WO2023070921A1

WO2023070921A1 - Precision numerical control machining method for titanium alloy thin-walled lens barrel part

Info

Publication number: WO2023070921A1
Application number: PCT/CN2021/140856
Authority: WO
Inventors: 曹宏; 郭佳贺; 赵明亮; 李彦杰; 张亚晓; 樊恒岩
Original assignee: 航天精工股份有限公司
Priority date: 2021-10-28
Filing date: 2021-12-23
Publication date: 2023-05-04
Also published as: CN113909821A; CN113909821B

Abstract

Provided is a precision numerical control machining method for a titanium alloy thin-walled lens barrel part (1), comprising the following steps: S1: performing rough turning, reserving a margin of 30 mm at one end of a blank close to an end surface of a part (1), and carrying out a heat treatment; S2: machining the margin in step S1, and machining a process clamping platform (5); S3: mounting the processed part (1) in step S2 on a first self-made workpiece (2), carrying out semi-finish turning on a barrel body (6), and carrying out milling on the side close to the process clamping platform (5); S4: separating the part (1) from the first self-made workpiece (2), placing a supporting block into an inner hole of the part (1), and cutting the process clamping platform (5) of the part (1); S5: machining an outer contour of the part (1) and machining a process threaded hole; S6: mounting the part (1) on a second self-made workpiece (7), and carrying out finish turning; and S7: machining the process threaded hole into a through hole. In the precision numerical control machining method for a titanium alloy thin-walled lens barrel part (1), deformation does not easily occur, and the quality of the part (1) is high.

Description

A precision numerical control machining method for titanium alloy thin-wall lens barrel parts

technical field

The invention belongs to the field of numerical control, and in particular relates to a precision numerical control processing method for titanium alloy thin-walled lens barrel parts.

Background technique

In modern industrial production, CNC machining occupies a dominant position. With the support of CNC machining technology, the processing of parts is diversified, and parts can obtain higher precision and surface quality. Titanium alloy, a new type of metal material, is widely used in aviation and aerospace fields because of its low specific gravity, high strength, heat resistance, corrosion resistance and a series of excellent comprehensive physical and mechanical properties. However, titanium alloys have poor machinability and are difficult to process. The processing of thin-walled parts has always been a difficult problem in the machining industry. The reason is that its rigidity is poor, deformation is easy to occur during processing, and processing quality is difficult to guarantee. The processing of thin-walled parts using titanium alloy materials is even more difficult. In the case, the shape and position tolerance requirements of the parts are strict. The inner hole requires a cylindricity of Φ0.01mm as the reference A, and the outer circle requires a coaxiality of Φ0 relative to the reference A. .02mm, both ends of the surface relative to the benchmark A require a verticality of 0.015mm, and the parts will be scrapped if they are slightly deformed during the processing process, which has become a real problem in CNC machining.

Contents of the invention

In view of this, the present invention aims to propose a precision numerical control machining method for titanium alloy thin-walled lens barrel parts, so as to solve the problem that titanium alloy thin-walled parts are difficult to process and easily deformed, and the size and surface quality cannot be guaranteed.

In order to achieve the above object, the technical solution created by the present invention is achieved in this way:

A precision numerical control machining method for a titanium alloy thin-walled lens barrel part, comprising the following steps:

S1: Rough turning, a 30mm margin is reserved at the end of the blank close to the end face of the part, and heat treatment is performed;

S2: Process the surplus in S1 to process a process clamping table;

S3: Install the parts processed in S2 on the first self-made workpiece, perform semi-finished turning on the cylinder body and milling on the side close to the process clamping table;

S4: Separate the part from the first self-made workpiece, put a support block in the inner hole of the part, and cut the process clamping table of the part;

S5: Process the outer contour of the part and process the threaded hole;

S6: install the parts on the second self-made workpiece, and carry out fine turning;

S7: Process the threaded hole of the process hole into a through hole.

Overall process route: Rough turning - heat treatment - turning process benchmark - drilling and milling process threaded hole - semi-finishing turning - milling plane, keyway, drilling radial hole, thread milling - removal of process table - milling outside the right end Contour and process thread - finishing turning - milling hole - cleaning - inspection.

A margin of 30mm is reserved in the length direction of the blank for processing a process clamping table, the purpose is to improve the rigidity of the part in subsequent processing, and axial clamping can be used to avoid deformation caused by clamping force generated by radial clamping .

Design and manufacture two sets of special tooling fixtures to ensure accurate positioning of workpieces, and adopt axial clamping methods to avoid deformation caused by clamping force generated by radial clamping.

In the step S1 and step S2, the clamping table and the outer contour of the processing technology have a machining allowance of 1mm on one side of the direction dimension, and the heat treatment in the step S1 adopts vacuum stress relief annealing to eliminate the internal stress generated by the rough car and reduce the parts. Deformation in subsequent processing.

The machining process clamping table in the step S2 includes punching a turning process reference hole in the middle of the part margin in the step S1 to form a round table, which is used as a positioning reference for the subsequent semi-finishing and four-axis processing, and clamping the workpiece on the first self-made tooling, A number of threaded holes for drilling and milling process are evenly drilled on the round table along the circumferential direction. The purpose is to fix and tighten the workpiece on the first self-made tooling for subsequent semi-finishing and four-axis machining.

The first self-made workpiece is cylindrical, with a circular platform at one end of the cylinder, several arc-shaped grooves in the middle of the cylinder, and four threaded holes evenly distributed along the circumference of the cylinder near the circular platform. The position of the threaded holes is Corresponding to the threaded hole of the drilling and milling process on the part in step S2.

In the step S3, the parts are installed on the first self-made tooling, the first self-made tooling is clamped with the chuck of the machine tool, the gap between the tooling and the reference hole is Φ0.02mm, and the process clamping table and the first self-made tooling pass through the second A screw connection, so that the reference end face fits the tooling, the internal thread and the thread undercut are processed to the final size, and the remaining unilateral side is left with a margin of 0.5mm. Milling on the machining center includes milling the plane, keyway, and drill diameter of the part To the hole, thread milling. The use of self-made tooling to clamp parts is to avoid the clamping force deformation caused by the radial tightening of traditional chucks.

In the step S4, the inner hole of the part is put into the support block, the process clamping table is cut on the CNC lathe, and the outer circle cutting process clamping table is supported by the soft gripper. The diameter of the clamping surface of the soft claw is basically the same as the outer diameter of the part The tolerance is 0 to +0.03mm. Cutting off craft table on CNC lathe. The purpose is to reduce the deformation of the part caused by the radial clamping force.

In the step S5, the outer contour of the part is processed, and four process threaded holes are processed on the outer contour. The use of self-made tooling to clamp parts is to avoid the clamping force deformation caused by the radial tightening of traditional chucks.

The second self-made tooling includes a main body, the main body is provided with several arc-shaped grooves, and the arc-shaped grooves are provided with four threaded holes, the positions of the threaded holes correspond to the positions of the process threaded holes in step S5, and the total number of threaded holes Same as the total number of process threaded holes.

In the step S6, the parts are mounted on the second self-made tooling, and the radial reference gap between the second self-made tooling and the parts is required to be less than Φ0.02 mm, and the workpiece is clamped by pressing the upper end. The purpose is to avoid the deformation of the clamping force caused by the radial tightening of the traditional chuck. When finishing the inner hole, the alloy damping tool holder with a diameter of Φ20 is used to avoid the scrapping of the workpiece due to the vibration caused by the long overhang of the tool. G96 constant linear speed command is used in the processing program (G97 constant speed command is used for internal thread and tool relief), and low cutting speed vc, medium and small depth of cut ap, and medium and high feed rate F are selected for cutting parameters.

A CNC milling machine is used when the process threaded hole is processed into a through hole in the step S6.

After the step S7, it also includes separating the parts from the second self-made workpiece, and then cleaning and testing with a three-coordinate measuring instrument.

Compared with the prior art, the invention creates a precision numerical control machining method for a titanium alloy thin-walled lens barrel part that has the following beneficial effects:

The invention provides a set of practical and effective precision numerical control processing method for titanium alloy thin-walled lens tube parts, successfully solves the problem that titanium alloy thin-walled parts are difficult to process and easily deformed, and cannot guarantee the size and surface quality. Two sets of special tooling fixtures are designed and manufactured to ensure The positioning of the workpiece is accurate, and the axial clamping method is adopted to avoid the deformation caused by the clamping force generated by the radial clamping. At the same time, the precision of the parts processed by this method reaches cylindricity Φ0.0053mm, coaxiality Φ0.003mm, and verticality 0.007mm. Precision machining level.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute improper limitations to the present invention. In the attached picture:

Figure 1 is a schematic diagram of parts;

Fig. 2 is a schematic diagram after rough machining;

Figure 3 is a schematic diagram of the clamping of the semi-finishing car and the four-axis machining center using the first self-made tooling;

Fig. 4 is a schematic diagram of the contents of the milling process of the four-axis machining center;

Fig. 5 is a schematic diagram of the content of the CNC milling machine milling process;

Figure 6 is a schematic diagram of the clamping of the finished car using the self-made tooling 2.

Explanation of reference signs:

1-parts; 2-first self-made tooling; 3-first screw; 4-machine chuck; 5-process clamping table; 6-cylinder body; 7-second self-made tooling; 8-second screw.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", The orientations or positional relationships indicated by "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention Creation and simplification of description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, a feature defined as "first", "second", etc. may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be interpreted in a broad sense, for example, it can be a fixed connection or a flexible connection. Detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention based on specific situations.

The invention will be described in detail below with reference to the accompanying drawings and examples.

(1) Rough turning is divided into two steps as shown in Figure 2, and the machining process clamping table 5 and the outer contour are left with a machining allowance of 1mm on one side of each dimension.

(2) Heat treatment, vacuum stress relief annealing is used to eliminate the internal stress generated by rough turning, and reduce the deformation of part 1 in subsequent processing.

(3) As shown in Figure 2, turning process reference hole Φx, and the right end face of part 1. As a follow-up semi-finished car and four-axis machining, the positioning reference for clamping the workpiece on the first self-made tooling 2.

(4) Drilling and milling process threaded holes 4*Mx*1 as shown in Figure 3, the purpose is to fix and tighten the workpiece on the first self-made tooling 2 for subsequent semi-finishing and four-axis processing of the cylinder body 6.

(5) Semi-finished car, as shown in Figure 3, install the part 1 on the first self-made tooling 2, and the clearance between the tooling and the reference hole is Φ0.02mm. Use 4 first screws 3 to fix and tighten, so that the reference end face fits the tooling. The use of self-made tooling to clamp part 1 is to avoid the deformation of the clamping force caused by the radial tightening of the traditional chuck. Process the Mx*0.5 internal thread and thread undercut to the final size according to the requirements in Figure 1, and leave a margin of 0.5mm on the other sides.

(6) On the four-axis machining center, as shown in Figure 3, install the part 1 on the first self-made tooling 2, and the gap between the tooling and the reference hole is Φ0.02mm. Use 4 first screws to fix and tighten, so that the reference end face fits the tooling. The use of self-made tooling to clamp the part 1 is to avoid the deformation of the clamping force caused by the radial tightening of the chuck 4 of the traditional machine tool. Plane milling, keyway, radial hole drilling, and thread milling are required as shown in Figure 4.

(7) Put the support block into the inner hole of part 1, and use the soft grip to hold the outer circle. The diameter of the clamping surface of the soft claw is required to be the same as the basic size of the outer diameter of part 1, and the tolerance is 0 to +0.03mm. The purpose is to reduce the deformation of the part 1 caused by the radial clamping force. Cutting off craft table on CNC lathe.

(8) Put the supporting block into the inner hole of part 1, and use the soft grip to hold the outer circle. The diameter of the clamping surface of the soft claw is required to be the same as the basic size of the outer diameter of part 1, and the tolerance is 0 to +0.03mm. The purpose is to reduce the deformation of the part 1 caused by the radial clamping force. According to the right view of Figure 5, process the outer contour of part 1 and the 4*M2.5 process threaded holes on the CNC milling machine (borrow the positions of the 4 light holes in the right view of Figure 1, and the purpose of processing the process threaded holes is for the next sequence of fine turning For the fixed part 1, it will be processed into the light hole in Fig. 1 in the final processing process), because the dimensional accuracy of the outer contour Φx is high, it is over-selected as the radial positioning reference for the next sequence of finishing. Among them, the process has a special requirement for one end face, requiring a flatness of 0.01mm, which is not required on the design drawings of part 1. This requirement is to ensure that it finally meets the verticality of 0.015mm relative to the reference A, and at the same time it is faked It is formulated as the axial positioning datum plane of the subsequent finishing car.

(9) Install the part 1 on the self-made tooling 2 as shown in Figure 6. The radial reference clearance between the tooling and the part 1 is required to be less than Φ0.02mm. Fix and tighten with four second screws 8 so that the axial reference plane of the workpiece is completely aligned with the tooling. fit. The use of self-made tooling to clamp part 1 is to avoid the deformation of the clamping force caused by the radial tightening of the traditional chuck. According to Figure 1, the finish turning part 1 to the final size, the alloy damping tool holder with a diameter of Φ20 is used when finishing the inner hole, so as to avoid the scrapping of the workpiece due to the vibration caused by the long overhang of the tool.

(10) Take the inner hole marked as reference A in Figure 1 as the positioning reference, and clamp the workpiece by pressing the upper end. The purpose is to avoid the deformation of the clamping force caused by the radial tightening of the traditional chuck. According to the right view of Figure 1, milling and processing 5 light holes.

(11) After cleaning, it is tested by a three-coordinate measuring instrument, and part 1 fully meets the design requirements.

3. According to the cutting characteristics of titanium alloy materials, select the tool and cutting amount as follows:

Reasonable use of the part structure, pre-processing 4 process clamping threaded holes, used for clamping parts in the finishing process, the process threaded holes can be processed into light holes required by the drawing design in the subsequent process. During CNC turning, because titanium alloy materials are difficult to process, in order to obtain the optimal surface processing quality and ensure that the tool is always working under the optimal cutting conditions, the G96 constant linear speed command (internal thread and retraction) is used in the processing program. The tool groove adopts G97 constant speed command), and the cutting amount is selected as low cutting speed vc, medium and small depth of cut ap, and medium and high feed rate F.

At the same time, the precision of the parts processed by this method reaches the precision machining level of cylindricity Φ0.0053mm, coaxiality Φ0.003mm, and verticality 0.007mm.

Using the processing precision in the prior art, the cylindricity is Φ0.01-0.02mm, the coaxiality is Φ0.01mm, and the perpendicularity is 0.015-0.03mm. The accuracy in the prior art cannot reach the accuracy in the present invention.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the Within the scope of protection of the present invention.

Claims

A precision numerical control machining method for a titanium alloy thin-walled lens barrel part, characterized in that it includes the following steps: S1: rough turning, leaving a margin of 30mm at the end of the blank close to the end face of the part, and heat treatment;

S2: Process the surplus in S1 to process a process clamping table;

S3: Install the parts processed in S2 on the first self-made workpiece, perform semi-finished turning on the cylinder body and milling on the side close to the process clamping table;

S4: Separate the part from the first self-made workpiece, put a support block in the inner hole of the part, and cut the process clamping table of the part;

S5: Process the outer contour of the part and process the threaded hole;

S6: install the parts on the second self-made workpiece, and carry out fine turning;

S7: Process the threaded hole of the process hole into a through hole.
A precision numerical control machining method for titanium alloy thin-walled lens barrel parts according to claim 1, characterized in that: in the step S1 and step S2, the machining process clamping table and the outer contour leave a 1mm processing on one side of the direction dimension For the balance, the heat treatment in step S1 adopts vacuum stress relief annealing.
A precision numerical control machining method for titanium alloy thin-walled lens barrel parts according to claim 1, characterized in that: the machining process clamping table in the step S2 is formed by punching a turning process reference hole in the middle of the part allowance in the step S1 Round table, four key slots evenly distributed along the circumference and four threaded holes of drilling and milling process evenly distributed along the circumference are processed on the round table.
A precision numerical control machining method for titanium alloy thin-walled lens barrel parts according to claim 1, characterized in that: the first self-made workpiece is cylindrical, one end of the cylinder is provided with a circular platform, and the middle of the cylinder is provided with several arcs For the slot, the end of the cylinder near the circular platform is provided with four threaded holes evenly distributed along the circumference, and the positions of the threaded holes correspond to the threaded holes of the drilling and milling process on the part in step S2.
A precision numerical control machining method for titanium alloy thin-wall lens barrel parts according to claim 4, characterized in that: in the step S3, the parts are mounted on the first self-made tooling, and the first self-made tooling is clamped with the chuck of the machine tool, The matching gap between the tooling and the reference hole is Φ0.02mm. Connect the process clamping table and the first self-made tooling with the first screw so that the reference end surface fits the tooling, and the internal thread and thread undercut are processed to the final size. A margin of 0.5mm is left on the edge, and the milling in S3 includes plane milling, keyway, radial hole drilling and thread milling on the side of the part.
A precision numerical control machining method for titanium alloy thin-wall lens barrel parts according to claim 1, characterized in that: in the step S4, the inner hole of the part is placed into a support block, and the clamping table of the excircle cutting process is supported by a soft gripper, and the The process clamping table is cut on the CNC lathe, and the diameter of the clamping surface of the soft claw is the same as the basic size of the outer diameter of the part, and the tolerance is 0 to +0.03mm.
A precision numerical control machining method for titanium alloy thin-wall lens barrel parts according to claim 1, characterized in that: in the step S5, the outer contour of the part is processed on a numerical control milling machine, and four process threaded holes are processed on the outer contour.
According to claim 7, a precision numerical control machining method for titanium alloy thin-walled lens barrel parts, characterized in that: the second self-made tooling includes a main body, a plurality of arc-shaped grooves are arranged on the main body, and four arc-shaped grooves are arranged on the arc-shaped grooves. threaded holes, the positions of the threaded holes correspond to the positions of the process threaded holes in step S5.
A precision numerical control machining method for titanium alloy thin-walled lens barrel parts according to claim 1, characterized in that: in step S6, the parts are mounted on the second self-made tooling, the second self-made tooling is clamped with the chuck of the machine tool, and the parts The outer contour of the second self-made tooling is connected with the second screw through the second screw. It is required that the clearance between the second self-made tooling and the radial reference of the part is less than Φ0.02mm. When finishing the inner hole, an alloy damping tool rod with a diameter of Φ20 is used. G96 constant linear speed command (G97 constant speed command is used for internal thread and tool relief), and low cutting speed vc, medium and small depth of cut ap, and medium and high feed rate F are selected for the cutting amount.
A precision numerical control machining method for titanium alloy thin-walled lens barrel parts according to claim 1, characterized in that: in the step S7, a numerical control milling machine is used when the process threaded hole is processed into a through hole.