Injection molding part and injection molding process

Abstract

The present application relates to an injection molded part and an injection molding process, and belongs to the field of injection molding technology. The injection molded part includes a tubular body, and the tubular body includes a first bent end, a middle portion, and a second straight-connected end. A connecting channel running through both ends is provided inside the tubular body, and the connecting channel includes a first core-pulling channel located at the first bent end, a bending channel located at the middle portion, and a second core-pulling channel located at the second straight-connected end. The side of the first core-pulling channel is connected to the bending channel, and the top arc of the second core-pulling channel is connected to the bending channel. The inner walls of the connecting channel are all connected by arcs, and the bending channel is flat. The injection molding process includes the following steps: S1, making a molten core by melting a tin block; S2, placing the molten core in an injection molding machine; S3, injection molding an injection molded part, at which time the injection molded part wraps the molten core and is removed together; S4, melting the molten core in the injection molded part to obtain a final injection molded part. The present application has the effect of molding an injection molded part whose internal cavity cannot be core-pulled in one step.

Description

Technical Field

[0001] The present application relates to the field of injection molding, and in particular to an injection molded part and an injection molding process. Background Art

[0002] Injection molding is a method for producing industrial products. Rubber and plastic injection molding are commonly used. Injection molding can be further categorized into compression molding and die casting. Plastic injection molding involves injecting molten plastic into a mold under pressure, followed by cooling and forming the desired plastic part. Mechanical injection molding machines are specifically designed for this purpose. Currently, the most commonly used plastics include polyethylene, polypropylene, ABS, PA, and polystyrene.

[0003] The commonly used injection molding process is often very troublesome when producing some injection molded parts with irregular cavities inside. For some injection molded parts with regular cavities, the core pulling method can be used to complete the injection molding. Generally, it is only necessary to fill the cavity of the injection molding machine with components. However, for some injection molded parts with irregular cavities and bends, the cavity filling method cannot be used because it will lead to the situation that demolding is impossible. At this time, it is often necessary to adopt the method of partial injection molding and then fix it, or complete the overall shape injection molding first to form the core-pulling cavity, and finally process the remaining cavity.

[0004] The above-mentioned production method for injection molded parts whose internal cavities cannot be cored out is cumbersome in secondary processing and causes serious material waste. In addition, partial molding will affect the quality of the injection molded parts. Summary of the Invention

[0005] In a first aspect, it is necessary to produce the following injection molded parts for curved conveying media, and the present application provides an injection molded part.

[0006] The present application provides an injection molded part that adopts the following technical solution:

[0007] An injection molded part includes a tubular body, which includes a first bent end, a middle portion and a second straight-connected end. A connecting channel is opened inside the tubular body and passes through both ends. The connecting channel includes a first core-pulling channel located at the first bent end, a bent channel located at the middle portion, and a second core-pulling channel located at the second straight-connected end. The side of the first core-pulling channel is connected to the bent channel, and the top arc of the second core-pulling channel is connected to the bent channel. The inner walls of the connecting channels are all connected by arcs, and the bent channel is flat.

[0008] Secondly, in order to form the above-mentioned injection molded parts whose internal cavities cannot be core-pulled in one step, the present application provides an injection molding process, which adopts the following technical solutions:

[0009] An injection molding process comprises the following steps:

[0010] S1, melt the tin block to make a molten core;

[0011] S2. Place the molten core in the injection molding machine;

[0012] S3, injection molding the injection molded part, at this time the injection molded part wraps the molten core and is removed together;

[0013] S4, melting the molten core in the injection molded part to obtain the final injection molded part.

[0014] By adopting the above technical solution, a molten core is made, and during injection molding, a cavity inside the injection molded part is formed by the molten core, and then the molten core is melted by hot melting to finally obtain the corresponding injection molded part. In this way, injection molded parts with complex internal cavity shapes that are not conducive to core pulling can be injection molded, and the molten core and the injection molded part can be demolded together, which is convenient for demolding.

[0015] Optionally, in step S1, a through cooling channel is machined inside the molten core, and during injection molding, a coolant is circulated back and forth inside the molten core. The cooling channel can be formed by grinding the molten core after molding, or the molten core can be divided into two halves and then assembled into a whole molten core.

[0016] By adopting the above technical solution, a cooling channel is machined inside the molten core and a coolant is flowed through the channel, thereby solving the problem that the melting point of the molten core made of tin is relatively close to the melting temperature of the injection molded part, so that the molten core is not easily melted on the surface before the injection molded part is formed, and the temperature of the molten core is better taken away by the coolant, so that the molten core is not easily affected by the surface flatness of the inner wall of the injection molded part due to melting. At the same time, the filling of the coolant also maintains the strength of the molten core, so that after the molten core is hollowed out, it is not easy to deform during injection molding. The coolant can also accelerate the molding of the injection molded part and improve the production efficiency of the injection molded part.

[0017] Optionally, when the molten core is formed in step S1, the size of the molten core is formed in a form smaller than the size of the bending channel, and then a layer of flexible polymer heat-resistant coating is coated on the surface of the molten core to finally reach the size of the bending channel.

[0018] By adopting the above technical solution, the molten core is manufactured in a reduced size manner, and then coated with a flexible polymer heat-resistant coating so that the molten core finally reaches the required size for the molding of injection molded parts. The presence of the flexible polymer heat-resistant coating makes the surface of the molten core not easily deformed at high temperatures, thereby maintaining the stability of the molding effect. After the molten core is melted, the flexible polymer heat-resistant coating itself can be flexibly deformed and removed from the injection molded part, thereby improving the molding effect without affecting the core removal process. At the same time, the method of coating the flexible polymer heat-resistant coating is suitable for various different injection molded part cavities. Even if the surface is uneven, the corresponding function can be achieved, and the adaptability is wide.

[0019] Optionally, the size of the molten core is smaller than the size of the bending channel, the surface of the molten core is wrapped with a layer of flexible material, a large number of cooling holes are arranged in an array on the surface of the molten core, and the cooling holes are connected to the cooling channel inside the molten core.

[0020] By adopting the above technical solution, the molten core is manufactured in a reduced size manner and then wrapped with a layer of flexible material layer so that the molten core finally reaches the required size for the molding of the injection molded part. The molten core and the injection molded part are separated by the flexible material layer, so that the surface of the molten core will not melt at high temperature when the raw material of the injection molded part is injected into the mold cavity, affecting the molding of the injection molded part. At the same time, the flexible material layer is fully cooled by opening cooling holes on the molten core, and is not easy to dissolve. The flexible material layer is also mainly supported by the coolant to maintain its state. Compared with the coating, the flexible material layer is more convenient to use, but is mainly suitable for situations where the inner cavity of the injection molded part is relatively flat, and it is easy to control the surface error. The flexible material layer can also be taken out together after the molten core is melted. At this time, the molten core can also be removed by partial melting and then breaking into pieces.

[0021] Optionally, the flexible material layer is wrapped with a high-temperature resistant material layer, the melting point of the high-temperature resistant material layer is greater than the melting point of the injection molded part, and the melting point of the flexible material layer is lower than the melting point of the molten core.

[0022] By adopting the above technical solution, by wrapping the high-temperature resistant material layer outside the flexible material layer, the part in direct contact with the injection molded part can withstand higher temperatures without changing itself, ensuring the maximum stability of the injection molding process and not prone to problems. Then, the flexible material layer can be melted in the high-temperature area during injection molding. At this time, the space between the high-temperature resistant material layer and the molten core completes the flow of the coolant. The flexible material layer mainly plays a role in supporting the setting of the high-temperature resistant material layer, so that a gap is formed between the high-temperature resistant material layer and the molten core, allowing the coolant to flow fully, especially in the high-temperature area. Then, during subsequent demolding, when the molten core melts, the injection molded part is not easily deformed due to the similar melting point. After the molten core melts and flows out, the high-temperature resistant material layer can be cut or deformed and extruded. Because it is thin, it is easy to deform, thereby completing the removal of the high-temperature resistant material.

[0023] Optionally, in step S2, the injection molding machine is provided with a first core pulling block and a second core pulling block, the first core pulling block forms a first core pulling channel, the second core pulling block forms a second core pulling channel, the first core pulling block and the molten core are slidably matched through a slider and a slide groove, the second core pulling block is plug-fitted with the molten core, the second core pulling block is partially inserted into the cooling channel, and the end face of the second core pulling block located in the cooling channel is provided with a coolant inlet and a coolant outlet, and at the same time, the second core pulling block is rotatably installed.

[0024] By adopting the above technical solution, a first core-pulling block and a second core-pulling block are provided. On the one hand, the size of the molten core can be as small as possible, and the injection molded part can be formed by core-pulling at both ends. On the other hand, the first core-pulling block and the second core-pulling block can also serve as supporting parts of the molten core to support the molten core in the cavity during injection molding. At the same time, the first core-pulling block is slidably installed, and the second core-pulling block is plug-fitted and rotatably installed. When demolding, the demolding can be rotated to drive the injection molded part to stand upright, which is convenient for the recovery of the coolant.

[0025] Optionally, the molten core is formed in half by a molten core forming device, which includes a forming block, a pressing block, a hole-forming column and a pressing semicircular plate. The forming block is adapted to the inner wall of the molten core, and the pressing block is adapted to the outer wall of the molten core. The hole-forming column is slidably installed in the pressing block and is provided with a reset spring. Both ends of the hole-forming column pass through the pressing block respectively, and the pressing semicircular plate is slidably installed on the pressing block. The end face of the hole-forming column is provided with a pressing guide surface that cooperates with the pressing semicircular plate. The pressing semicircular plate pushes the hole-forming column to abut against the forming block.

[0026] By adopting the above technical solution, the molten core is formed in half, which will not affect the quality of the injection molded parts, but facilitates the production of the molten core. When the molten core is formed, the inner wall of the molten core is formed by the forming block, and the outer wall of the molten core is formed by the lower pressing block, and the cooling hole is formed by the porous column. During molding, the porous column is pushed to protrude and abut against the molding block by pressing the semicircular plate. Then, after the molten core is formed, when it needs to be demoulded, the porous column is reset under the action of the reset spring, so that the porous column will not affect the upward movement of the lower pressing block, and will not affect the demoulding of the molten core. The molten core can be molded in one time.

[0027] Optionally, the forming block is provided with a socket for inserting the hole-forming column, a reset column is slidably installed in the socket, and a reset rotating column is also rotatably installed in the forming block. Half of the reset rotating column around the rotation center line is a cylindrical surface, and the other half gradually increases in distance from the rotation center line around the rotation direction. The reset rotating column rotates and drives the reset column to slide in the socket.

[0028] By adopting the above technical solution, the hole-forming column is inserted into the socket of the forming block, so that the cooling hole of the molten core is more completely formed and is not easily closed. Then, the reset column is pushed by the reset rotating column, so that when there is a jam between the hole-forming column and the molten core, demoulding can be better completed, the demoulding effect is better, and the elastic force requirement of the reset spring is reduced. The reset structure and the stable forming structure are combined together to simplify the equipment.

[0029] Optionally, step S1 includes the following steps:

[0030] S1.1, forming each high-temperature surface sheet;

[0031] S1.2. Each high-temperature surface sheet is attached to the surface of each module of the core forming mold to form a cavity. Multiple high-temperature surface sheets form a high-temperature shell. Molten tin is injected into the high-temperature shell to form a complete core.

[0032] Step S4 includes the steps of:

[0033] S4.1, the tin core portion of the molten core;

[0034] S4.2. Remove the detached high-temperature surface film.

[0035] By adopting the above technical solution, a high-temperature mold shell is set on the outer wall of the molten core, so that the molten core and the injection molded part are not in direct contact, so that even if the molten core is deformed and melted at the high temperature during the molding of the injection molded part, it will not affect the molding of the injection molded part. The molten core is mainly used to support the high-temperature mold shell, so that the high-temperature mold shell can remain stable to mold the interior of the injection molded part, and then it is not easy to affect the injection molded part when the molten core is melted and removed. The high-temperature mold shell is assembled from multiple high-temperature surface mold pieces, so that the high-temperature mold shell can be removed more conveniently later, and the strip shape is easy to adjust the angle and easy to deform.

[0036] In summary, by making a fusible core, during injection molding, a cavity inside the injection molded part is formed by the fusible core, and then the fusible core is melted by hot melting to finally obtain the corresponding injection molded part, so that the injection molded part with a complex internal cavity shape that is not conducive to core pulling can be injection molded. The fusible core and the injection molded part are demoulded together, which is convenient for demoulding. By processing a cooling channel inside the fusible core and flowing coolant, the fusible core is not easy to melt on the surface before the injection molded part is molded, so that the fusible core is not easy to affect the surface smoothness of the inner wall of the injection molded part due to melting, and the coolant can also accelerate the injection molding. The molding of parts can be improved, and the production efficiency of injection molded parts can be improved. At the same time, a high-temperature shell is set on the outer wall of the molten core, so that the molten core and the injection molded part are not in direct contact. Even if the molten core is deformed and melted at the high temperature during the molding of the injection molded part, it will not affect the molding of the injection molded part. The molten core is mainly used to support the high-temperature shell, so that the high-temperature shell can remain stable to mold the interior of the injection molded part, and then it is not easy to affect the injection molded part when the molten core is melted and removed. The high-temperature shell is assembled from multiple high-temperature surface sheets, so that the high-temperature shell can be removed more conveniently later. The strip is easy to adjust the angle and easy to deform. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the structure of the injection molded part in the embodiment of this application Figure 1 ;

[0038] Figure 2 This is a schematic diagram of the structure of the injection molded part in the embodiment of this application Figure 2 ;

[0039] Figure 3is a cross-sectional view of a fusible core in an embodiment of the present application;

[0040] Figure 4 is a cross-sectional view of a molten core forming device in an embodiment of the present application;

[0041] Figure 5 is another cross-sectional view of the molten core forming device in an embodiment of the present application;

[0042] Figure 6 Schematic diagram of the first core pulling block and the second core pulling block in an embodiment of the present application.

[0043] Explanation of reference numerals: 1, tubular body; 11, first bent end; 12, middle portion; 13, second straight end; 14, first core-pulling channel; 15, bent channel; 16, second core-pulling channel; 2, high-temperature shell; 21, high-temperature surface sheet; 3, molten core; 31, cooling channel; 32, cooling hole; 4, molten core forming device; 41, forming block; 411, jack; 42, pressing block; 421, sliding column hole; 43, hole-forming column; 431, reset ring; 432, pressing guide surface; 4 4. Press down semicircular plate; 45. Return spring; 46. Return column; 47. Return rotary column; 471. Injection surface; 472. Push surface; 51. First core-pulling block; 52. Second core-pulling block; 521. Coolant inlet; 522. Coolant outlet; 53. Coolant outlet pipe; 54. Coolant inlet pipe; 6. Filter ball; 61. Upper hemisphere; 62. Lower hemisphere; 63. Filter screen assembly; 7. Coolant tank; 8. Valve; 91. Hydraulic detection assembly; 92. Receiver; 93. Electric control valve. DETAILED DESCRIPTION

[0044] The following is combined with Figure 1-6 This application is described in further detail.

[0045] The present application discloses an injection molded part. The injection molded part includes a tubular body 1, the tubular body 1 including a first bent end 11, a middle portion 12, and a second straight end 13. A connecting channel is defined within the tubular body 1, extending through both ends. The connecting channel includes a first core-pulling channel 14 located at the first bent end 11, a bent channel 15 located at the middle portion 12, and a second core-pulling channel 16 located at the second straight end 13. The sides of the first core-pulling channel 14 are connected to the bent channel 15, and the top arc of the second core-pulling channel 16 is connected to the bent channel 15. The inner walls of the connecting channels are all connected by arcs, and the bent channel 15 is flat.

[0046] The embodiments of the present application also disclose an injection molding process.

[0047] An injection molding process includes the following steps:

[0048] S1, melt the tin block to make the molten core 3;

[0049] S1.1, forming each high-temperature surface layer sheet 21, which can be formed by a mold;

[0050] S1.2. Each high-temperature surface sheet 21 is attached to the surface of each module of the mold cavity of the molten core 3. The multiple high-temperature surface sheets 21 form a high-temperature shell 2. Molten tin is injected into the high-temperature shell 2 to form a complete molten core 3.

[0051] Specifically, the mold for forming the molten core 3 can be divided into multiple movable molds, each movable mold fixes a high-temperature surface sheet 21 on the surface of the forming cavity, and then the high-temperature surface sheet 21 is driven by the movable mold to form a high-temperature shell 2, and finally molten tin is injected to complete the molding of the entire molten core 3; the high-temperature surface sheet 21 can be fixed to the movable mold by gluing and fall off after heating, or it can be fixed to the movable mold by negative pressure adsorption. Of course, other feasible fixing methods that do not affect the surface state of the high-temperature shell 2 can also be used.

[0052] The edges of the high temperature surface sheets 21 are tilted so that the high temperature surface sheets 21 are mainly supported by the molten core 3. When the molten core 3 melts, the high temperature surface sheets 21 can be easily removed.

[0053] Then, a through cooling channel 31 is processed inside the molten core 3. During processing, the cooling channel 31 can be formed by removing part of the inside of the molten core 3 by drilling or grinding, or by melting a cooling channel 31 by hot melting and punching.

[0054] Among them, the high-temperature surface sheet 21 can also be directly glued and fixed on the surface of the molten core 3, or inserted on the surface of the molten core 3. At this time, the high-temperature surface sheet 21 and the molten core 3 are produced separately and then assembled. At this time, the molten core 3 can be formed into a cavity using the above-mentioned molding, or the molten core 3 can be divided into two halves and then assembled into a whole molten core 3. The splicing form can be edge hot-melt welding or assembly fixation. When the molten core 3 is produced and molded, the size of the molten core 3 is molded in a form smaller than the size of the bending channel 15. Finally, after the high-temperature shell 2 is installed, the size is adapted to the internal cavity of the injection molded part.

[0055] Obviously, the above two production methods are also applicable when no cooling channel 31 is provided in the molten core 3 .

[0056] In order to accelerate cooling, the surface of the molten core 3 is wrapped with a layer of flexible material. A large number of cooling holes 32 are arranged in an array on the surface of the molten core 3. The cooling holes 32 are connected to the cooling channel 31 inside the molten core 3. The high-temperature shell 2 is wrapped outside the flexible material layer. At this time, the high-temperature surface sheet 21 and the flexible material layer are fixed by gluing.

[0057] The cooling hole 32 can be opened in the molten core 3 by punching or by integral molding. When integral molding is adopted, the molten core 3 needs to be molded in half, and the molten core 3 is molded by the molten core molding device 4. The molten core molding device 4 includes a molding block 41, a lower pressing block 42, a hole-forming column 43 and a lower pressing semicircular plate 44. The side wall of the molding block 41 facing the lower pressing block 42 is adapted to the inner wall of the molten core 3. The lower pressing block 42 is located above the molding block 41. The side wall of the lower pressing block 42 facing the molding block 41 is adapted to the outer wall of the molten core 3. The molding block 41 is installed on the fixed film plate, and the lower pressing block 42 is installed on the movable template, wherein the molding block 41 can be embedded in the lower pressing block 42 to form a complete cavity, or the two end openings of the space formed between the molding block 41 and the lower pressing block 42 can be closed by the movable template.

[0058] The side wall of the lower pressing block 42 facing away from the forming block 41 is also a cylindrical surface. The lower pressing block 42 is provided with an array of sliding column holes 421 extending through the radial and axial directions of the cross section. A hole-forming column 43 is slidingly installed in each sliding column hole 421. A reset ring 431 is provided in the middle of the hole-forming column 43. The sliding column hole 421 is a stepped hole, and the opening diameter of the end of the sliding column hole 421 away from the forming block 41 is larger. A reset spring 45 is clamped between the reset ring 431 and the stepped surface of the sliding column hole 421. When the hole-forming column 43 is not squeezed by an external force but squeezes the reset spring 45, the end of the hole-forming column 43 facing the forming block 41 is located inside the sliding column hole 421, and the other end of the hole-forming column 43 is located outside the lower pressing block 42.

[0059] When the injection molded part uses a complete columnar part with only the end cavity bent, which makes it difficult to remove the core, the pressing semicircular plate 44 can be slidably installed on the pressing block 42, and the end face of the hole-forming column 43 is inclinedly provided with a pressing guide surface 432 that cooperates with the pressing semicircular plate 44. The pressing semicircular plate 44 pushes the hole-forming column 43 to squeeze the reset spring 45 and protrude the sliding column hole 421 to move toward the molding block 41. At this time, a matching sliding groove and slider are provided between the outer wall of the hole-forming column 43 and the hole wall of the sliding column hole 421, thereby limiting the rotation of the hole-forming column 43.

[0060] When the injection molded part uses a curved part instead of a complete columnar part in the molten core 3, the above-mentioned pressing semicircular plate 44 can also be directly installed on the movable mold, and then a driving part is provided to drive the pressing semicircular plate 44 to move toward the pressing block 42, thereby further squeezing the hole column 43 out of the pressing block 42. Alternatively, the pressing semicircular plate 44 can be fixed to the movable mold, and the pressing block 42 can be slidably installed on the movable mold along the direction of movement. When the pressing block 42 moves to the corresponding position, the movable mold continues to press down, thereby pushing the hole column 43 to continue to press down.

[0061] When the injection molded part uses a molten core 3 that is a complete columnar part but the end cavity is bent, making it difficult to remove the core, a socket 411 is provided on the outer wall of the molding block 41 for inserting the hole-forming column 43, and a reset column 46 is slidably installed in the socket 411. The interior of the molding block 41 is hollow and a reset rotating column 47 is also rotatably installed. Half of the reset rotating column 47 around the rotation center line is a cylindrical surface set as an injection surface 471, and the other half is set as a pushing surface 472 with a gradually increasing distance from the rotation center line in the rotation direction. When the reset column 46 abuts the injection surface 471, one end of the reset column 46 is located in the socket 411. When the reset rotating column 47 rotates, it drives the reset column 46 to slide in the socket 411, and one end of the reset rotating column 47 rotates through the side wall of the molding block 41 to be connected to a driving member that drives the rotation.

[0062] When the molten core 3 of the injection molded part is not a complete columnar part but a bent part, the reset rotating column 47 pushes the reset column 46 to move outward by moving upward.

[0063] The above-mentioned flexible material layer can be made of a low-melting-point material with a melting point lower than that of the molten core 3. Before the molten core 3 is installed in the injection molding machine, the flexible material layer can be melted and removed first. Then, during injection molding, coolant can be injected into the cooling channel 31, and coolant is also filled between the high-temperature mold shell 2 and the molten core 3. At this time, the open end of the molten core 3 is glued and fixed to the high-temperature mold shell 2, and the flexible material layer is only arranged in the area outside the end of the molten core 3. The flexible material layer does not need to be melted and removed in advance. When injection molding is performed, the flexible material layer can melt by itself in the area where the temperature of the injection molded part is higher, especially the area of ​​the injection port. The melted flexible material layer enters the coolant, and the corresponding area can directly contact the coolant to better transfer the temperature and reduce the impact on the molten core 3. When using this method, the coolant delivery equipment needs to be equipped with a corresponding filtering device to filter the coolant and filter out the corresponding flexible material layer residue, but in most cases, the flexible material layer will not be directly melted.

[0064] Depending on the situation of the injection molded part, the molten core 3 can be used in a variety of ways. For example, a high-temperature shell 2 is not set outside the flexible material layer, but a layer of high-temperature resistant material layer is wrapped. It is mainly suitable for the situation where the internal cavity of the injection molded part is flat, the entire cavity is connected in a circular arc, or even the cross-section of each position is the same, but the central axis is bent, which makes it inconvenient to remove the core. It is best if the cross-section is arc-shaped, and the high-temperature resistant material layer can also be a metal sheet that is wrapped and polished to complete the coating, or it can be coated with molten metal to form a surface layer and then polished to form. At this time, it is also necessary to inject coolant to ensure that the flexible material layer is not easy to melt. Then, when demolding subsequently, cutting or deformation extrusion is adopted because it is thin and easy to deform; or a layer of flexible polymer heat-resistant coating is coated on the outside of the flexible material layer. This method is suitable for the situation where the internal cavity of the injection molded part is uneven. At this time, cooling holes 32 are no longer opened, so that the flexible material layer is not easy to bulge outward during production.

[0065] The above-mentioned high-temperature resistant material layer and flexible polymer heat-resistant coating can also be directly arranged on the surface of the molten core 3 without setting a flexible material layer. When the high-temperature resistant material layer is coated with molten metal, the molten core 3 no longer has a cooling hole 32, but the size of the cooling channel 31 should be larger to reduce the wall thickness of the molten core 3 and better transfer the temperature.

[0066] Finally, a thin high-temperature shell 2 can also be directly formed. The high-temperature shell 2 can also be produced by using a molten core 3, or it can be fixed in half. Then, during injection molding, coolant is injected into the high-temperature shell 2 to maintain the pressure inside the high-temperature shell 2 through the coolant, thereby maintaining the shape of the high-temperature shell 2. During injection molding, deformation will not affect the molding, and the deformed high-temperature shell 2 can be subsequently demolded by cutting or extruding.

[0067] S2, placing the molten core 3 in the injection molding machine;

[0068] The injection molding machine is provided with a first core pulling block 51 and a second core pulling block 52. The first core pulling block 51 forms the first core pulling channel 14, and the second core pulling block 52 forms the second core pulling channel 16. The first core pulling block 51 and the molten core 3 are slidably matched through a slider and a slide groove, and the second core pulling block 52 is plugged into the molten core 3, wherein the second core pulling block 52 is partially inserted into the cooling channel 31, and the end surface of the second core pulling block 52 located in the cooling channel 31 is provided with a coolant inlet 521 and a coolant outlet 522. At the same time, the second core pulling block 52 is rotatably installed so that the second core pulling block 52 can be flipped upward for rotational demoulding and cooling. The liquid inlet 521 and the coolant outlet 522 are arranged up and down, the coolant inlet 521 protrudes from the surface of the second core pulling block 52 and is located at the bottom, and the coolant outlet 522 is recessed and located above the coolant inlet 521, adapting to the trend of the coolant flowing upward at high temperature. At the same time, the end of the molten core 3 connected to the first core pulling block 51 is tilted downward at a certain angle, so that the second core pulling block 52 is located at a higher position, so that the air in the cooling channel 31 can be discharged as much as possible. At the same time, when the cooling water is recovered, the second core pulling block 52 is synchronously flipped upward, cooperating with the recessed coolant outlet 522, to better complete the discharge of the cooling water.

[0069] The cooling water recovery process can be completed by injecting air, and the cooling water recovery can also be completed by extracting the cooling water. The second core-pulling block 52 is provided with a coolant outlet pipe 53 and a coolant inlet pipe 54. A filter ball 6 is provided on the coolant outlet pipe 53 and the coolant outlet pipe 53 is divided into two sections. The filter ball 6 is divided into an upper hemisphere 61 and a lower hemisphere 62 that are assembled and fixed. A filter mesh assembly 63 is provided at the opening of the upper hemisphere 61. The part of the coolant outlet pipe 53 that is connected to the second core-pulling block 52 is fixed to the upper hemisphere 61 and passes through the filter mesh assembly 63. The other part of the coolant outlet pipe 53 is connected and fixed to the upper hemisphere 61. When it is necessary to remove the filtered material, after completing the coolant extraction or discharge, the lower hemisphere 62 can be removed for cleaning.

[0070] A hydraulic detection component 91 is set on the coolant outlet pipe 53. When the fusible core 3 form that requires control of the cooling hydraulic pressure is adopted, the coolant is pumped in through the coolant inlet 521. The coolant inlet 521 is connected to the coolant inlet pipe 54 and is provided with a receiver 92 and an electric control valve 93. The water pressure is controlled by controlling the opening and closing degree of the electric control valve 93.

[0071] The coolant inlet pipe 54 is divided into two branches and a valve 8 is provided separately, which are connected to the air and the coolant tank 7 storing the coolant respectively. According to the demand, it is selected whether to draw air or coolant into (inject) the coolant channel.

[0072] S3, injection molding the injection molded part, at this time the injection molded part wraps the fusible core 3 and is removed together;

[0073] Among them, the coolant can be selected at different temperatures according to the properties of the injection molded part material, or the coolant temperature can be controlled to continuously decrease to complete a better cooling and molding process.

[0074] S4, melting the molten core 3 in the injection molded part to obtain the final injection molded part;

[0075] S4.1, melting the tin core portion of the molten core 3;

[0076] S4.2. Remove the detached high-temperature surface sheet 21. Depending on the cavity conditions inside the injection molded part and the number and shape of the high-temperature surface sheet 21, the sheet can be directly removed after deformation, or the high-temperature surface sheet 21 can be removed without deformation by adjusting the angle, so that it can be reused.

[0077] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. An injection molding process, characterized in that, The injection molding process is used to form an injection molded part, and the injection molded part includes a tubular body (1), the tubular body (1) includes a first bent end (11), a middle part (12) and a second straight-connected end (13), and a connecting channel running through both ends is opened inside the tubular body (1), the connecting channel includes a first core-pulling channel (14) located at the first bent end (11), a bending channel (15) located at the middle part (12), and a second core-pulling channel (16) located at the second straight-connected end (13), the side of the first core-pulling channel (14) is connected to the bending channel (15), the top arc of the second core-pulling channel (16) is connected to the bending channel (15), the inner walls of the connecting channels are all connected by arcs, and the bending channel (15) is flat; The steps include: S1, melt the tin block to make a molten core (3); S2, placing the molten core (3) in the injection molding machine; S3, injection molding the injection molded part, at this time the injection molded part wraps the molten core (3) and is removed together; S4, melting the molten core (3) in the injection molded part to obtain the final injection molded part; In step S1, a cooling channel (31) is provided inside the molten core (3). During injection molding, a coolant circulates back and forth inside the molten core (3). A large number of cooling holes (32) are arranged in an array on the surface of the molten core (3). The cooling holes (32) are connected to the cooling channel (31) inside the molten core (3). The molten core (3) is formed in two halves and then assembled into a whole molten core (3). The molten core (3) is formed in two halves and then formed by a molten core forming device (4). The molten core forming device (4) includes a forming block (41), a lower pressing block (42), a hole forming column (43) and a lower pressing semicircular plate (44). The forming block (41) is adapted to the inner wall of the molten core (3), the lower pressing block (42) is adapted to the outer wall of the molten core (3), the hole forming column (43) is slidably installed in the lower pressing block (42) and is provided with a return spring (45). The two ends of the column (43) respectively pass through the lower pressing block (42), the lower pressing semicircular plate (44) is slidably installed on the lower pressing block (42), and the end face of the hole-forming column (43) is provided with a lower pressing guide surface (432) cooperating with the lower pressing semicircular plate (44), and the lower pressing semicircular plate (44) pushes the hole-forming column (43) to abut against the forming block (41); the forming block (41) is provided with a socket (411) for inserting the hole-forming column (43), and a reset column (46) is slidably installed in the socket (411), and a reset rotating column (47) is also rotatably installed in the forming block (41), half of the reset rotating column (47) around the rotation center line is a cylindrical surface, and the other half is gradually increased in distance from the rotation center line around the rotation direction, and the reset rotating column (47) rotates and drives the reset column (46) to slide in the socket (411).

2. An injection molding process according to claim 1, characterized in that: When the molten core (3) is formed in step S1, the size of the molten core (3) is formed in a form smaller than the size of the bending channel (15), and then a layer of flexible polymer heat-resistant coating is coated on the surface of the molten core (3) to finally reach the size of the bending channel (15).

3. An injection molding process according to claim 2, characterized in that: The size of the fusible core (3) is smaller than the size of the bending channel (15), and the surface of the fusible core (3) is wrapped with a layer of flexible material.

4. An injection molding process according to claim 3, characterized in that: The flexible material layer is wrapped with a high-temperature resistant material layer, the melting point of the high-temperature resistant material layer is greater than the melting point of the injection molded part, and the melting point of the flexible material layer is lower than the melting point of the molten core (3).

5. The injection molding process according to claim 2, characterized in that: In step S2, a first core pulling block (51) and a second core pulling block (52) are provided in the injection molding machine, the first core pulling block (51) forms a first core pulling channel (14), the second core pulling block (52) forms a second core pulling channel (16), the first core pulling block (51) and the molten core (3) are slidably matched through a slider and a slide groove, the second core pulling block (52) and the molten core (3) are plugged into each other, the second core pulling block (52) is partially inserted into the cooling channel (31), the end face of the second core pulling block (52) located in the cooling channel (31) is provided with a coolant inlet (521) and a coolant outlet (522), and at the same time, the second core pulling block (52) is rotatably installed.

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