Combined forming die and forming process of metal worm and plastic gear
By accurately controlling temperature and pressure in plastic gear molds, the mold design and manufacturing accuracy problems during plastic gear molding process are solved, the accuracy and quality of the finished product are improved, and the stability and efficiency of gear transmission are ensured.
Patent Information
- Application Number
- CN202411906592.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-02-11
AI Technical Summary
During the plastic gear molding process, there are problems such as mold design, manufacturing accuracy and wear, which lead to defects in the finished product and affect the noise, wear and efficiency of gear transmission.
Design a combined mold of metal worm and plastic gear. By precisely controlling the temperature and injection pressure in the injection process, combined with reasonable parameter relationship adjustment, we ensure that the filling process of plastic in the mold is stable and uniform.
It improves the molding accuracy and quality of plastic gears, ensures accurate tooth shape, is closely matched with metal worms, has a smooth and accurate transmission, reduces mold deformation, and improves product strength and quality stability.
Smart Images
Figure CN119408076A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of production moulds for turbine worm gear structures, in particular to a combined moulding mould for a metal worm gear and a plastic gear and a moulding process. Background Art
[0002] Plastic gears have the advantages of light weight, good self-lubrication, low transmission noise, no need for post-processing and fewer processes. Because their strength and rigidity are close to those of metal materials, they can replace non-ferrous metals and alloys. Therefore, their industrial applications are gradually expanding and are now widely used in machinery, instruments, telecommunications, household appliances, toy products and various timing devices. Gears are often made of polyoxymethylene, which has good performance, process performance and economy, and has excellent comprehensive performance, strength, rigidity, impact resistance, fatigue resistance and creep performance, excellent self-lubricating performance, small friction coefficient and good wear resistance, small water absorption, stable product size, suitable for manufacturing various gears, transmission parts or anti-friction parts, etc. However, the temperature of polyoxymethylene during the injection molding process has an important influence on the entire injection process. To have the highest filling speed and maintain the characteristics of the plastic parts at the same time, an appropriate melt temperature is required. The higher the mold temperature, the faster the mold filling speed. The mold temperature controls the filling speed of the plastic, the cooling time of the finished product and the crystallinity of the finished product. Production practice shows that the defects of molding gears mainly lie in the design, manufacturing accuracy and degree of wear of the mold. If the injection molding machine and mold used in more mature plastic factories are ideal in all aspects, it is easy to obtain qualified product quality. Process adjustment in the production process is a necessary way to improve the output and quality of products. The defects of molding gears can easily lead to noise, increased wear, reduced efficiency and even jamming of the gear transmission. The main reasons for the main defects in the molding gear injection process are as follows: first, improper feed adjustment, incorrect adjustment of the calculation device or the compacted and slightly melted plastic in the loading chamber forms a "material plug", causing part of the plastic to jump out of the loading chamber and partially block the discharge port of the loading chamber. Secondly, the amount of material injected into the mold is too small, the plastic temperature is low, the plastic fluidity is poor or the temperature of the mold is low, and the plastic flowing along the left side of the molding part is quickly cooled to lose fluidity, so that it cannot completely fill every corner of the mold cavity. Improper injection pressure will also affect the filling molding. Summary of the invention
[0003] The object of the present invention is to provide a combined molding die and molding process of a metal worm and a plastic gear, so as to solve the problem of poor molding effect of the plastic gear mentioned in the above background technology.
[0004] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a combined molding die of a metal worm and a plastic gear, comprising a movable mold base plate, a movable mold plate is arranged on the upper surface of the movable mold base plate, a lower guide column is arranged on the upper surface of the movable mold base plate, and the lower guide column is fixedly connected to the movable mold base plate by bolts, a core mold fixing plate is placed on the upper surface of the movable mold base plate, a lower insert is arranged on the upper surface of the core mold fixing plate, a fixed mold plate is arranged above the lower insert, and a fixed mold base plate is arranged on the upper surface of the fixed mold base plate, and the fixed mold base plate and the fixed mold plate are fixedly installed by bolts, an upper insert is arranged on the lower surface of the fixed mold base plate, an upper guide column is arranged on the lower surface of the fixed mold base plate, a mold core is arranged between the lower insert and the upper insert, a worm is arranged inside the mold core, a runner is arranged between the fixed mold base plate and the lower insert, and a gate is arranged on the upper surface of the fixed mold base plate.
[0005] Preferably, the upper end of the lower guide column passes through the movable template and the core mold fixing plate, and the movable template and the core mold fixing plate are connected to the lower guide column through a guide sleeve.
[0006] Preferably, the upper surface of the lower insert is fitted with the lower surface of the upper insert, the lower insert is fixedly mounted to the core mold fixing plate by bolts, and the upper insert is fixedly mounted to the fixed mold plate by bolts.
[0007] Preferably, the upper guide column is fixedly connected to the fixed mold plate by bolts, and the lower end of the upper guide column is fixedly mounted to the upper surface of the core mold fixing plate by a guide sleeve.
[0008] Preferably, the mold core is mounted on the inner surface of the lower insert, and the mold core is fixedly connected to the lower insert by bolts.
[0009] Preferably, the runner is opened on the lower surface of the fixed mold plate and the upper end of the mold core, and the upper end of the runner is connected to the lower end of the gate, the lower end of the runner is a multi-point fork design, and the lower end of the runner is connected to the internal cavity of the mold core where the worm is located, and the gate is located in the middle of the upper surface of one end of the fixed mold base plate.
[0010] A forming process of a combined forming die of a metal worm and a plastic gear, the forming process comprising the following steps: S1. Polyoxymethylene is selected as the material of plastic gears; S2, set the melt temperature, control the temperature of each section of the barrel, the nozzle temperature and the mold temperature of the forming gear; S3. According to the injection pressure and mold temperature relationship diagram determined by the injection molding drawing method, select the injection pressure and mold temperature combination that can produce high-quality products Preferably, the module of the molded gear is 0.4218, and the thickness of the molded gear is 4 mm.
[0011] Preferably, the temperature of the rear section of the barrel is 160-170°C, the temperature of the middle section of the barrel is 170-180°C, and the temperature of the front section of the barrel is 180-190°C.
[0012] Preferably, the nozzle temperature is 170-180°C, and the mold temperature of the formed gear is controlled at 90°C-120°C.
[0013] Compared with the prior art, the invention has the following beneficial effects: the combined forming mold of the metal worm and the plastic gear: 1. By precisely controlling the temperature and injection pressure in the injection process and adjusting them according to reasonable parameter relationships, the filling process of the plastic in the mold is ensured to be stable and uniform, effectively avoiding product defects caused by improper temperature or pressure, making the molded plastic gears more precise, with accurate tooth shapes, more closely matched with the metal worm, and more stable and precise transmission, thus improving the overall quality of the product; Furthermore, the upper insert and the lower insert are tightly fitted to form a cavity, and the mold core is clamped and fixed on the inner surface of the lower insert. This structure can effectively reduce the deformation of the mold during the molding process, ensure uniform wall thickness of the product, avoid stress concentration and product defects caused by uneven wall thickness, and further improve the strength and quality stability of the product.
[0014] Furthermore, the multi-point bifurcated design of the runner enables the plastic melt to be evenly filled into the internal cavity of the mold core, ensuring the uniformity of filling of each part of the plastic gear, avoiding defects such as local lack of material and bubbles, and improving the molding quality and consistency of the product; 2. The reasonable range of each process parameter is clarified, and a method for determining the optimal parameter combination is given, making the production process more scientific and standardized, facilitating operators to carry out precise control, reducing the scrap rate caused by unstable or unreasonable process parameters, and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a schematic diagram of the overall front cross-sectional structure of the present invention; Figure 2 It is a schematic diagram of the overall top view structure of the present invention; Figure 3 It is a schematic diagram of the overall side sectional structure of the present invention; Figure 4 It is a schematic diagram of the side cross-sectional structure of the connection between the lower insert and the mold core of the present invention; Figure 5 This is a schematic diagram of the front view structure of the worm after molding of the present invention; Figure 6 It is a schematic diagram of the three-dimensional structure of the worm after molding of the present invention.
[0016] In the figure: 1. movable mold base plate; 2. movable mold plate; 3. lower guide column; 4. core mold fixing plate; 5. lower insert; 6. fixed mold base plate; 7. fixed mold plate; 8. upper insert; 9. upper guide column; 10. mold core; 11. worm; 12. runner; 13. gate. DETAILED DESCRIPTION
[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0018] See also Figure 1-Figure 6 The present invention provides a technical solution: a combined molding die of a metal worm and a plastic gear, comprising a movable die plate 1, a movable die plate 2 is arranged on the upper surface of the movable die plate 1, a lower guide column 3 is arranged on the upper surface of the movable die plate 1, and the lower guide column 3 is fixedly connected to the movable die plate 1 by bolts, a core die fixing plate 4 is placed on the upper surface of the movable die plate 2, a lower insert 5 is arranged on the upper surface of the core die fixing plate 4, a fixed die plate 7 is arranged above the lower insert 5, and a fixed die plate 6 is arranged on the upper surface of the fixed die plate 7, and the fixed die plate 6 and the fixed die plate 7 are fixedly installed by bolts, an upper insert 8 is arranged on the lower surface of the fixed die plate 7, an upper guide column 9 is arranged on the lower surface of the fixed die plate 7, a mold core 10 is arranged between the lower insert 5 and the upper insert 8, a worm 11 is arranged inside the mold core 10, a runner 12 is arranged between the fixed die plate 6 and the lower insert 5, and a gate 13 is arranged on the upper surface of the fixed die plate 6; The upper end of the lower guide column 3 passes through the movable template 2 and the core mold fixing plate 4, and the movable template 2 and the core mold fixing plate 4 are connected to the lower guide column 3 through a guide sleeve; The upper surface of the lower insert 5 is fitted with the lower surface of the upper insert 8, the lower insert 5 is fixedly installed with the core mold fixing plate 4 by bolts, and the upper insert 8 is fixedly installed with the fixed mold plate 7 by bolts; The upper guide column 9 is fixedly connected to the fixed mold plate 7 by bolts, and the lower end of the upper guide column 9 is fixedly installed to the upper surface of the core mold fixing plate 4 by a guide sleeve; The mold core 10 is mounted on the inner surface of the lower insert 5, and the mold core 10 is fixedly connected to the lower insert 5 by bolts; The runner 12 is opened on the lower surface of the fixed mold plate 7 and the upper end of the core 10, and the upper end of the runner 12 is connected with the lower end of the gate 13. The lower end of the runner 12 is a multi-point fork design, and the lower end of the runner 12 is connected with the internal cavity of the core 10 where the worm 11 is located. The gate 13 is located in the middle of the upper surface of one end of the fixed mold base plate 6.
[0019] During injection molding, first, the movable mold base plate 1 moves toward the fixed mold base plate 6 under the action of the power device, and the movable mold plate 2 moves together with the movable mold base plate 1. The lower guide pillar 3 plays a guiding role to ensure that the movable mold plate 2 and the core mold fixing plate 4 can be accurately installed, and the upper guide pillar 9 ensures that the movable mold base plate 1 and the fixed mold plate 7 are aligned and closed. The movable mold base plate 1 and the fixed mold plate 7 cooperate with the upper guide pillar 9 through the guide sleeve, so that the moving process is smooth and accurate, ensuring that each part of the mold cavity can be accurately docked; At the same time, the upper insert 8 and the lower insert 5 fit tightly together when the mold is closed to form a complete cavity structure for molding plastic gears. The mold core 10 is snap-fitted and installed on the inner surface of the lower insert 5 and fixed by bolts. After the mold is closed, it is located in the center of the cavity, providing an accurate shape basis for the molding of the plastic gear. The plastic raw material is heated and plasticized in the barrel of the injection molding machine to form a molten plastic melt. Pressure is applied by the screw or plunger of the injection molding machine to inject the plastic melt into the mold through the gate 13. The plastic melt first enters the runner 12. Since the upper end of the runner 12 is connected to the gate 13, the plastic melt flows along the runner 12 under pressure. The plastic melt can be evenly diverted to various positions connected to the internal cavity of the mold core 10 where the worm 11 is located, thereby ensuring that the plastic can evenly fill the cavity space formed by the mold core 10 and the upper insert 8 and the lower insert 5 to achieve the molding of the plastic gear. During the injection process, the plastic melt gradually fills the cavity under pressure, and at the same time, the mold core The air inside 10 is discharged from the mold through the gap between the parting surfaces, the exhaust grooves, etc. When the cavity is filled with the plastic melt, the injection molding machine maintains a certain pressure to maintain the pressure of the plastic. When the plastic gear is cooled and solidified, the movable mold base plate 1 moves in the opposite direction under the action of the power device, driving the movable mold plate 2, the core mold fixing plate 4 and other movable mold parts to separate from the fixed mold plate 7 to realize the mold opening action. During the mold opening process, the upper guide column 9 and the lower guide column 3 play a guiding role again to ensure that the movable mold and the fixed mold are separated smoothly to prevent mold damage or product strain. As the movable mold part moves, the molded plastic gear remains on one side of the movable mold, and the plastic gear and the worm 11 are ejected from the mold core 10 by the ejection mechanism. Since the mold core 10 is fixedly connected to the lower insert 5, and the lower insert 5 is fixedly installed with the core mold fixing plate 4, the ejection mechanism acts on the core mold fixing plate 4 or directly acts on the plastic gear and the worm 11 to overcome the adhesion between the plastic gear and the mold core 10, so that the plastic gear can be smoothly separated from the mold to complete a molding cycle.
[0020] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.
Claims
1. A combined molding die for a metal worm and a plastic gear, comprising a movable die base plate (1), a movable die plate (2) being arranged on the upper surface of the movable die base plate (1), a lower guide column (3) being arranged on the upper surface of the movable die base plate (1), and the lower guide column (3) being fixedly connected to the movable die base plate (1) by bolts, and a core die fixing plate (4) being placed on the upper surface of the movable die plate (2), characterized in that: The upper surface of the core mold fixing plate (4) is provided with a lower insert (5), a fixed mold plate (7) is provided above the lower insert (5), and a fixed mold base plate (6) is provided on the upper surface of the fixed mold plate (7), and the fixed mold base plate (6) and the fixed mold plate (7) are fixedly installed by bolts, an upper insert (8) is provided on the lower surface of the fixed mold plate (7), and an upper guide column (9) is provided on the lower surface of the fixed mold plate (7), a mold core (10) is provided between the lower insert (5) and the upper insert (8), a worm (11) is provided inside the mold core (10), a runner (12) is provided between the fixed mold base plate (6) and the lower insert (5), and a gate (13) is provided on the upper surface of the fixed mold base plate (6).
2. The combined molding die of a metal worm and a plastic gear according to claim 1, characterized in that: The upper end of the lower guide column (3) passes through the movable mold plate (2) and the core mold fixing plate (4), and the movable mold plate (2) and the core mold fixing plate (4) are connected to the lower guide column (3) via a guide sleeve.
3. The combined forming mold of a metal worm and a plastic gear according to claim 1, characterized in that: The upper surface of the lower insert (5) is fitted with the lower surface of the upper insert (8); the lower insert (5) is fixedly mounted to the core mold fixing plate (4) by bolts; and the upper insert (8) is fixedly mounted to the fixed mold plate (7) by bolts.
4. The combined forming mold of a metal worm and a plastic gear according to claim 1, characterized in that: The upper guide column (9) is fixedly connected to the fixed mold plate (7) via bolts, and the lower end of the upper guide column (9) is fixedly mounted to the upper surface of the core mold fixing plate (4) via a guide sleeve.
5. The combined forming mold of a metal worm and a plastic gear according to claim 1, characterized in that: The mold core (10) is mounted on the inner surface of the lower insert (5) by snapping, and the mold core (10) is fixedly connected to the lower insert (5) by bolts.
6. The combined forming mold of a metal worm and a plastic gear according to claim 1, characterized in that: The runner (12) is opened on the lower surface of the fixed mold plate (7) and the upper end of the mold core (10), and the upper end of the runner (12) is connected to the lower end of the gate (13). The lower end of the runner (12) is a multi-point bifurcated design, and the lower end of the runner (12) is connected to the internal cavity of the mold core (10) where the worm (11) is located. The gate (13) is located in the middle of the upper surface of one end of the fixed mold base plate (6).
7. A forming process of a combined forming die of a metal worm and a plastic gear according to claims 1-6, characterized in that: The molding process includes the following steps: S1. Polyoxymethylene (POM) is selected as the material of plastic gears; S2, set the melt temperature, control the temperature of each section of the barrel, the nozzle temperature and the mold temperature of the forming gear; S3. According to the injection pressure and mold temperature relationship diagram determined by the injection molding drawing method, select the injection pressure and mold temperature combination that can produce high-quality products.
8. The forming process of the combined forming die of a metal worm and a plastic gear according to claim 7, characterized in that: The module of the molded gear is 0.4218, and the thickness of the molded gear is 4 mm.
9. The forming process of the combined forming die of a metal worm and a plastic gear according to claim 7, characterized in that: The temperature of the rear section of the barrel is 160-170°C, the temperature of the middle section of the barrel is 170-180°C, and the temperature of the front section of the barrel is 180-190°C.
10. The forming process of the combined forming die of a metal worm and a plastic gear according to claim 7, characterized in that: The nozzle temperature is 170-180°C, and the mold temperature of the formed gear is controlled at 90°C-120°C.