatment is passivation treatment or coating of rust-proof oil;

S2, taking the pretreated blank of the S1 as a unique processing reference;

The following description is made in connection with specific embodiments:

Examples

A metal piece precision machining process comprises the following steps:

s1, selecting an aluminum alloy blank by raw material screening and pretreatment, detecting no internal defects by adopting ultrasonic flaw detection, and obtaining a pretreated blank with initial size deviation of +/-0.1 mm;

s2, performing rough machining and stress elimination by taking the pretreated blank of the S1 as a unique machining standard, performing cutting machining by a numerical control milling machine, wherein the cutting speed is 80m/min, the feeding amount is 0.1mm/r, and the dimensional tolerance of a machined rough workpiece is +/-0.1 mm, then performing vacuum heat treatment, wherein the treatment temperature is 850 ℃, the heat preservation time is 2h, the cooling rate is 30 ℃ per hour, and detecting the internal stress elimination rate is 90%, so as to obtain a stress elimination piece;

S3, carrying out numerical control milling on the stress relief piece on the premise that the internal stress relief rate of S2 reaches the standard, carrying out boring processing on the stress relief piece at the speed of 100m/min and the coaxiality error of 0.01mm, reserving the finish grinding allowance of 0.05mm on the processed surface roughness Ra1.6 mu m to obtain a semi-finished piece, and then sequentially carrying out mechanical deburring and ultrasonic cleaning on the semi-finished piece, wherein deionized water is used as a medium, and carrying out hot air drying at 40 ℃ and 10min and 80 ℃ and 30min to obtain a clean workpiece without burrs and oil dirt residues;

And S4, performing precision grinding and finished product detection, namely grinding the key surface of the clean workpiece by using a diamond grinding wheel with the grinding speed of 30m/S and the grinding depth of 0.001 mm/time by using the finish grinding allowance of S3 meeting the requirement and the clean workpiece without impurities as the execution condition, cooling and lubricating by using oil-based cutting liquid in the grinding process, wherein the dimensional tolerance of the machined ground workpiece is +/-0.005 mm and the surface roughness Ra0.2mu m. Detecting by a three-coordinate measuring instrument, a laser interferometer and a roughness meter, wherein each index is qualified, regrinding is not carried out, and the regrinding times are not more than 2 times;

S5, boring the ground workpiece by adopting the boring machine;

And S6, carrying out rust prevention on the grinding workpiece which is qualified in detection by post-treatment of the finished product, adopting a rust prevention oil coating mode to coat the grinding workpiece to a thickness of 5 mu m, and then sealing and packaging the grinding workpiece to obtain the finished product of the aluminum alloy precise connecting piece.

Examples

A metal piece precision machining process comprises the following steps:

S1, selecting a stainless steel 304 blank by raw material screening and pretreatment, detecting that no internal defect exists by adopting ultrasonic flaw detection, and obtaining a pretreated blank with initial size deviation of +/-0.3 mm;

S2, performing rough machining and stress relief by taking the pretreated blank of the S1 as a unique machining standard, performing cutting machining by adopting a machining center, wherein the cutting speed is 100m/min, the feeding amount is 0.2mm/r, and the dimensional tolerance of a machined rough workpiece is +/-0.2 mm, then performing vacuum heat treatment, wherein the treatment temperature is 900 ℃, the heat preservation time is 3h, the cooling rate is 40 ℃ per hour, and detecting the internal stress relief rate is 95%, so as to obtain a stress relief piece;

s3, carrying out numerical control milling on the stress relief piece on the premise that the internal stress relief rate of S2 reaches the standard, carrying out boring processing on the stress relief piece at the speed of 120m/min and the coaxiality error of 0.008mm, reserving the finish grinding allowance of 0.08mm on the processed surface roughness Ra1.2 mu m to obtain a semi-finished piece, and then sequentially carrying out mechanical deburring and ultrasonic cleaning on the semi-finished piece, wherein deionized water is used as a medium, and carrying out hot air drying at 50 ℃ and 15min and 100 ℃ and 40min to obtain a clean workpiece without burrs and oil dirt residues;

and S4, precisely grinding and detecting a finished product, wherein the finish grinding allowance of S3 meets the requirement, the clean workpiece is free of impurities, the critical surface of the clean workpiece is ground by adopting a cubic boron nitride grinding wheel, the grinding speed is 40m/S, the grinding depth is 0.002 mm/time, the grinding process adopts oil-based cutting fluid for cooling and lubrication, and the dimensional tolerance of the machined ground workpiece is +/-0.003 mm and the surface roughness Ra0.15 mu m. The three-dimensional measuring instrument, the laser interferometer and the roughness meter are used for detection, so that various indexes are excellent, and regrinding is not carried out;

S5, boring the ground workpiece by adopting the boring machine;

And S6, performing post-treatment on the finished product, performing rust prevention on the grinding workpiece which is qualified in detection, performing passivation treatment for 20min, and then sealing and packaging to obtain the finished product of the stainless steel 304 precise shaft part.

Examples

A metal piece precision machining process comprises the following steps:

S1, selecting a titanium alloy blank by raw material screening and pretreatment, detecting no internal defects by adopting ultrasonic flaw detection, and obtaining a pretreated blank with initial size deviation of +/-0.5 mm;

S2, performing rough machining and stress relief by taking the pretreated blank of the S1 as a unique machining standard, performing cutting machining by adopting a machining center, wherein the cutting speed is 120m/min, the feeding amount is 0.3mm/r, and the dimensional tolerance of a machined rough workpiece is +/-0.3 mm, then performing vacuum heat treatment, wherein the treatment temperature is 950 ℃, the heat preservation time is 4h, the cooling rate is 50 ℃ per hour, and the internal stress relief rate is detected to be 90 percent, so as to obtain a stress relief piece;

S3, carrying out numerical control milling on the stress relief piece on the premise that the internal stress relief rate of S2 reaches the standard, carrying out boring processing on the stress relief piece at the speed of 150m/min and the coaxiality error of 0.01mm, reserving the finish grinding allowance of 0.1mm for the surface roughness Ra1.6 mu m to obtain a semi-finished piece, and then sequentially carrying out mechanical deburring and ultrasonic cleaning on the semi-finished piece, wherein deionized water is used as a medium, and the temperature is 60 ℃ and 20min, and hot air drying is carried out for 120 ℃ and 60min to obtain a clean workpiece without burrs and oil dirt residues;

and S4, performing precision grinding and finished product detection, namely grinding the key surface of the clean workpiece by using a diamond grinding wheel with the grinding speed of 50m/S and the grinding depth of 0.003 mm/time by using the finish grinding allowance of S3 meeting the requirement and the clean workpiece without impurities as the execution condition, cooling and lubricating by using oil-based cutting fluid in the grinding process, wherein the dimensional tolerance of the machined ground workpiece is +/-0.005 mm and the surface roughness Ra0.2mu m. Detecting by a three-coordinate measuring instrument, a laser interferometer and a roughness meter, wherein each index is qualified, regrinding is not carried out, and the regrinding times are not more than 2 times;

S5, boring the ground workpiece by adopting the boring machine;

And S6, carrying out rust prevention on the grinding workpiece which is qualified in detection by post-treatment of the finished product, adopting a rust prevention oil coating mode to coat the grinding workpiece to a thickness of 10 mu m, and then sealing and packaging the grinding workpiece to obtain the finished product of the titanium alloy precise structural member.

Examples

A metal piece precision machining process comprises the following steps:

s1, selecting a hastelloy C-276 blank by raw material screening and pretreatment, detecting no internal defects by adopting ultrasonic flaw detection, and obtaining a pretreated blank with initial size deviation of +/-0.4 mm;

S2, performing rough machining and stress relief by taking the pretreated blank of the S1 as a unique machining standard, performing cutting machining by adopting a machining center, wherein the cutting speed is 90m/min, the feeding amount is 0.15mm/r, and the dimensional tolerance of a machined rough workpiece is +/-0.2 mm, then performing vacuum heat treatment, wherein the treatment temperature is 920 ℃, the heat preservation time is 3.5h, the cooling rate is 35 ℃ per hour, and detecting the internal stress relief rate to be 94 percent to obtain a stress relief piece;

S3, carrying out numerical control milling on the stress relief piece on the premise that the internal stress relief rate of S2 reaches the standard, carrying out boring processing on the stress relief piece at the speed of 130m/min and the coaxiality error of 0.009mm, reserving the finish grinding allowance of 0.07mm on the processed surface roughness Ra1.4 mu m to obtain a semi-finished piece, and then sequentially carrying out mechanical deburring and ultrasonic cleaning on the semi-finished piece, wherein deionized water is used as a medium, and the temperature is 55 ℃ and 18min, and hot air drying is carried out for 110 ℃ and 50min to obtain a clean workpiece without burrs and oil dirt residues;

And S4, performing precision grinding and finished product detection, namely grinding the key surface of the clean workpiece by using a diamond grinding wheel with the grinding speed of 45m/S and the grinding depth of 0.0025 mm/time by using the finish grinding allowance of S3 meeting the requirement and the clean workpiece without impurities as the execution condition, cooling and lubricating by using special corrosion-resistant cutting liquid in the grinding process, wherein the dimensional tolerance of the machined workpiece is +/-0.004 mm and the surface roughness Ra0.18 mu m. Detecting by a three-coordinate measuring instrument, a laser interferometer and a roughness meter, detecting that the form and position tolerance is slightly out of tolerance for the first time, performing 1-time regrinding, and then qualified, wherein the regrinding times are not more than 2 times;

S5, boring the ground workpiece by adopting the boring machine;

And S6, performing double rust prevention on the grinding workpiece which is qualified in detection after finished product post treatment, firstly performing passivation treatment for 25min, then coating special corrosion-resistant rust prevention oil with the thickness of 8 mu m, and then performing sealed moisture-proof packaging to obtain the finished product of the hastelloy precise chemical accessory.

Comparative example 1

Based on the procedure of example 2, the vacuum heat treatment step in S2 roughing and stress relief was not performed, and the roughing was directly followed by semi-finishing, with the remaining steps being identical to those of example 2.

Comparative example 2

Based on the procedure of example 2, in S3, surface pretreatment is first performed and then semi-finishing is performed, that is, washing, drying and then milling and boring are performed, and the remaining procedures are the same as those of example 2.

Comparative example 3

Based on the procedure of example 2, the cooling of the superabrasive wheel and the oil-based cutting fluid in S4 was replaced with a common white corundum wheel and dry grinding, and the remaining procedure was identical to that of example 2.

Comparative example 4

Based on the procedure of example 2, the steps were directly joined, no precondition verification was performed, and the remaining steps were identical to example 2.

TABLE 1 Performance index data sheet

As can be seen by combining examples 1-4 with comparative examples 1-4 and the performance index data table, each key influencing factor in the invention has a significant influence on the dimensional accuracy, surface quality, structural stability and yield of the metal part processing, and has good synergistic effect among the factors, specifically as follows:

In the comparative example 1, the core stress is omitted to eliminate the vacuum heat treatment link, the internal stress generated by rough machining cannot be effectively released, so that deformation is accumulated in subsequent machining, in the comparative example 2, burrs and greasy dirt generated by semi-finishing cannot be thoroughly removed and pollute the subsequent grinding process by reversing the process sequence of semi-finishing and surface pretreatment, in the comparative example 3, the common white corundum grinding wheel and dry grinding are used for replacing the core grinding combination of the superhard abrasive grinding wheel and the oil-based cutting fluid, the hardness supporting and heat dissipation capacity required by high-precision grinding is lost, in the comparative example 4, the precondition verification is cancelled, the prior process defect is directly transmitted to the subsequent link, the accumulated error is increased, the four cause the comprehensive machining performance of the metal piece to be obviously reduced, and in the embodiment, the conventional machining precision and the special process scheme of the special use requirement of the special scene of the metal piece are realized by optimizing the process logic, the precise control process parameters, the matching materials and the machining mode.

In the embodiment, the dimensional tolerance of the metal piece is +/-0.003 mm- +/-0.005 mm, the surface roughness Ra is 0.15 mu m-0.2 mu m, the qualification rate of the finished product is 92% -98%, wherein the specific scene of the embodiment 4 also has high corrosion resistance, and the embodiment 1-4 has error controllability caused by step linkage and is obviously superior to that of the comparative example.

The method is characterized in that the method is in an optimal general scene, the dimensional tolerance is +/-0.003 mm, the surface roughness is Ra0.15 mu m, the qualification rate is 98%, the comprehensive performance is balanced, the method is characterized in that the method is in a high corrosion-resistant scene, the dimensional tolerance is +/-0.004 mm, the antibacterial rate of staphylococcus aureus is 99.6%, the corrosion resistance is up to standard, the method is adapted to the chemical corrosion environment requirements, and the optimal requirements of general precision machining and special machining under special working conditions are respectively covered.

From the comprehensive processing performance of the metal piece, each performance in the examples is obviously higher than that of the comparative example, and the core is the synergistic effect of each key factor:

The process logic and step linkage conditions in examples 1-4 are precisely matched with the requirements of error accumulation control and defect early avoidance in metal processing. The working procedure connection and parameter combination in the embodiment 2 effectively control errors of all links, the fluctuation range of form and position tolerance is less than or equal to 0.002mm through detection and confirmation of a three-coordinate measuring instrument and a laser interferometer, an integrated processing system with unified standard, stress release, progressive precision and closed detection loop is formed, the balance performance of the dimensional tolerance + -0.003 mm, the surface roughness Ra0.15 mu m and the qualification rate of 98% is benefited, the embodiment 4 specifically adjusts the cutting fluid to be of a special corrosion-resistant type, and the post-treatment is of a double rust-proof scheme, the corrosion resistance is enhanced, the grinding parameters are optimized, the precision and the corrosion resistance are considered, and the severe use requirements of chemical equipment accessories are finally met.

The core process combination and the depth of the material characteristics are coordinated, the vacuum heat treatment is matched with the material characteristics of the stainless steel 304 in the embodiment 2, the internal stress elimination rate reaches 95%, the subsequent processing deformation is effectively avoided, the combination of the superhard abrasive cubic boron nitride grinding wheel and the oil-based cutting fluid enables uniform heat dissipation in the grinding process, surface burn is avoided, the balance between high precision and high efficiency is realized by matching the milling speed of 120m/min and the accurate grinding allowance of 0.08mm, the deformation rate reaches 45% due to the internal stress residue caused by omitting the vacuum heat treatment in the embodiment 1, the surface burn and scratch occurrence rate reaches 25% due to the replacement grinding process in the embodiment 3, the linkage verification is cancelled in the embodiment 4, the grinding defect does not appear in the workpiece of 12% due to the front cleanliness, and the synergistic necessity of the core process combination and the working procedure logic is further highlighted.

In comparative example 1, the vacuum heat treatment link is omitted, the internal stress release channel cannot be formed, the dimensional tolerance is only +/-0.012 mm, the surface roughness Ra0.45 mu m is enlarged by 4 times compared with that of example 2, obvious grinding cracks appear, the qualification rate is only 62%, the structural stability of a metal part is greatly reduced, in comparative example 2, the new burrs and greasy dirt generated by semi-finishing cannot be thoroughly removed due to the fact that the semi-finishing and surface pretreatment sequence is reversed, the coaxiality error of a boring hole is enlarged to 0.018mm, the surface roughness Ra0.32 mu m, the qualification rate is 81%, the basic condition of accurate grinding is destroyed, in comparative example 3, the surface deterioration is caused by the fact that the temperature is too high in the grinding process is replaced by a common white corundum grinding wheel and dry grinding, the dimensional tolerance is +/-0.009 mm, the surface burn rate is 30%, the qualification rate is 75%, the precision and surface quality requirements of accurate machining cannot be met, in contrast example 4, defects such as the preamble internal stress does not reach standard, the finish allowance is insufficient, the defects such as excessive grinding or residual greasy dirt appear on 12%, the dimensional tolerance is +/-0.007 mm, the basic condition is damaged, the qualification rate is 83%, and the closed-loop failure is caused by the process.

The method has the advantages that the dimensional tolerance of +/-0.005 mm and the qualification rate of 92% of the embodiment 1 meet basic precision requirements, the efficiency is moderate, the adaptation is sensitive to cost and the precision is moderate, the embodiment 3 is high in processing efficiency due to the fact that the upper limit is taken by parameters, the dimensional tolerance of +/-0.005 mm and the qualification rate of 93%, the processing efficiency is high, the adaptation to heavy precision equipment scenes with large machining allowance is achieved, the conventional precision of the embodiment 4 is slightly lower than that of the embodiment 2, the adaptation to corrosion resistance and special working conditions is outstanding, the requirements of high corrosion environments such as chemical engineering and ocean engineering are met accurately, and the embodiments 1-4 can achieve controllable errors due to the fact that core working procedure logic and linkage verification are kept, so that the scene adaptation flexibility of the scheme of the invention is further embodied.

In summary, the key factors of the process logic design, the core process combination, the parameter and material adaptation and the scene pertinence adjustment are mutually matched, and the synergistic effect ensures that the metal part precision machining process not only can meet the requirements of high precision and high stability of a general scene, but also can adapt to the requirements of special scenes such as high corrosion resistance, heavy duty machining and the like and the requirements of cost sensitive scenes, and simultaneously, the irreplaceability of stress relief vacuum heat treatment, process sequence rationality, superhard abrasive grinding wheel and oil-based cutting fluid combination and step linkage verification is respectively verified through comparative examples 1-4, and finally, the optimal balance of the dimensional precision, the surface quality, the structural stability and the working condition adaptation effect under different use scenes is realized.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A precision machining process for metal parts, characterized by comprising the following steps:

S1, Raw material screening and pretreatment: Select metal billets that meet the preset composition requirements, conduct flaw detection and initial size calibration, and obtain pretreated billets when there are no internal defects and the initial size deviation is within the preset range.

S2, Rough Machining and Stress Relief: Based on the pre-processed blank size data of S1, cutting is performed to obtain a rough-machined part; then the rough-machined part is heat-treated, and after the internal stress relief effect meets the standard, a stress-relieved part is obtained;

S3, Semi-finishing and surface pretreatment: The stress-relief part is milled and bored to obtain a semi-finished part; then deburring, ultrasonic cleaning and drying are performed in sequence to obtain a clean workpiece;

S4, Precision Grinding and Finished Product Inspection: The critical surfaces of the clean workpiece are ground using an ultrahard abrasive grinding wheel. Cooling and lubrication measures are taken during the grinding process to obtain the ground workpiece. Then, the dimensional accuracy, geometric tolerances and surface quality are inspected by special inspection equipment. If they pass the inspection, the workpiece proceeds to the next step; otherwise, it is returned to this step for re-grinding.

S5, Precision machining: Boring is performed on the ground workpiece using a boring machine;

S6, Post-processing of finished products: Rust prevention treatment and sealing packaging are carried out on the qualified workpieces to obtain finished metal parts.

2. The precision machining process for metal parts according to claim 1, characterized in that: the boring machine includes a frame (1), a boring assembly is provided on the side wall of the frame (1), a mounting frame (6) is fixedly connected to the side wall of the frame (1), and a fixing assembly (7) is provided on the side wall of the mounting frame (6), the fixing assembly (7) including:

A fixing rod (701) is fixedly connected to a fixing plate (706) on its end face, and a bolt (707) is threadedly connected to the side wall of the fixing plate (706).

Movable plate one (702), a connecting rod (703) is fixedly connected to the side wall of the movable plate one (702), a limit plate (704) is sleeved on the side wall of the connecting rod (703), and a movable plate two (705) is sleeved on the side wall of the fixed rod (701).

A sliding frame (708) has a cam (710) rotatably connected to its side wall.

The boring assembly includes a drive motor (2) fixedly connected to the side wall of the frame (1), the output end of the drive motor (2) is fixedly connected to a bidirectional screw (3), the side wall of the bidirectional screw (3) is threadedly connected to a mounting base (4), and the side wall of the mounting base (4) is fixedly connected to a boring device (5).

The fixing rod (701) is fixedly connected to the side wall of the mounting bracket (6), and the end face of the bolt (707) is fixedly connected to a knob;

The side wall of the connecting rod (703) is fitted with a spring (709), and the number of springs (709) is set in several groups. The spring (709) abuts against the sliding frame (708), the spring (709) abuts against the movable plate (705), and the spring (709) abuts against the limiting plate (704).

The sliding frame (708) is sleeved with the connecting rod (703), the cam (710) is movably connected with the movable plate (705), and the cam (710) is movably connected with the fixed plate (706);

A handle is fixedly connected to the outer wall of the cam (710), and the movable plate (702) is sleeved with the fixed rod (701);

The side walls of the first movable plate (702) and the second movable plate (705) are fixedly connected to a hinge frame (8). An arc-shaped block (9) is hinged to the end face of the hinge frame (8). A torsion spring (10) is sleeved on the side wall of the arc-shaped block (9). One end of the torsion spring (10) abuts against the hinge frame (8), and the other end of the torsion spring (10) abuts against the arc-shaped block (9).

3. The precision machining process for metal parts according to claim 1, characterized in that: in step S1, the flaw detection adopts ultrasonic flaw detection, the metal blank is any one of stainless steel, aluminum alloy or titanium alloy, and the initial dimensional deviation is ≤ ±0.5mm.

4. The precision machining process for metal parts according to claim 1, characterized in that: in step S2, the cutting process adopts CNC cutting equipment, the cutting speed is 80-120m/min, the feed rate is 0.1-0.3mm/r, and the dimensional tolerance of the rough-machined part is controlled within ±0.1-0.3mm; the heat treatment is vacuum heat treatment, the treatment temperature is 850-950℃, the holding time is 2-4h, the cooling rate is ≤50℃/h, and the internal stress relief rate is ≥90%.

5. A precision machining process for metal parts according to claim 1, characterized in that: in step S3, the milling speed is 100-150 m/min, the coaxiality error of the boring is ≤0.01 mm, the surface roughness Ra of the semi-finished part is ≤1.6 μm, and a fine grinding allowance of 0.05-0.1 mm is reserved; the ultrasonic cleaning uses deionized water as the medium, the cleaning temperature is 40-60℃, and the cleaning time is 10-20 min;

The drying process is hot air drying, with a drying temperature of 80-120℃ and a drying time of 30-60 minutes.

6. The precision machining process for metal parts according to claim 1, characterized in that: in step S4, the superhard abrasive wheel is a cubic boron nitride wheel or a diamond wheel, the grinding speed is 30-50 m/s, the grinding depth is 0.001-0.003 mm/cycle, and the cooling and lubrication measures are oil-based cutting fluid; the dimensional tolerance of the ground workpiece is ≤ ±0.005 mm, and the surface roughness Ra is ≤ 0.2 μm;

The number of regrinding operations is ≤2 times. Specialized testing equipment includes a coordinate measuring machine, a laser interferometer, and a surface roughness tester.

7. The precision machining process for metal parts according to claim 1, characterized in that: in step S6, the rust prevention treatment is passivation treatment or coating with rust-preventive oil;

The passivation treatment time is 15-30 min, and the anti-rust oil coating thickness is 5-10 μm.

8. The precision machining process for metal parts according to claim 1, characterized in that: S2 uses the pre-treated blank of S1 as the sole machining reference;

S3 takes the achievement of the internal stress relief rate of S2 as the sole prerequisite for implementation;

S4 is executed under the condition that the fine grinding allowance of S3 meets the requirements and the clean workpiece is free of burrs and oil residue.

If the re-grinding in S4 fails after more than 2 cycles, return to S3 for semi-finishing, and adjust the finishing allowance after the semi-finishing to 0.08-0.12mm.