A small thermoplastic composite propeller forming die and method

Abstract

The application discloses a small thermoplastic composite propeller forming die, which comprises a front die assembly, a rear die assembly, a main runner and a slide assembly; the front die assembly comprises a front die base plate, a stripping plate, a front die frame and a front die core; the rear end surface of the front die core is provided with a boss metal part positioning boss, a local blade back forming surface and a blade back forming slide avoidance position; one blade back forming slide avoidance position is arranged on the side surface of each local blade back forming surface for accommodating the slide; the slide surface and the local blade back forming surface jointly form a complete blade back forming surface; the rear die assembly comprises a rear die core, a rear die frame, a stripping plate and a rear die base plate; the front end surface of the rear die core is provided with a blade surface forming surface; in the closed die state, the slide surface, the local blade back forming surface and the blade surface forming surface jointly form a blade forming sealing cavity; the application is suitable for the injection molding process of thermoplastic composite materials, greatly improves the die turnover efficiency and the equipment utilization rate, and directly gives the propeller better type value precision in the forming process.

Description

Technical Field

[0001] This invention relates to the field of propeller molding technology, and in particular to a small thermoplastic composite material propeller molding die and method. Background Technology

[0002] Currently, the demand for small composite material propellers with a diameter of less than 400mm is continuously growing in various ships and underwater vehicles. The performance of the matching molds directly determines the manufacturing efficiency, cost, and product reliability of the propellers. Existing small composite material propellers mostly use thermosetting resin / carbon fiber (or glass fiber) materials. Their matching molds need to be adapted to the molding process of manual / semi-automatic raw material laying and long-term thermosetting, which has multiple limitations. The mold utilization rate is low. If the laying process requires several hours to several days, the mold is in a standby state for a long time. The mold turnover efficiency is insufficient. The subsequent thermosetting process requires several hours or more. The turnover cycle of a single mold is long, the production capacity is limited, and the poor shape value of the molded composite material propellers has limited their application in actual ships. Summary of the Invention

[0003] To address the issues of low mold utilization and poor shape accuracy in small composite material propellers with a diameter of 400mm or less, the main objective of this invention is to propose a molding die and method for small thermoplastic composite propellers. This die structure is adapted to the injection molding process of thermoplastic composite materials. Through optimization of the cavity structure, the molding cycle for a single propeller can be ≤8 minutes, significantly improving die turnover efficiency and equipment utilization. Simultaneously, the die adopts a modular and positioning structure design, directly imparting better shape accuracy to the propeller during the molding process, and reducing die maintenance costs. In mass production, the high-efficiency production capacity of this die significantly enhances the cost and delivery advantages on the production side.

[0004] The technical solution adopted in this invention is: A small thermoplastic composite propeller molding die includes a front die assembly, a rear die assembly, and a main runner. The die also includes several sets of sliding components disposed between the front and rear die assemblies, the number of which corresponds to the number of propeller blades. Each sliding component includes a sliding member and a sliding cylinder, with the sliding member mounted on the power output end of the sliding cylinder. The front die assembly includes a front die base plate, a stripper plate, a front die frame, and a front die core, arranged sequentially along the material injection direction. The front die base plate is fixedly connected to the stripper plate, and the main runner passes through the front die base plate and the stripper plate. The rear end face of the front die frame has a front die core mounting groove, and the front end face has a branch channel connecting the main runner and the front die core mounting groove. The front die core is installed in the front die core mounting groove, and the rear end face of the front die core has a propeller hub metal part positioning boss, a partial blade back forming surface, and a blade back forming sliding clearance. Several partial blade... The back forming surface is arranged around the positioning boss of the propeller hub metal part. Each partial blade back forming surface has a blade back forming slide clearance on its side to accommodate the slide. The slide surface and the partial blade back forming surface together form a complete blade back forming surface. An axially penetrating injection gate is provided between each partial blade back forming surface and the positioning boss of the propeller hub metal part. The rear mold assembly includes a rear mold core, a rear mold frame, a stripper plate and a rear mold frame base plate arranged sequentially along the material injection direction. The front end face of the rear mold core has a blade forming surface. In the mold closed state, the slide surface, the partial blade back forming surface and the blade forming surface together form a blade forming sealed cavity. The front end face of the rear mold frame has a rear mold core mounting groove, a slide rail and a slide cylinder fixing groove. The rear mold core is installed as a whole in the rear mold core mounting groove, the slide is installed on the slide rail, and the slide cylinder is installed in the slide cylinder fixing groove. The slide is driven to reciprocate on the slide rail by the extension and retraction of the slide cylinder push rod.

[0005] In the above scheme, the stripper plate is slidably installed on the partition plate on both sides. The front end face of the partition plate is fixedly connected to the rear mold frame, and the rear end face is fixedly connected to the bottom plate of the rear mold frame. An ejector pin mechanism is provided inside the stripper plate. During the demolding process, the rear mold frame, the partition plate and the bottom plate of the rear mold frame move backward as a whole. The stripper plate moves forward relative to the rear mold frame, which drives the ejector pin mechanism to push the propeller out of the cavity for demolding.

[0006] In the above scheme, the front end face of the front mold base plate is connected to the fixed platen of the injection molding machine, and the rear end face of the rear mold base plate is connected to the moving platen of the injection molding machine. The opening and closing process is realized by the reciprocating motion of the rear mold base plate driven by the moving platen of the injection molding machine.

[0007] In the above scheme, the mold also includes a pull plate disposed on the side. The pull plate has a sliding groove at the front end and a mounting hole at the rear end. The mounting hole at the rear end of the pull plate is connected to the rear mold frame through a fixing member, and the sliding groove at the front end of the pull plate is connected to the front mold frame through a connecting member. During the mold opening process, the rear mold frame moves backward, which drives the pull plate to move backward until the front end of the sliding groove abuts against the connecting member, thereby pulling the front mold frame to move backward and separating the front mold frame from the stripper plate.

[0008] In the above scheme, a heating pipeline is provided inside the row position, and the heating pipeline is connected to the oil pipeline of an external heating device through an oil pipe interface.

[0009] In the above scheme, the mold also includes positioning guide pillars, the front mold base plate is provided with guide pillar mounting holes, the stripper plate is provided with a first guide hole, the front mold frame is provided with a second guide hole, the rear mold frame is provided with a third guide hole, the front end of the positioning guide pillar is installed in the guide pillar mounting hole, and the rear end of the positioning guide pillar passes through the first guide hole, the second guide hole and the third guide hole in sequence.

[0010] In the above scheme, the rear end face of the front mold frame is also provided with a sliding clearance groove and a sliding cylinder clearance groove.

[0011] In the above scheme, the front end face of the rear mold core is also equipped with a positioning pin for the propeller hub metal part, which is adapted to the positioning hole on the propeller hub metal part.

[0012] In the above scheme, the number of flow channels corresponds to the number of propeller blades, and the injection port is located at the end face of the propeller.

[0013] This invention also proposes a method for molding small thermoplastic composite propellers, which uses the aforementioned mold and includes the following steps: S1. Load the mold into the injection molding machine, align and fix the injection molding machine gate with the main runner; S2. Connect the oil pipeline of the heating device to the heating oil pipeline of the sliding position; S3. Install the propeller hub metal part into the locating pin position inside the rear mold core. S4. Clean the mold cavity area of ​​the front mold core, rear mold core, and slide; S5. Add thermoplastic composite material raw materials into the injection molding machine, turn on the injection molding machine heating system and external heating device, and heat the raw materials and the mold to the set temperature respectively; S6. Activate the injection molding machine's mold closing mechanism, push the rear mold base plate forward as a whole, close the front and rear mold bases, activate the slide cylinder to extend and push the slide into the clearance space of the front mold core's blade back forming slide, and complete the mold closing; S7. Set the injection parameters, including screw speed 120-170rpm, injection pressure 170-210MPa, and injection speed 130-170mm / s. The molten viscous raw material enters the main runner of the mold from the injection machine gate, then to the sub-runner, and finally fills the entire cavity area of ​​the mold through the injection gate. S8, Input holding pressure 8-20MPa, cooling time 160-240s; S9. After the pressure holding and cooling are completed, open the injection molding machine's mold opening mechanism, start the slide cylinder to retract and pull out the slide. The rear mold base plate moves backward with the injection molding machine's mold opening mechanism, the mold opens, and the rear mold base moves backward. The stripper plate remains in its original position due to the limitation of the injection molding machine's limit pins. The ejector pins push out the product, completing the demolding. After the pull plate moves to a certain position after the rear mold base, it drives the front mold base to move backward, pulling the front mold base and stripper plate apart, and removing the waste material in the main runner and branch runner. S10. Remove the product and cool it to room temperature. Then demold and trim the edges to obtain a small thermoplastic composite propeller.

[0014] The beneficial effects of this invention are: 1. The mold of this invention forms a complete blade forming sealed cavity by cooperating with the front and rear mold cores through the circumferentially arranged sliding components, which makes it easy to demold complex propellers and can achieve a single propeller forming cycle of ≤8min, greatly improving the mold turnover efficiency and equipment utilization rate. At the same time, the propeller hub metal parts are set in the mold for positioning, which can realize the injection molding of multi-bladed ultra-complex small composite material propellers without secondary assembly of blades and hub. The overall structure of the propeller is stable and meets the market's demand for rapid mass supply and low cost.

[0015] 2. The mold of this invention adopts injection molding technology, which can accurately form the complex curved surface of small propeller blades, solving the problem of low blade forming accuracy in traditional molds. The front mold core and the rear mold core are respectively provided with a positioning boss and a positioning pin for the propeller hub metal part. The slide and the clearance position of the front mold core are also positioned by surface contact. This makes the cavity accuracy higher when the mold is closed, and the manufactured product has higher precision.

[0016] 3. The parting line of each blade is designed on the back of the blade, which will not cause interference for multiple blades with undercuts. It can realize the forming and demolding of blades with various complex curved surfaces, and solve the key technical difficulties of mold opening and closing due to undercut blades.

[0017] 4. When opening the mold, the slide cylinder is used to pull out the slide position first, and then the ejector mechanism pushes out the product. With the help of the pull plate, the front mold components are opened in stages to avoid the blade forming surface from sticking to the mold and reduce the product demolding deformation rate.

[0018] 5. The mold side is equipped with a pull plate structure. The pull plate is driven by the rear mold frame to separate the front mold frame from the stripper plate, so as to discharge the waste material in the gate and improve production efficiency.

[0019] 6. Heating the mold cavity through the sliding heating pipes makes the raw materials flow more smoothly in the cavity and improves injection efficiency.

[0020] 7. The sub-gating gate design, which matches the number of blades, ensures the density of the filling for each blade, achieving high-quality casting.

[0021] 8. The use of multiple runners and multiple gates for simultaneous mold filling shortens the injection molding time; automated driving of slides and automated step-by-step mold opening improve the overall production efficiency of the mold. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of the mold of the present invention; Figure 2 This is a schematic diagram of the main channel structure of the mold of the present invention; Figure 3 This is a schematic diagram of the structure of the front mold base plate of the mold of the present invention; Figure 4 This is a schematic diagram of the stripping plate of the mold of the present invention; Figure 5 This is a schematic diagram of the front mold frame of the mold of the present invention; Figure 6 This is a schematic diagram of the structure of the front mold core of the mold of the present invention; Figure 7 This is a schematic diagram of the structure of the rear mold core of the mold of the present invention; Figure 8 This is a schematic diagram of the slide assembly of the mold of the present invention; Figure 9 This is a schematic diagram showing the position of the slide relative to the front mold core when the mold cavity is closed, controlled by the slide cylinder of the mold of the present invention. Figure 10 This is a schematic diagram showing the position of the slide and the rear mold core when the mold cavity is closed, controlled by the slide cylinder of the mold of the present invention. Figure 11 This is a schematic diagram of the structure of the rear mold frame of the mold of the present invention; Figure 12This is a schematic diagram of the structure of the pull plate of the mold of the present invention; Figure 13 This is a schematic diagram showing the position of the pull plate of the mold in the mold-closed state. Figure 14 This is a schematic diagram showing the position of the pull plate of the mold in the mold-opening state. Figure 15 This is a schematic diagram of the propeller product structure formed by the mold of the present invention.

[0024] In the diagram: 11. Front mold base plate; 111. Guide pillar mounting hole; 112. First main runner positioning groove; 113. First threaded hole; 12. Stripper plate; 121. Second main runner positioning groove; 122. First guide hole; 13. Front mold base; 131. Runner; 132. Front mold core mounting groove; 133. Slide clearance groove; 134. Slide cylinder clearance groove; 135. Second guide hole; 136. Pull plate mounting hole; 14. Front mold core; 141. Propeller hub metal part positioning boss; 142. Partial blade back forming surface; 143. Blade back forming slide clearance; 144. Gating gate; 21. Rear mold core; 211. Propeller hub metal part positioning pin; 212. Blade forming surface; 213. Blade forming slide clearance; 22. Rear mold base; 221. Rear mold core mounting slot; 222. Slide rail; 223. Slide cylinder fixing slot; 224. Third guide hole; 225. Pull plate fixing hole; 23. Stripper plate; 24. Partition plate; 25. Rear mold base plate; 30. Main channel; 31. Main channel hole; 32. Second threaded hole; 40. Sliding assembly; 41. Sliding mechanism; 42. Sliding cylinder; 43. Heating piping; 50. Positioning guide post; 60. Pull plate; 61. Slide groove; 62. Mounting hole; 200. Small composite material propeller; 201. Propeller hub metal parts; 202. Thermoplastic composite material; 203. Positioning hole. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] It should be noted that the illustrations provided in the embodiments of the present invention are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0027] In this invention, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0028] Furthermore, it should be noted that the features of the various embodiments of the present invention can be combined or integrated in whole or in part, and as those skilled in the art will understand, they can interact and operate in different ways. Each embodiment can be implemented independently of each other or in association with one another.

[0029] like Figure 1 As shown, this invention proposes a small thermoplastic composite propeller molding die. This die is an injection molding die, mainly used for molding small composite propellers 200 with a diameter within 400mm. The small composite propeller 200 to be manufactured includes metal parts and composite material parts. The metal parts are the inner ring portion of the propeller hub, i.e. Figure 15 The rotor hub metal component 201 shown is a composite material component, which is an integral structure including the outer ring of the rotor hub and all the blades, i.e. Figure 15 The thermoplastic composite material 202 is shown. The mold includes a front mold assembly, a rear mold assembly, a main runner 30, a sliding assembly 40, positioning guide pillars 50, and a pull plate 60. The front mold assembly and the rear mold assembly achieve precise mold closing through the positioning guide pillars 50. The sliding assembly 40 is arranged circumferentially between the front and rear mold assemblies. The number of sliding assemblies 40 is consistent with the number of propeller blades and is used to form the complex curved surface of the propeller blades. The main runner 30 is installed in the front mold assembly to realize the injection of thermoplastic composite material. The pull plate 60 assists in realizing the step-by-step mold opening of the front mold assembly, which facilitates the removal of waste material.

[0030] like Figure 1 As shown, the front mold assembly includes a front mold base plate 11, a stripper plate 12, a front mold base 13, and a front mold core 14 arranged sequentially along the material injection direction. The front mold base plate 11 serves as the base mounting plate for the front mold assembly; its front end is bolted to the injection molding machine's fixed mold plate, and its rear end is bolted to the stripper plate 12, forming an integral structure. Figure 3 As shown, the front mold base plate 11 has a first main channel positioning groove 112 in the middle, and first threaded holes 113 on both sides of the first main channel positioning groove 112. Four guide post mounting holes 111 are provided on the edge of the front mold base plate 11. Figure 4 As shown, the stripper plate 12 has a second main channel positioning groove 121 in the middle, and four first guide holes 122 are provided on the edge of the stripper plate 12. Figure 2 As shown, a main channel 30 has a main channel hole 31 in the middle for injecting thermoplastic composite material; second threaded holes 32 are provided on both sides of the main channel hole 31 for fixing the main channel 30. The main channel 30 is installed in the first main channel positioning groove 112 and the second main channel positioning groove 121, and is fixed by bolts connecting the first threaded hole 113 and the second threaded hole 32.

[0031] like Figure 5 As shown, the front end face of the front mold frame 13 is fitted with the stripper plate 12, and the rear end face has a front mold core mounting groove 132 (for mounting the front mold core 14), a sliding clearance groove 133, and a sliding cylinder clearance groove 134. The front end face also has a flow distribution channel 131 (the number is the same as the number of propeller blades, which is 7 in this embodiment). One end of the flow distribution channel 131 is connected to the main flow channel 30, and the other end is connected to the front mold core mounting groove 132 to realize material diversion. In addition, the front mold frame 13 has a second guide hole 135 (adapted to the positioning guide post 50) and a pull plate mounting hole 136 (for connecting the pull plate 60).

[0032] like Figure 8 As shown, each sliding assembly 40 includes a sliding position 41, a sliding cylinder 42, and a heating pipe 43. The sliding position 41 is installed at the power output end of the sliding cylinder 42, and the heating pipe 43 is installed inside the sliding position 41. The heating pipe 43 is used to heat the cavity surface, making the material flow more smoothly in the cavity, resulting in better internal product quality and a higher pass rate.

[0033] like Figure 6 As shown, a hub metal part positioning boss 141 is provided in the middle of the rear end face of the front mold core 14 for positioning and installing the hub metal part 201. Seven partial blade back forming surfaces 142 are arranged circumferentially around the hub metal part positioning boss 141. Each partial blade back forming surface 142 has a blade back forming slide clearance 143 on its side to accommodate the slide 41. An axially penetrating gate 144 is provided between each partial blade back forming surface 142 and the hub metal part positioning boss 141. The gate 144 is located at the propeller end face, which can achieve uniform internal quality of blade forming, and the gate 144 is not on the blade surface, so it does not affect the appearance and performance. Figure 9 As shown, the front mold core 14 is integrally embedded in the front mold core 14 mounting groove by bolts. When the sliding cylinder 42 pushes the sliding part 41 into the blade back forming sliding clearance 143, the surface of the sliding part 41 and the partial blade back forming surface 142 together form a complete blade back forming surface. The parting line is formed at the docking position of the partial blade back forming surface 142 and the sliding part 41, which facilitates the forming and demolding of blades with various complex curved surfaces, and solves the key technical difficulty of mold opening and closing due to blade undercut. like Figure 1 As shown, the rear mold assembly includes a rear mold core 21, a rear mold base 22, a stripper plate 23, and a rear mold base plate 25 arranged sequentially along the material injection direction. The rear mold core 21 and the front mold core 14 are combined to form a mold, as shown below. Figure 7 As shown, the front end face of the rear mold core 21 has seven blade forming surfaces 212. When the mold is closed, the surface of the slide 41, the partial blade back forming surface 142, and the blade forming surfaces 212 together form a blade forming sealed cavity. A propeller hub metal part positioning pin 211 is also installed in the middle of the front end face of the rear mold core 21, which is adapted to the positioning hole 203 on the propeller hub metal part 201. A blade forming slide clearance 213 is also installed on the front end face of the rear mold core 21.

[0034] like Figure 11 As shown, the front end face of the rear mold frame 22 is provided with a rear mold core mounting groove 221, a sliding rail 222, and a sliding cylinder fixing groove 223. Figure 10 As shown, the rear mold core 21 is installed in the rear mold core mounting groove 221, the slide 41 is installed on the slide rail 222, and the slide cylinder 42 is installed in the slide cylinder fixing groove 223. The slide 41 is driven to reciprocate on the slide rail 222 by the extension and retraction of the push rod of the slide cylinder 42: when the mold is closed, it is pushed into the blade back forming slide clearance 143 to complete the mold closing of the blade forming surface; when the mold is opened, it is contracted to pull the slide 41 out of the cavity, which facilitates the demolding of the product.

[0035] The stripper plate 23 is slidably mounted on the partition plate 24 on both sides. The thickness of the partition plate 24 is greater than that of the stripper plate 23, allowing the stripper plate 23 to slide relative to the partition plate 24. The front end of the partition plate 24 is fixedly connected to the rear mold frame 22 by bolts, and the rear end is fixedly connected to the rear mold frame base plate 25 by bolts. An ejector pin mechanism is provided inside the stripper plate 23. During the demolding process, the rear mold frame 22, the partition plate 24, and the rear mold frame base plate 25 move backward as a whole. The stripper plate 23 is restricted by the injection molding machine mechanism to remain in its original position and move forward relative to the rear mold frame 22, driving the ejector pin mechanism to push the propeller out of the cavity for demolding.

[0036] The rear mold base plate 25 serves as the base mounting plate for the rear mold assembly. Its rear end face is connected to the moving platen of the injection molding machine. The reciprocating motion of the rear mold base plate 25 driven by the moving platen of the injection molding machine realizes the mold opening and closing process.

[0037] like Figure 12 As shown, the pull plate 60 has a sliding groove 61 at its front end and a mounting hole 62 at its rear end. The mounting hole 62 at the rear end of the pull plate 60 is fixedly connected to the rear mold frame 22 by a fastener (such as a bolt). The sliding groove 61 at the front end of the pull plate 60 is connected to the front mold frame 13 by a connector (such as a bolt). The side of the front mold frame 13 has a pull plate mounting hole 136 for installing the connector. The side of the rear mold frame 22 has a pull plate fixing hole 225 for installing the fastener. Figure 13-14As shown, during the mold opening process, the rear mold frame 22 moves backward, causing the pull plate 60 to move backward until the front end of the slide groove 61 abuts against the connecting piece, thereby pulling the front mold frame 13 backward, so that the front mold frame 13 separates from the stripper plate 12.

[0038] In this embodiment, a heating pipe 43 is provided inside the slide 41. The heating pipe 43 is connected to the oil pipe of an external heating device (not shown) through an oil pipe interface. It is used to heat the slide 41 to keep the temperature of the cavity area uniform, so that the material has good fluidity, high product qualification rate, and good internal quality.

[0039] In this embodiment, the front end of the positioning guide post 50 is installed in the guide post mounting hole 111, and the rear end of the positioning guide post 50 passes through the first guide hole 122, the second guide hole 135 and the third guide hole 224 in sequence to achieve precise guidance and positioning of the front and rear mold components and ensure mold closing accuracy.

[0040] Accordingly, the present invention also proposes a method for molding small thermoplastic composite propellers, which uses the above-mentioned mold and includes the following steps: S1. Mold assembly and positioning The mold is loaded into the injection molding machine. The front mold base plate 11 of the mold is fixedly connected to the fixed template of the injection molding machine, and the rear mold base plate 25 is fixedly connected to the moving template of the injection molding machine. The injection molding machine gate is precisely aligned with the main runner 30 and fixed by bolts.

[0041] S2, Heating pipe 43 connection Connect the oil circuit of the external heating device to the heating oil circuit of the slide 41 through the oil circuit interface to ensure the oil circuit is sealed and prepare for subsequent mold heating.

[0042] S3, pre-assembled propeller hub metal parts The propeller hub metal part is installed on the positioning pin inside the rear mold core 21. The positioning hole 203 and the positioning pin cooperate to achieve precise fixation of the propeller hub metal part and avoid the metal part from shifting during the molding process.

[0043] S4. Mold cavity cleaning Compressed air or a lint-free cloth is used to clean the molding cavity areas of the front mold core 14, the rear mold core 21, and the slide 41 to remove dust and impurities and ensure product molding accuracy.

[0044] S5. Heating of raw materials and molds Add thermoplastic composite material raw materials into the injection molding machine's feed tube, turn on the injection molding machine's heating system, and heat the feed tube temperature to 370℃~430℃ to melt the raw materials; at the same time, start the external heating device, and deliver hot oil to the heating pipe 43 of the slide 41 through the oil circuit to heat the mold to the set temperature of 200℃~300℃ to ensure the melt flowability and molding quality of the thermoplastic composite material.

[0045] S6. Mold preparation and mold closing (1) The injection molding machine's mold closing mechanism is activated. The injection molding machine's moving platen drives the rear mold base plate 25, rear mold base 22, and rear mold core 21 to move forward as a whole. The front mold base 13 and rear mold base 22 are precisely guided by the positioning guide post 50. (2) Open the slide cylinder 42 and drive the slide 41 to advance into the blade back forming slide clearance 143 of the front mold core 14. The surface of the slide 41 is connected with the partial blade back forming surface 142 and the blade surface forming surface 212 of the rear mold core 21 to form a complete blade forming sealed cavity, and complete the mold closing of the front and rear mold components.

[0046] S7, Injection Molding Set the injection parameters, including screw speed 120-170 rpm, injection pressure 170-210 MPa, and injection speed 130-170 mm / s; start the injection system of the injection molding machine, and inject the molten viscous raw material from the injection machine gate, which passes through the main runner 30, the branch runner 131, and the gate 144 in sequence, filling the entire cavity area of ​​the mold.

[0047] S8, Pressure Holding Cooling During the pressure holding stage, the pressure is set to 8-20MPa, and the pressure holding time is adjusted according to the product wall thickness. After the pressure holding is completed, the cooling stage begins, and the cooling time is set to 160-240s to allow the product to cool and solidify fully in the cavity and avoid demolding deformation.

[0048] S9. Mold Opening and Demolding (1) After the pressure holding and cooling are completed, the injection molding machine mold opening mechanism is turned on. First, the sliding cylinder 42 is started to retract, and the sliding part 41 is pulled out from the blade back forming sliding part clearance 143 and separated from the product blade forming surface. (2) The injection molding motor template drives the rear mold base plate 25, the rear mold frame 22, and the rear mold core 21 to move backward, and the mold opens; (3) During the mold opening process, the rear mold frame 22 moves backward, and the stripper plate 23 remains in its original position due to the limit post (not shown) of the injection molding machine. The ejector mechanism moves to push the propeller product out from the blade forming surface 212 of the rear mold core 21, thus completing the product demolding. (4) When the rear mold frame 22 moves to the preset position, the front end of the slide groove 61 of the pull plate 60 abuts against the connecting part of the front mold frame 13, pulling the front mold frame 13 to move backward, so that the front mold frame 13 separates from the stripper plate 12, and the waste material in the main channel 30 and the branch channel 131 can be removed.

[0049] S10, Product Post-processing Remove the product and cool it to room temperature. Then demold and trim the edges to obtain a small thermoplastic composite propeller.

[0050] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0051] The order of the steps in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0052] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A small thermoplastic composite propeller molding die, comprising a front die assembly, a rear die assembly, and a main runner; characterized in that, The mold also includes several sets of sliding components disposed between the front mold assembly and the rear mold assembly. The number of sliding components is the same as the number of propeller blades. Each set of sliding components includes a sliding member and a sliding cylinder. The sliding member is installed at the power output end of the sliding cylinder. The front mold assembly includes a front mold base plate, a stripper plate, a front mold frame, and a front mold core arranged sequentially along the material injection direction; the front mold base plate is fixedly connected to the stripper plate, and the main runner passes through the front mold base plate and the stripper plate; the rear end face of the front mold frame is provided with a front mold core mounting groove, and the front end face of the front mold frame is provided with a branch runner to connect the main runner and the front mold core mounting groove; the front mold core is installed in the front mold core mounting groove, and the rear end face of the front mold core is provided with a propeller hub metal part positioning boss, a partial blade back forming surface, and a blade back forming slide clearance; several partial blade back forming surfaces are arranged around the propeller hub metal part positioning boss, and a blade back forming slide clearance is provided on the side of each partial blade back forming surface to accommodate the slide; the slide surface and the partial blade back forming surface together constitute a complete blade back forming surface; an axially penetrating sprue is provided between each partial blade back forming surface and the propeller hub metal part positioning boss; The rear mold assembly includes a rear mold core, a rear mold frame, a stripper plate, and a rear mold frame base plate arranged sequentially along the material injection direction. The front end face of the rear mold core is provided with a blade forming surface. When the mold is closed, the slide surface, the partial blade back forming surface, and the blade forming surface together form a blade forming sealed cavity. The front end face of the rear mold frame is provided with a rear mold core mounting groove, a slide rail, and a slide cylinder fixing groove. The rear mold core is installed as a whole in the rear mold core mounting groove, the slide is installed on the slide rail, and the slide cylinder is installed in the slide cylinder fixing groove. The slide is driven to reciprocate on the slide rail by the extension and retraction of the slide cylinder push rod.

2. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The stripper plate is slidably mounted on the partition plate on both sides. The front end of the partition plate is fixedly connected to the rear mold frame, and the rear end is fixedly connected to the bottom plate of the rear mold frame. An ejector mechanism is provided inside the stripper plate. During the demolding process, the rear mold frame, the partition plate, and the bottom plate of the rear mold frame move backward as a whole, and the stripper plate moves forward relative to the rear mold frame, which drives the ejector mechanism to push the propeller out of the cavity for demolding.

3. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The front end face of the front mold base plate is connected to the fixed mold plate of the injection molding machine, and the rear end face of the rear mold base plate is connected to the moving mold plate of the injection molding machine. The opening and closing process is realized by the reciprocating motion of the rear mold base plate driven by the moving mold plate of the injection molding machine.

4. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The mold also includes a pull plate disposed on the side. The pull plate has a sliding groove at the front end and a mounting hole at the rear end. The mounting hole at the rear end of the pull plate is connected to the rear mold frame through a fixing member, and the sliding groove at the front end of the pull plate is connected to the front mold frame through a connecting member. During the mold opening process, the rear mold frame moves backward, which drives the pull plate to move backward until the front end of the sliding groove abuts against the connecting member, thereby pulling the front mold frame to move backward and separating the front mold frame from the stripper plate.

5. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The row position is equipped with a heating pipeline, which is connected to the oil pipeline of an external heating device through an oil pipe interface.

6. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The mold also includes positioning guide pillars. The front mold base plate is provided with guide pillar mounting holes, the stripper plate is provided with a first guide hole, the front mold frame is provided with a second guide hole, and the rear mold frame is provided with a third guide hole. The front end of the positioning guide pillar is installed in the guide pillar mounting hole, and the rear end of the positioning guide pillar passes through the first guide hole, the second guide hole, and the third guide hole in sequence.

7. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The rear end face of the front mold frame is also provided with a sliding clearance groove and a sliding cylinder clearance groove.

8. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The front end face of the rear mold core is also equipped with a positioning pin for the propeller hub metal part, which is adapted to the positioning hole on the propeller hub metal part.

9. The small thermoplastic composite propeller molding die according to claim 1, characterized in that, The number of the flow channels corresponds to the number of propeller blades, and the injection port is located at the end face of the propeller.

10. A method for molding a small thermoplastic composite propeller, characterized in that, This method uses the mold described in any one of claims 1-9, and includes the following steps: S1. Load the mold into the injection molding machine, align and fix the injection molding machine gate with the main runner; S2. Connect the oil pipeline of the heating device to the heating oil pipeline of the sliding position; S3. Install the propeller hub metal part into the locating pin position inside the rear mold core. S4. Clean the mold cavity area of ​​the front mold core, rear mold core, and slide; S5. Add thermoplastic composite material raw materials into the injection molding machine, turn on the injection molding machine heating system and external heating device, and heat the raw materials and the mold to the set temperature respectively; S6. Activate the injection molding machine's mold closing mechanism, push the rear mold base plate forward as a whole, close the front and rear mold bases, activate the slide cylinder to extend and push the slide into the clearance space of the front mold core's blade back forming slide, and complete the mold closing; S7. Set the injection parameters, including screw speed 120-170rpm, injection pressure 170-210MPa, and injection speed 130-170mm / s. The molten viscous raw material enters the main runner of the mold from the injection machine gate, then to the sub-runner, and finally fills the entire cavity area of ​​the mold through the injection gate. S8, Input holding pressure 8-20MPa, cooling time 160-240s; S9. After the pressure holding and cooling are completed, open the injection molding machine's mold opening mechanism, start the slide cylinder to retract and pull out the slide. The rear mold base plate moves backward with the injection molding machine's mold opening mechanism, the mold opens, and the rear mold base moves backward. The stripper plate remains in its original position due to the limitation of the injection molding machine's limit pins. The ejector pins push out the product, completing the demolding. After the pull plate moves to a certain position after the rear mold base, it drives the front mold base to move backward, pulling the front mold base and stripper plate apart, and removing the waste material in the main runner and branch runner. S10. Remove the product and cool it to room temperature. Then demold and trim the edges to obtain a small thermoplastic composite propeller.

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