WO2018090989A1

WO2018090989A1 - Pressure forming device and pressure forming method

Info

Publication number: WO2018090989A1
Application number: PCT/CN2017/111837
Authority: WO
Inventors: 王利民
Original assignee: 内蒙古万鼎科技有限公司
Priority date: 2016-11-18
Filing date: 2017-11-20
Publication date: 2018-05-24

Abstract

Disclosed are a pressure forming device and a corresponding pressure forming method. The pressure forming device comprises an upper mould (1), a lower mould (2) and a movable mould (4), wherein the upper mould (1) and the lower mould (2) are arranged opposite each other and can move relative to each other, and the movable mould (4) is arranged in at least one of the following cases: the movable mould is inserted into the lower mould (2) and is sheathed outside the upper mould (1) and the lower mould (2), and the movable mould (4) is able to move up and down relative to the upper mould (1) and the lower mould (2); the upper mould (1), the lower mould (2) and the movable mould (4) jointly enclose a mould cavity (3); and during the forming process of a blank to be processed, the movable mould (4) is able to move up and down relative to the upper mould (1) and the lower mould (2), so as to dynamically increase the volume of the mould cavity (3). The pressure forming device and the corresponding pressure forming method are high in machining precision and small in cutting machining allowance for workpieces with a relatively large length and a relatively thin wall thickness.

Description

Pressure forming device and pressure forming method

Technical field

The present disclosure relates to the field of metal workpiece processing technology, for example, to a pressure forming apparatus and a pressure forming method based on the pressure forming apparatus.

Background technique

Die forging is a forging method in which a metal blank is plastically deformed in a mold under an external force and filled into a cavity to obtain a forged piece of a desired shape and size. In the die forging process, the billet overall undergoes significant plastic deformation, and a large amount of plastic flow; the flowing billet fills the cavity, and after filling, maintains the pressure to form the desired shape.

Most metals are die forged in the hot state, so die forging is also known as hot die forging. Compared with free forging, die forging can forge forgings with more complex shapes and relatively accurate dimensions, and the production efficiency is relatively high. It can mass produce forgings with the same shape and size, which is convenient for the subsequent cutting process using automatic machine tools and automatic production line. The forged piece after forging has a directional fibrous structure, that is, a streamline. The reasonable die forging process and the mold are selected to make the distribution of the streamline consistent with the shape of the part, which can significantly improve the mechanical properties of the forging.

A typical die forging die and a die forging process based on the die are shown in FIG. As shown in a of FIG. 1, the die forging die includes an upper die 1 and a lower die 2 which are oppositely disposed and relatively movable, and a cavity 3 is formed between the upper die 1 and the lower die 2; as shown by b in FIG. The billet 5 is placed in the cavity 3, and the pressure P acts on the upper mold to act on the billet 5; as shown by c in Fig. 1, under the action of the pressure P, the billet 5 is deformed and flows, and gradually fills the cavity 3. The gap, while the upper die 1 moves downward, continuously applies pressure to the blank 5; as shown by d in Fig. 1, the blank 5 fills all the voids in the cavity, and the upper die 1 moves downward to the extreme position, and the pressure P continues to be maintained. For a period of time, the blank 5 is sufficiently flow-deformed to achieve the function of dense tissue.

However, the above conventional die forging die and die forging process have the following disadvantages:

After the billet 5 is deformed by pressure, it fills the space of the nearest cavity 3, and then the pressure is increased, pushing the billet 5 to fill further, the whole filling process is from near to far, if the shape of the workpiece is relatively complicated, it has a larger The length of the part, then because the flow path of the blank 5 is too long, often resulting in poor molding, uneven texture of the workpiece, especially when forging a thin wall structure with a large length, the difficulty will be greatly increased;

In order to be able to form well, the wall thickness of the workpiece is often deliberately increased during the design of the mold, which brings about a negative effect of increasing the amount of machining in the later stage, and the process is complicated and economically unreasonable;

After the deformation of the blank 5 is filled and filled into the cavity 3, the pressure can be gradually increased to the preset maximum molding pressure, and then the pressure is maintained. At this time, due to the influence of the frictional resistance, the pressure applied to the lower portion of the blank 5 is inevitably smaller than the upper portion of the blank 5 The pressure received causes the force of the entire workpiece to be unbalanced;

The blank material flow should fill the cavity 3, at least the frictional resistance of the inner and outer surfaces, the frictional resistance required for molding is large, the molding pressure is high, and the mold is easy to wear and has a short service life;

Mold lubrication requirements are high. Due to the difference in lubrication of the mold surface, the resistance of the flow channel is uneven. It is easy to lubricate the position with low resistance. It is easy to form the flow prematurely. The position with high lubrication resistance is likely to form the flow too late. The entire forming end face is prone to material folding and flow disorder, which affects product quality.

Summary of the invention

The present disclosure proposes a pressure forming device that can solve the problem of molding difficulty and unevenness of the shape of the formed workpiece caused by the too long flow path of the blank.

The present disclosure also proposes a pressure forming method with high machining precision and small cutting allowance for a workpiece having a large length.

A pressure forming device comprising: an upper die, a lower die and a movable die;

The upper mold and the lower mold are oppositely disposed and relatively movable;

The movable mold is disposed at at least one of: being inserted into the lower mold and sleeved outside the upper mold and the lower mold;

And the movable mold is movable up and down with respect to the upper mold and the lower mold;

The upper mold, the lower mold and the movable mold together form a cavity, and the movable mold can be dynamically increased relative to the upper mold and the lower mold during molding of the blank to be processed. The volume of the mold cavity.

Optionally, the movable mold is sleeved outside the upper mold and the lower mold, and a projected area of an upper surface of the lower mold is not equal to a projected area of a lower surface of the upper mold.

Optionally, the moving mold comprises at least two sub-moving molds arranged to move in a radial direction of the sub-moving mold under the driving of the power unit.

Optionally, the lower die includes at least two sub-dies that are radially movable under the drive of the power unit to cause the lower die to expand or contract in its own radial direction.

Optionally, all of the sub-die forms a solid cylinder or a hollow cylinder during the pressure forming process, and after the pressure forming is finished, the motor is driven to move radially outward to drive the lower mold to expand. The inner side is moved radially inward to contract the lower mold.

Optionally, the lower die includes at least two sub-dies that are fan-shaped and at least two sub-dies that are in the shape of a dove, the sub-die of the fan shape and the sub-die of the dome shape are arranged in a cross All of the sub-dies are arranged to form a hollow cylinder during the pressure forming process, and the sub-die and the fan-shaped sub-die are sequentially formed along the power device after the pressure forming is completed. The inner side is moved radially inward to contract the lower mold.

Optionally, the gap width between the sidewall of the movable mold and the sidewall of the lower mold satisfies at least one of: unequal along the circumferential direction of the lower mold 2, and an axis along the lower mold 2 Not waiting.

A pressure forming method applied to any of the pressure forming devices described above, comprising:

Putting the blank to be processed into a cavity surrounded by the upper mold, the lower mold and the movable mold;

Applying pressure to at least one of the upper mold and the lower mold, and transmitting pressure to the billet;

The movable mold is moved by a power device at a predetermined speed in a direction to increase the volume of the cavity to deform the blank and fill the cavity space formed by the movement of the movable mold until the movable mode moves. To the end, cavity molding, workpiece forming;

The pressure applied to the upper mold and the lower mold is removed to open the pressure forming device and take out the workpiece.

Optionally, the pressure is applied to at least one of the upper mold 1 and the lower mold 2, and pressure is transmitted to the blank, and the pressure applied to the upper mold and/or the lower mold is pre- a maximum forming pressure P, at which pressure is applied to at least one of the upper mold 1 and the lower mold 2, pressure is transmitted to the blank, until the movable mold 4 is moved to a dead center, and the cavity 3 is formed. The pressure value is always maintained during the forming process of the workpiece.

Optionally, the movable mold is sleeved outside the upper mold and the lower mold, and the method for opening the pressure forming device during the taking out of the workpiece comprises:

Raising back to the upper mold;

Moving the sub-mold of the movable mold radially outward to open the movable mold;

The sub-die is moved radially inward to contract the lower mold to separate the lower mold from the workpiece.

Optionally, the movable mold 4 is sleeved outside the upper mold 1 and the lower mold 2, and the opening pressure forming device comprises:

Moving the movable mold of the movable mold 4 radially outward to open the movable mold 4;

Raising back to the upper die 1;

The sub-die 21 is moved radially inward to contract the lower mold 2, and the lower mold 2 is separated from the workpiece.

Optionally, the moving the sub-die 21 radially inwardly shrinks the lower mold 2, The lower die 2 is separated from the workpiece and further includes:

Moving the sub-die 21 of the lower mold 2 radially outward to cause the lower mold 2 to expand the workpiece in a radial direction, and then moving the sub-die 21 radially inward to contract the lower portion The die 2 separates the lower die 2 from the workpiece.

The pressure forming device of the present disclosure has the following advantages:

Including the movable mold which can move up and down with respect to the upper mold and the lower mold, during the pressure forming process, the volume of the mold cavity is dynamically increased, and the billet will quickly fill the enlarged space in time to start filling from the nearest point, thus ensuring the filling. The billet only takes the shortest process, the billet process is balanced, the streamline is even and stable, and the workpiece quality is uniform;

Since the billet flow is short, in the mold design, it is not necessary to consider the rounding transition of the flow through the passage to reduce the resistance, the design that does not need to increase the wall thickness to ensure the smooth flow of the material, and the thin-walled parts. High machining accuracy and small cutting allowance, even no longer cutting;

The movement speed of the outer mold can be controlled to accurately control the increase speed of the cavity volume, thereby achieving a perfect balance between the deformation amount of the blank and the volume increase of the cavity, and avoiding the deformation of the blank in the conventional pressure forming device. And the problem of difficulty in controlling the flow rate;

The pressure can be kept at the maximum during the whole molding process and the movement of the movable mold can be stopped at any time to maintain the pressure on the workpiece. The strength of the billet structure is balanced and stable, and the quality of the formed workpiece is better, which avoids the traditional die forging process can only be completed at the end of the die forging. The problem of maintaining pressure and uneven workpiece texture during the stage;

Since the movable mold is movable, the frictional resistance of the flow is from a friction surface of the upper or lower mold, the frictional resistance required to be formed is low, the molding pressure is low, the average life of the apparatus is long, and the cost is low;

Low lubrication requirements.

The pressure forming method based on the above-described pressure forming apparatus provided by the present disclosure has high processing precision and a small cutting allowance for a workpiece having a large length and a thin wall thickness.

DRAWINGS

1 is a schematic structural view of a pressure forming process of a pressure forming device in the related art;

2 is a schematic structural view of a pressure forming process of a pressure forming device of a first structure according to an embodiment;

3 is a schematic structural view of a pressure forming apparatus of a second structure according to an embodiment;

4 is a schematic structural view of a lower mold in a contracted state according to an embodiment;

FIG. 5 is a schematic structural view of a lower mold in an open state according to an embodiment; FIG.

6 is a schematic structural view of a lower mold in a contracted state according to another embodiment;

FIG. 7 is a schematic structural view of a lower mold in an open state according to another embodiment.

In the picture:

1, the upper mold; 2, the lower mold; 3, the mold cavity; 4, the movable mold; 5, the billet; 21, the sub-die.

detailed description

In the description of the embodiments, it is to be understood that the orientation or positional relationship of the terms "upper", "lower", "inside" and "outside" is based on the orientation or positional relationship shown in the drawings, only for the purpose of The invention is not limited by the scope of the invention, and is not intended to limit the scope of the invention.

The pressure forming device provided in this embodiment comprises: an upper die 1, a lower die 2 and a movable die 4. The upper die 1 and the lower die 2 are oppositely disposed and relatively movable, and the movable die 4 is sleeved outside the upper die 1 and the lower die 2. And the upper mold 1 and the lower mold 2 can move up and down, the upper mold 1, the lower mold 2 and the movable mold 4 together form a cavity 3. During the molding process, the movable mold 4 moves relative to the upper mold 1 and the lower mold 2, and the movable mold The gap between the inner wall of 4 and the outer wall of the upper die 1 or the lower die 2 is increased to dynamically increase the volume of the cavity 3; the pressure forming device further includes a pressure assembly that provides pressure to the pressure forming device. The pressure component can be a hydraulic cylinder.

The pressure forming device provided in this embodiment comprises: a movable mold 4 which can move up and down with respect to the upper mold 1 and the lower mold 2. During the pressure forming process, the volume of the cavity 3 is dynamically increased, and the blank 5 is quickly and continuously filled. The large cavity space starts to fill from the nearest point, which ensures that the blank 5 is the shortest process, the billet 5 is balanced, the streamline is even and stable, and the workpiece texture is uniform, and because the billet 5 process is short, When designing the mold, it is not necessary to consider the rounding transition of the flow through the passage to reduce the resistance, the design that does not need to increase the wall thickness to ensure the smooth flow of the material, the processing precision for the thin-walled parts, and the cutting allowance. Small or even no longer cut; at the same time, the movement speed of the outer mold can be controlled to accurately control the increase speed of the cavity 3 volume, thereby achieving a perfect balance between the deformation amount of the blank 5 and the volume increase of the cavity 3, avoiding the tradition. In the pressure forming device, the deformation amount and the flow velocity of the blank 5 after the force is hard to control; in addition, the pressure can be kept the maximum during the entire molding process and the movement of the movable mold 4 can be stopped at any time to protect the workpiece. Pressure, the material structure of the billet is balanced and stable, and the quality of the formed workpiece is better, which avoids the problem that the conventional die forging can only maintain the pressure and the unevenness of the workpiece at the end of the die forging; furthermore, because the movable mold 4 can Moving, so the frictional resistance of the flow is from a friction surface of the upper die 1 or the lower die 2, the frictional resistance required for molding is low, the molding pressure is low, the average life of the device is long, and the cost is low; The flow of the stroke occurs, so the difference in resistance does not cause a change in the quality of the molding, so It can guarantee the stability of product quality and low lubrication requirements.

Alternatively, the projected area of the upper surface of the lower mold 2 is not equal to the projected area of the lower surface of the upper mold 1, so that the blank 5 flows during the molding process.

Optionally, the movable mold 4 includes at least two sub-moving molds that are radially movable under the driving of the power unit to facilitate opening of the sub-moving mold by radially outwardly after the molding process ends. Mode 4. The number of sub-moving molds is not particularly limited, and can be specifically set according to the size of the pressure forming device and the workpiece. The power unit for driving the movable mold to move up and down with respect to the upper mold 1 and the lower mold 2 and to drive the movable mold to move in the radial direction may be a hydraulic cylinder.

Alternatively, the lower mold 2 includes at least two sub-down molds that are radially movable under the driving of the power unit to cause the lower mold 2 to expand and contract in the radial direction. In order to separate the lower mold 2 and the workpiece by moving the sub-die radially in the radial direction after the end of the molding process. The power unit for driving the lower mold can be a hydraulic cylinder.

Optionally, the gap width between the sidewall of the movable mold 4 and the sidewall of the lower mold 2 is not equal along the circumferential direction of the lower mold 2; or is unequal in the axial parallel direction of the lower mold 2; The gap width between the side wall of 4 and the side wall of the lower mold 2 is unequal in the circumferential direction and is not equal in the axial direction. As shown in Fig. 3, the upper mold 1, the lower mold 2 and the movable mold 4 together form a cavity 3, and the cavity 3 has an irregular shape, and the gap width between the upper portion and the lower mold 2 of the movable mold 4 portion on the left side in the figure is shown. D1 is smaller than the gap width d2 between the upper portion of the movable mold 4 portion on the right side in the drawing and the lower mold 2, and the gap width d2 between the upper portion and the lower mold 2 of the movable mold 4 portion on the right side in the drawing is smaller than the lower portion and the lower portion thereof. The gap width d3 between the dies 2. In the conventional die forging process, the billet 5 is deformed downward to fill the cavity 3, d2 is larger than d1, and the forming resistance is low, the billet 5 is preferentially filled with a space having a gap width of d2, and the billet 5 passes through the gap width. The space of d2, when the width of the lower gap is d3, the volume of the space suddenly increases, and the flow of the lower part is bound to accumulate, so that the folded material is likely to occur. In the above molding process, it is difficult to ensure uniform and stable flow lines, and the product quality cannot be guaranteed. In the pressure forming device of the embodiment, the cavity 3 is dynamically increased, and the blank 5 is gradually filled into the cavity 3 from the lower portion, so the lower gap width is obtained. The d3 position has a large cross section and a large space, but it is also filled first. During the filling process, the movable mold 4 is controlled to gradually decrease, and the blank 5 gradually fills the vacant space, so although the dimensions of d1 and d2 are different. Large, segregation of the flow does not occur, the position of the two will be filled simultaneously with the flow, so that the formation of workpieces with unequal wall thickness and axial unequal wall thickness in the circumferential direction can be well realized.

The embodiment further provides a pressure forming method based on the above pressure forming device, comprising:

The blank 5 to be processed is placed in a cavity 3 surrounded by the upper mold 1, the lower mold 2 and the movable mold 4;

Applying pressure to at least one of the upper mold 1 and the lower mold 2, and the pressure is transmitted to the blank 5;

The movable mold 4 is moved at a predetermined speed under the driving of the power unit to increase the volume of the cavity 3, and the billet 5 is rapidly deformed and filled with the cavity space formed by the movement of the movable mold 4 until the movable mold 4 moves to the end. Point, cavity 3 molding, workpiece forming;

The pressure applied to at least one of the upper mold 1 and the lower mold 2 is removed, the pressure forming device is opened, and the workpiece is taken out.

Applying pressure to at least one of the upper mold 1 and the lower mold 2, the pressure is transmitted to the blank, optionally, the maximum molding pressure preset to the pressure applied to the upper mold 1 and/or the lower mold 2 P, and applying pressure to at least one of the upper mold 1 and the lower mold 2 until the movable mold 4 is moved to a dead point, the cavity 3 is formed and the pressure value is always maintained during the forming of the workpiece.

The pressure forming method based on the above-described pressure forming apparatus provided by the present embodiment has high processing precision for a workpiece having a large length and a small wall thickness, uniform workpiece texture, and small cutting allowance.

The embodiment provides a pressure forming device, the structure of which is different from the pressure forming device provided by the above embodiment in that, as shown in FIGS. 4 and 5, all of the sub-die 21 are formed into a solid cylinder or hollow during the pressure forming process. The cylinder, after the end of the pressure forming, is first moved radially outwardly under the driving of the power unit to expand the lower mold and then move radially inward to contract the lower mold. The power unit for driving the lower mold 21 in the radial direction may be a hydraulic cylinder disposed in a direction parallel to the axis of the pressure forming device and connected to the output shaft of the hydraulic cylinder to convert the linear reciprocating motion of the hydraulic cylinder output into the radial direction. Movement mechanism.

The embodiment further provides a pressure forming method based on the above pressure forming device, which is different from the pressure forming method provided in the first embodiment described above in that:

The method of opening the pressure forming device during the taking out of the workpiece includes:

Raise back to the upper die 1;

Moving the sub-movement radially outward to open the movable mold 4;

The sub-die 21 is moved radially outward to cause the lower mold 2 to expand the workpiece in a radial direction, and then the sub-die 21 is moved radially inward to contract the lower mold to separate the lower mold 2 from the workpiece.

Wherein, the step of raising the step of returning to the upper mold 1 and moving the sub-moving mold radially outward to open the movable mold 4 is not limited, that is, the step of returning to the upper mold 1 may be performed first, and then the radial movement of the sub-moving mold may be performed. The step of moving the movable mold 4 to the outer side is also performed, and the step of moving the movable mold radially outward to open the movable mold 4 can be advanced, and the step of raising and returning to the upper mold 1 is performed.

The embodiment provides a pressure forming device, the structure of which is different from the pressure forming device provided by the above embodiment in that, as shown in FIG. 6 and FIG. 7, the lower die includes at least two sub-dies 21 which are fan-shaped and There are two sub-shaped lower molds 21, the fan-shaped sub-lower mold 21 and the sub-shaped sub-low mold 21 are alternately arranged, and all the sub-low molds 21 form a hollow cylinder during the pressure forming process, at the end of the pressure forming. The sub-die 21 and the fan-shaped sub-die 21, which are driven by the power unit, are sequentially moved radially inwardly to contract the lower mold.

The embodiment further provides a pressure forming method based on the above pressure forming device, which is different from the pressure forming method provided by the above embodiment in that:

The method of opening the pressure forming device during the removal of the workpiece includes:

Raise back to the upper die 1;

Moving the sub-movement radially outward to open the movable mold 4;

The lower mold 21 is moved radially inward to contract the lower mold 2, and the lower mold 2 is separated from the workpiece. Alternatively, the sub-lower mold 21 in the shape of a dome and the sub-low mold 21 in the fan shape are sequentially radially. Moving inward to contract the lower die 2;

Among them, the order of raising the returning upper mold 1 and moving the sub-moving mold radially outward to open the movable mold 4 is not limited.

Embodiment 4:

The embodiment provides a pressure forming device, which has the same structure as the pressure forming device provided by the above embodiment, and includes an upper die, a lower die and a movable die. The upper die and the lower die are oppositely arranged and relatively movable, and the movable die is inserted. In the lower mold, the upper mold, the lower mold and the movable mold together form a cavity. During the molding process, the movable mold moves relative to the upper mold and the lower mold, and the gap between the outer wall of the movable mold and the inner wall of the lower mold increases. The volume of the cavity is increased; the pressure forming device further includes a pressure assembly that provides pressure to the pressure forming device. The pressure component can be a hydraulic cylinder.

In this embodiment, a set of movable molds disposed on the outer side of the upper mold and the lower mold and movable relative to the upper mold and the lower mold may be simultaneously provided.

Industrial applicability

According to the pressure forming device and the pressure forming method of the present disclosure, the volume of the cavity of the pressure forming device can be dynamically increased, so that the billet flow is shorter, the billet flow is more balanced, the streamline is more uniform and the workpiece texture is more uniform.

Claims

A pressure forming device comprising: an upper die (1), a lower die (2) and a movable die (4);

The upper mold (1) and the lower mold (2) are oppositely disposed and relatively movable;

The movable mold (4) is disposed at least one of the following: inserted in the lower mold (2) and sleeved outside the upper mold (1) and the lower mold (2);

And the movable mold (4) is movable up and down with respect to the upper mold (1) and the lower mold (2);

The upper mold (1), the lower mold (2) and the movable mold (4) together form a cavity (3), and during the molding process of the blank to be processed, the movable mold (4) can be Movement relative to the upper mold (1) and the lower mold (2) to dynamically increase the volume of the mold cavity (3).
The pressure forming apparatus according to claim 1, wherein said movable mold (4) is sleeved outside said upper mold (1) and said lower mold (2), and said upper surface of said lower mold (2) The projected area is not equal to the projected area of the lower surface of the upper mold (1).
The pressure forming apparatus according to claim 2, wherein said movable mold (4) comprises at least two sub-movements arranged to move in a radial direction of said sub-movement under driving of a power unit .
A pressure forming apparatus according to claim 2, wherein said lower mold (2) comprises at least two sub-dies (21) which are rotatable in their own radial direction under the driving of the power unit The movement is such that the lower mold (2) expands or contracts in the radial direction.
The pressure forming apparatus according to claim 4, wherein all of said sub-dies (21) form a solid cylinder or a hollow cylinder during the pressure forming process, and are radially driven by the power unit after the pressure forming is completed. The outer side is moved to cause the lower mold (2) to expand and then to move radially inward to cause the lower mold (2) to contract.
A pressure forming apparatus according to claim 4, wherein said lower mold (2) comprises at least two sub-dies (21) in the shape of a sector and at least two sub-dies (21) in the shape of a dome, which are fan-shaped The sub-die (21) and the sub-die (21) in the shape of a cross are disposed, and all of the sub-dies (21) are arranged to form a hollow cylinder during pressure forming, and are formed by pressure molding. The sub-lower mold (21) and the sub-lower mold (21) which are fan-shaped after being driven by the power unit are sequentially moved radially inward to cause the lower mold (2) to contract.
The pressure forming apparatus according to any one of claims 1 to 6, wherein a gap width between a side wall of the movable mold (4) and a side wall of the lower mold (2) satisfies at least one of the following: The circumferential directions of the lower molds (2) are not equal, and are not equal along the axial direction of the lower mold (2).
A pressure forming method applied to the pressure forming apparatus according to any one of claims 1 to 7, wherein:

Putting the blank to be processed into a cavity (3) surrounded by the upper mold (1), the lower mold (2) and the movable mold (4);

Applying pressure to at least one of the upper mold (1) and the lower mold (2), and pressure is transmitted to the blank;

The movable mold (4) is moved by a power device at a predetermined speed in a direction to increase the volume of the cavity (3) to deform the blank and fill the mold formed by the movement of the movable mold (4). a cavity space until the movable mold (4) moves to a dead point, the cavity (3) is formed, and the workpiece is formed;

The pressure applied to the upper mold (1) and the lower mold (2) is removed to open the pressure forming device and take out the workpiece.
The pressure forming method according to claim 8, wherein said at least one of said upper mold (1) and said lower mold (2) applies pressure to said blank, to said upper mold (1) and The pressure applied by at least one of the lower molds (2) is a preset maximum molding pressure P at which at least one of the upper mold (1) and the lower mold (2) is to be processed. The billet applies pressure until the moving mold (4) moves to the dead center, and the cavity (3) is formed, and the pressure value is always maintained during the forming process of the workpiece.
The pressure forming method according to claim 8 or 9, wherein the movable mold (4) is sleeved outside the upper mold (1) and the lower mold (2), and the opening pressure forming device comprises:

Raising back to the upper mold (1);

Moving the sub-mold of the movable mold (4) radially outward to open the movable mold (4);

The sub-die (21) is moved radially inward to contract the lower mold (2) to separate the lower mold (2) from the workpiece.
The pressure forming method according to claim 8 or 9, wherein the movable mold (4) is sleeved outside the upper mold (1) and the lower mold (2), and the opening pressure forming device comprises:

Moving the movable mold of the movable mold (4) radially outward to open the movable mold (4);

Raising back to the upper mold (1);

The sub-die (21) is moved radially inward to contract the lower mold (2) to separate the lower mold (2) from the workpiece.
The pressure forming method according to claim 10 or 11, wherein said moving said sub-die (21) radially inwardly contracts said lower mold (2), said lower mold (2) and Separation of workpieces also includes:

The sub-die (21) of the lower mold (2) is moved radially outward to cause the lower mold (2) to expand the workpiece radially, and then the sub-die (21) is along the diameter Movement to the medial side The mold (2) separates the lower mold (2) from the workpiece.