An integral metal core mold for a large-diameter and long-stroke cylinder and a processing method thereof

Abstract

The present invention discloses an integral metal core mold and processing method for a large-diameter long-stroke cylinder body, including multiple core mold sub-pieces, each of which includes an outer cylinder, multiple rectangular steel bars and multiple annular rib plates, multiple rectangular steel bars are staggered along the axial direction of the outer cylinder on the inner side of the outer cylinder, each annular rib plate is provided with multiple rectangular through holes for the rectangular steel bars to pass through, an annular rib plate is provided at a certain interval on the multiple rectangular steel bars, and each core mold sub-piece is staggered and overlapped and welded into a whole by the rectangular steel bars; wherein the core mold sub-pieces at the left and right ends are provided with end surface connection plates, a first support seat is provided on the end surface connection plate at one end, a rivet hole is provided on the first support seat, a demoulding rivet is installed on the first support seat through a connecting pin and the rivet hole, and a second support seat is provided on the end surface connection plate at the other end. The present invention has a simple structure, high rigidity, high precision, and high surface quality; it is suitable for medium and large-scale production of composite cylinders such as carbon fiber.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber and other composite material production, and in particular to an integral metal core mold for a large-diameter, long-stroke cylindrical component and its processing method. Background Technology

[0002] With the rapid development of the chemical industry, large-capacity cylinders are becoming increasingly common. The performance of composite materials has improved rapidly in recent decades, leading to their widespread application in aerospace, defense, gas storage and transportation, and other fields. The molding method for composites such as carbon fiber is fiber winding. The basic method involves winding continuous fiber strips impregnated with resin onto a mandrel according to a specific pattern, followed by curing and demolding to obtain the composite material product.

[0003] Existing composite molding methods are already quite diverse and are increasingly widely used in various fields. In foreign countries, low-melting-point metals are often used to manufacture core molds, which are then melted and cast into shells. When demolding, they are melted again, but this is not suitable for mass production. There are also gypsum core molds, which are inexpensive and have a simple molding process, but they have low strength, poor thermal conductivity, and moisture in the core mold affects the curing of the product. However, it is still difficult to control high precision in the molding process of large composite parts due to the difficulty in controlling the rigidity of the core mold, processing accuracy, welding deformation, and other aspects. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing an integral metal core mold for large-diameter, long-stroke cylindrical components and its processing method. The core mold has a simple structure and exhibits high rigidity, high precision, and high surface quality; it is suitable for medium to large-volume production of composite cylindrical components such as carbon fiber.

[0005] The technical solution of this invention is:

[0006] A large-diameter, long-stroke cylindrical integral metal core mold includes multiple core mold segments. Each core mold segment includes an outer cylinder, multiple rectangular steel bars, and multiple ring reinforcement plates. The multiple rectangular steel bars are staggered along the axial direction of the outer cylinder inside the outer cylinder. Each ring reinforcement plate has multiple rectangular through holes for the rectangular steel bars to pass through. A ring reinforcement plate is set at regular intervals on the multiple rectangular steel bars. The core mold segments are welded into a whole by staggered overlapping of the rectangular steel bars. The core mold segments at both ends are provided with end face connecting plates. One end end face connecting plate is provided with a first support seat. The first support seat has a pull stud hole. The first support seat is installed with a demolding pull stud by connecting pins cooperating with the pull stud hole. The other end end face connecting plate is provided with a second support seat.

[0007] Furthermore, the length of the middle section of each core mold component is 1800-2500mm, and the length of the core mold components at the left and right ends is greater than 1 / 2 of the length of the middle section.

[0008] Furthermore, the spacing between adjacent ring reinforcement plates is 360–400 mm, and the angle between each rectangular steel bar is 40–60°.

[0009] Furthermore, the outer surface of the core mold's outer cylinder is provided with a taper of 5000 to 10000:1 for demolding.

[0010] Furthermore, the first support and the second support are provided with cam sleeves for connecting to the end face connecting plate. The cam sleeves of the first support and the second support are respectively connected to the end face connecting plate by bolts, and the bolts are provided with anti-loosening washers.

[0011] Furthermore, both the first and second support seats have reinforcing plates on their cam sleeves, and the first and second support seats are solid cylinders.

[0012] Furthermore, each of the left and right end core mold components is provided with several reinforcing ribs distributed along the circumference of the outer cylinder. One side of the reinforcing rib is fixed to the ring rib plate, and the other side is fixed to the end face connecting plate.

[0013] Another technical solution of the present invention is:

[0014] A method for machining a large-diameter, long-stroke cylindrical integral metal core mold, based on the aforementioned structure of the large-diameter, long-stroke cylindrical integral metal core mold, employs the following machining steps:

[0015] S001 manufactures an outer cylinder with multiple core mold components. First, based on the fact that the length of the middle core mold component is 1800-2500mm and the length of the core mold components at the left and right ends is greater than 1 / 2 of the length of the middle core mold component, the core mold is divided into multiple core mold components. Then, based on the length and diameter of each core mold component, the rolled material is processed sequentially through leveling, splitting, and rolling to form the outer cylinder with multiple core mold components.

[0016] S002 is assembled in sections. First, a rectangular steel bar is welded into the outer cylinder made by S001. Then, a ring reinforcement plate is welded into the inner wall of the outer cylinder made by S001. Next, other rectangular steel bars are passed through the rectangular through holes on the ring reinforcement plate and welded to the outer cylinder and the ring reinforcement plate. The rectangular steel bars are staggered. Finally, a ring reinforcement plate is set at a certain interval and welded to the outer cylinder and the rectangular steel bars to form a segmented core mold.

[0017] S003 is assembled as a whole, using a positioning and strengthening process plate to weld the segmented core molds into a whole by interlacing rectangular steel bars;

[0018] S004 machining taper, S003 the assembled mandrel is machined by rough turning, semi-finish turning and finish turning of the mandrel outer cylinder taper in sequence by lathe, the outer cylinder taper is 5000 to 10000:1;

[0019] After grinding to remove excess material, the surface is then precision turned and polished on a lathe to remove further excess material, achieving a surface roughness of 0.8µm.

[0020] Furthermore, ultrasonic flaw detection is required after the S002 segment assembly and the S003 overall assembly.

[0021] Furthermore, before machining the taper on the S004 machine, straightening, annealing, and surface treatment are required in sequence.

[0022] The above technical solution has the following beneficial effects:

[0023] The present invention features a simple structure, employing multiple segmented core molds welded together as a whole, facilitating processing and operation. This core mold boasts high rigidity, high precision, high surface quality, long service life, and reusability. Demolding is quick and convenient using a demolding machine, enabling rapid reuse. It is suitable for medium to large-volume production of carbon fiber and other composite material cylinders. The present invention ensures that the core mold maintains reliable rigidity and precision under the same weight.

[0024] The following description, in conjunction with the accompanying drawings and specific embodiments, will provide further details. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the core mold in specific embodiment 1;

[0026] Figure 2 for Figure 1 The front view;

[0027] Figure 3 for Figure 2 Sectional view of AA;

[0028] Figure 4 for Figure 2 Side view from direction B;

[0029] Figure 5 for Figure 2 Side view from the center (C);

[0030] Figure 6 This is a structural diagram of the outer cylinder, rectangular steel bars, and ring reinforcement plate of the core mold in this specific embodiment 1;

[0031] Figure 7 This is a flowchart of the core mold processing method in specific embodiment 1.

[0032] In the attached diagram, 1 is the outer cylinder, 2 is the first support seat, 3 is the second support seat, 4 is the demolding rivet, 5 is the demolding ring, 6 is the pin, 7 is the bolt, 8 is the cam sleeve, 9 is the reinforcing plate, 10 is the reinforcing rib plate, 11 is the rectangular steel bar, 12 is the ring rib plate, and 13 is the positioning and reinforcing process plate. Detailed Implementation Specific Implementation Example 1:

[0034] See Figures 1 to 6As shown, a large-diameter, long-stroke cylindrical integral metal mandrel includes multiple mandrel segments, dividing the mandrel of the product to be processed into multiple structural segments. The length of the middle segment of each mandrel segment is 1800-2500 mm, and the length of the mandrel segments at the left and right ends is greater than 1 / 2 the length of the middle segment. The mandrel segments at the ends are shorter than the middle mandrel assembly. This length facilitates welding and controls the bending deformation of the segment mandrel segments. Each mandrel segment includes an outer cylinder 1, multiple rectangular steel bars 11, and multiple ring stiffening plates 12. The outer cylinder 1 has the same shape and structure as the pre-processed product. In this specific embodiment, the rectangular reinforcing bars 11 are rectangular tubes. Multiple rectangular reinforcing bars 11 are staggered along the axial direction of the outer cylinder 1 inside the outer cylinder 1. Each ring-shaped reinforcing plate 12 has multiple rectangular through holes for the rectangular reinforcing bars 11 to pass through. A ring-shaped reinforcing plate 12 is placed at regular intervals on the multiple rectangular reinforcing bars 11, with a spacing of 360–400 mm between adjacent ring-shaped reinforcing plates 12. The angle between each rectangular reinforcing bar 11 is 40–60°. In this specific embodiment, the length of the intermediate core mold component is 2000 mm, i.e., the length of the outer cylinder 1 is 2000 mm. The spacing between adjacent ring-shaped reinforcing plates 12 is 360 mm. Each ring-shaped reinforcing plate 12 has eight rectangular through holes, each corresponding to one rectangular reinforcing bar 11. The angle between each rectangular reinforcing bar 11 is 45°, and the rectangular reinforcing bars 11 are staggered. The ring-shaped reinforcing plates 12 provide radial rigidity to the outer cylinder 1, while the rectangular reinforcing bars provide longitudinal rigidity. Each segment of the core mold is welded together into a whole by staggered overlapping of rectangular steel bars 11. The staggered overlapping facilitates the installation of multiple core mold segments during welding. After welding, it can withstand radial and axial forces and maintain axial accuracy. The segmented welding method facilitates processing, and the ring reinforcement plate 12 not only facilitates the fixing of the rectangular steel bars 11, but also enhances the strength of the outer cylinder 1, making the core mold stronger and enabling repeated use in multiple production runs. The core mold segments at both ends are equipped with end face connecting plates. One end face connecting plate is equipped with a first support seat 2, which has a pull pin hole. The first support seat 2 is fitted with a demolding pull pin 4 by connecting pin 6. The other end face connecting plate is equipped with a second support seat 3. The first support seat 2 and the second support seat 3 are equipped with cam sleeves 8 for connecting to the end face connecting plates. The cam sleeves 8 are connected to the end face connecting plates by bolts 7, and the bolts are equipped with anti-loosening washers. The first support seat 2 and the second support seat 3 are both provided with reinforcing plates 9, and the reinforcing plates 9 are provided with lifting holes. The first support seat 2 and the second support seat 3 are made of solid cylinders, so the overall deformation of the core mold is minimized under external load, which enhances the strength of the first support seat 2 and the second support seat 3.Each of the left and right end core mold components is provided with a plurality of reinforcing ribs 10 distributed circumferentially along the outer cylinder 1. One side of each reinforcing rib 10 is welded and fixed to the annular rib 12, and the other side is welded and fixed to the end face connecting plate. The reinforcing ribs and ribs enhance the strength of both ends of the core mold. Possibly, the cam sleeves 8 of the first support seat 2 and the second support seat 3 extend to the other end of the first support seat and the second support seat. The extension of the cam sleeve enhances the strength of the first support seat and the second support seat and reduces the deformation of the first support seat and the second support seat. In this specific embodiment, the length of the cam sleeve of the first support seat and the second support seat is 450-520 mm.

[0035] The outer surface of the outer cylinder 1 of the core mold is provided with a taper of 5000 to 10000:1 for demolding. A demolding ring 5 is fitted on the core mold. The taper makes it easier for the core mold to be demolded from the core mold when it is demolded by the demolding device.

[0036] See Figures 1 to 7 As shown, a method for machining a large-diameter, long-stroke cylindrical integral metal core mold is described, and the machining steps are as follows, based on the aforementioned structure of the large-diameter, long-stroke cylindrical integral metal core mold:

[0037] S001 manufactures the outer cylinder of the multi-segment core mold components. Based on the shape requirements of the product to be processed, the core mold is divided into multiple segments. First, the middle segment is evenly divided according to the required length of 1800-2500mm. Then, the remaining length of the entire core mold is evenly distributed to the left and right end segments, with the length of the left and right end segments being greater than half the length of the middle segment. In this specific embodiment: the total length of the core mold is 12390mm, the length of the left and right end segments is 1195mm, and the length of the middle segment is 2000mm. The core mold is divided into 7 segments, and 7 outer cylinders 1 are manufactured. The length and diameter of the outer cylinders are the same as those of each core mold component. Based on the length and diameter of each segment, the rolled material is sequentially leveled, split, and coated to produce the outer cylinder 1 for each segment.

[0038] The assembly method for each core mold component in S002 is as follows: First, a rectangular steel bar 11 is welded into the outer cylinder 1 made in S001. Next, a ring-shaped reinforcing plate 12 is welded to the inner wall of the outer cylinder 1 made in S001. Then, according to the distribution of rectangular through holes on the ring-shaped reinforcing plate 12, other rectangular steel bars 11 are passed through these rectangular through holes and welded to the outer cylinder 1 and the ring-shaped reinforcing plate 12. The rectangular steel bars 11 are staggered, creating an irregular arrangement to facilitate overlapping during subsequent overall assembly. Finally, a ring-shaped reinforcing plate 12 is placed at a certain interval and welded to the outer cylinder 1 and the rectangular steel bars 11 to form a segmented core mold. In this embodiment, eight rectangular steel bars 11 are used. The outer cylinders of the core mold components at the left and right ends use two ring-shaped reinforcing plates 12, and the outer cylinder 1 of the middle section of the core mold component uses five ring-shaped reinforcing plates 12. The core mold components at both ends are welded with end face connecting plates. A first support seat is mounted on one end of the end face connecting plate. The first support seat has pull pin holes, and a demolding pull pin is installed on the first support seat by connecting pins that mate with the pull pin holes. A second support seat is mounted on the other end of the end face connecting plate. In this specific embodiment: the first and second support seats are solid cylinders. Cam sleeves for connecting to the end face connecting plates are welded to the first and second support seats. Reinforcing plates are provided on the cam sleeves, and lifting holes are drilled in the reinforcing plates. The cam sleeves are connected to the end face connecting plates by bolts, and anti-loosening washers are provided on the bolts.

[0039] Possibly, each of the left and right end mandrel components is provided with several reinforcing ribs distributed circumferentially along the outer cylinder 1. One side of each reinforcing rib is welded and fixed to the annular rib plate 12, and the other side is welded and fixed to the end face connecting plate. The strength of both ends of the mandrel is enhanced by the reinforcing ribs and the reinforcing plates. After each mandrel segment is assembled, ultrasonic testing is used to ensure that the welds of the mandrel components are free of defects.

[0040] The S003 assembly utilizes a positioning and reinforcing process plate 13 to weld the segmented core molds together using rectangular steel bars 11 in an alternating lap joint. First, the relative positions of the two core mold segments are adjusted so that the rectangular steel bars 11 of the two core mold segments are interlocked in a dog-tooth pattern. The longitudinal splicing welds of the cylinder are staggered. The coaxiality of the spliced ​​parts is checked, and spot welding is performed. Then, the two core mold segments are clamped together using the positioning and reinforcing process plate 13, and spot welding is used to weld the ends together. The axial diameter accuracy of the two core mold segments is positioned using the positioning and reinforcing process plate 13. After adjusting the radial and axial runout, the components are welded together to ensure the cylindricity of the core mold. The spot welding process includes:

[0041] Step 1: Perform the root pass weld on the butt weld of outer cylinder 1;

[0042] Step 2: Perform symmetrical and intermittent welding on the inner cavity of the outer cylinder 1;

[0043] Step 3: Perform full cap welding on the longitudinal weld seam of outer cylinder 1;

[0044] Step 4: Remove the outer circle positioning reinforcement plate 13.

[0045] The seven core mold components were welded together sequentially using this method. After the core mold was assembled, a PXUT-320C fully digital ultrasonic flaw detector was used. After sanding, a 2.5P20 straight probe was used for flaw detection using the oil coupling contact method to ensure that the welds of each core mold component were free of defects.

[0046] S004 machining taper. The mandrel assembled in S003 is machined using a heavy-duty horizontal lathe. The outer cylinder taper of the mandrel is machined sequentially by rough turning, semi-finish turning, and finish turning. The outer cylinder taper is 5000~10000:1. During machining, a center rest is required to support the mandrel. 3-5 center rests are evenly distributed in the middle to prevent the mandrel from bending and deforming due to its own weight during machining. First, during rough turning, the outer circle is aligned and the surface is smoothed. After rough turning, it is vibrated and aged for 30-50 minutes. Next, semi-finish turning is performed to determine the taper size. In this specific embodiment, the semi-finish turning taper is 13290:2, leaving a allowance of 0.5mm on each side, with a surface roughness of 3.2um. Finally, finish turning is performed to further correct the taper, leaving a allowance of 0.1mm, with a surface roughness of 1.6um.

[0047] Possibly, before machining the S004 machine, straightening, annealing, and surface treatment are performed sequentially. During annealing, multi-point support is required to prevent deformation due to its own weight, and the annealing temperature is 600°C for 3 hours to eliminate welding stress. For surface treatment, shot peening is used to remove rust and expose the metal's natural color, removing the oxide scale.

[0048] After grinding to remove excess material in S005, the material is precision turned and then polished on a lathe. The surface roughness reaches 0.8um after grinding. Grinding removes excess material and reduces surface roughness. Reducing surface roughness and taper facilitates subsequent demolding.

[0049] According to the shape of the outer cylinder 1 of the product to be processed, if the product to be processed also has a raised guide rail, a groove is set according to the product requirements, and a milling process is also required. After S005 grinding, the outer cylinder 1 is milled. The groove required by the product is milled on the outer cylinder 1 by a milling cutter, and then the groove is ground. The roughness of the polished groove after grinding reaches 0.8um.

[0050] It is possible that after the above operations, the core mold can be inspected to ensure that it meets the design requirements. The inspection process can verify whether the processed core mold meets the design requirements, thus ensuring the product quality of the core mold processing.

[0051] The mandrel of the present invention is a large-diameter, long-stroke integral metal mandrel that is processed in sections and then welded together. This ensures that the mandrel has reliable rigidity and precision under the same weight. It can be used to produce large composite cylindrical parts and is applicable to the field of composite materials such as carbon fiber.

Claims

1. An integral metal core mold for a large-diameter and long-stroke cylinder, characterized in that: The invention comprises a plurality of core mold parts, wherein the length of the core mold parts in the middle section of each core mold part is 1800-2500 mm, and the length of the core mold parts at the left and right ends is greater than 1 / 2 of the length of the core mold parts in the middle section. Each core mold part comprises an outer tube, a plurality of rectangular steel bars and a plurality of annular rib plates, and the spacing between each adjacent annular rib plates is 360-400 mm, and the spacing angle between each rectangular steel bar is 40-60°. The plurality of rectangular steel bars are staggered on the inner side of the outer tube along the axial direction of the outer tube, and each annular rib plate is provided with a plurality of rectangular through holes for the rectangular steel bars to pass through, and each of the plurality of rectangular steel bars is spaced at a certain distance. A ring rib plate is arranged separately, and each section of the core mold component is welded into a whole by staggered overlap of each rectangular steel bar; wherein the core mold components at the left and right ends are provided with end face connecting plates, and the end face connecting plate at one end is provided with a first support seat, and a rivet hole is provided on the first support seat, and a demoulding rivet is installed on the first support seat through a connecting pin and the rivet hole, and a second support seat is provided on the end face connecting plate at the other end, and the first support seat and the second support seat are provided with a cam sleeve for connecting with the end face connecting plate, and the cam sleeves of the first support seat and the second support seat are respectively connected to the end face connecting plate by bolts, and the bolts are provided with anti-loosening washers.

2. According to claim 1, the large-diameter and long-stroke cylindrical integral metal core mold is characterized in that: The outer surface of the outer cylinder of the core mold is provided with a taper of 5000-10000:1 for demoulding.

3. The large-diameter and long-stroke cylindrical integral metal core mold according to claim 1 is characterized in that: The cam sleeves of the first support seat and the second support seat are both provided with reinforcement plates, and the first support seat and the second support seat are solid cylinders.

4. The large-diameter and long-stroke cylindrical integral metal core mold according to claim 1 is characterized in that: The core mold parts at the left and right ends are both provided with a plurality of reinforcing rib plates distributed along the circumference of the outer cylinder. One side of the reinforcing rib plate is fixed to the annular rib plate, and the other side is fixed to the end surface connecting plate.

5. A method for processing a large-diameter long-stroke cylindrical integral metal core mold, used for processing the large-diameter long-stroke cylindrical integral metal core mold structure according to any one of claims 1 to 4, using the following processing steps: S001 manufactures an outer cylinder of multiple core mold parts. First, the core mold is divided into multiple core mold parts according to the core mold part length of the middle section being 1800-2500 mm, and the lengths of the core mold parts at the left and right ends being greater than 1 / 2 of the length of the core mold part of the middle section; then, according to the length and diameter of each core mold part, the coil is leveled, broken, and rolled to form an outer cylinder of multiple core mold parts; S002 is a segmented assembly, firstly, a rectangular steel bar is welded into the outer cylinder made in S001, then a ring rib plate is welded to the inner wall of the outer cylinder made in S001, then other rectangular steel bars are passed through the rectangular through holes on the ring rib plate and welded to the outer cylinder and the ring rib plate, and the rectangular steel bars are arranged alternately, and finally a ring rib plate is arranged at a certain interval, and the ring rib plate is welded to the outer cylinder and the rectangular steel bars to form a segmented core mold; S003 overall assembly, using the positioning reinforcement process plate to weld each segmented core mold into a whole through the staggered overlap of rectangular steel bars; S004 machining taper, S003 the assembled core mold is sequentially rough-turned, semi-finished and finished on a lathe to machine the taper of the outer cylinder of the core mold, and the taper of the outer cylinder is 5000-10000:1; S005 is ground to remove the excess, and after fine turning, it is ground and polished on a lathe to remove the excess and make the roughness reach 0.8um.

6. The method for processing the integral metal core mold of a large-diameter and long-stroke cylinder according to claim 5, characterized in that: Ultrasonic flaw detection is required after the S002 segmented assembly and the S003 overall assembly.

7. The method for processing the integral metal core mold of a large-diameter and long-stroke cylinder according to claim 5 or 6, characterized in that: Before the S004 taper machining, straightening, annealing and surface treatment are required in sequence.

Images