A method for integrally forming a straight-tapered composite cylinder

Abstract

The present application relates to a kind of integral forming method of straight cone composite cylinder, belong to precision hot forming processing technical field, solve the problems such as complex process, long cycle, processing difficulty, poor product precision, high cost of existing straight cone composite cylinder.The forming method includes: establishing straight cone composite cylinder three-dimensional model;Design and make mould, including bulging core and closing die;Blanking, circle and welding, obtain whole cone cylinder blank;The blank is preheated, and is sleeved on the bulging core of the mould;The closing die of the mould is sleeved on the bulging core;The mould is heated to the assembled mould, the closing die is pressed, and remains;The mould is cooled, and is demoulded, to obtain the straight cone composite cylinder.The method can realize the whole forming process of straight cone composite cylinder closing, flaring and bulging, simplify processing procedure, shorten processing cycle, reduce processing difficulty and cost, improve product size precision.

Description

Technical Field

[0001] This invention relates to the field of precision thermoforming technology, and in particular to a method for integral molding of a straight conical composite cylinder. Background Technology

[0002] Aerospace components are becoming increasingly complex, and the straight-cone composite titanium cylinder is a typical component widely used in aerospace vehicles.

[0003] Currently, due to the different diameter variation patterns of conical composite titanium cylinders, direct bulging is not possible. Traditional processes involve bulging the product through three stages: narrowing, flaring, and overall bulging. However, these traditional methods have several drawbacks: First, the process is complex and has a long processing cycle; second, it requires numerous tooling fixtures, leading to high tooling costs; third, processing is difficult, requiring three stages of thermal bulging for each product, with each stage requiring mold clamping and positioning, placing high demands on datum transfer and operational procedures; finally, the product's surface accuracy is poor, as traditional processes involve three stages—narrowing, flaring, and overall bulging—each with its own bulging error. The cumulative error across these three stages results in a significant final product surface accuracy error.

[0004] To address the shortcomings of existing technologies, a new molding method for straight conical composite cylinders is needed. This method can not only simplify the molding process, shorten the processing cycle, reduce costs and processing difficulty, but also improve the surface accuracy of the product. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide an integral molding method for a straight conical composite cylinder, in order to solve at least one of the problems of complex processes, long cycles, high processing difficulty, poor product precision, and high costs in the existing traditional process of straight conical composite cylinders.

[0006] In a first aspect, embodiments of the present invention provide a method for integrally molding a straight conical composite cylinder, the method comprising:

[0007] (1) Establish a three-dimensional model of a straight conical composite cylinder, design and manufacture a mold, the mold including an bulging core and a closing mold, the bulging core including a conical section, and a large-diameter cylindrical section and a small-diameter cylindrical section located at both ends respectively;

[0008] (2) Based on the linear expansion coefficient of the straight cone composite cylinder and its dimensions at room temperature, the linear expansion coefficient of the mold component, and the difference between the thermoforming temperature and room temperature, design the dimensions of the mold;

[0009] (3) Based on the unfolded material dimensions of the straight conical composite cylinder three-dimensional model in the software, the blank is cut, circled and welded to obtain the whole conical cylinder blank;

[0010] (4) First, fix the large diameter end face of the bulging core, then preheat the whole conical blank, and put it on the bulging core from the large diameter end of the whole conical blank, wherein the preheating temperature is equal to the forming temperature;

[0011] (5) The closing mold is fitted onto the conical section of the bulging tire core to complete the assembly of the mold;

[0012] (6) The mold is heated and maintained. Pressure is applied to the closing mold through the heating device platform, causing the closing mold to move downward and cooperate with the large-diameter cylindrical section of the bulging core to close the blank and form the large-diameter straight cylindrical section of the straight cone composite cylinder. In addition, at the molding temperature, the conical section and the small-diameter cylindrical section of the bulging core bulge to form the conical section and the small-diameter straight cylindrical section of the straight cone composite cylinder, respectively.

[0013] (7) Cool the mold and demold it to obtain the straight cone composite cylinder.

[0014] Furthermore, in step (2), at the thermoforming temperature, the mold and the part are completely fitted together, i.e., L 零件 =L 模具 The dimensions of the mold at room temperature meet the following requirements:

[0015] L 模具0 = L 零件0 *(1+α 零件 ·ΔT) / (1+α 模具 ·ΔT) (1)

[0016] Among them, L 模具0 —Mold dimensions at room temperature;

[0017] L 模具 —Die dimensions at thermoforming temperature;

[0018] α 模具 —Coefficient of linear expansion of the mold;

[0019] ΔT—Difference between thermoforming temperature and room temperature;

[0020] L 零件0 —Part dimensions at room temperature;

[0021] L 零件 —Part dimensions at thermoforming temperature

[0022] α 零件 —Coefficient of linear expansion of the part.

[0023] Furthermore, the large-diameter cylindrical section, conical section, and small-diameter cylindrical section of the expanded tire core are an integral structure.

[0024] Furthermore, in step (4), before heating the billet, a step of calculating the amount of plastic deformation at the flared end of the billet is included, wherein the amount of plastic deformation satisfies the formula... Where η is the amount of plastic deformation at the flared end of the preform, and γ 锥2 γ is the radius of the flared end of the preform. 直2 This is the theoretical radius of the flared straight conical composite cylinder.

[0025] Furthermore, when the amount of plastic deformation is ≥8%, the blank is pre-expanded.

[0026] Furthermore, the deviation between the inner diameter of the billet and the outer diameter of the bulging core is controlled within 8%, thus completing the pre-expansion of the billet.

[0027] Furthermore, step (4) also includes installing a clamping plate on the small-diameter end face of the bulging core to prevent the blank from moving upward relative to the bulging core during the forming process.

[0028] Furthermore, in step (7), the demolding includes adding lubricant to the middle of the mold and the part, and demolding the part by pressing down on the upper surface of the part.

[0029] Furthermore, when the material of the straight cone composite cylinder is TA15, the pressure of the die closing the blank through the closing die is 20-80 tons.

[0030] Secondly, embodiments of the present invention provide a mold for the above-described method, the mold comprising a base, an bulging core, a pressing plate, a closing mold, and a padding ring;

[0031] The base is used to support the weight of the mold and blank and to position the bulging core.

[0032] The clamping plate is used to position the bulging tire core and the connecting lug;

[0033] The bulging core is used for the integrated molding of the conical composite cylinder, including the closing, bulging, and widening processes.

[0034] The closing mold has a cylindrical inner cavity, which is used to cooperate with the expanded core to complete the closing of the part;

[0035] The pad block ring is used to transmit external pressure to the closing mold to achieve the closing of the blank.

[0036] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0037] The present invention enables the integrated forming process of conical composite cylinders, including closing, flaring, and bulging. Compared with traditional methods for preparing conical composite cylinders, the present invention simplifies the processing steps, reducing the number of processes from three to one, shortening the processing cycle by two-thirds; the number of tooling sets is reduced from three to one, saving more than half of the tooling components; the closing, flaring, and bulging processes can be completed in a single clamping operation, reducing operational difficulty, processing difficulty, and cost; at the same time, it avoids the accumulation of errors from multiple processes, improving the surface accuracy of the product.

[0038] 2. The method of the present invention designs the mold size according to the material and size of the part to be processed and the material of the mold, so that the mold fits the part completely at the thermoforming temperature, thereby improving the product forming quality and reducing the product surface accuracy error; preferably, the present invention calculates the mold size used by the method of the present invention to realize the integrated forming process of the straight conical composite cylinder closing, flaring and expansion based on the linear expansion coefficient of the part and its size at room temperature, the linear expansion coefficient of the mold and the difference between the thermoforming temperature and room temperature.

[0039] 3. In the method of the present invention, the coefficient of thermal expansion of the bulging core material is equal to or greater than the coefficient of thermal expansion of the straight conical composite cylinder material to be processed. Preferably, when the whole conical cylinder blank is thermoformed using a mold with a larger coefficient of thermal expansion, not only is a better forming effect achieved, but it is also easy to demold after the forming and cooling process. The material constituting the bulging core of the present invention can be stainless steel.

[0040] 4. In the method of the present invention, before the blank is formed, the inner diameter of the closing mold fitted on the expanding core is smaller than the outer diameter of the end of the whole conical blank to be closed, so that the closing mold is located in the conical section of the expanding core; during the blank forming, the closing mold moves downward under the action of external pressure, and cooperates with the large-diameter cylindrical section of the expanding core to realize the closing of the blank, forming the large-diameter straight cylindrical section of the straight conical composite cylinder.

[0041] 5. The method of the present invention determines whether the flared end of the billet needs to be pre-flared based on the amount of plastic deformation at the flared end of the straight conical cylinder billet to ensure successful mold loading; wherein, when the amount of plastic deformation at the flared end of the billet is ≥8%, the billet is pre-flared.

[0042] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0043] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0044] Figure 1 This is a schematic diagram of the mold assembly for the integral molding method of the straight conical composite cylinder of the present invention;

[0045] Figure 2 This is a schematic diagram of the blank (a) and product (b) of the straight cone composite cylinder 1 according to Embodiment 1 of the present invention;

[0046] Figure 3 This is a schematic diagram of the blank (a), pre-flared blank (b), and product (c) of the straight conical composite cylinder 2 according to Embodiment 2 of the present invention.

[0047] Figure label:

[0048] 1-Base; 2-Pressure plate; 3-Expanded core; 4-Closing mold; 5-Padded ring; 6-Blank. Detailed Implementation

[0049] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0050] As aerospace components become increasingly complex, tapered composite titanium cylinders, as a typical component, are widely used in aerospace vehicles. Due to their varying diameter variations, tapered composite titanium cylinders cannot currently be directly integrally bulged. Traditional processes involve three steps: constriction bulging, flaring bulging, and integral bulging, which have the following drawbacks: complex processes leading to long processing cycles; the need for numerous tooling fixtures resulting in high costs; difficult processing, requiring three thermal bulging stages for each product, each requiring mold clamping and positioning, placing high demands on datum transfer and operational processes; and poor product surface accuracy, as each step in the traditional process introduces bulging errors, and the cumulative error across the three stages results in significant surface accuracy errors in the final product.

[0051] Therefore, this invention discloses an integral molding method for a straight conical composite cylinder, the method comprising:

[0052] (1) Establish a three-dimensional model of a straight conical composite cylinder, design and manufacture a mold, the mold including an bulging core and a closing mold, the bulging core including a conical section, and a large-diameter cylindrical section and a small-diameter cylindrical section located at both ends respectively;

[0053] (2) Based on the linear expansion coefficient of the straight cone composite cylinder and its dimensions at room temperature, the linear expansion coefficient of the mold component, and the difference between the thermoforming temperature and room temperature, design the dimensions of the mold;

[0054] (3) Based on the unfolded material dimensions of the straight conical composite cylinder three-dimensional model in the software, the blank is cut, circled and welded to obtain the whole conical cylinder blank;

[0055] (4) First, fix the large diameter end face of the bulging core, then preheat the whole conical blank, and put it on the bulging core from the large diameter end of the whole conical blank, wherein the preheating temperature is equal to the forming temperature;

[0056] (5) The closing mold is fitted onto the conical section of the bulging tire core to complete the assembly of the mold;

[0057] (6) The mold is heated and maintained. Pressure is applied to the closing mold through the heating device platform, causing the closing mold to move downward and cooperate with the large-diameter cylindrical section of the bulging core to close the blank and form the large-diameter straight cylindrical section of the straight cone composite cylinder. In addition, at the molding temperature, the conical section and the small-diameter cylindrical section of the bulging core bulge to form the conical section and the small-diameter straight cylindrical section of the straight cone composite cylinder, respectively.

[0058] (7) Cool the mold and demold it to obtain the straight cone composite cylinder.

[0059] Specifically, in step (1), the mold designed by the three-dimensional model of the straight conical composite cylinder has the same shape as the straight conical composite cylinder. The structure of the straight conical composite cylinder in this invention includes a conical segment, a large-diameter cylindrical segment located at the large-diameter end of the conical segment, and a small-diameter cylindrical segment located at the small-diameter end of the conical segment. Correspondingly, the bulging core includes a conical segment, and a large-diameter cylindrical segment and a small-diameter cylindrical segment located at both ends, which are solid or hollow, so as to complete the process of closing, widening and bulging of the straight conical composite cylinder in one process. Compared with the traditional preparation method, the number of processes is simplified and the processing cycle is shortened.

[0060] Furthermore, the large-diameter cylindrical section, conical section, and small-diameter cylindrical section of the expanded tire core are an integral structure.

[0061] The method of the present invention designs the mold size according to the material and size of the part to be processed and the material of the mold, so that the mold can be completely fitted with the part at the thermoforming temperature, thereby improving the product forming quality and reducing the product surface accuracy error.

[0062] Specifically, in step (2), the dimensions of the mold are designed based on the linear expansion coefficient of the straight cone composite cylinder and its dimensions at room temperature, the linear expansion coefficient of the mold component, and the difference between the thermoforming temperature and room temperature.

[0063] Furthermore, at the thermoforming temperature, the mold and the part are completely fitted together, i.e., L 零件 =L 模具The dimensions of the mold at room temperature meet the following requirements:

[0064] L 模具0 = L 零件0 *(1+α 零件 ·ΔT) / (1+α 模具 ·ΔT) (1)

[0065] Among them, L 模具0 —Mold dimensions at room temperature;

[0066] L 模具 —Die dimensions at thermoforming temperature;

[0067] α 模具 —Coefficient of linear expansion of the mold;

[0068] ΔT—Difference between thermoforming temperature and room temperature;

[0069] L 零件0 —Part dimensions at room temperature;

[0070] L 零件 —Part dimensions at thermoforming temperature

[0071] α 零件 —Coefficient of linear expansion of the part.

[0072] In this invention, the structure and dimensions of the mold bulging core and the closing mold are designed to ensure the stability and adaptability of the parts during hot working. The design principle is as follows:

[0073] Assuming the part is formed at a certain temperature T, the part and the mold fit together perfectly, i.e., R 胎芯 =r 零件 R 零件 =r 收口模 The following relationship exists:

[0074] R 零件 =R 零件0 (1+α 零件 ·ΔT) (2)

[0075] r 零件 =r 零件0 (1+α 零件 ·ΔT) (3)

[0076] R 胎芯 =R 胎芯0 (1+α 胎芯 ·ΔT) (4)

[0077] r 收口模 =r 收口模0 (1+α 收口模 ·ΔT) (5)

[0078] In the formula, R 零件0 —Outer diameter of the straight conical composite cylinder at room temperature;

[0079] r 零件0 —Inner diameter of the straight conical composite cylinder at room temperature;

[0080] R 零件 —Outer diameter of the straight tapered composite cylinder at the thermoforming temperature;

[0081] r 零件 —Inner diameter of the straight tapered composite cylinder at the thermoforming temperature;

[0082] R 胎芯0 —Outer diameter of the tire core at room temperature;

[0083] R 胎芯 —Outer diameter of the tire core at thermoforming temperature;

[0084] r 收口模0 —Inner diameter of the closing mold at room temperature;

[0085] r 收口模 —Inner diameter of the die at the thermoforming temperature;

[0086] α 零件 —Coefficient of linear expansion of the part;

[0087] α 胎芯 —Tire coreline expansion coefficient;

[0088] α 收口模 —Coefficient of linear expansion of the seam trimmer;

[0089] ΔT — the difference between thermoforming temperature and room temperature.

[0090] From equations (1)-(4), we can obtain:

[0091] R 胎芯0 = r 零件0 *(1+α 零件 ·ΔT) / (1+α 胎芯 ·ΔT) (6)

[0092] r 收口模0 = R 零件0 *(1+α 零件 ·ΔT) / (1+α 收口模 ·ΔT) (7)

[0093] Therefore, the scaling dimensions of the process parts are as shown in formulas (6) and (7), that is, when designing the mold, the size of the expansion core and the closing mold that need to be enlarged or reduced; by accurately controlling the mold size, the forming quality of the parts can be further improved and the accuracy error can be reduced.

[0094] Specifically, in step (3), the three-dimensional model of the straight cone composite cylinder is unfolded, and the unfolded material size is accurately calculated. The method is as follows: In the UG software, a new plane is created in the modeling module, and the product model is divided into two parts. Then, one of the cutting edges is offset by 0.1mm on both sides, so that there is a gap of 0.2mm on this edge. Then, the split model is summed to obtain a solid. The solid is unfolded by sheet metal unfolding operation. After unfolding, the theoretical unfolded model size can be obtained by offsetting 0.1mm on each side.

[0095] Furthermore, the blank is cut according to the unfolded material size. The blanking method can be laser cutting, wire cutting, CNC punching, shearing machine, water jet cutting, machining, etc. According to the preferred embodiment of the present invention, laser cutting is used for blanking. The blank is rounded to ensure that the end faces on both sides of the weld can be flush and butt-jointed. The rounded product is pickled to clean the oil stains and excess material on the surface of the blank. The blank is welded, and the welded part is an irregularly shaped conical cylinder.

[0096] Furthermore, the material of the straight conical composite cylinder of the present invention is TA15, TC4 or aluminum alloy.

[0097] In the method of the present invention, the coefficient of thermal expansion of the bulging core material is equal to or greater than the coefficient of thermal expansion of the straight conical composite cylinder material to be processed. Preferably, when the entire conical cylinder blank is thermoformed using a mold with a larger coefficient of thermal expansion, not only is a better forming effect achieved, but it is also easy to demold after forming and cooling. The material of the bulging core of the present invention can be selected from stainless steel, carbon steel, forging die steel, medium silicon molybdenum ductile iron, heat-resistant alloy steel, and ceramic materials.

[0098] The material of the closing mold described in this invention is one of stainless steel, carbon steel, forging die steel, medium silicon molybdenum ductile iron, heat-resistant alloy steel, or ceramic material. When the coefficient of thermal expansion of the closing mold material is less than that of the part being prepared, it is easy to demold after molding and cooling; when the coefficient of thermal expansion of the closing mold material is greater than or equal to that of the part being prepared, it is not easy to demold after molding and cooling, and demolding requires the use of lubricating oil and the application of pressure. The specific operation is discussed later.

[0099] The dimensions and quality of the conical blank obtained through step (3), such as flatness, do not meet the requirements of actual application. Therefore, it needs to be flared, closed, and heat-treated using a mold. An assembly diagram of the method of this invention using a mold for thermoforming of parts is shown below. Figure 1 As shown; the working principle is:

[0100] Firstly, the roundness of the product can be adjusted by selecting materials with different coefficients of thermal expansion. Materials with a larger coefficient of thermal expansion than the blank material can be selected as the mold core material. The blank with a room temperature diameter larger than the room temperature core diameter, or a blank with a diameter larger than the room temperature core diameter after heating, can be installed on the core. After heating together to a certain temperature T, the core diameter will be larger than the product diameter, thus achieving the effect of expansion.

[0101] According to some preferred embodiments of the present invention, the material of the billet conical cylinder is TA15 titanium alloy, and the coefficient of thermal expansion at a temperature of (20-800)℃ is 9.7×10⁻⁶. -6 The tire core material is 316 stainless steel, and its coefficient of thermal expansion at temperatures ranging from 20 to 800°C is approximately 16.5 × 10⁻⁶. -6 / ℃, the outer diameter of the tire core reaches the theoretical inner diameter of the straight conical composite cylinder when heated to 700℃, then the diameter of the blank at room temperature is greater than the diameter of the tire core.

[0102] Secondly: The blank is a conical cylinder, and the large-diameter end of the conical cylinder needs to be narrowed to a straight cylinder. The working principle of narrowing is as follows: After assembling the blank onto the core, install the narrowing mold. The steps are as follows: Figure 1 As shown; when heated to the target temperature, the inner diameter of the closing mold is the theoretical outer diameter of the product's straight conical composite cylinder. The blank is a whole cone shape. The closing mold cannot be directly installed to the bottom. It needs to be installed as shown in the figure before heating. After heating to the target temperature T, the platform on the equipment transmits pressure to the closing mold through the clamping ring. The closing mold moves downward until the closing mold and the base are in complete contact. This process is the closing process.

[0103] Thirdly: Since the billet is a conical cylinder, the smaller diameter end of the conical cylinder needs to be flared into a straight cylinder. The maximum flaring range is determined by the ratio of the difference between the product's neutral layer perimeter and the billet's neutral layer perimeter to the billet's neutral layer perimeter, which must be within the material's elongation after fracture range. That is: (Product neutral layer perimeter - Billet neutral layer perimeter) / Billet neutral layer perimeter ≤ Material elongation after fracture. For example: if the material's elongation after fracture is 10%, then... Where l2 is the perimeter of the neutral layer of the product, and l1 is the perimeter of the neutral layer of the billet.

[0104] Specifically, in step (4), the large-diameter end face of the bulging core is first fixed, then the whole conical blank is preheated and fitted onto the bulging core from the large-diameter end of the whole conical blank, wherein the preheating temperature is equal to the molding temperature.

[0105] According to some preferred embodiments of the present invention, the large-diameter end face of the bulging tire core is fixed to the base by a threaded connection; the base has a disc-shaped or annular structure, wherein, for a hollow bulging tire core, the annular structure of the base facilitates heat transfer and improves the heat utilization rate and uniformity during the hot working of the blank; the inner circumference of the upper surface of the annular base has an annular protrusion, the outer diameter of the annular protrusion being smaller than the inner diameter of the large-diameter end of the hollow bulging tire core, which is used to position the large-diameter end of the bulging tire core.

[0106] Furthermore, before heating the billet, the method includes a step of calculating the amount of plastic deformation at the flared end of the billet, wherein the amount of plastic deformation satisfies the formula... Where η is the amount of plastic deformation at the flared end of the preform, and γ 锥2 γ is the radius of the flared end of the preform. 直2 This is the theoretical radius of the flared straight conical composite cylinder.

[0107] According to some preferred embodiments of the present invention, when the amount of plastic deformation is ≥8%, if the billet is directly placed on the expansion mold, it is difficult to place the billet on the mold due to the small diameter of the billet and the large diameter of the expansion core. Therefore, it is necessary to pre-expand the flared end first.

[0108] The specific steps of the pre-expansion are as follows: using conventional expansion methods, a certain length of the small-diameter section of the whole cone blank is pre-expanded. Pre-expansion can be completed in three ways:

[0109] The first method uses calculus to pre-expand the small-diameter conical section into a cylinder. First, a cylindrical section 1 is used for pre-expansion. The diameter of the cylindrical section 1 is half the sum of the outer diameter of the flared end of the bulging core and the inner diameter of the small end of the conical cylinder in the billet. The length of the cylindrical section 1 is greater than or equal to the length of the straight cylinder section in the theoretical model. The cylindrical section 1 is inserted into the billet at room temperature, and then the billet is heated to perform the first step of pre-expansion. If the deviation between the inner diameter of the pre-expanded billet and the outer diameter of the bulging core is within 8%, the pre-expansion is complete. If the deviation of the tire core's outer diameter exceeds 8%, pre-expansion is performed using cylindrical segment 2. The diameter of cylindrical segment 2 is the sum of half the outer diameter of the expanded tire core's flared end and the inner diameter of the blank after the first pre-expansion. This is repeated until the deviation between the inner diameter of the blank and the outer diameter of the expanded tire core is within 8%, thus completing the pre-expansion of the blank. The pre-formed blank is then heated or not heated, and the pre-expansioned blank is installed on the expanded tire core, ensuring that the bottom of the blank contacts the base. Finally, the clamping plate is installed on the small-diameter end of the expanded tire core.

[0110] The second method involves machining a stainless steel straight column with a diameter equal to that of the blank end face. The pre-expanded cylinder is placed into the blank at room temperature, and then heated for pre-expansion. After cooling, this step of expansion is repeated until the deviation between the blank diameter and the expansion core diameter is within 8%.

[0111] The third method involves processing a conical column with a diameter equal to the inner diameter of the small end of the billet. The conical column is placed into the billet at room temperature, and then heated for pre-expansion. After cooling, this step is repeated to perform iterative pre-expansion until the deviation between the billet diameter and the diameter of the bulging core is within 8%.

[0112] When the amount of plastic deformation is less than 8%, it is not necessary to pre-expand the entire conical blank. It can be expanded directly, that is, the blank is heated or not heated and then installed on the expansion core, ensuring that the bottom of the blank contacts the base; then the clamping plate is installed at the small diameter end of the expansion core.

[0113] It should be noted that the present invention heats the straight conical preform to cause thermal expansion, so that it can be fitted onto the expanded core, thereby achieving a small live part and a large core, and improving the product expansion quality.

[0114] It should be noted that the temperature at which the billet is heated before installation should be lower than the melting point of the billet, so as not to change the microstructure of the billet. The preferred heating temperature is the temperature at which the billet is heat-processed.

[0115] Furthermore, step (4) also includes installing a clamping plate on the small-diameter end face of the expanded core to prevent the blank from moving upward relative to the expanded core during the forming process, wherein the diameter of the clamping plate is larger than the diameter of the small-diameter end face of the expanded core.

[0116] Specifically, in step (5), the closing mold is fitted onto the conical section of the bulging tire core to complete the assembly of the mold.

[0117] According to some preferred embodiments of the present invention, the mold in the method of the present invention further includes a pad ring, which is fitted on top of the bulging core and the closing mold, for transmitting external pressure to the closing mold to realize the closing of the blank. The height of the fitted ring is much greater than the height of the bulging core, which facilitates the application of external pressure.

[0118] It should be noted that, according to some preferred embodiments of the present invention, when the material of the straight conical composite cylinder is TA15, the total weight of the closing die and the retaining ring is 150-200Kg, the pressure of closing the blank by the closing die is 20-80 tons, and when the inner diameter of the closing die at the hot working temperature is equal to the theoretical outer diameter of the large diameter cylinder of the straight conical composite cylinder, when the closing die and the retaining ring are sequentially placed on the bulging core, the closing die will not reach the bottom of the bulging core and contact the base.

[0119] It should be noted that, in the method of the present invention, before the blank is formed, the inner diameter of the closing mold fitted on the expanding core is smaller than the outer diameter of the end of the whole conical blank to be closed, so that the closing mold is located in the conical section of the expanding core; during the blank forming, the closing mold moves downward under the action of external pressure, and cooperates with the large-diameter cylindrical section of the expanding core to realize the closing of the blank, forming the large-diameter straight cylindrical section of the straight conical composite cylinder.

[0120] Specifically, in step (6), the mold is heated and maintained, and pressure is applied to the closing mold through the heating device platform to make the closing mold move downward and cooperate with the large-diameter cylindrical section of the bulging core to realize the closing of the blank and form the large-diameter straight cylindrical section of the straight cone composite cylinder; in addition, at the molding temperature, the conical section and the small-diameter cylindrical section of the bulging core are bulged to form the conical section and the small-diameter straight cylindrical section of the straight cone composite cylinder, respectively.

[0121] According to some specific embodiments of the present invention, the mold is heated to the heat treatment processing temperature of the straight cone composite cylinder, and then pressure is applied to the mold by controlling the upper and lower platforms. The pad ring and the closing mold part move downward until the closing mold and the base are in contact. After the closing mold and the base are in contact, the temperature is kept for a period of time to ensure that the heat treatment forming is in place.

[0122] According to a preferred embodiment of the present invention, a straight conical composite cylinder preform made of TA15 titanium alloy is heated to 600-700°C; then a pressure of 20-80 tons is applied to the mold, and the retaining ring and closing mold part moves downward until the closing mold and the base are in contact. After the closing mold and the base are in contact, the heat and pressure are maintained for 1-5 hours.

[0123] Specifically, in step (7), after the billet has undergone heat treatment, the equipment is naturally cooled down, the mold is removed from the equipment, and the mold is demolded.

[0124] Based on some preferred embodiments of the present invention, the pad ring, the clamping plate, the base, and the bulging core are first disassembled, and then the closing mold is disassembled.

[0125] It should be noted that when the coefficient of thermal expansion of the material constituting the bulging tire core is greater than that of the material of the conical composite cylinder, a pore is formed between the bulging tire core and the conical composite cylinder after the conical composite cylinder cools down, so the bulging tire core can be easily disassembled.

[0126] It should be noted that when the coefficient of thermal expansion of the closing mold is less than that of the straight tapered composite cylinder, it can be directly demolded after cooling; when the coefficient of thermal expansion of the closing mold is greater than that of the straight tapered composite cylinder, it cannot be directly demolded after cooling. Lubricant needs to be added between the closing mold and the heat-treated part, and left for a period of time, at least 20 minutes. Then, the closing mold and the part are placed on the press platform, the clamping plate is placed on the upper surface of the part, and the upper surface of the part is slowly pressed down (speed ≤ 5 mm / s) by controlling the platform of the equipment to demold the part.

[0127] This invention enables zero-angle demolding of straight conical composite cylinders, expanding the boundaries of thermoformed product structures.

[0128] This method enables the one-step forming of a straight conical composite cylinder, encompassing the closing, flaring, and bulging processes, in a single operation. Compared to traditional methods for manufacturing straight conical composite cylinders, this reduces the number of processes from three to one, shortening the processing cycle by two-thirds. The number of tooling sets is reduced from three to one, saving more than half the tooling components. The closing, flaring, and bulging processes can be completed in a single clamping operation, reducing operational difficulty, processing complexity, and cost. Simultaneously, it avoids the accumulation of errors from multiple processes, improving the surface accuracy of the product.

[0129] The present invention also provides a mold for integral molding of a straight conical composite cylinder, such as... Figure 1 As shown, the mold includes a base 1, an expanded tire core 3, a pressing plate 2, and a closing mold 4 and a pad ring 5, which are rigidly connected from bottom to top on the expanded tire core.

[0130] The bulging core includes a conical section in the middle, and a large-diameter cylindrical section and a small-diameter cylindrical section at both ends. The conical section is used for bulging the billet to form the conical section of the straight-conical composite cylinder; the small-diameter cylindrical section is used for flaring the billet to form the small-diameter straight section of the straight-conical composite cylinder; the large-diameter cylindrical section is used for closing the billet to form the large-diameter straight section of the straight-conical composite cylinder, wherein the billet is a whole conical billet;

[0131] The closing mold has a cylindrical inner cavity, which is fitted onto the bulging core and is used to cooperate with the large-diameter cylindrical section of the bulging core to close the blank and form a large-diameter straight cylindrical section of the straight conical composite cylinder.

[0132] The pad block ring includes an upper bottom ring surface, a lower bottom ring surface, and a support column located in the middle, which is used to transmit external pressure to the closing mold to realize the closing of the blank.

[0133] The bulging core of this invention includes a conical section in the middle, and large-diameter cylindrical sections and small-diameter cylindrical sections at both ends. Besides supporting the blank and controlling the shape of the product, it is mainly used to achieve the integrated forming process of closing, flaring, and bulging of the straight-cone composite cylinder part. The base is used to support the weight of the mold and position the bulging core. The clamping plate, together with the base, is used to fix the bulging core. The closing mold is used to cooperate with the large-diameter cylindrical section of the bulging core to close the blank. The pad ring is used to transmit external pressure to the closing mold.

[0134] Specifically, the dimensions of the expanded tire core of the present invention at room temperature satisfy the following:

[0135] R 胎芯0 = r 零件0 *(1+α 零件 ·ΔT) / (1+α 胎芯 ·ΔT) (6)

[0136] Among them, R 胎芯0 —Outer diameter of the inflated tire core at room temperature;

[0137] α 胎芯 —Coefficient of expansion of the tire core wire;

[0138] ΔT—Difference between thermoforming temperature and room temperature;

[0139] r 零件0 —Inner diameter of the straight conical composite cylinder at room temperature;

[0140] α 零件 —Coefficient of linear expansion of the straight cone composite cylinder.

[0141] Specifically, the structure and dimensions of the bulging core are determined by the structure and dimensions of the straight conical composite cylinder part to be produced. To ensure the stability and adaptability of the part during hot working, the design principle of the bulging core is as follows:

[0142] Assuming the part is formed at a certain temperature T, the straight tapered composite cylinder part is completely fitted with the bulging core, and the inner diameter r of the part... 零件 Equal to the outer diameter R of the bulging tire core 胎芯 R 胎芯 =r 零件 Among them, the following relationships also exist:

[0143] r 零件 =r 零件0 (1+α 零件 ·ΔT) (3)

[0144] R 胎芯 =R 胎芯0 (1+α 胎芯 ·ΔT) (4)

[0145] Where, r 零件0 —Inner diameter of the straight conical composite cylinder at room temperature, R 胎芯 —The outer diameter of the expanded tire core at the thermoforming temperature; and the outer diameter of the expanded tire core at room temperature is derived from the above relationship.

[0146] Specifically, the lengths and diameters of the cylindrical and conical sections of the expanded tire core are determined by the dimensions of the straight conical composite cylinder to be processed. The length of the conical section is equal to the length of the conical part in the straight conical composite cylinder to be processed. The length of the cylindrical section is 20-50mm longer than the length of the straight part in the straight conical composite cylinder to be processed. It is used for finishing the rough product after hot working to remove the excess material and remove the uneven parts at both ends. The outer diameter of each section of the expanded tire core is calculated by formula (6).

[0147] In addition, the thickness of the expansion core described in this invention is based on being able to withstand the pressure and temperature during the hot working process, ensuring the strength and stability of the expansion core. A suitable thickness range of the expansion core is beneficial to the expansion performance of the expansion core and the convenience of demolding.

[0148] The inflatable core is solid or hollow, preferably hollow, which helps with heat conduction and dissipation, preventing deformation or damage due to overheating, helping to maintain the machining accuracy and stability of the parts, and also facilitating movement and operation, improving efficiency and reducing costs.

[0149] Specifically, in this invention, the large-diameter end of the expanded tire core is threaded to the base, and the small-diameter end is threaded to the pressure plate; preferably, the large-diameter end of the expanded tire core with a hollow structure can also be sleeved around the annular protrusion of the base, and the small-diameter end can be sleeved around the cylindrical protrusion of the pressure plate.

[0150] Furthermore, the large-diameter end face of the expanded tire core has symmetrically distributed built-in threaded holes along the circumference. The number of built-in threaded holes is the same as the corresponding threaded holes on the base, which is 4-6. The large-diameter end of the expanded tire core is fixed to the base by bolts. The small-diameter end of the expanded tire core has symmetrically distributed built-in threaded holes along the circumference. The number of built-in threaded holes is the same as the corresponding threaded holes on the pressure plate, which is 4-6. The small-diameter end of the expanded tire core is fixed to the pressure plate by bolts.

[0151] Furthermore, in order to ensure that the bulging core has sufficient strength and rigidity, and to facilitate heat conduction and dissipation, the material of the bulging core can be selected from stainless steel, carbon steel, forging die steel, medium silicon molybdenum ductile iron, heat-resistant alloy steel, and ceramic materials.

[0152] Specifically, the coefficient of thermal expansion of the bulging core material of the present invention is greater than that of the blank to be processed. When the entire conical blank is thermoformed using a mold with a larger coefficient of thermal expansion, not only is a better forming effect achieved, but it is also easy to demold after the forming and cooling process.

[0153] According to some preferred embodiments of the present invention, when hot-working the TA15 titanium alloy straight tapered composite cylinder, the bulging core can be prepared by selecting 316 stainless steel with a thermal expansion coefficient greater than that of TA15 titanium alloy.

[0154] The materials for other parts of this invention are one of stainless steel, carbon steel, forging die steel, medium silicon molybdenum ductile iron, and heat-resistant alloy steel.

[0155] Based on the shape of the desired conical composite cylinder, the inner cavity of the closing mold is designed to be cylindrical for closing and forming the conical composite cylinder. The dimensions of the closing mold at room temperature satisfy the following requirements:

[0156] r 收口模0 = R 零件0 *(1+α 零件 ·ΔT) / (1+α 收口模 ·ΔT) (7)

[0157] Where, r 收口模0 —Inner diameter of the closing mold at room temperature;

[0158] α 收口模 —Coefficient of linear expansion of the seam trimmer;

[0159] ΔT—Difference between thermoforming temperature and room temperature;

[0160] R 零件0 —Outer diameter of the straight conical composite cylinder at room temperature;

[0161] α 零件 —Coefficient of linear expansion of the straight cone composite cylinder.

[0162] Specifically, the structure and dimensions of the closing die are determined by the structure and dimensions of the straight tapered composite cylinder part to be produced. To ensure the stability and adaptability of the part during the hot working process, the design principle of the closing die is as follows:

[0163] Assuming the part is formed at a certain temperature T, the straight tapered composite cylinder part fits perfectly with the closing mold, and the outer diameter L of the part... 零件 Equal to the inner diameter R of the closing die 收口模 L 零件 =R 收口模 Among them, the following relationships also exist:

[0164] R 零件 =R 零件0 (1+α 零件·ΔT) (2)

[0165] r 收口模 =r 收口模0 (1+α 收口模 ·ΔT) (5)

[0166] Among them, R 收口模 —Inner diameter of the die at the thermoforming temperature, r 收口模 —The inner diameter of the closing die at the thermoforming temperature; and the inner diameter of the closing die at room temperature is derived from the above relationship.

[0167] Specifically, the length of the closing mold is greater than or equal to the length of the hollow cylindrical section at the large diameter end of the bulging core. At the part forming temperature, it cooperates with the large diameter cylindrical section of the bulging core to close the blank.

[0168] Before the blank is formed, the inner diameter of the closing mold fitted on the expanding core is smaller than the outer diameter of the end of the conical blank to be closed, so that the closing mold does not contact the base; during the blank forming, the closing mold moves downward under external pressure and contacts the base, and cooperates with the large-diameter cylindrical section of the expanding core to realize the closing of the blank, forming the large-diameter straight cylindrical section of the straight conical composite cylinder.

[0169] According to some preferred embodiments of the present invention, the end of the closing mold that contacts the pad ring is designed as a circular ring structure with an outer diameter larger than the outer diameter of other parts of the closing mold, which is used to withstand the external pressure transmitted by the pad ring. The other parts of the closing mold are cylindrical. The structure of the straight conical composite cylinder of the present invention facilitates movement and operation, improves efficiency, and reduces material costs.

[0170] Furthermore, the straight cylindrical portion of the closing mold is symmetrically provided with threaded through holes for installing lifting lugs during mold assembly and for installing thermocouples during hot working; the annular portion of the closing mold is symmetrically provided with threaded internal holes for installing lifting lugs during mold assembly and for fixing to the pad ring with bolts during hot working.

[0171] Furthermore, the closing die needs to have high strength to withstand external pressure of 20-80 tons, improve durability, and ensure hot working accuracy; in addition, the selection of the closing die material should also take into account the material characteristics of the parts to be processed and the working environment.

[0172] Specifically, the material of the closing mold is one of stainless steel, carbon steel, forging die steel, medium silicon molybdenum ductile iron, heat-resistant alloy steel, or ceramic material. When the coefficient of thermal expansion of the closing mold material is less than that of the part being prepared, it is easy to demold after molding and cooling; when the coefficient of thermal expansion of the closing mold material is greater than or equal to that of the part being prepared, it is not easy to demold after molding and cooling, and demolding requires the use of lubricating oil and the application of pressure. The specific operation will be discussed later.

[0173] The present invention utilizes the base as a positioning standard for the expanded tire core, and together with the clamping plate, it is used to fix the expanded tire core.

[0174] Specifically, the base is used to support the weight of the mold and blank, as well as external pressure. It needs to have a certain thickness and strength. The thickness range is determined by the material of the base, the material and size of the blank that needs to be heat-treated. For example, when the TA15 titanium alloy straight tapered composite cylinder of the embodiment is made of 304 stainless steel, the thickness of the base can be 10-30mm. The base has a disc-shaped or ring-shaped structure. The ring-shaped structure is conducive to heat transfer and improves the heat utilization rate and uniformity during the hot working of the blank. The inner circumference of the upper surface of the ring-shaped base has an annular protrusion with a height of 5-30mm. The outer diameter of the annular protrusion is less than or equal to the inner diameter of the large diameter end of the hollow bulging core, which is used to position the large diameter end of the bulging core.

[0175] It should be noted that the thickness of a certain annular area on the outer edge of the base is reduced in order to fix it to the heat treatment equipment of the parts when installing the mold. It is preferable to use a pressure plate for fixing, and the thickness of the annular area is controlled to be 10-30mm.

[0176] Furthermore, the base has threaded through holes I evenly distributed along a certain circumference, the diameter of which matches the size of the large diameter end of the bulging core, for threaded fixing of the bulging core, and the number of these through holes is 4-6. In addition, in order to facilitate mold assembly and precise control of the heating temperature during hot working, threaded through holes II are provided around the through holes I on the base, the number of which is 4-6, for installing lifting lugs during mold assembly and for installing thermocouples during hot working.

[0177] Specifically, the clamping plate has a disc-shaped structure and is used together with the base to fix the bulging core. The clamping plate is connected to the core by bolts, which can prevent the blank from moving upward relative to the core during the forming process.

[0178] Preferably, the central area of ​​the lower surface of the pressure plate has a cylindrical protrusion with a height of 10-20mm. The diameter of the cylindrical protrusion is less than or equal to the inner diameter of the small diameter end of the hollow inflatable tire core, so as to position the small diameter end of the inflatable tire core.

[0179] Furthermore, the clamping plate is threadedly connected to the expanded tire core. Specifically, the base has threaded through holes A evenly distributed along a certain circumference. The diameter of the circumference matches the size of the small diameter end of the expanded tire core, used to thread-fix the expanded tire core. The number of through holes is 4-6. Furthermore, to facilitate the disassembly and assembly of the clamping plate, the hole for the threaded connection between the clamping plate and the expanded tire core can be designed as an irregular hole. The irregular hole includes two connected circular holes with different diameters, namely a large-diameter hole and a small-diameter hole. During normal use, the bolts are not removed, the clamping plate is removed, and when installing the clamping plate, the nut passes through the large-diameter hole. After installation, the nut is turned to the small-diameter hole for positioning.

[0180] In addition, a lifting lug is threaded at the center of the upper surface of the clamping plate to facilitate mold loading and unloading.

[0181] Specifically, the padding ring includes an upper bottom ring surface, a lower bottom ring surface, and a support column located in the middle, used to transmit external pressure to the closing mold to achieve the closing of the blank; before the forming of the straight tapered composite cylinder, the closing mold and the padding ring are sleeved on the expanding core from bottom to top, with the padding ring on top of the closing mold and the two being threaded together, wherein the closing mold does not contact the base; at the blank forming temperature, pressure is applied to the upper ring surface of the padding ring through the heating device platform, and the pressure is transmitted to the closing mold through the padding ring. Under the action of external pressure, the closing mold moves downward and contacts the base, cooperating with the large-diameter cylindrical section of the expanding core to achieve the closing of the blank, forming the large-diameter straight cylindrical section of the straight tapered composite cylinder.

[0182] According to some preferred embodiments of the present invention, the upper and lower bottom surfaces of the pad ring are circular ring structures of the same size, the diameter of the hollow circle in the middle is equal to the diameter of the cylindrical inner cavity of the closing mold, and the outer diameter is greater than or equal to the outer diameter of the circular portion of the closing mold. The closing mold needs to have high strength to withstand external pressure of 20-80 tons, improve durability, and ensure the accuracy of heat treatment.

[0183] Furthermore, threaded through holes are provided on the upper and lower bottom surfaces of the pad ring. The support column is a cylinder with threads at both ends. After being connected to the lower bottom surface, the support column can penetrate the lower bottom surface and be fixed by a nut below the lower bottom surface. After being connected to the upper bottom surface, the support column cannot penetrate the upper bottom surface and is fixed by a nut inside the upper bottom surface so as to apply pressure to the upper bottom surface of the pad ring.

[0184] Furthermore, in order to ensure the stability of the mold under external force during the hot processing of the parts, the outer diameter of the base is greater than or equal to the diameter of the bottom surface of the pad ring.

[0185] The magnification factor of the mold described in this invention is 3-6‰, which on the one hand facilitates the installation of the thermally expanded blank onto the bulging core, and on the other hand ensures the dimensional accuracy of the thermoformed product and avoids molding defects, achieving a small blank with a large core and improving the product molding quality.

[0186] According to some preferred embodiments of the present invention, when preparing the TA15 titanium alloy straight conical composite cylinder, the material of the bulging core is 316 stainless steel, and the material of other parts of the mold is 304 stainless steel.

[0187] The mold described above in this invention is prepared by casting and machining methods.

[0188] Mold: The bulging core material is 316 stainless steel, with a coefficient of thermal expansion of approximately 16.5 × 10⁻⁶ at temperatures ranging from 20 to 800°C. -6 / ℃; the coefficient of thermal expansion is 18.2×10⁻⁶ for the other parts of the mold material, which is 304 stainless steel. -6 / ℃.

[0189] Example 1

[0190] A method for preparing a TA15 titanium alloy straight conical composite cylinder 1, wherein the dimensions of the TA15 titanium alloy straight conical composite cylinder 1 are: a thickness of 2 mm, a total length of 1420 mm, a top end being a cylinder with a length of 40 mm and an outer diameter of 288 mm, a bottom end being a cylinder with a length of 40 mm and an outer diameter of 400 mm, and a cone in the middle, as shown below. Figure 2 As shown in (b), the method includes:

[0191] (1) A 3D model of a TA15 titanium alloy straight conical composite cylinder was created using UG. Based on the 3D model, mold 1 was designed and manufactured using conventional methods. Mold 1 includes a base, an bulging core, a clamping plate, a closing mold, and a pad ring, with the structure as follows: Figure 1 As shown;

[0192] (2) After calculation, the outer diameter of the large-diameter cylindrical section of the bulging tire core is 389.6 mm, the outer diameter of the small-diameter cylindrical section of the bulging tire core is 278.3 mm, and the inner diameter of the closing mold is 398.2 mm.

[0193] (3) Unfold the three-dimensional model in step (1) and calculate the unfolded material dimensions; use laser cutting to cut the TA15 titanium alloy; align the end faces on both sides of the weld and perform a circular operation; pickle the circularized blank to clean the surface oil, excess material, etc.; weld the blank to obtain an irregularly shaped conical cylinder blank, which is the TA15 titanium alloy straight conical composite cylinder 1 preform blank, such as... Figure 2 As shown in (a);

[0194] (4) According to calculation, the plastic deformation of the flared end of the billet is 1.6%. First, the large diameter end face of the bulging core is connected to the base 1 by thread. The preform obtained in step (3) is directly heated at 680℃ for 2 hours. The billet is put on the bulging core through the large diameter end of the whole conical billet, so that the bottom of the preform is in contact with the base of the mold, and a pressure plate is installed at the small diameter end of the bulging core.

[0195] (5) First, put the closing mold on the conical section of the expansion core, then put the pad ring on the expansion core and the closing mold, and connect the two with threads to complete the assembly of the mold. The distance between the closing mold and the base is 40mm.

[0196] (6) Install the assembled mold on the heat treatment equipment platform, ensuring that the closing mold and the retaining ring are perpendicular to the base, raise the temperature to 700°C, apply 40 tons of pressure to the mold through the upper and lower platforms of the equipment until the closing mold contacts the base, and continue to keep it hot and pressured for 2 hours.

[0197] (7) Cool the equipment to 20°C by natural air cooling, remove the mold, disassemble the pad ring, pressure plate, base and expansion core; add lubricant to the middle of the closing mold and parts, let it stand for 20 minutes, place the closing mold and parts on the press platform, place the pressure plate on the upper end of the parts, and press the upper surface of the parts at a speed of 2 mm / s by controlling the platform of the equipment to demold, and obtain TA15 titanium alloy straight cone composite cylinder 1.

[0198] Example 2

[0199] A method for preparing a TA15 titanium alloy straight conical composite cylinder 2. The dimensions of the TA15 titanium alloy straight conical composite cylinder 2 are: thickness 2mm, total length 1200mm, top end is a cylinder with a length of 100mm and an outer diameter of 102mm, bottom end is a cylinder with a length of 100mm and an outer diameter of 202mm, and the middle is a cone. Figure 3 As shown in (c), the method includes:

[0200] (1) Same as step (1) in Example 2;

[0201] (2) After calculation, the outer diameter of the large-diameter cylindrical section of the inflatable tire core is 201.2 mm, the outer diameter of the small-diameter cylindrical section of the inflatable tire core is 101.6 mm, and the inner diameter of the closing mold is 211.1 mm.

[0202] (3) Same as step (3) in Example 2, the obtained TA15 titanium alloy straight tapered composite cylinder 2 preform blank is as follows: Figure 3 As shown in (a);

[0203] (4) Calculations show that the plastic deformation at the flared end of the billet is 10.8%, requiring pre-flaring of the flared end. The pre-flared billet should be as follows: Figure 3 (b) shows

[0204] (5) Same as step (5) in Example 2;

[0205] (6) Same as step (6) in Example 2;

[0206] (7) Same as step (7) in Example 2;

[0207] TA15 titanium alloy straight cone composite cylinder 2 was obtained.

[0208] A three-dimensional scan was performed on the straight conical composite cylinder product processed according to the embodiments of the present invention. The results showed that the straight conical composite cylinder obtained by the present invention matched the theoretical model with a degree of 98%, and the product surface dimensional accuracy was within ±0.2mm. The same three-dimensional scanning method was used to test the straight conical composite product made by the traditional processing method. The results showed that the straight conical composite product made by the traditional processing method matched the theoretical model with a degree of only 75%, and the product surface dimensional accuracy was within ±2mm. The mechanical property test results showed that the mechanical properties of the straight conical composite cylinder integrally formed by the method of the present invention can reach more than 90% of the mechanical properties of the base material, which is much higher than the mechanical properties of the straight conical composite cylinder made by the traditional processing method.

[0209] Furthermore, compared to traditional processing methods, this invention eliminates two thermoforming steps in the production of a straight conical composite cylinder, saving a 4-day processing cycle and two sets of thermoforming molds, resulting in cost savings of over 50%. Additionally, traditional processing requires tooling for closing, flaring, and bulging, each set costing approximately 30,000 yuan, totaling 90,000 yuan, with a processing cycle of about 6 days and a processing cost of approximately 3,600 yuan. In contrast, this invention uses only one set of tooling to achieve closing, flaring, and bulging, with a tooling cost of approximately 60,000 yuan, reducing the processing cycle to 2 days and the processing cost to approximately 1,200 yuan. In other words, this invention reduces the processing cycle by 67%, saves over 50% on mold costs, and lowers the overall processing cost by 67%.

[0210] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for integrally molding a straight conical composite cylinder, characterized in that, The method includes: (1) Establish a three-dimensional model of a straight conical composite cylinder, design and manufacture a mold, the mold including an bulging core and a closing mold, the bulging core including a conical section, and a large-diameter cylindrical section and a small-diameter cylindrical section located at both ends respectively; (2) Based on the linear expansion coefficient of the straight cone composite cylinder and its dimensions at room temperature, the linear expansion coefficient of the mold component, and the difference between the thermoforming temperature and room temperature, design the dimensions of the mold; (3) Based on the unfolded material dimensions of the straight conical composite cylinder three-dimensional model in the software, the blank is cut, circled and welded to obtain the whole conical cylinder blank; (4) First, fix the large diameter end face of the bulging core, then preheat the whole conical blank, and put it on the bulging core from the large diameter end of the whole conical blank, wherein the preheating temperature is equal to the forming temperature; (5) The closing mold is fitted onto the conical section of the bulging tire core to complete the assembly of the mold; (6) The mold is heated and maintained. Pressure is applied to the closing mold through the heating device platform, causing the closing mold to move downward and cooperate with the large-diameter cylindrical section of the bulging core to close the blank and form the large-diameter straight cylindrical section of the straight cone composite cylinder. In addition, at the molding temperature, the conical section and the small-diameter cylindrical section of the bulging core bulge to form the conical section and the small-diameter straight cylindrical section of the straight cone composite cylinder, respectively. (7) Cool the mold and demold it to obtain the straight cone composite cylinder; The mold also includes a base, a clamping plate, and a pad ring; The base is used to support the weight of the mold and blank and to position the bulging core. The clamping plate is used to position the bulging tire core and the connecting lug; The bulging core is used for the integrated molding of the conical composite cylinder, including the closing, bulging, and widening processes. The closing mold has a cylindrical inner cavity, which is used to cooperate with the expanded core to complete the closing of the part; The pad block ring is used to transmit external pressure to the closing mold to achieve the closing of the blank.

2. The method according to claim 1, characterized in that, In step (2), at the thermoforming temperature, the mold and the part are completely fitted together, i.e., L 零件 =L 模具 The dimensions of the mold at room temperature meet the following requirements: L 模具0 =L 零件0 *(1+a 零件 ·ΔT) / (1+α 模具 ·ΔT) (1) Among them, L 模具0 —Mold dimensions at room temperature; L 模具 —Die dimensions at thermoforming temperature; α 模具 —Coefficient of linear expansion of the mold; ΔT—Difference between thermoforming temperature and room temperature; L 零件0 —Part dimensions at room temperature; L 零件 —Part dimensions at thermoforming temperature α 零件 —Coefficient of linear expansion of the part.

3. The method according to claim 1 or 2, wherein the large-diameter cylindrical segment, conical segment and small-diameter cylindrical segment of the expanded tire core are an integral structure.

4. The method according to claim 1, characterized in that, In step (4), before heating the billet, a step of calculating the amount of plastic deformation at the flared end of the billet is included, wherein the amount of plastic deformation satisfies the formula Where η is the amount of plastic deformation at the flared end of the preform, and γ 锥2 γ is the radius of the flared end of the preform. 直2 This is the theoretical radius of the flared straight conical composite cylinder.

5. The method according to claim 4, characterized in that, When the amount of plastic deformation is ≥8%, the billet is pre-expanded.

6. The method according to claim 5, characterized in that, The deviation between the inner diameter of the billet and the outer diameter of the bulging core is controlled within 8%, thus completing the pre-expansion of the billet.

7. The method according to claim 1, characterized in that, Step (4) also includes installing a clamping plate on the small-diameter end face of the bulging core to prevent the blank from moving upward relative to the bulging core during the forming process.

8. The method according to claim 1, characterized in that, In step (7), demolding includes adding lubricant to the middle of the mold and the part, and demolding the part by pressing down on the upper surface of the part.

9. The method according to claim 1, characterized in that, When the material of the straight cone composite cylinder is TA15, the pressure of the die closing the blank through the closing die is 20-80 tons.

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