Milling cutter injection molding mold and molding method

Abstract

The forming mold comprises a fixed mold plate, a movable mold plate, a base plate, a lead screw, a wire cylinder, a sliding sleeve, a cylindrical cavity, a spiral groove cavity, an ejector plate and an ejector pin, the cylindrical cavity is formed in the fixed mold plate, the wire cylinder and the sliding sleeve are arranged on the movable mold plate, the base plate is located below the movable mold plate, and the ejector plate is located below the movable mold plate. The upper end of the lead screw penetrates through the wire cylinder and the sliding sleeve and is connected with the spiral groove cavity, the lower end of the lead screw is connected with the base plate, the lead screw is matched with the wire cylinder and can rotate and slide in the sliding sleeve, the wire cylinder is provided with spiral grooves with the same spiral angle as the spiral groove cavity, and the ejector plate is located below the base plate. The structure is simple, faults are few, maintenance is easy, the manufacturing cost is low, according to the forming method, spiral retreating is achieved during mold opening of the mold, the mold is simple and reliable, product stress is small, and hard alloy products can be formed.

Description

Technical Field

[0001] The present invention mainly relates to metal cutting tools, and in particular to a milling cutter injection molding die and a molding method thereof. Background Art

[0002] In the prior art, the products of cemented carbide milling cutters for metal cutting are usually processed by grinding spiral grooves on cylindrical bar stock. While the injection molding method can directly produce milling cutter products with spiral grooves. During the injection molding process, since the toughness of the cemented carbide injection blank is poor, during the demolding process, the products are prone to breakage or inability to demold. Moreover, most of the existing injection molding dies adopt a rack, gear and screw linkage conversion mechanism, which has a complex structure and high cost, and the products are subject to large forces during demolding and are prone to damage.

[0003] For example, Chinese Patent Document CN103121277A discloses a spiral demolding die for an inclined gear injection mold. The inclined gear product is demolded from the inclined tooth cavity along the core. Through the spiral ejection demolding method in which the straight inclined gear product drives the rotating cavity to make a rotating motion, this technical solution has high requirements for the toughness of the injection product, and the product is subject to large forces during demolding and is prone to damage.

[0004] Chinese Patent Document CN103496112A discloses a rack-driven spiral demolding die. After the front mold is demolded, the air cylinder drives the linear rack to move horizontally, driving the driving gear, the intermediate rotating shaft and the intermediate gear to rotate, and further causing the two transmission gears and the two rear mold inserts to rotate. Since the product in the cavity has formed an internal thread, it will move upward under the rotation of the rear mold insert with an external thread, and finally the product and the rear mold insert are separated. This injection molding die has a high manufacturing cost, a complex structure that requires multiple motion form conversions, many faults, inconvenient maintenance and complex operation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a milling cutter injection molding die with small force on the product during demolding, simple structure, few faults, easy to maintain, and a milling cutter injection molding method that is easy to operate and has good molding quality.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A milling cutter injection molding die, comprising a fixed template, a movable template, a backing plate, a lead screw, a wire barrel, a sliding sleeve, a cylindrical cavity, a spiral groove cavity, an ejection plate and ejector pins. The cylindrical cavity is installed on the fixed template. The wire barrel and the sliding sleeve are installed on the movable template. The backing plate is located below the movable template. The upper end of the lead screw passes through the wire barrel and the sliding sleeve and is connected to the spiral groove cavity, and the lower end is connected to the backing plate. The lead screw cooperates with the wire barrel and can rotate and slide within the sliding sleeve. The wire barrel is provided with a spiral groove having the same spiral angle as that of the spiral groove cavity. The ejection plate is located below the backing plate. A through hole for the ejector pin is provided at the center of the lead screw. The lower end of the ejector pin is connected to the ejection plate, and the upper end can pass through the through hole for the ejector pin to reach the spiral groove cavity.

[0008] As a further improvement of the above technical solution:

[0009] The backing plate includes an upper backing plate, a lower backing plate and an end face bearing. The end face bearing is arranged between the upper backing plate and the lower backing plate. The lead screw is connected to the end face bearing.

[0010] The upper backing plate is provided with through holes facilitating the installation of the wire barrel, the movement of the lead screw, and the installation and rotation of the end face bearing. The lower backing plate is provided with counterbore holes facilitating the installation and rotation of the end face bearing and the movement of the ejector pin.

[0011] A central stepped through hole facilitating the movement clearance of the wire barrel, the sliding sleeve, the spiral groove cavity and the lead screw is provided at the center of the movable template.

[0012] A connecting rubber plug is provided between the fixed template and the movable template.

[0013] A needle valve type hot runner is provided on the fixed template.

[0014] A hinge bolt is provided between the ejection plate and the movable template.

[0015] A milling cutter injection molding method using the above milling cutter injection molding die includes the following steps:

[0016] S1. Injection molding: The cylindrical cavity, the spiral groove cavity, the lead screw and the ejector pins are clamped to form a closed cavity, and a high-temperature and high-pressure material flow is injected. After the milling cutter is molded, it is cooled.

[0017] S2. First mold opening: The backing plate moves downward to drive the lead screw to move vertically downward. The lead screw is converted into a downward spiral movement by the reaction force of the wire barrel, and drives the spiral groove cavity to move downward in a spiral along the spiral groove of the milling cutter to be disengaged.

[0018] As a further improvement of the above technical solution: <~

[0019] After the step S2, it further includes the step: S3. Secondary molding: The backing plate continues to move downward to drive the movable template to separate from the fixed template.

[0020] In the step S1, a needle valve type hot runner is used to inject a high-temperature and high-pressure material flow. The injection pressure is 100 Mpa - 120 MPa, the material temperature is 120°C - 150°C, and the cooling temperature after forming the milling cutter is 30°C - 40°C.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] For the injection molding die of the milling cutter of the present invention, after the injection molding of the milling cutter is completed, the backing plate is pulled down to drive the lead screw to move vertically downward. The downward lead screw is subjected to the reaction force of the wire barrel, and the lead screw changes from vertical downward movement to downward spiral movement. The spiral groove cavity moves in a spiral manner together with the lead screw, and the spiral groove cavity spirally disengages along the spiral groove of the milling cutter, thereby realizing the demolding of the milling cutter. The structure is simple, not prone to failure, and the manufacturing cost is low. The product is subjected to small force during demolding, and products with poor toughness can be molded.

[0023] For the injection molding method of the milling cutter of the present invention, by using the injection molding die of the milling cutter of the present invention, when the mold is opened, the backing plate moves downward to drive the lead screw to move vertically downward. The lead screw is subjected to the reaction force of the wire barrel and changes to downward spiral movement, and drives the spiral groove cavity to move downward in a spiral manner along the spiral groove of the milling cutter and spirally disengage. It is simple and reliable, the product is subjected to small force, and products with poor toughness can be molded. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a three-dimensional structure diagram of the injection molding die of the milling cutter of the present invention.

[0025] Figure 2 is a three-dimensional structure diagram of the cylindrical cavity of the injection molding die of the milling cutter of the present invention.

[0026] Figure 3 is a three-dimensional structure diagram of the spiral groove cavity of the injection molding die of the milling cutter of the present invention.

[0027] Figure 4 is a three-dimensional structure diagram of the sliding sleeve of the injection molding die of the milling cutter of the present invention.

[0028] Figure 5 is a three-dimensional structure diagram of the lead screw of the injection molding die of the milling cutter of the present invention.

[0029] Figure 6 is a three-dimensional structure diagram of the wire barrel of the injection molding die of the milling cutter of the present invention.

[0030] Figure 7 is a three-dimensional structure diagram of the injection molding die of the milling cutter during the first mold opening of the injection molding method of the milling cutter of the present invention.

[0031] Figure 8 is a three-dimensional structure diagram of the injection molding die of the milling cutter during the second mold opening of the injection molding method of the milling cutter of the present invention.

[0032] Figure 9 It is a three - dimensional structure diagram of a milling cutter formed by using the injection molding method of the milling cutter of the present invention.

[0033] Each mark in the figure represents:

[0034] 1. Fixed template; 2. Movable template; 3. Backing plate; 31. Upper backing plate; 32. Lower backing plate; 33. End face bearing; 4. Lead screw; 5. Screw barrel; 6. Sliding sleeve; 7. Cylindrical cavity; 8. Spiral groove cavity; 9. Ejector plate; 10. Ejector pin; 11. Hinged bolt; 12. Connecting rubber plug; 13. Needle valve type hot runner; 14. Central stepped through - hole; 20. Milling cutter. Specific embodiments

[0035] The following will further elaborate on the present invention in detail with reference to the accompanying drawings of the specification and specific embodiments.

[0036] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "horizontal", "inner", "outer", "top", "bottom", etc. indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0037] Figures 1 to 6 An embodiment of the injection molding die for a milling cutter of the present invention is shown. The injection molding die for a milling cutter includes a fixed template 1, a movable template 2, a backing plate 3, a lead screw 4, a screw barrel 5, a sliding sleeve 6, a cylindrical cavity 7, a spiral groove cavity 8, an ejector plate 9 and an ejector pin 10. As Figure 1 shown, the cylindrical cavity 7 is installed on the fixed template 1, the screw barrel 5 and the sliding sleeve 6 are installed on the movable template 2, the backing plate 3 is located below the movable template 2, the upper end of the lead screw 4 passes through the screw barrel 5 and the sliding sleeve 6 and is connected to the spiral groove cavity 8, and the lower end is connected to the backing plate 3. The lead screw 4 cooperates with the screw barrel 5 and can rotate and slide within the sliding sleeve 6. The screw barrel 5 is provided with a spiral groove having the same spiral angle as that of the spiral groove cavity 8. The ejector plate 9 is located below the backing plate 3. A through - hole for the ejector pin is provided in the center of the lead screw 4. The lower end of the ejector pin 10 is connected to the ejector plate 9, and the upper end can pass through the through - hole for the ejector pin to reach the spiral groove cavity 8. After the injection molding of the milling cutter is completed, as Figure 7 shown, by pulling down the backing plate 3 to drive the lead screw 4 to move vertically downward, the downward - moving lead screw 4 is subjected to the reaction force of the screw barrel 5, and the lead screw 4 changes from vertical downward movement to downward spiral movement. The spiral groove cavity 8 moves in a spiral manner together with the lead screw 4, and the spiral groove cavity 8 spirally disengages along the spiral groove of the milling cutter, thereby realizing the demolding of the milling cutter. The structure is simple, not prone to failure, and has a low manufacturing cost. When demolding, the product is subjected to a small force, and products with poor toughness can be molded.

[0038] In this embodiment, the backing plate 3 includes an upper backing plate 31, a lower backing plate 32, and an end face bearing 33. The end face bearing 33 is arranged between the upper backing plate 31 and the lower backing plate 32. The lead screw 4 is connected to the end face bearing 33. The end face bearing 33 clamped between the upper backing plate 31 and the lower backing plate 32 is provided. The lower end of the lead screw 4 is connected to the end face bearing 33. When the upper backing plate 31 and the lower backing plate 32 move up and down, the end face bearing 33 can drive the lead screw 4 to move up and down without restricting the rotation of the lead screw 4, facilitating the spiral rotation of the lead screw 4.

[0039] In this embodiment, the upper backing plate 31 is provided with through holes facilitating the installation of the wire spool 5, the movement of the lead screw 4, and the installation and rotation of the end face bearing 33. The lower backing plate 32 is provided with counterbore holes facilitating the installation and rotation of the end face bearing 33 and the movement of the ejector pin 10.

[0040] In this embodiment, a central stepped through hole 14 facilitating the movement clearance of the wire spool 5, the sliding sleeve 6, the spiral groove cavity 8, and the lead screw 4 is provided at the center of the moving template 2.

[0041] In this embodiment, a connecting rubber plug 12 is arranged between the fixed template 1 and the moving template 2. Before mold opening, the connecting rubber plug 12 can keep the distance between the fixed template 1 and the moving template 2 unchanged. During secondary mold opening, the connecting rubber plug 12 separates, and the distance between the fixed template 1 and the moving template 2 becomes larger, facilitating the removal of the formed milling cutter.

[0042] In this embodiment, a needle valve type hot runner 13 is provided on the fixed template 1.

[0043] In this embodiment, a hinge bolt 11 is arranged between the ejector plate 9 and the moving template 2.

[0044] The milling cutter injection molding method of the present invention uses the milling cutter injection molding die in the above embodiment and includes the following steps:

[0045] S1. Injection molding: The cylindrical cavity 7, the spiral groove cavity 8, the lead screw 4, and the ejector pin 10 are closed to form a closed cavity, and a high-temperature and high-pressure material flow is injected. After the milling cutter 20 is formed, it is cooled.

[0046] S2. First mold opening: The backing plate 3 moves downward to drive the lead screw 4 to move vertically downward. The lead screw 4 is converted into a downward spiral movement under the reaction force of the wire spool 5 and drives the spiral groove cavity 8 to move downward spirally along the spiral groove of the milling cutter 20. In this step, as Figure 7 shown, the lead screw 4 moves downward, and the spiral groove cavity 8 is driven by the lead screw 4 to move downward spirally along the spiral groove of the milling cutter. It is simple and reliable, and the product is less stressed. Products with poor toughness can be formed. The milling cutter formed by the method of the present invention is as Figure 9 shown.

[0047] In this embodiment, after step S2, the following step is further included: S3. Secondary molding: The backing plate 3 continues to move downward to drive the moving template 2 away from the fixed template 1. As Figure 8 shown, as the backing plate 3 continues to move downward, the moving template 2 is separated from the fixed template 1, and the milling cutter 20 can be easily taken out.

[0048] In this embodiment, in step S1, a needle valve type hot runner is used to inject a high-temperature and high-pressure material flow. The injection pressure is 100 Mpa - 120 MPa, the material temperature is 120°C - 150°C, and the cooling temperature after molding the milling cutter 20 is 30°C - 40°C.

[0049] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A milling cutter injection molding die, characterized in that: It includes a fixed template (1), a movable template (2), a backing plate (3), a lead screw (4), a wire barrel (5), a sliding sleeve (6), a cylindrical cavity (7), a spiral groove cavity (8), an ejector plate (9) and ejector pins (10). The cylindrical cavity (7) is installed on the fixed template (1). The wire barrel (5) and the sliding sleeve (6) are installed on the movable template (2). The backing plate (3) is located below the movable template (2). The upper end of the lead screw (4) passes through the wire barrel (5) and the sliding sleeve (6) and is connected to the spiral groove cavity (8), and the lower end is connected to the backing plate (3). The lead screw (4) cooperates with the wire barrel (5) and can rotate and slide within the sliding sleeve (6). The wire barrel (5) is provided with a spiral groove having the same spiral angle as that of the spiral groove cavity (8). The ejector plate (9) is located below the backing plate (3). A through hole for the ejector pin is provided in the center of the lead screw (4). The lower end of the ejector pin (10) is connected to the ejector plate (9), and the upper end can pass through the through hole for the ejector pin to reach the spiral groove cavity (8).

2. The milling cutter injection molding die according to claim 1, wherein: The backing plate (3) includes an upper backing plate (31), a lower backing plate (32) and a thrust bearing (33). The thrust bearing (33) is arranged between the upper backing plate (31) and the lower backing plate (32). The lead screw (4) is connected to the thrust bearing (33).

3. The milling cutter injection molding die according to claim 2, wherein: The upper backing plate (31) is provided with through holes facilitating the installation of the wire barrel (5), the movement of the lead screw (4), and the installation and rotation of the thrust bearing (33). The lower backing plate (32) is provided with counterbore holes facilitating the installation and rotation of the thrust bearing (33) and the movement of the ejector pins (10).

4. The milling cutter injection molding die according to claim 2 or 3, characterized in that: A central stepped through hole (14) facilitating the movement clearance of the wire barrel (5), the sliding sleeve (6), the spiral groove cavity (8) and the lead screw (4) is provided in the center of the movable template (2).

5. The milling cutter injection molding die according to claim 2 or 3, characterized in that: A connecting rubber plug (12) is provided between the fixed template (1) and the movable template (2).

6. The milling cutter injection molding die according to claim 2 or 3, characterized in that: A needle valve type hot runner (13) is provided on the fixed template (1).

7. The milling cutter injection molding die according to claim 2 or 3, characterized in that: A hinge bolt (11) is provided between the ejector plate (9) and the movable template (2).

8. A method for injection molding of a milling cutter, using the milling cutter injection molding die according to any one of claims 1 to 7, characterized in that, It includes the following steps: S1. Injection molding: The cylindrical cavity (7), the spiral groove cavity (8), the lead screw (4) and the ejector pins (10) are clamped to form a closed cavity, and a high-temperature and high-pressure material flow is injected. After the forming milling cutter (20) is formed, it is cooled. S2. First mold opening: The backing plate (3) moves downward to drive the lead screw (4) to move vertically downward. The lead screw (4) is converted into a downward spiral movement under the reaction force of the wire barrel (5), and drives the spiral groove cavity (8) to move downward spirally along the spiral groove of the milling cutter (20) and be disengaged.

9. The milling cutter injection molding method according to claim 8, characterized in that: After the step S2, it further includes the step: S3. Second forming: The backing plate (3) continues to move downward to drive the movable template (2) to separate from the fixed template (1).

10. The milling cutter injection molding method according to claim 8, characterized in that: In the step S1, a needle valve type hot runner is used to inject a high-temperature and high-pressure material flow. The injection pressure is 100 Mpa - 120 MPa, the material temperature is 120 °C - 150 °C, and the cooling temperature after the forming milling cutter (20) is formed is 30 °C - 40 °C.

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