CN111729986A - Two-point numerical control incremental forming and synchronous connection composite forming method for heterogeneous laminated plate - Google Patents

Abstract

The invention relates to a two-point numerical control incremental forming and synchronous connection composite forming method of a heterogeneous laminated plate, wherein a composite forming device comprises a clamping system, a tool head and a supporting die, the clamping system is used for fixing the laminated plate, the tool head is in autorotation contact with one surface of the laminated plate and makes spiral linear motion outwards from the center of the plane of the plate according to a preset track, the other surface of the supporting die in contact with the laminated plate makes synchronous linear motion in a direction vertical to the plane of the plate, and a preset gap between the tool head and the supporting die is controlled to apply a certain extrusion force to the laminated plate to perform incremental forming and synchronous connection. Compared with the prior art, the method can obviously improve the surface quality of the composite plate and improve the geometric precision of the finally formed part.

Description

Two-point numerical control incremental forming and synchronous connection composite forming method for heterogeneous laminated plate

Technical Field

The invention relates to the field of processing of three-dimensional parts of heterogeneous metal plates, in particular to a two-point numerical control incremental forming and synchronous connection composite forming method of a heterogeneous laminated plate.

Background

The heterogeneous metal composite laminate can be vigorously developed due to the excellent comprehensive service performance and the defect of overcoming the attribute of a single material, and is popularized and applied in the fields of aerospace, automobiles, electronic equipment, household appliances and the like. The heterogeneous metal composite layer plate is usually manufactured by adopting a process of firstly preparing a metal laminated plate and then carrying out plastic processing on the laminated plate. In order to improve the processing efficiency, reduce the processing cost and improve the utilization rate of materials, the forming and synchronous connection process is becoming a hot spot.

The Chinese patent application with publication number CN109249118A discloses a device and a method for double-point progressive forming and synchronous connection of laminated plates based on resistance welding, which utilize driving and driven tool heads capable of translating as resistance welding electrodes to realize the progressive forming and synchronous connection of heterogeneous metal plates. However, this method requires precise control of the current when performing composite forming, and the loss of the ram at high temperature is significant. Meanwhile, the principle of the method is resistance fusion welding, so that a large amount of brittle phases are generated during forming and connecting heterogeneous metal plates, and the connecting strength of formed parts is reduced.

The Chinese invention application with the publication number of CN110116265A discloses a composite forming method for single-point progressive forming and synchronous connection of heterogeneous laminated plates, which is based on a single-layer plate single-point numerical control progressive forming technology and realizes the progressive forming and synchronous connection of heterogeneous laminated metal plates. However, the connection quality of the method depends heavily on the plastic deformation capacity of the plastic auxiliary plate, and the pressure used for connection cannot be actively controlled; on the other hand, the inner surface of the workpiece is directly rubbed by the tool head, the quality of the formed surface is poor, and the geometric accuracy of the formed part is low.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a two-point numerical control incremental forming and synchronous connection composite forming method of a heterogeneous laminated plate, which is used for improving the forming characteristic and the connection characteristic of the heterogeneous laminated plate and improving the surface quality and the geometric precision of a formed part.

The purpose of the invention can be realized by the following technical scheme:

a composite forming method for two-point numerical control incremental forming and synchronous connection of a heterogeneous laminated plate comprises a clamping system, a tool head and a supporting die, wherein the clamping system is used for fixing laminated plates, the tool head is in autorotation contact with one surface of the laminated plates and makes spiral linear motion outwards from the center of the plane of the plates according to a preset track, the other surface of the supporting die in contact with the laminated plates makes synchronous linear motion in a direction perpendicular to the plane of the plates, and a preset gap between the tool head and the supporting die is controlled to apply a certain extrusion force to the laminated plates to perform incremental forming and synchronous connection.

Furthermore, the tool head has three translational degrees of freedom and one rotational degree of freedom, and the support die has at least one translational degree of freedom.

Further, the supporting die is provided with a working end for contacting the laminated plate, and the outer contour shape of the working end is consistent with the inner contour shape of the part to be formed.

Further, the fillet transition radius on the working end is not less than 5 mm.

Further, the material of the supporting die is hot die steel.

Further, the tool head is provided with a working end for contacting the laminated plates, and the working end is of a flat-bottom round-corner structure or a hemispherical head structure.

Further, the preset gap is smaller than the thickness of the laminated plate by a certain value, and the preset gap is controlled by a certain amount of displacement of the tool head which is offset towards the center direction of the plate plane, or the support die is controlled by a certain amount of displacement which is offset along the feeding direction, or the tool head is controlled by a certain amount of displacement which is offset along the normal direction in the part profile plane.

Further, the offset displacement is 0-0.3 mm.

Further, the laminated plate material comprises an auxiliary processing layer contacting the tool head, and the auxiliary processing layer and other layers of the laminated plate material are isolated through a solder resist.

Further, the method specifically comprises the following steps:

s1: processing and manufacturing a support die according to the inner contour shape of the formed part, obtaining a processing track of a tool head according to the outer contour shape of the formed part, and simultaneously generating a track program;

s2: according to design requirements, adjusting the machining track of the tool head according to a preset gap required by machining;

s3: loading a trajectory program in a motion control system of the tool head;

s4: carrying out uniform mechanical polishing or chemical corrosion on the mutually contacted surfaces of each layer of the laminated plates, removing an oxide layer, and then cleaning with acetone or alcohol;

s5: mounting the laminated plates on a clamping system;

s6: the tool head performs rotary friction on the laminated plate based on the machining track, and generates extrusion force on the laminated plate together with the supporting die which performs synchronous linear motion, so that the progressive forming and synchronous connection of the laminated plate are completed.

Compared with the prior art, the invention has the following advantages:

1. the tool head is used for heating the laminated plate materials in a pressure friction heat generation mode, and meanwhile, the extrusion force between the supporting die and the tool head is used for finally realizing the solid connection and synchronous plastic deformation of the two heterogeneous plate materials. The tool head which moves spirally outwards from the center of the plane of the laminated plate is matched with the supporting die which moves linearly and synchronously in the direction vertical to the plane of the plate, so that the surface quality of the part can be obviously improved, and the geometric precision of the finally formed part can be improved. Meanwhile, the invention can realize the high-strength solid metallurgical connection of heterogeneous laminated plates and the manufacture of customized and flexible composite plates, and finally improve the connection performance and the forming performance of the composite plates.

2. Compared with the traditional single-point progressive forming process, the single-point progressive forming process does not need to adopt a plastic auxiliary plate, has a simpler structure and improves the flexibility of the process.

3. The invention adopts the control of the preset gap between the tool head and the supporting die to finely operate and manage the extrusion force applied by the tool head to the laminated plate, thereby improving the controllability and flexibility of the process and providing a reliable and effective means for obtaining better connection and forming performance.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a diagram of a spiral machining trajectory of the center of the working end of the tool head in the plane of the sheet.

Fig. 3a is a front view and a top view of a supporting die structure of a truncated cone-shaped part.

Fig. 3b is a front view and a top view of a support die structure for a frustum-shaped part.

Fig. 4 is a schematic diagram of a tool head and support mold preset gap control strategy a.

Fig. 5 is a schematic diagram of a tool head and support die predetermined gap control strategy B.

Reference numerals: 1. the tool head comprises a tool head body 2, a supporting die 3, a laminated plate 31, a first layer of plate 32, a second layer of plate 33, a third layer of plate 4 and a clamp.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

Example one

The embodiment provides a two-point numerical control incremental forming and synchronous connection composite forming method for a heterogeneous laminated plate. As shown in fig. 1, the composite forming apparatus includes a clamping system, a tool head 1 and a support die 2. The laminated plate 3 to be formed is a three-layer structure of a first layer plate 31, a second layer plate 32 and a third layer plate 33 which are sequentially laminated from bottom to top. The laminated plate 3 is clamped and fixed by a clamp 4 of the clamping system, the tool head 1 is positioned above the laminated plate 3, and the support die 2 is positioned below the laminated plate 3.

The bottom of the tool head 1 is the working end for contacting the stacked sheets 3. The operation end adopts a flat-bottom round-corner structure or a hemispherical head structure. The tool head 1 is made of a material with high obdurability, surface hardness, high-temperature wear resistance and high fatigue resistance, such as tungsten carbide hard alloy. The top of the tool head 1 is connected to a motion control system, which moves in a spiral pattern from the inside to the outside in the plane of the sheet as shown in figure 2.

The top of the support die 2 is the working end for contacting the stacked sheets 3. The outer contour shape of the working end is consistent with the inner contour shape of the part to be formed, and a truncated cone structure or a frustum structure shown in fig. 3a or fig. 3b is adopted in the embodiment. The material of the supporting die 2 is heat-resistant and wear-resistant hot die steel, such as H11 die steel. The bottom of the support die 2 is also connected with a motion control system and can move up and down along the direction vertical to the plane of the plate.

The tool head 1 has three translational degrees of freedom and three rotational degrees of freedom and can realize high-speed rotation, and the support die 2 has at least one translational degree of freedom and at most three translational degrees of freedom and at most three rotational degrees of freedom.

When the composite forming is carried out, the tool head 1 carries out high-speed self-switching on the third layer of plate material 33 and carries out spiral line type motion outwards from the center of the plane of the laminated plate material 3 according to a set track; the supporting die 2 moves upwards in a synchronous linear mode from the position below the first layer of plate 31 and perpendicular to the plane direction of the plate, and a preset gap between the tool head 1 and the supporting die 2 is controlled to apply certain extrusion force to the laminated plate 3 to perform gradual forming and synchronous connection. The control strategy for biasing is generally divided into three categories: as shown in the control strategy a of fig. 4, the trajectory of the tool head 1 is offset to the center direction of the sheet plane by a displacement of T to control the gap between the tool head 1 and the support die 2, so as to provide the required extrusion force when the laminated sheet 3 is formed. As shown in fig. 5, the supporting die 2 is biased in the feeding direction by a displacement of T to control the gap between the tool head 1 and the supporting die 2, so as to provide the required pressing force when the laminated sheet 3 is formed. The control strategy C is as follows: the tool head is controlled by a displacement normally offset by an amount along the part profile plane. In this embodiment, a control strategy a is adopted. The rotating speed of the tool head 1 is controlled to be 2000-6000 RPM during processing, the layer feeding amount is 0.2-0.6 mm, the forming depth is not less than 20mm, the offset displacement amount of the tool head 1 and the supporting die 2 is 0-0.3 mm, and 0.3mm is adopted in the embodiment.

In the embodiment, the tool head 1 is used for heating the laminated plate 3 in a pressure friction heating mode, so that solid connection and synchronous plastic deformation of a plurality of heterogeneous plates are finally realized, and the problems of poor forming capability, low efficiency, multiple process steps and poor surface quality and geometric accuracy of a formed part of the heterogeneous metal composite plate are solved. Meanwhile, the gap between the tool head 1 and the supporting die 2 can be adjusted according to design requirements and equipment conditions, so that the reliability, controllability and flexibility of the process are greatly improved.

In order to ensure the compaction degree of the contact surface, the inner surfaces of the support die 2 and the laminated plate 3 are attached, and the fillet transition radius on the working end of the support die 2 is not less than 5mm, so that the phenomenon of drawing fracture is avoided.

The specific steps of this embodiment include:

step S1: machining and manufacturing a circular truncated cone type supporting die 2 according to the inner contour shape of the formed part, obtaining a machining track of a tool head 1 according to the outer contour shape of the formed part, and simultaneously generating a track program;

step S2: according to the design requirement, the machining track of the tool head 1 is adjusted according to the preset gap required by machining. Offsetting the machining track of the tool head 1 to the center direction of the plane of the plate by displacement of T, wherein T is set to be 0.3mm, so as to apply certain extrusion force to the laminated plate 3;

step S3: loading a corresponding processing track program in a motion control system;

step S4: carrying out uniform mechanical polishing or chemical corrosion on the mutually contacted surfaces of each layer of the laminated plates 3, removing an oxide layer, and then cleaning with acetone or alcohol;

step S5: clamping the laminated plate 3 to be formed through a clamping system, wherein each layer of plate (31, 32 and 33) is tightly attached in the same rolling direction during clamping, so that air and dust are prevented from entering a contact surface to damage a connection effect;

step S6: the tool head 1 performs high-rotation friction heating on the laminated plate 3 based on the processing track to cause frictional heating and plastic deformation of the plate, and is matched with the action of extrusion force generated by track offset between the supporting dies 2 to complete synchronous connection and incremental forming of the laminated plate 3.

Example two

The overall implementation of this embodiment is the same as the first embodiment, and the difference is that: the third sheet material 33 is an auxiliary sheet material. A boron nitride solder resist of about 0.2mm thickness is applied between the contact surfaces of the auxiliary plate material and the second layer plate material 32. In the forming process, the auxiliary plate provides surface protection and back pressure support, the tool head 1 is prevented from directly contacting the surface of a formed part, the auxiliary plate is taken away after the composite forming is completed, and the surface quality of a formed part is further improved.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (10)

1. The two-point numerical control incremental forming and synchronous connection composite forming method of the heterogeneous laminated plate is characterized in that a composite forming device comprises a clamping system, a tool head and a supporting die, wherein the clamping system is used for fixing the laminated plate, the tool head is in autorotation contact with one surface of the laminated plate and makes spiral linear motion outwards from the center of the plane of the plate according to a preset track, the other surface of the supporting die in contact with the laminated plate makes synchronous linear motion in a direction perpendicular to the plane of the plate, and a preset gap between the tool head and the supporting die is controlled to apply a certain extrusion force to the laminated plate to perform incremental forming and synchronous connection.

2. A method of two-point nc incremental forming and simultaneous joining composite forming of heterogeneous laminate sheets as claimed in claim 1, wherein the tool head has three translational degrees of freedom and one rotational degree of freedom, and the support mold has at least one translational degree of freedom.

3. A method of two-point nc incremental forming and simultaneous joining composite forming of heterogeneous laminate sheets as claimed in claim 1, wherein the support die has a working end for contacting the laminated sheets, the outer contour of the working end conforming to the inner contour of the part to be formed.

4. A two-point digitally controlled incremental forming and simultaneous joining composite forming method of heterogeneous laminate sheets according to claim 3, wherein the radius of the rounded transition at the working end is not less than 5 mm.

5. A two-point nc incremental forming and simultaneous joining composite forming method of heterogeneous laminate sheets as claimed in claim 1, wherein the material of the supporting mold is hot mold steel.

6. A method of two-point nc incremental forming and simultaneous joining composite forming of a heterogeneous laminate according to claim 1, wherein the tool head has a working end for contacting the laminate, the working end having a flat bottom rounded corner type structure or a hemispherical head structure.

7. A two-point numerical control incremental forming and simultaneous joining composite forming method of a heterogeneous laminate according to claim 1, wherein the preset gap is smaller than the thickness of the laminated sheets by a certain amount, and the preset gap is controlled by a displacement of the tool head by a certain amount toward the center of the plane of the sheets, or the support die by a certain amount in the feeding direction, or the tool head by a certain amount in the normal direction in the contour plane of the part.

8. A two-point NC incremental forming and synchronous connection composite forming method of a heterogeneous laminated plate according to claim 7, wherein the offset displacement is 0 to 0.3 mm.

9. A method of two-point nc progressive forming and interconnect composite forming of a heterogeneous laminate panel as claimed in claim 1, wherein the laminate panel includes an auxiliary process layer contacting the tool head, the auxiliary process layer being separated from other layers of the laminate panel by a solder resist.

10. The two-point numerical control incremental forming and synchronous connection composite forming method of the heterogeneous laminated plate according to claim 1, which comprises the following steps:

s1: processing and manufacturing a support die according to the inner contour shape of the formed part, obtaining a processing track of a tool head according to the outer contour shape of the formed part, and simultaneously generating a track program;

s2: according to design requirements, adjusting the machining track of the tool head according to a preset gap required by machining;

s3: loading a trajectory program in a motion control system of the tool head;

s4: carrying out uniform mechanical polishing or chemical corrosion on the mutually contacted surfaces of each layer of the laminated plates, removing an oxide layer, and then cleaning with acetone or alcohol;

s5: mounting the laminated plates on a clamping system;

s6: the tool head performs rotary friction on the laminated plate based on the machining track, and generates extrusion force on the laminated plate together with the supporting die which performs synchronous linear motion, so that the progressive forming and synchronous connection of the laminated plate are completed.

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