CN109014464B

CN109014464B - Wire cutting method for three-dimensional sheet metal part

Info

Publication number: CN109014464B
Application number: CN201811135364.5A
Authority: CN
Inventors: 陈明和; 苏楠; 谢兰生; 叶建华; 罗峰
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2019-12-20
Anticipated expiration: 2038-09-28
Also published as: CN109014464A

Abstract

The invention discloses a linear cutting method of a three-dimensional sheet metal part, which comprises the steps of making a simple tool clamp, making a linear cutting process by combining a three-dimensional drawing of the sheet metal part, making a supporting clamp by the simple tool according to an inner profile of a section, fixing the part by adopting a plurality of groups of flexible suckers, establishing a cutting coordinate system and obtaining a profile linear cutting path by a projection method. The invention converts the sheet metal part cutting track with a three-dimensional profile into one or more two-dimensional cutting tracks according to a scheme, inputs the two-dimensional cutting tracks into a cutting machine tool and cooperates with a specific tool fixture to finish the cutting process, reduces the cost in the research and development trial-manufacturing process of the sheet metal part, ensures the cutting quality and efficiency, and is particularly suitable for cutting and forming sample pieces in small batches.

Description

Wire cutting method for three-dimensional sheet metal part

Technical Field

The invention relates to the field of sheet metal part cutting, in particular to a linear cutting method for a three-dimensional sheet metal part.

Background

The sheet metal parts are formed by processing metal plates through means of stamping, bending, stretching and the like, and have important application in various fields of transportation, aerospace, electronic and electric appliances, medical appliances, petrochemical industry, daily life and the like. In the application of aircrafts, spacecrafts, deep sea exploration and the like, the complex curved surface can obtain a better streamline form, the requirements of fluid mechanics and aerodynamics are met, and the strict profile requirement ensures important technical indexes of the flight speed, the operation orbit or the submergence depth and the like of the whole aircraft.

The last processing procedure of the production and manufacturing of the three-dimensional sheet metal part with the complex profile is cutting and forming, and the common technical scheme in the industry is as follows: high energy beam cutting (laser, plasma), water jet cutting, wire electrical discharge cutting. The cost of the three components is in a decreasing trend, the high-energy beam cutting is more suitable when the batch size is larger, and the precise cutting in the space can be realized by combining a mechanical arm, so that the optimal cost performance is embodied; impact force is generated on the part in the water jet cutting process, burrs at the cut part are serious, and meanwhile, the machine tool needs to collect water and sand after cutting, and is relatively large in matching; the wire cutting utilizes the principle of electric spark, the force generated on parts can be ignored, the processing speed is relatively slow, and the wire cutting machine is suitable for small batches. For small-batch production of three-dimensional sheet metal parts with complex profiles in China, patents are mainly focused on a three-dimensional cutting device and are more suitable for laser cutting in mass production, for example, CN201721280085.9 and CN201510538139.6 both disclose a mechanical transmission type three-dimensional cutting device, which can better exert the excellent characteristics of laser vector cutting, but the laser cost is high, the requirements on quality of personnel compiling processing tracks are extremely high, and meanwhile, certain heat influence is generated on cutting edges. The high-pressure water three-dimensional cutting method provided in CN201410701674.4 requires high requirements for design and manufacture of the evasive type supporting tool, and has poor versatility for small batches and multiple types.

Disclosure of Invention

The invention aims to solve the technical problem of providing a linear cutting method of a three-dimensional sheet metal part aiming at the defects related in the background technology.

The invention adopts the following technical scheme for solving the technical problems:

a wire cutting method of a three-dimensional sheet metal part comprises the following steps:

step 1), obtaining a CAD three-dimensional drawing of a sheet metal part and a forming mode thereof, and if the forming is performed by adopting a die, constructing an X0Y plane of a coordinate system by using a parting surface of the sheet metal part die; if the die forming is not adopted, analyzing the CAD three-dimensional drawing of the sheet metal part, and placing the surface with the most concave surfaces of the sheet metal part on a horizontal plane, wherein the horizontal plane is an X0Y plane;

step 2), projecting the sheet metal part on an X0Y plane, making two vertical straight lines through the gravity center of a closed graph formed by a projection outline, respectively calling the straight line sections of the two straight lines in the outline as a long axis and a short axis according to length, making the straight line where the long axis is located when the short axis is shortest be a Y axis, making the midpoint of the long axis be an origin O and the length of the long axis be l, making the plane perpendicular to an XOY plane through the Y axis be a YOZ plane, making the plane perpendicular to an X0Y plane through the origin O, and making the plane perpendicular to a Y0Z plane be an X0Z plane, so as to form a complete machining coordinate system, wherein the intersection line of the XOY plane and the outer surface of the sheet metal part is an;

step 3), manufacturing a tool clamp for fixing the sheet metal part on a workbench of the linear cutting machine according to the size of the sheet metal part;

the tool clamp comprises a base rotating mechanism, a Y-axis rotating mechanism, three supports and two sucker modules;

the base rotating mechanism comprises a fixed base, a rotating platform, a tapered roller bearing, a first locking nut and two limiting bolts;

a fixing column vertical to the fixing base is arranged on the upper end face of the fixing base, and a thread matched with the thread of the inner ring of the first locking nut is arranged on the fixing column;

a round hole for the fixed column to pass through is formed in the center of the rotating platform, the rotating platform is sleeved on the fixed column and is connected with the fixed base through the tapered roller bearing, an inner ring of the tapered roller bearing is fixedly connected with the fixed column, and an outer ring of the tapered roller bearing is fixedly connected with the rotating platform, so that the rotating platform can freely rotate around the fixed column;

a first limiting hole and a second limiting hole which are symmetrical about the center of the fixing column are formed in the upper end face of the fixing base; a first limiting through hole and a second limiting through hole which correspond to the first limiting hole and the second limiting hole in the fixed base are formed in the rotating platform; the two limiting bolts are used for being matched with the first limiting hole, the second limiting hole, the first limiting through hole and the second limiting through hole to be used, so that the first limiting through hole of the rotating platform and the first limiting hole or the second limiting hole of the fixed platform are relatively fixed;

the first locking nut is in threaded connection with the fixed column and is used for locking or loosening the rotary platform and the fixed base;

the Y-axis rotating mechanism comprises first to second deep groove ball bearings, first to second bearing seats, a rotating shaft, a hand wheel, a second locking nut, an angle indicating disc and a pointer;

the first bearing block and the second bearing block are fixed on the rotating platform;

two ends of the rotating shaft are respectively arranged on the first bearing block and the second bearing block through a first deep groove ball bearing and a second deep groove ball bearing, so that the rotating shaft can freely rotate;

the center of the angle indicating disc is provided with a through hole for a rotating shaft to pass through, the through hole is sleeved outside one end of the rotating shaft close to the first bearing seat, the through hole is coaxial with the rotating shaft and fixedly connected with the first bearing seat, and angle scales are arranged on the through hole;

the root part of the pointer is sleeved at one end, close to the first bearing seat, of the rotating shaft and fixedly connected with the rotating shaft, points to an angle scale on the angle indicating disc and is used for representing the rotating angle of the rotating shaft;

the rotating shaft of the hand wheel is fixedly connected with one end, close to the first bearing seat, of the rotating shaft and is used for driving the rotating shaft to rotate;

one end of the rotating shaft, which is close to the second bearing seat, is provided with a thread matched with the thread of the inner ring of the second lock nut and is connected with the thread of the second lock nut;

the second locking nut is used for being matched with the second bearing seat to lock or unlock the rotating shaft;

the sucker module comprises a sucker support and a plurality of vacuum suckers uniformly arranged at the upper end of the sucker support;

the bottom of three support, two sucking disc supports is all fixed to be set up on the rotation axis, wherein, three support is used for holding up the panel beating rough part, two sucking disc modules are used for holding panel beating rough part, cooperate three support in order to fix the panel beating rough part.

Step 4), mounting the tool clamp on a workbench of a linear cutting machine, carrying out tool setting on the tool clamp by using a linear cutting wire, and unifying a coordinate system of the blank and the tool on the linear cutting machine;

placing the sheet metal blank on a tool fixture, so that the lower surface of the sheet metal blank is completely attached to three contour lines of the three supports, and meanwhile, two groups of eight vacuum suckers are used for sucking the sheet metal blank;

step 5), establishing a reference plane and a projection function by using three-dimensional software, performing contour projection of the three-dimensional sheet metal part on an X0Y plane, and observing whether a cross line exists in the contour projection of the sheet metal part;

step 5.1), if no cross line exists, directly introducing a contour line into the linear cutting machine tool software to cut a three-dimensional sheet metal part for a path, polishing the cut surface to be smooth, and finishing the part cleaning;

step 5.2), if a cross line exists:

step 5.2.1), in three-dimensional software, an included angle a is formed between the Y-axis construction of a coordinate system and the counterclockwise direction of an X0Y plane_i9 projection planes of a_iI is multiplied by 10 degrees, i is a natural number which is greater than or equal to 1 and less than or equal to 9;

step 5.2.2), acquiring contour projections of the three-dimensional sheet metal part on 9 projection planes by adopting a projection function of software;

step 5.2.3), observing whether cross lines exist in the contour projection on the 9 projection planes:

step 5.2.3.1), if the contour projection without the crossed line exists, selecting a contour projection without the crossed line at will, taking a corresponding projection plane as a cutting reference plane, rotating the tool clamp through a hand wheel to enable the fixed sheet metal blank to correspond to the cutting reference plane, guiding the contour projection of the three-dimensional sheet metal part on the cutting reference plane, cutting the three-dimensional sheet metal part by taking the path as the path, polishing the cutting surface to be smooth, and finishing the cleaning of the three-dimensional sheet metal part;

step 5.2.3.2), if the cross lines exist in the contour projection of the 9 projection planes:

5.2.3.2.1), selecting a projection plane corresponding to the contour projection with the smallest cross area as an initial projection plane, rotating the tool clamp through a hand wheel to enable the fixed sheet metal blank to correspond to the initial projection plane, and selecting a closed contour line formed by the outermost sides of cross lines as a cutting path to finish primary cutting;

step 5.2.3.2.2), a local area with crossed lines in the contour projection of the initial projection surface is made to be an area A, contour projection without crossed lines in any area A is selected from contour projections of 8 projection planes outside the initial projection surface and the original X0Y plane, the corresponding projection plane is used as a secondary projection surface for cutting the area A, the tooling fixture is rotated through a hand wheel to enable the sheet metal blank to correspond to the secondary projection surface, contour projection of the three-dimensional sheet metal part on the secondary projection surface is led in, and the area A of the three-dimensional sheet metal part is cut by taking the contour projection as a path;

and 5.2.3.2.3), polishing the cut surface to be smooth, and finishing the cleaning of the three-dimensional sheet metal parts.

As a further optimized scheme of the wire cutting method of the three-dimensional sheet metal part, the specific manufacturing method of the three supports and the two sucker supports in the step 3) is as follows:

step 3.1), performing section on the three-dimensional sheet metal part model by utilizing first to fifth planes in three-dimensional CAD software, wherein the first to fifth planes are sequentially arranged along the Y axis and are parallel to each other, the third plane is an X0Z plane, the distance between the first plane, the fifth plane and the third plane is m, andthe distances among the second plane, the fourth plane and the third plane are all

Step 3.2), cutting a steel plate by a wire to manufacture three supports according to inner contour curves cut by the first plane, the third plane and the fifth plane;

and 3.3) according to the inner contour curves cut by the second plane and the fourth plane, linearly cutting the steel plate to manufacture two sucker supports.

As a further optimization scheme of the wire cutting method of the three-dimensional sheet metal part, the number of the vacuum suction cups in the suction cup module is 4.

As a further optimized scheme of the wire cutting method of the three-dimensional sheet metal part, the vacuum chucks are NBR rubber vacuum chucks with the diameter of 20mm, and the vacuum degree is-0.5 Pa.

As a further optimization scheme of the wire cutting method for the three-dimensional sheet metal part, when the closed contour line is cut in the step 5), the specific steps are as follows:

step A), dividing a closed contour line into two sections by adopting a projection line of an optimal smooth section line on a projection plane, combining a lengthened preset distance threshold value of one section of the contour line with a feed path and a retracting path to form a path A, and combining a lengthened preset distance threshold value of the other section of the contour line with the feed path and the retracting path to form a path B;

step B), locking the rotary platform and the fixed base, relatively fixing a first limiting through hole of the rotary platform and a first limiting hole of the fixed platform, relatively fixing a second limiting through hole of the rotary platform and a second limiting hole of the fixed platform, and cutting by adopting the path A;

and step C), locking the rotary platform and the fixed base, relatively fixing the first limiting through hole of the rotary platform and the second limiting hole of the fixed platform, relatively fixing the second limiting through hole of the rotary platform and the first limiting hole of the fixed platform, and cutting by adopting the path B.

As a further optimization scheme of the wire cutting method of the three-dimensional sheet metal part, the preset distance threshold is 2 mm.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects:

1. the design and the manufacturing of the tool clamp are simple and convenient, the good universality is realized on the complex three-dimensional sheet metal parts conforming to the working stroke of the linear cutting equipment, the assembly and the use operation of the tool clamp are simple, and the manufacturing cost and the trial-manufacturing period of the complex three-dimensional sheet metal parts in a small batch in the research and development trial-manufacturing process are greatly reduced by combining a high-efficiency low-cost linear cutting technology.

2. The blank is accurately positioned by adopting a plurality of inner contour supports, and the parts are adsorbed by the vacuum chuck, so that the effect of fixing the parts is achieved. The vacuum chuck solves the problem that sheet metal parts made of nonmagnetic materials such as aluminum, aluminum alloy, stainless steel, titanium alloy and the like are difficult to fix, and realizes the precise clamping of complex three-dimensional sheet metal blank parts without damage.

3. The transformation of a three-dimensional contour and a two-dimensional cutting path is realized by adopting the projection function of three-dimensional software, and the cutting and forming of the complex three-dimensional sheet metal part are realized by simple and convenient steps with low cost under the condition of unifying a coordinate system. Compared with the existing cutting and forming technology of the complex three-dimensional sheet metal part, the method provided by the invention can be used as a new method for cutting and forming the complex three-dimensional sheet metal part, and the cutting quality and efficiency are ensured while the cost of the extra-small batch of parts in the research and development trial-and-manufacture process is reduced.

Drawings

FIG. 1 is a flow chart of an embodiment of the present invention;

fig. 2(a) is a schematic diagram of a three-dimensional sheet metal part coordinate system, and fig. 2(b) is a schematic diagram of a projection of the three-dimensional sheet metal part on an X0Y plane;

fig. 3(a) is a schematic structural view of three support and two suction cup supports of the tooling fixture of the present invention, fig. 3(b) is a front view of the tooling fixture, fig. 3(c) is a top view of the tooling fixture, and fig. 3(d) is a schematic structural view of the tooling fixture;

FIG. 4(a) is a schematic view of a 0 assembly between the rotary platform and the stationary base in the present invention, and FIG. 4(b) is a schematic view of a 180 assembly between the rotary platform and the stationary base;

FIG. 5 is a schematic view of 9 projection planes in the present invention;

FIG. 6 is a schematic representation of the conversion of a closed contour to a cut path in the present invention;

FIG. 7(a) is a schematic diagram of a coordinate system of a second embodiment of the present invention; fig. 7(b) is a projection schematic diagram of a three-dimensional sheet metal part in a plane X0Y in a second embodiment of the present invention; FIG. 7(c) is a schematic cross-line projection of a second embodiment of the present invention; FIG. 7(d) is a schematic diagram of a partial area cutting path according to a second embodiment of the present invention;

in the figure, 21-a three-dimensional sheet metal part, 22-an XOY plane, 23-a YOZ plane, 24-an optimal smooth section line, 25-a projection contour line of the three-dimensional sheet metal part on the XOY plane, 26-a projection straight-line segment (namely a Y axis) of the optimal smooth section line on the XOY plane, 27-the XOZ plane, 311-a simple support, 312-a sucker support, 321-a bearing base, 322-a deep groove ball bearing, 323-a rotating shaft, 324-an angle display component, 325-a second locking nut, 326-a hand wheel, 327-a rotating platform, 331-a conical roller bearing, 332-a fixed base, 333-a machine tool universal support, 334-a first locking nut, 335-a limiting bolt, 341-an installation reference seat, 342-a vacuum sucker and 61-a cutter retracting path, 62-a cutting path, 63-a path a, 64-a path B, 71-a horizontal plane (i.e. XOY plane in the second embodiment of the present invention), 72-an optimal smooth section line in the second embodiment of the present invention, 73-a YOZ plane in the second embodiment of the present invention, 74-a projection contour line of the three-dimensional metal plate in the XOY plane in the second embodiment of the present invention, 75-a projection straight-line segment of the optimal smooth section line in the second embodiment of the present invention in the XOY plane, 76-an XOZ plane in the second embodiment of the present invention, 77-a region a, 771-a local contour line in the second embodiment of the present invention, 772-a cutting path of the local region a in the second embodiment of the present invention.

Detailed Description

The technical scheme of the invention is further explained in detail by combining the attached drawings:

the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, components are exaggerated for clarity.

Example 1: the invention provides a simple and convenient linear cutting solution and a simple tool design method. The process is shown in fig. 1, and the following takes a titanium alloy complex three-dimensional sheet metal part 21 as an example to describe the implementation steps of the present invention in detail.

Step 1: obtaining a CAD three-dimensional drawing of a three-dimensional sheet metal part and a forming mode thereof, wherein the part is subjected to mold hot forming, and an X0Y plane 22 of a coordinate system is constructed by utilizing a parting surface of a three-dimensional sheet metal part mold;

step 2: as shown in fig. 2(a), a projection of the three-dimensional sheet metal part on an X0Y plane 22 is made, two vertical straight lines are made through the gravity center of a closed figure formed by the projection outline 25, the straight line segments of the two straight lines in the outline are respectively called as a long axis and a short axis according to length, the straight line where the long axis is located when the short axis is shortest is made to be a Y axis, the midpoint of the long axis is made to be an origin O, the length of the long axis is 632mm, the plane perpendicular to an XOY plane 22 through the Y axis is made to be a YOZ plane 23, the plane perpendicular to an X0Y plane and a Y0Z plane is made to be an X0Z plane 27, and a complete machining coordinate system as shown in fig. 2 (b). Meanwhile, the intersection line of the XOY plane and the sheet metal part is an optimal smooth section line 24;

and 3), determining the size of the rotating shaft to be 620mm multiplied by 50mm according to the size of the sheet metal part, and manufacturing a tool clamp for fixing the sheet metal part on the workbench of the linear cutting machine according to the schematic diagrams in the figures 3(b) and 3 (c). The tool clamp comprises a base rotating mechanism, a Y-axis rotating mechanism, three supports, two sucker supports and two groups of vacuum suckers;

the base rotating mechanism comprises a fixed base 332, a rotating platform 327, a tapered roller bearing 331, a first locking nut 334 and two limiting bolts 335; the base rotating mechanism for realizing 180-degree conversion assembly of the base realizes rotation of the rotating platform 327 by means of the tapered roller bearing 331, the fixed base 332 is connected to the universal support 333 of the machine tool through a screw, the limiting bolt 335 realizes accurate positioning, and the first locking nut 334 realizes locking and unlocking of the rotating platform and the fixed base.

The Y-axis rotating mechanism comprises a first second deep groove ball bearing 322, a first bearing seat 321, a second bearing seat 321, a rotating shaft 323, a hand wheel 326, a second locking nut 325, an angle display part 324 consisting of an angle indicating disc and a pointer; a rotating shaft 323 is assembled on a first second bearing seat by a pair of deep groove ball bearings 322, the rotation of a Y axis is realized by rotating a hand wheel 326, an angle display part 324 composed of a pointer fixed on the rotating shaft 323 and an angle indicator disc on the bearing seat 321 accurately displays the rotating angle, and a second locking nut 325 realizes the fixation of the rotating angle.

In the three-dimensional CAD software, five planes (1-5 of which are numbered from left to right) parallel to an X0Z plane are utilized to perform section cutting on a three-dimensional sheet metal part model, and one side close to an XOY plane is selected as an inner contour curve aiming at two curves above and below the section. Three simple supports are manufactured according to inner contour curves cut by planes 1, 3 and 5, three simple supports 311 are manufactured by designing and linearly cutting a steel plate with the thickness of 1mm according to the three inner contour curves, wherein the plane 3 is a plane X0Z, and the planes 1 and 5 are parallel planes which are 180mm away from a plane X0Z at equal intervals, and the requirement that m is more than or equal to 158mm and less than or equal to 210.7mm is met; the vacuum cup holder 312 is manufactured by fabricating a vacuum cup holder according to an inner contour curve cut by 2, 4 planes, which are two parallel symmetrical planes equidistant from the X0Z plane by 158mm, and designing and linearly cutting a 1mm steel plate according to the two inner contour curves obtained by the two planes, as shown in fig. 3 (a). Three simple supports and two sucker supports are fixedly connected on the rotating shaft through an installation reference seat, eight NBR rubber vacuum suckers with the diameter of 20mm are fixed on the sucker supports, and the assembly is finished as shown in figure 3 (d).

Step 4), mounting the tool clamp on a workbench of a linear cutting machine, aligning the tool clamp with a linear cutting wire, adjusting a universal base 333 to ensure that a rotating shaft 323 of the tool clamp is parallel to a Y axis of the machine tool, determining the original point position of a cuboid section of the rotating shaft, and unifying a coordinate system of a blank and the upper clamp of the linear cutting machine; and placing the blank on a tool fixture, enabling the lower surface of the blank to be completely attached to the three contour lines of the three supports, adjusting the vacuum degree to be-0.5 Pa, turning on a control switch of a vacuum chuck, and fixing the blank.

And 5) fixing the blank according to the graph (a) in FIG. 4, creating a reference plane and a projection function by using three-dimensional software, performing contour projection of the three-dimensional sheet metal part on an X0Y plane, and observing no cross line in the contour projection of the sheet metal part. According to fig. 6, the projection line segment of the optimal smooth section line on the projection plane divides the closed contour line into two segments, and the two segments of the contour line are lengthened by a preset distance threshold of 2mm to form a 63-path a and a 64-path B respectively in combination with the feed path 62 and the retract path 61; when the rotary platform is in a 0-degree assembly state, namely a state shown in fig. 4(a), line cutting is completed by using the path A, the first locking nut 334 is loosened, the limiting bolt 335 is taken down, the rotary platform is adjusted to a 180-degree assembly state, namely a state shown in fig. 4(B), the first locking nut 334 is screwed down, the limiting bolt 335 is installed, the other side of the outline of the blank is cut by using the path B, the cutting surface of the outline of the part is polished to be smooth, and the part is cleaned and is withdrawn from the cutting task.

Example 2: the invention provides a simple and convenient linear cutting solution and a simple tool design method. The process is shown in fig. 1, and the steps of the present invention will be described in detail below by taking the titanium alloy complex three-dimensional part 21 trial-produced in fig. 2 as an example.

Step 1: consulting a workpiece side, wherein the forming mode of the part is unknown and no CAD three-dimensional drawing exists, laying the template on a horizontal plane, scanning the template by using a 3D scanner to construct a needed CAD software drawing, and constructing an X0Y plane of a coordinate system by using a horizontal plane 71;

step 2: as shown in fig. 7(a), a projection of the three-dimensional sheet metal part on an X0Y plane 71 is made, two vertical straight lines are made through the gravity center of a closed figure formed by the projection outline 74, the straight line segments of the two straight lines in the outline are respectively called as a long axis and a short axis according to length, the straight line where the long axis is located when the short axis is shortest is made to be a Y axis, the midpoint of the long axis is made to be an origin O, the length of the long axis is made to be 524mm, a plane perpendicular to an XOY plane 71 through the Y axis is made to be a YOZ plane 73, and a plane perpendicular to an X0Y plane and a Y0Z plane is made to be an X0Z plane 76 through the origin O, so that a complete machining coordinate system. Meanwhile, the intersection line of the XOY plane and the sheet metal part is an optimal smooth section line 72;

and step 3: the size of the rotating shaft is 620mm multiplied by 50mm according to the size of the sheet metal part, and a tool clamp for fixing the sheet metal part on a workbench of a linear cutting machine is manufactured according to the schematic diagrams in fig. 3(b) and 3 (c). The tool clamp comprises a base rotating mechanism, a Y-axis rotating mechanism, three supports, two sucker supports and two groups of vacuum suckers;

In the three-dimensional CAD software, five planes (1-5 of which are numbered from left to right) parallel to an X0Z plane are utilized to perform section cutting on a three-dimensional sheet metal part model, and one side close to an XOY plane is selected as an inner contour curve aiming at two curves above and below the section. Three simple supports are manufactured according to inner contour curves cut by planes 1, 3 and 5, three simple supports 311 are manufactured by designing and linearly cutting a steel plate with the thickness of 1mm according to the three inner contour curves, wherein the plane 3 is a plane X0Z, the planes 1 and 5 are parallel planes which are 150mm away from a plane X0Z at equal intervals, and the condition that m is more than or equal to 131mm and less than or equal to 174.7mm is met; 2. the plane 4 is two parallel symmetry planes which are equidistant from the plane X0Z by 131mm, and the vacuum chuck support 312 is manufactured by designing and line-cutting 1mm steel plate according to the two inner contour curves obtained from the two planes, as shown in fig. 3 (a). Three simple supports and two sucker supports are fixedly connected on the rotating shaft through an installation reference seat, eight NBR rubber vacuum suckers with the diameter of 20mm are fixed on the sucker supports, and the assembly is finished as shown in figure 3 (d).

Step 4, mounting the tool clamp on a workbench of a linear cutting machine, aligning the tool clamp with a linear cutting wire, adjusting a universal base 333 to ensure that a rotating shaft 323 of the tool clamp is parallel to a Y axis of the machine tool, determining the original point position of a cuboid section of the rotating shaft, and unifying a blank and a coordinate system of the tool clamp mounted on the linear cutting machine; and placing the blank on a tool fixture, enabling the lower surface of the blank to be completely attached to the three contour lines of the three supports, adjusting the vacuum degree to be-0.5 Pa, turning on a control switch of a vacuum chuck, and fixing the blank.

And 5: fixing a blank according to the figure 4(a), creating a reference plane and a projection function by using three-dimensional software, performing contour projection of the three-dimensional sheet metal part on an X0Y plane, and observing that the contour projection has crossed lines, as shown in figure 7 (c).

Step 6: according to the figure 5, the angle a between the Y-axis construction and the X0Y plane is anticlockwise_i9 planes (a)_iI × 10 °, i is a natural number of 1 or more and 9 or less), a closed contour line is selected as the outermost projection line when the projection plane has a cross line in all of the 9 contour projections and the cross line region 77 has the smallest area of 0 °. According to fig. 6, the projection line segment of the optimal smooth section line on the projection plane divides the closed contour line into two segments, and the two segments of the contour line are lengthened by a preset distance threshold of 2mm to form a 63-path a and a 64-path B respectively in combination with the feed path 62 and the retract path 61; when the rotary platform is in the state shown in fig. 4(a) when the rotary platform is in the state of 0 degree assembly, the line cutting is completed by using the path a, the first locking nut 334 is loosened, the limiting bolt 335 is taken down, the rotary platform is adjusted to the state of 180 degrees assembly when the rotary platform is in the state shown in fig. 4(B), the first locking nut 334 is screwed down, the limiting bolt 335 is installed, and the cutting of the other side of the outline of the blank is completed by using the path B.

And 7: for the local area A with the cross line, a is found in the contour projection of 8 projection planes outside the initial projection plane and the original X0Y plane_iWhen the projection contour of the local area a corresponding to the plane at 20 ° does not have a cross line, the local projection is performed on the three-dimensional sheet metal part in the three-dimensional software by taking the plane as the projection plane, so as to obtain a local contour line 771, the two ends of the local contour line are lengthened by 2mm, and a cutting path 772 is formed by combining the tool start point and the tool retreat point, as shown in fig. 7 (d). Meanwhile, the rotating shaft 323 is rotated clockwise by the hand wheel at an angle of 20 degrees, a blank on the tool clamp is fixed through the second locking nut, and the cutting of the local area A is completed by combining with the cutting path 772.

And 8: and (5) polishing the cutting surface of the part contour line until the cutting surface is smooth, and cleaning the part to finish and quit the cutting task.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wire cutting method of a three-dimensional sheet metal part is characterized by comprising the following steps:

the bottom parts of the three supports and the two sucker supports are all fixedly arranged on the rotating shaft, wherein the three supports are used for supporting the sheet metal blank, and the two sucker modules are used for sucking the sheet metal blank and are matched with the three supports to fix the sheet metal blank;

step 4), mounting the tool clamp on a workbench of a linear cutting machine, and aligning the tool clamp with a linear cutting wire to unify the blank and a coordinate system of the tool clamp on the linear cutting machine;

placing the sheet metal blank on a tool fixture, so that the lower surface of the sheet metal blank is completely attached to three contour lines of the three supports, and meanwhile, the two sucker modules suck the sheet metal blank;

step 5.2), if a cross line exists:

2. The wire-cutting method of three-dimensional sheet metal parts according to claim 1, wherein the specific manufacturing method of the three supports and the two suction cup supports in step 3) is as follows:

3. The wire cutting method of a three-dimensional sheet metal part of claim 1, wherein the number of vacuum suction cups in the suction cup module is 4.

4. The wire cutting method of three-dimensional sheet metal parts according to claim 1, wherein the vacuum chucks are all NBR rubber vacuum chucks with a diameter of 20mm, and the vacuum degree is-0.5 Pa.

5. The wire cutting method of the three-dimensional sheet metal part according to claim 1, wherein when the closed contour line is cut in the step 5), the specific steps are as follows:

6. The wire cutting method of three-dimensional sheet metal parts according to claim 5, wherein the preset distance threshold is 2 mm.