CN108817189B - A method for spinning and forming the outer groove of a cup-shaped part - Google Patents

Abstract

The invention belongs to the field of processing cup-shaped parts, and specifically discloses a method for spinning an outer groove of a cup-shaped part, which includes the following steps: placing the cup-shaped part to be processed in the groove of the lower pressure plate of the spinning machine Make it centered, preset the pressing force of the upper platen of the spinning machine, and the upper platen moves down so that the cup-shaped piece to be processed is embedded in the groove of the upper platen, and it is pressed under the action of the pressing force. Close on the lower platen; the upper platen and the lower platen drive the cup to be processed to rotate, and during the rotation of the cup, the rotary wheel located outside the cup is used to feed along the radial direction of the cup to squeeze side of the cup to form the desired outer groove on the side of the cup to be machined. The invention can effectively solve the technical problems of insufficient stability of formed parts, uneven upper and lower thicknesses, raised surfaces and poor forming quality.

Description

A method for spinning and forming the outer groove of a cup-shaped part

technical field

The invention belongs to the field of cup-shaped piece processing, and more particularly relates to a method for spinning an outer groove of a cup-shaped piece.

Background technique

At present, cup-shaped products are widely used in many fields, such as missile shells, nozzles, and engine casings in the military field, and cathode tubes and cathode rollers in the communication industry. Because of the large demand for cup-shaped parts, it is necessary to study its processing methods. At present, the traditional processing methods of cup-shaped parts mainly include stretching and reverse extrusion. Stretching processing has the characteristics of high processing efficiency and low cost. The efficiency of reverse extrusion forming cup-shaped parts is not as good as that of stretching. However, due to the compressive stress in the forming process, the forming quality of cup-shaped parts is obviously better than that of stretching. The above forming methods of stretching and reverse extrusion are difficult to directly form more complex cup-shaped parts with specific shapes, such as splines, grooves, teeth, etc. And if multiple steps are used to form, although the productivity is high, the tonnage of the press required by it is large, and more molds are required.

Spinning forming has its own unique advantages in volume forming of rotating parts (such as cup-shaped parts). Unlike other stamping methods, it is more convenient to manufacture products with various shapes. If combined with efficient and precise With CNC technology, the advantages of spinning will be more obvious. The special structure and shape on the cup can be quickly formed by using the spinning process, such as forming grooves, changing wall thickness, etc. However, when the outer groove of the cup-shaped part is formed by spinning, the surface is often raised and the wall thickness is uneven, sometimes even seriously affecting the performance of the product. Therefore, it is necessary to re-study and design a spinning forming method to form cup-shaped parts with uniform wall thickness and outer grooves.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention provides a spinning forming method for the outer groove of the cup-shaped part, through the structure of the upper and lower pressure plates in the spinning forming process and the design of the main process parameters To control the flow of materials during the forming process, realize the optimization of the forming direction and area extrusion, thereby solving the technical problems of insufficient stability of the formed parts, uneven upper and lower thickness, surface bulge and poor forming quality.

In order to achieve the above object, the present invention proposes a method for spinning the outer groove of a cup-shaped part, which includes the following steps:

S1 Place the cup-shaped piece to be processed in the groove of the lower platen of the spinning machine and center its position. The pressing force of the upper platen of the spinning machine is preset, and the upper platen moves downward to make the cup-shaped piece to be processed The parts are embedded in the groove of the upper platen and pressed against the lower platen under the action of the pressing force;

S2 The upper platen and the lower platen drive the cup to be processed to rotate, and during the rotation of the cup, the rotary wheel located outside the cup is used to feed along the radial direction of the cup to squeeze the side of the cup , so as to form the desired outer groove on the side of the cup to be machined.

As a further preference, the structural shapes of the grooves on the upper and lower pressure plates are respectively adapted to the cross-sectional shapes of the upper and lower ends of the cup.

As a further preference, the depth of the grooves of the upper and lower pressure plates is 3-5 mm, preferably 4 mm, and the edges of the grooves of the upper and lower pressure plates are all chamfered.

As a further preference, the pressing force exerted by the upper platen on the cup-shaped piece to be processed needs to meet the following conditions:

F＝ _0.2σs ·A/1000

Among them, F is the pressing force exerted by the upper platen, σ _s is the yield strength of the cup material, and A is the contact area between the cup and the upper platen.

As a further preference, the ratio of the middle diameter to the wall thickness of the side wall of the cup is (4-10):1, preferably 7:1.

As a further preference, the feed ratio V of the rotary wheel needs to satisfy the following condition: V=exp{(6.2-0.11F)/7}.

Generally speaking, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. The present invention utilizes the upper and lower pressure plates to clamp the cup to be processed, and moves the outer wheel of the cup along the radial direction of the cup to form the groove on the side of the cup. The forming does not require a mandrel, and has the advantages of There are few forming molds, simple steps, high production efficiency, and low requirements for mold tonnage.

2. The upper and lower platens of the present invention are provided with grooves that fit the blank to be processed, so that the blank to be processed can be positioned accurately during the process of applying pressure and forming, effectively avoiding the deviation caused by the blank during the forming process. cause ground instability.

3. By chamfering the grooves of the upper and lower pressure plates, the present invention can facilitate unloading of the formed workpiece and reduce damage to the workpiece during the unloading process, improving the forming quality of the spinning part.

4. The present invention designs a reasonable groove depth of the upper and lower pressure plates, combined with a reasonable pressing force, and the pressing force satisfies F=0.2σ _s A/1000, which is related to the mechanical properties of the material itself and the cross-sectional area of the workpiece , so that the blank to be processed is always clamped on the upper and lower pressure plates during the entire spinning forming process, ensuring the reliability and stability of the forming, and ensuring the final forming quality of the workpiece.

5. The present invention satisfies V=exp{(6.2-0.11F)/7} by designing a reasonable rotary wheel feed force, and combines the feed force satisfying the above conditions with the pressing force designed by the present invention to make the blank to be processed Under the combined effect of feed force and pressing force, the material flow between the upper and lower sides of the blank during the forming process is effectively eased, so that the upper and lower wall thicknesses of the formed workpiece are uniform, and the forming quality of the spinning parts is improved.

Description of drawings

Fig. 1 is a schematic diagram of the forming die structure used to realize the spin forming of the cup outer groove;

Fig. 2 is a comparison diagram before and after forming of the cup-shaped part to be processed, a is before forming, and b is after forming;

Fig. 3 is a flow chart of the volume forming method for spinning the outer groove of a cup-shaped part constructed according to a preferred embodiment of the present invention, where a is before forming, and b is after forming;

Fig. 4 is a schematic diagram of the structure of the groove of the pressure plate constructed according to the preferred embodiment of the present invention, a is the groove of the upper pressure plate, and b is the groove of the lower pressure plate.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

The invention provides a method for spinning the outer groove of a cup-shaped piece, which mainly involves spinning a cup-shaped piece with uniform wall thickness to obtain a cup-shaped piece with an equal wall thickness with an outer groove. The method of the present invention is used to realize the above-mentioned forming The forming mold of the method is shown in Figure 1, including the lower platen 1, the upper platen 2 and the rotary wheel 3 on the spinning machine, the lower platen 1 and the upper platen 2 are used to clamp the cup-shaped piece 4 to be processed , the rotary wheel 2 is located outside the cup-shaped part 4. When forming, the blank to be processed is placed in the groove of the lower platen, and the upper platen of the spinning machine moves downward so that the upper end of the blank to be processed is embedded in the groove of the upper platen. Position and compact the billet, the upper and lower pressure plates clamp the billet to drive the billet to rotate at a high speed with the spindle of the spinning machine, and at the same time, the rotary wheel at a certain height feeds the billet to the designated position along the radial direction at a uniform speed, During the feeding process, the rotary wheel is driven by the blank to rotate passively during the contact process with the blank, and then the rotary wheel exits after the spinning is completed.

The spinning forming method of the cup outer groove of the present invention comprises the following steps:

S1 Place the cup-shaped piece to be processed in the groove of the lower platen of the spinning machine and make its position centered (even if the cup-shaped piece is coaxially set with the lower platen), preset the pressure of the upper platen of the spinning machine The upper platen goes down so that the upper end surface of the cup to be processed is embedded in the groove of the upper platen, and the cup is pressed against the lower platen under the action of the pressing force;

S2 The upper platen and the lower platen drive the cup to be processed to rotate, and during the rotation of the cup, the rotary wheel located outside the cup is used to feed along the radial direction of the cup to squeeze the side of the cup , so as to form the desired outer groove on the side of the cup to be machined.

Specifically, the forming method of the present invention is a spinning volume forming method, which performs spinning according to the principle that the total volume of the blank remains unchanged during the deformation process, and adopts the following specific operation steps for forming:

(1) Place the blank to be processed in the groove of the lower pressure plate of the vertical spinning machine, and ensure that the center of the blank is located on the center line of the spindle of the spinning machine; make the upper pressure plate press the blank downward with the calculated pressure;

(2) The upper and lower pressure plates drive the billet to rotate at a high speed and uniform speed with the spindle of the spinning machine, and the billet speed is generally set between 150 and 300rmp;

(3) The rotary wheel feeds and extrudes the blank in the radial direction, and at the same time rotates in reverse under the action of the friction force, and the material flows radially inward under the extrusion of the rotary wheel;

(4) After the rotary wheel is fed to the specified position, it will idle for a certain period of time, and then exit, and finally obtain a spinning thickened formed part that meets the requirements. The specified position is set according to actual needs. The idle rotation time is preferably greater than or equal to one rotation of the blank half the time to ensure that the grooved sections are fully formed into the desired shape.

Further, in order to ensure effective and reliable clamping of the blank to be processed, the structural shapes of the grooves on the upper and lower pressure plates are respectively adapted to the cross-sectional shapes of the upper and lower ends of the cup. As shown in Figure 4, the groove of the upper platen adapts to the cross-sectional shape of the upper end of the cup, which is circular, and the groove of the lower platen adapts to the shape of the lower cross-section of the cup, which is circular, so as to ensure The upper and lower ends of the cup are just embedded in the grooves of the upper and lower pressure plates to ensure reliable clamping.

The present invention is coreless spinning forming, that is, there is no core mold support inside the blank to be processed during the forming process, and it directly utilizes the spinning wheel on the outside of the blank to be processed, and the rotary wheel produces a The radial extrusion force realizes the forming of the groove. During this process, due to the extrusion effect of the rotary wheel on the side of the blank to be processed, there is a tendency for the blank to be processed to break away from the clamp (that is, the upper platen and the lower platen). Therefore, it is very important to the design of the structural parameters of the clamp and the specific pressing force. The present invention finds through research that the groove depth of the upper and lower pressure plates is designed to be 3-5mm, especially designed to be 4mm, and the pressing force F is satisfied with the following condition F=0.2σ _s ·A/1000, wherein, F is The pressing force exerted by the upper platen, KN; σ _s is the yield strength of the cup material, Mpa; A is the contact area between the cup and the upper platen, mm ² ; The pressing force can make the blank to be processed be always clamped on the upper and lower platens during the whole spinning forming process, ensuring the reliability and stability of forming.

In order to facilitate the unloading of molded parts, as shown in Figure 4, the edges of the grooves of the upper and lower pressure plates are chamfered, and the chamfers of 2mm are specifically designed, so that the blanks to be processed can be positioned accurately through the grooves, and through the design The chamfering is convenient for unloading and reduces the damage to the blank due to the slight inclination of the blank position during spinning. Further, the ratio of the middle diameter to the wall thickness of the side wall of the cup-shaped part is (4-10): 1, preferably 7: 1. Under this ratio, the flow resistance of the material in the outer groove part during the forming process is small, and at the same time, it effectively guarantees the thickness of the blank. There is enough friction between the upper and lower platens when rotating at a constant speed to prevent the billet from slipping.

In the spinning forming process, in order to ensure the quality of the formed parts, the feed speed of the rotary wheel is very important. The present invention has determined the following rotary wheel feed ratio V (mm/r)=exp{(6.2-0.11F )/7}, where F(KN) is the pressing force exerted by the upper platen, that is, the feed ratio of the rotary wheel V=e ^{(6.2-0.11F)/7} , under the feed ratio of the rotary wheel, the rotary wheel pair The radial force of the blank can prevent the radial diffusion of the material at the upper and lower ends of the groove, and make the axial force of the rotary wheel on the blank always smaller than the pre-pressure, avoiding the lifting of the material at both ends of the blank, ensuring that the height is basically unchanged, and thus ensuring the forming the quality of the piece.

The following is an embodiment of the present invention. The initial blank used in this example is an inner diameter of 30mm, an outer diameter of 46mm, a height of 80mm, a cup bottom thickness and a cup wall thickness of 8mm. Fig. 2a-b is a cup to be processed The comparison diagram before and after molding, where a is before molding, and b is after molding. The target part that needs to be formed has an inner diameter of 30mm, an outer diameter of 46mm, and a height slightly less than 80mm. There is a semicircular concave with a radius of 8mm at a distance of 40mm from the outer wall to the bottom of the cup. The cup bottom thickness and the cup wall thickness are both 8mm cups with outer grooves.

Fig. 3 is a flow chart of the volume forming method for spinning the outer groove of a cup-shaped part constructed according to a preferred embodiment of the present invention, in which a is before forming, and b is after forming, and its specific implementation steps are as follows:

(1) Place the cup-shaped blank with an inner diameter of 30mm, an outer diameter of 46mm, and a height of 80mm in the circular groove of the lower platen of the vertical spinning machine with the bottom of the cup down, and fit them together to ensure that the center of the blank is on the spinning machine On the center line of the main shaft, the groove depth of the upper and lower pressure plates is 4mm;

(2) Adjust the pressure valve so that the pressure F of the upper platen is 50kn, and the F is calculated by the following formula: F=0.2σs·A/1000=0.2×260×(23 ² -15 ² )×3.14÷1000≈50kn , where σs=260Mpa is the yield strength of the blank material 6061 aluminum alloy, A (mm ² ) is the contact area between the blank to be formed and the upper platen;

(3) The spindle pushes the upper platen to move downwards to compress the billet with the calculated pressing force. The upper and lower platens rotate simultaneously under the drive of their respective spindles and drive the round billet to rotate together. The diameter of the upper and lower platens is 62mm. The speed is set at 180rpm;

(4) The rotary wheel feeds the extrusion blank in the radial direction, so that the material flows continuously in the radial direction and the height direction, but due to the constraint effect of the upper and lower pressure plates, the material mainly flows in the radial direction to form an outer groove, and the rotary wheel feed ratio It is: V＝exp{(6.2-0.11×50)÷7}＝1.1≈1mm/r;

(5) When the rotary wheel is fed to a distance of 8 mm from the outer wall of the cup-shaped part to be formed, the rotary wheel spins idly for 1 second, and then the rotary wheel quickly withdraws, the upper and lower spindles of the spinning machine stop rotating, and the upper pressure plate moves upward to release the blank. The cup-shaped part with an outer groove in the middle, the final cup-shaped part is well formed, the outer surface of the formed outer groove is smooth, the thickness of the outer groove is 7.98mm, and the height of the workpiece is 79.14mm, which meets the actual industrial needs.

The upper and lower pressure plates in the forming method of the present invention have a groove structure, which fits with the upper and lower ends of the blank to be processed, can position the blank to be processed, and can also limit the flow of the workpiece metal material in the height direction during the forming process As well as the radial flow of the metal material at the upper and lower ends, during the entire forming process, an axial preload will be applied to the blank through the upper and lower pressure plates. The preload can make the metal material flow evenly up and down during the forming process. Appropriate rotary wheel feed ratio makes the upper and lower wall thickness of the part uniform after forming. Through the present invention, the forming process of the outer groove of the cup-shaped part can be controlled, the wall thickness of the formed cup-shaped part is uniform, the forming quality is high, and the forming process is stable. The present invention only forms the shape through the radial extrusion of the rotary wheel relative to the blank to be processed The outer groove is not only suitable for the spinning volume forming of the outer groove of the cup-shaped part, but also suitable for the spinning volume forming of the outer groove of similar pipe fittings.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (5)

1. a kind of cup shell outer groove spin forming method, which is characterized in that the manufacturing process is no core model mould pressing, i.e., to be added Work blank in forming process inside it without core mold support, directly utilize the spinning roller mould pressing outside blank to be processed, revolve It takes turns and a radial extruding force is generated to blank in blank forming process, realize the forming of groove comprising the following steps:

Cup shell to be processed is placed in the groove of spinning machine pressing disc and is made its position centering by S1, presets platen on spinning machine Pressing force, upper platen downlink is embedded in cup shell to be processed in the groove of upper platen, and makes it in the effect of pressing force Under be pressed on pressing disc, the depth of groove of the upper platen and pressing disc is 3-5mm, and the upper platen is to cup shell to be processed The pressing force of application meets the σ of condition F=0.2_sA/1000, wherein F is the pressing force that upper platen applies, σ_sFor cup shell material Yield strength, A are the area that cup shell is contacted with upper platen；

The upper platen of S2 and pressing disc drive cup shell to be processed to rotate, using outside cup shell in cup shell rotary course The spinning roller in portion squeezes the side of cup shell along the radial feed of cup shell, with this needed for the forming of the side of cup shell to be processed Outer groove, the feed ratio V of the spinning roller meets condition V=exp { (6.2-0.11F)/7 }.

2. cup shell outer groove spin forming method as described in claim 1, which is characterized in that groove on upper and lower platen Planform is adapted with the cross sectional shape of cup shell upper/lower terminal respectively.

3. cup shell outer groove spin forming method as claimed in claim 2, which is characterized in that the depth of groove of upper and lower platen For 4mm, the equal chamfering of the recess edge of upper and lower platen.

4. cup shell outer groove spin forming method as described in any one of claims 1-3, which is characterized in that cup shell side wall The ratio of central diameter and wall thickness is (4~10): 1.

5. cup shell outer groove spin forming method as claimed in claim 4, which is characterized in that the central diameter and wall of cup shell side wall Thick ratio is 7:1.