A demoulding device and method for electroforming a thin-walled seamless metal tube with a large aspect ratio

Abstract

The present invention discloses a demoulding device and method for electroforming a thin-walled seamless metal tube with a large aspect ratio, which belongs to the field of electroforming processing. The device mainly includes a cylinder, a guide rod, a magnetorheological fluid, an excitation coil, a lower base, an upper end cover with a circular through hole in the center, a core mold, an electroforming layer, a DC power supply, and a tension device. Based on the device, first, the core mold with the electroforming layer is sleeved on the guide rod, and its end is connected to the tension device. Then, the DC power supply is turned on, the excitation coil is energized, the magnetorheological fluid solidifies, and changes from a Newtonian fluid to a viscoplastic body, so that the cylinder and the electroforming layer are connected as one. Then, the tension device is started, and the core mold is pulled out under the action of tension. Finally, the DC power supply is turned off, the excitation coil is powered off, the magnetorheological fluid is restored from a viscoplastic body to a Newtonian fluid, and the electroforming layer is removed to complete the demoulding. The present invention is easy to operate, has a good demoulding effect, a fast clamping speed, a high demoulding efficiency, and a low process cost.

Description

Technical Field

[0001] The invention belongs to the field of electroforming processing, and in particular relates to a demoulding device and method for electroforming a thin-wall seamless metal pipe with a large aspect ratio. Background Art

[0002] Metal fixing film is a thin-walled seamless metal tube with a large aspect ratio. It is one of the important components in printers or copiers. Currently, there are mainly stamping and electroforming methods to prepare metal fixing films. Among them, electroformed metal fixing films are favored by high-end application fields due to their ultra-thin wall thickness, high material performance, high precision and many other advantages. However, when using the electroforming method to prepare metal fixing films, there is a strong bonding force between the electroformed layer and the core mold, and the metal tube has a large aspect ratio and high precision in matching with the core mold, which makes it extremely difficult to remove the seamless metal tube from the core mold after electroforming.

[0003] Japanese patents with patent numbers JP 2006-213960 A and JP 2012-58644 A respectively perform demolding by spraying high-pressure liquid and high-pressure gas between the core mold and the electroformed layer, but the electroformed layer is easily torn and damaged during the introduction of high-pressure liquid / gas, and they all rely on expensive special equipment, resulting in high demolding costs. Patent application number 201410688005.8 discloses a demolding device and demolding method for thin-walled tubes of composite materials with large aspect ratios. The device requires adjusting multiple baffle flaps so that the inner surface of each baffle flap is close to the outer surface of the thin-walled tube, and then the demolding is completed under the action of external force. The operation is relatively cumbersome, time-consuming, and the demolding efficiency is low. For this reason, it is urgent to develop a demolding device and method for thin-walled seamless metal tubes with large aspect ratios that are simple to operate, have good demolding effects, low demolding costs, and high demolding efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a demoulding device and method for electroforming a thin-walled seamless metal tube with a large aspect ratio, so as to solve the above-mentioned problems.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is: a demolding device for electroforming thin-walled seamless metal tubes with a large aspect ratio, which includes a cylinder, a guide rod, a magnetorheological fluid, an excitation coil, a lower base, an upper end cover with a circular through hole in the center, a core mold, an electroforming layer, a DC power supply, and a tension device; the inner surface of the cylinder is provided with grooves arranged along the circumferential direction at equal intervals; the core mold is a hollow cylindrical shape; one end of the cylinder is fixedly and sealedly connected to the lower base, and the other end is detachably and sealedly connected to the upper end cover; the guide rod is fixedly mounted on the lower base, and its rotation center axis coincides with the rotation center axis of the cylinder; the magnetorheological fluid is filled in the space formed by the lower base, the cylinder, and the upper end cover; the excitation coil is interference fit on the outer surface of the cylinder; the DC power supply is conductively connected to the excitation coil.

[0006] The material of the cylinder is electrically insulating polypropylene.

[0007] The number of the grooves is 3 or more.

[0008] The particle size of the magnetic particles in the magnetorheological fluid is 1-50 nanometers, so that the solidified magnetorheological fluid is more easily embedded in the microscopic depressions on the surface of the electroformed layer, thereby generating a strong holding and dragging effect on the electroformed layer.

[0009] A demoulding method for electroforming a thin-walled seamless metal tube with a large aspect ratio, comprising the following steps performed in sequence:

[0010] S1. Put the core mold with the electroforming layer on the outer surface onto the guide rod in the demoulding device, and connect its end with the tension device in a detachable transmission manner;

[0011] S2, turn on the DC power supply, energize the excitation coil, and excite the magnetic field. The magnetorheological fluid solidifies due to its characteristics (it is a Newtonian fluid when there is no magnetic field, and it instantly solidifies from a Newtonian fluid to a viscoplastic body when there is a magnetic field). At this time, the magnetorheological fluid is filled between the cylinder and the electroformed layer in a viscoplastic state and embedded in the groove and the microscopic depressions on the surface of the electroformed layer, so that the cylinder and the electroformed layer are reliably connected as a whole through the magnetorheological fluid;

[0012] S3, starting the pulling device, the core mold is pulled out under the action of the pulling force, while the electroformed layer continues to remain in the cylinder due to the strong holding effect of the viscoplastic magnetorheological fluid, thereby achieving the separation of the electroformed layer and the core mold;

[0013] S4. Turn off the DC power supply, cut off the power to the excitation coil, and the magnetic field disappears. The magnetorheological fluid changes from a viscoplastic to a Newtonian fluid. The magnetorheological fluid's holding and dragging effect on the electroformed layer disappears, and the electroformed layer is removed to complete demoulding.

[0014] The connection between the core mold and the tension device is a hinge connection.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. Easy operation and good demoulding effect. The present invention energizes the excitation coil to excite the magnetic field, and the magnetorheological fluid is solidified from a Newtonian fluid to a viscoplastic body, and the cylinder and the electroforming layer are connected as a whole. With the assistance of the tension device, the electroforming layer and the core mold can be effectively separated, which is easy to operate and has a good demoulding effect.

[0017] 2. Fast clamping speed and high demoulding efficiency. Magnetorheological fluid can be solidified from Newtonian fluid to viscoplastic in the presence of a magnetic field, and this solidification can be completed in an instant (milliseconds). Therefore, the clamping speed of the present invention is faster, the time is short, and the demoulding efficiency is high.

[0018] 3. Good adaptability. The magnetorheological fluid in the present invention is a Newtonian fluid in the absence of a magnetic field and has good fluidity. Therefore, the present invention can reliably clamp core molds with different outer diameters within a certain range and has good adaptability.

[0019] 4. Low process cost. The present invention has a simple structure and is easy to implement. Its demoulding process does not rely on overly expensive auxiliary equipment, is suitable for mass production, and has low process cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional schematic diagram of a part of the structure of the present invention.

[0021] Figure 2 It is a cross-sectional schematic diagram of the present invention.

[0022] Numbers and names in the figure: 1. Cylinder; 1-1. Groove; 2. Guide rod; 3. Magnetorheological fluid; 4. Excitation coil; 5. Lower base; 6. Upper end cover; 6-1. Circular through hole; 7. Core mold; 8. Electroforming layer; 9. DC power supply; 10. Tension device. DETAILED DESCRIPTION

[0023] The implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0024] like Figure 1 and Figure 2As shown, a demoulding device for electroforming a thin-walled seamless metal tube with a large aspect ratio comprises a cylinder 1, a guide rod 2, a magnetorheological fluid 3, an excitation coil 4, a lower base 5, an upper end cover 6 with a circular through hole 6-1 in the center, a core mold 7, an electroforming layer 8, a DC power supply 9, and a tension device 10; the cylinder 1 has an outer diameter of 60 mm, an inner diameter of 50 mm, and a length of 300 mm, and is made of electrically insulating polypropylene; the inner surface of the cylinder 1 is evenly spaced with grooves 1-1 arranged in the circumferential direction; the core mold 7 is in the shape of a hollow cylinder, and has an outer diameter of 30 mm, an inner diameter of 15 mm, and a length of 350 mm. The material is 304 stainless steel with a surface roughness of Rz=0.025; one end of the cylinder 1 is fixedly sealed with the lower base 5, and the other end is detachably sealed with the upper end cover 6; the diameter of the guide rod 2 is 15mm and the length is 250mm; the guide rod 2 is fixedly mounted on the lower base 5 through a threaded pair, and its rotation center axis coincides with the rotation center axis of the cylinder 1; the magnetorheological fluid 3 is filled in the space formed by the lower base 5, the cylinder 1, and the upper end cover 6; the excitation coil 4 is sleeved on the outer surface of the cylinder 1 with an interference fit; the positive and negative poles of the DC power supply 9 are respectively conductively connected to the two ends of the excitation coil 4.

[0025] The number of the grooves 1-1 is five.

[0026] The particle size of the magnetic particles in the magnetorheological fluid 3 is 25 nanometers.

[0027] A demoulding method for electroforming a thin-walled seamless metal tube with a large aspect ratio based on the above device comprises the following steps performed in sequence:

[0028] S1, a core mold 7 with an electroforming layer 8 on its outer surface, which is made by electroforming, is placed on a guide rod 2 in a demoulding device, and its end is detachably hingedly connected to a tension device 10;

[0029] S2, turn on the DC power supply 9, energize the excitation coil 4, and excite the magnetic field. The magnetorheological fluid 3 solidifies due to its characteristics (it is a Newtonian fluid when there is no magnetic field, and it instantly solidifies from a Newtonian fluid to a viscoplastic body when there is a magnetic field). At this time, the magnetorheological fluid 3 is filled between the cylinder 1 and the electroformed layer 8 in a viscoplastic state and embedded in the groove 1-1 and the microscopic depressions on the surface of the electroformed layer 8, so that the cylinder 1 and the electroformed layer 8 are reliably connected as a whole through the magnetorheological fluid 3;

[0030] S3, starting the tension device 10, the core mold 7 is pulled out under the action of the tension, while the electroformed layer 8 continues to remain in the cylinder 1 due to the strong holding and dragging effect of the viscoplastic magnetorheological fluid 3, thereby achieving the separation of the electroformed layer 8 and the core mold 7;

[0031] S4, turn off the DC power supply 9, the excitation coil 4 is powered off, the magnetic field disappears, the magnetorheological fluid 3 changes from a viscoplastic to a Newtonian fluid, the holding effect of the magnetorheological fluid 3 on the electroformed layer 8 disappears, and the electroformed layer 8 is taken out to complete the demoulding. The electroformed layer 8 is the obtained large aspect ratio thin-walled seamless metal tube.

Claims

1. A demoulding device for electroforming thin-walled seamless metal tubes with large aspect ratio, characterized in that: It comprises a cylindrical body (1), a guide rod (2), a magnetorheological fluid (3), an excitation coil (4), a lower base (5), an upper end cover (6) having a circular through hole (6-1) at the center, a core mold (7), an electroforming layer (8), a direct current power supply (9), and a tension device (10); the inner surface of the cylindrical body (1) is provided with grooves (1-1) arranged along the circumferential direction at equal intervals; the core mold (7) is in the shape of a hollow cylinder; one end of the cylindrical body (1) is fixed to the lower base (5) The guide rod (2) is fixedly mounted on the lower base (5), and its rotation center axis coincides with the rotation center axis of the cylinder (1); the magnetorheological fluid (3) is filled in a space formed by the lower base (5), the cylinder (1) and the upper end cover (6); the excitation coil (4) is sleeved on the outer surface of the cylinder (1) with an interference fit; the DC power supply (9) is conductively connected to the excitation coil (4); The material of the cylindrical body (1) is electrically insulating polypropylene; The number of the grooves (1-1) is 3 or more.

2. A demoulding device for electroforming a thin-walled seamless metal tube with a large aspect ratio according to claim 1, characterized in that: The particle size of the magnetic particles in the magnetorheological fluid (3) is 1-50 nanometers.

3. A demoulding method for electroforming a thin-walled seamless metal tube with a large aspect ratio, characterized in that: It consists of the following steps, performed in sequence: S1, a core mold (7) having an electroformed layer (8) on its outer surface is placed on a guide rod (2) in a demoulding device, and its end is detachably connected to a tension device (10); S2, turning on the DC power supply (9), energizing the excitation coil (4), exciting the magnetic field, and causing the magnetorheological fluid (3) to solidify due to its characteristics. At this time, the magnetorheological fluid (3) is filled between the cylindrical body (1) and the electroformed layer (8) in a viscoplastic state and embedded in the groove (1-1) and in the microscopic depressions on the surface of the electroformed layer (8), so that the cylindrical body (1) and the electroformed layer (8) are reliably connected as a whole through the magnetorheological fluid (3); S3, starting the pulling device (10), the core mold (7) is pulled out under the action of the pulling force, while the electroformed layer (8) continues to remain in the cylindrical body (1) due to the strong holding and pulling action of the viscoplastic magnetorheological fluid (3), thereby achieving the separation of the electroformed layer (8) and the core mold (7); S4, turn off the DC power supply (9), the excitation coil (4) is powered off, the magnetic field disappears, the magnetorheological fluid (3) changes from a viscoplastic to a Newtonian fluid, the magnetorheological fluid (3)'s holding and dragging effect on the electroformed layer (8) disappears, and the electroformed layer (8) is removed to complete demoulding.

4. A demoulding method for electroforming a thin-walled seamless metal tube with a large aspect ratio according to claim 3, characterized in that: The connection between the core mold (7) and the tension device (10) is a hinge connection.

Images