In-mold sprue cutting structure of plastic part mold

Abstract

The utility model provides an in-mold sprue cutting structure of a plastic part mold, and belongs to the technical field of molds. The technical problem that an existing in-mold gate cutting structure is high in cost is solved. The plastic part mold comprises a casting insert fixed to a lower mold base, a casting runner is arranged on the casting insert, a sprue is formed in one end of the casting runner, the in-mold sprue cutting structure comprises a cutter, a moving block and an oil cylinder, the cutter is arranged in the casting insert in a telescopic mode, the upper end of the cutter is aligned to the sprue, a guide groove is formed in the lower end of the casting insert, and the moving block is arranged in the guide groove. The moving block is arranged in the guide groove, the oil cylinder pushes the moving block to move upwards along the guide groove, the lower end of the cutter is fixedly connected with the moving block, a reset spring is arranged between the moving block and the casting insert, and when the oil cylinder pushes the moving block to move upwards, the cutter moves upwards to block the pouring gate, and at the moment, the reset spring is compressed. The device has the advantages of being simple in overall structure and lower in cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of molds and relates to an in-mold cutting gate structure of a plastic part mold. Background Art

[0002] In-mold cutting technology is an automated injection molding technology that uses a cutter to shear or squeeze out the gate before the plastic mold is opened, thereby achieving part-material separation after the plastic mold is opened.

[0003] The current in-mold gate cutting structure generally uses an oil cylinder as the driving force, such as the in-mold automatic gate cutting structure of the refrigerator parts injection mold disclosed in the Chinese patent document [Application No. 202122943549.2], which includes several groups of driving oil cylinders arranged on the mold, and several groups of driving oil cylinders are connected to oil supply components. Each group of driving oil cylinders is provided with a connecting rod driven by the driving oil cylinder to move up and down, and a cutter assembly for cutting the gate is provided on the end of the connecting rod away from the driving oil cylinder. In this structure, the movement of the cutter is completely driven by the driving oil cylinder, that is, the oil cylinder drives the cutter to move back and forth, which requires a two-way driving oil cylinder. The cost of the oil cylinder itself and the complexity of the oil circuit make the overall structure of the mold complex and costly. Utility Model Content

[0004] The purpose of the utility model is to solve the above problems in the existing technology and propose an in-mold cut gate structure for a plastic part mold. The technical problem solved by the utility model is to provide an in-mold cut gate structure with a simple structure.

[0005] The purpose of this utility model can be achieved through the following technical solutions:

[0006] A mold-in-gate cutting structure for a plastic part mold, the plastic part mold includes a casting insert fixed on a lower mold base, the casting insert is provided with a casting runner, one end of the casting runner is a gate, and is characterized in that the mold-in-gate cutting structure includes a cutter, a moving block and a cylinder, the cutter is telescopically arranged in the casting insert and the upper end of the cutter is aligned with the gate, the lower end of the casting insert is provided with a guide groove, the moving block is arranged in the guide groove, the cylinder pushes the moving block to move upward along the guide groove, the lower end of the cutter is fixedly connected to the moving block, and a return spring is provided between the moving block and the casting insert, when the cylinder pushes the moving block to move upward, the cutter moves upward to block the gate and the return spring is compressed at this time.

[0007] When the injection molding is completed, the oil cylinder pushes the moving block to move upward, and the moving block moves upward with the cutter. The upper end of the cutter moves upward to block the gate, thereby blocking the connection between the casting runner and the molding cavity, and achieving the purpose of cutting the gate internally. At this time, the reset spring is compressed. After the plastic part is molded, the oil cylinder is depressurized, and the moving block can be reset downward under the action of the reset spring. The reset spring can generate enough elastic force to overcome the resistance encountered when the cutter is reset, ensuring that the cutter is completely reset. Since the reset spring is used to achieve the reset of the cutter, the oil cylinder only needs to provide a one-way output, and a one-way drive oil cylinder can be used. The oil circuit structure is simple, and the cost of the oil cylinder is lower, which makes the overall structure of the mold simple, the cost is lower, and the stability is higher.

[0008] In the aforementioned in-mold gate cutting structure for a plastic part mold, the oil cylinder includes a piston rod with a flat end surface. When the piston rod moves upward, the end surface of the piston rod abuts against a movable block, and when the piston rod moves downward, the end surface of the piston rod separates from the movable block. The piston rod of the oil cylinder only contacts the movable block when the cutter is in-mold cutting the gate. The piston rod and movable block are separate and have no connection structure, resulting in a simpler structure and easier installation.

[0009] In the above-mentioned in-mold cut gate structure of the plastic part mold, a fixed limiting insert is embedded in the upper end of the casting insert, the upper end surface of the casting insert is flush with the upper end surface of the limiting insert, and the upper end surface of the casting insert and the upper end surface of the limiting insert are both provided with runners, one end of the runner on the casting insert is aligned and connected with one end of the runner of the limiting insert, and the other end of the runner of the limiting insert is a through end, the runners on the casting insert and the limiting insert form the above-mentioned casting runner, and the through end of the runner of the limiting insert is the above-mentioned gate.

[0010] In the above-mentioned in-mold gate structure of the plastic part mold, the through end of the flow channel of the limiting insert is in a trumpet shape.

[0011] In the aforementioned in-mold gate structure for a plastic part mold, a limit groove is defined at the lower end of the casting insert, located on one side of the guide groove. A limit block is fixed in the limit groove. A positioning groove is defined on the side of the movable block adjacent to the limit groove. One side of the limit block extends into the positioning groove. When the movable block moves downward to its lowest position, the limit block abuts against the bottom surface of the positioning groove. This structure limits the lowest position of the movable block and prevents the movable block from disengaging from the guide groove due to the return spring.

[0012] In the aforementioned in-mold gate structure for a plastic part mold, the upper end of the movable block is provided with four mounting slots, which surround the cutter. Each of the four mounting slots houses the aforementioned return springs, whose upper ends abut against the bottom of the guide slot. The four return springs provide greater elastic force, ensuring the cutter's complete return.

[0013] In the aforementioned in-mold gate structure for a plastic part mold, adjusting bolts are threaded onto the bottoms of two symmetrical mounting slots. Abutment plates are fixed to the inner ends of the adjusting bolts, which abut against the inner ends of corresponding return springs. The adjusting bolts can be used to adjust the position of the abutment plates within the mounting slots, thereby adjusting the position of the return springs, thereby adjusting the compression of the return springs and, consequently, their elastic force. After prolonged use, the friction between the cutter and the casting insert increases, and the compression of the return springs can be increased by adjusting the bolts, thereby ensuring that the return springs can reset the cutter.

[0014] In the aforementioned in-mold gate structure for a plastic part mold, the cutter comprises an upper cutter segment, a clearance segment, and a lower connecting segment. A clearance groove is defined on the sidewall of the limiting insert located on one side of the gate. The upper cutter segment extends between the clearance groove and the casting insert. A concave arc-shaped clearance surface is defined on the side of the clearance segment facing the limiting insert. The thickness of the clearance segment gradually increases from the upper cutter segment to the lower connecting segment. The lower connecting segment is fixedly connected to the moving block to prevent contact between the cutter and the limiting insert during movement.

[0015] In the above-mentioned in-mold gate structure of the plastic part mold, a lower edge of the clearance groove is provided with a clearance slope, which can further prevent the cutter from contacting the limiting insert when moving.

[0016] In the above-mentioned in-mold gate structure of the plastic part mold, the movable block is provided with an L-shaped connecting groove, and the lower connecting section is L-shaped and snapped into the connecting groove. This structure realizes the upper and lower fixation of the movable block and the cutter.

[0017] Compared with the prior art, the in-mold gate structure of the plastic part mold has the advantages of simple overall structure, lower cost and higher stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional structural diagram of the plastic mold.

[0019] Figure 2 It is a schematic diagram of the cross-sectional structure of a plastic mold.

[0020] Figure 3 It is a three-dimensional structural diagram of the in-mold cut gate structure.

[0021] Figure 4 It is a schematic diagram of the cross-sectional structure of the in-mold cut gate structure.

[0022] Figure 5 It is a three-dimensional structural diagram of the in-mold cut gate structure.

[0023] Figure 6 It is a schematic diagram of the structure of the in-mold cut gate structure viewed from above.

[0024] Figure 7 It is a schematic diagram of the positional relationship between the moving block and the limiting block.

[0025] Figure 8 It is a schematic diagram of the cross-sectional structure of the moving block.

[0026] In the figure, 1. base; 11. lower die base; 12. upper die base; 121. injection flow channel; 2. casting insert; 21. guide groove; 22. casting flow channel; 23. gate; 24. limiting groove; 3. cutter; 31. upper cutter section; 32. clearance section; 33. lower connecting section; 4. moving block; 41. positioning groove; 42. connecting groove; 43. mounting groove; 44. adjusting bolt; 45. abutment plate; 46. return spring; 5. oil cylinder; 51. piston rod; 6. limiting insert; 61. clearance slope; 7. limiting block. DETAILED DESCRIPTION

[0027] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0028] like Figures 1 to 8 As shown, the plastic part mold includes a base 1, a casting insert 2 fixed on the lower mold base 11, a casting runner 22 is provided on the casting insert 2, one end of the casting runner 22 is a gate 23, and a glue injection runner 121 is opened on the upper mold base 12, and the glue injection runner 121 is aligned and connected with the other end of the casting runner 22.

[0029] The structure of the in-mold gate 23 includes a cutter 3, a moving block 4 and a cylinder 5. The cutter 3 is telescopically arranged in the casting insert 2 and the upper end of the cutter 3 is aligned with the gate 23. The lower end of the casting insert 2 is provided with a guide groove 21. The moving block 4 is arranged in the guide groove 21. The lower end of the cutter 3 is fixedly connected to the moving block 4. The cylinder 5 is fixed on the base 1. The cylinder 5 includes a piston rod 51. The piston rod 51 passes through the lower mold base 11. The end face of the piston rod 51 is flat. When the piston rod 51 moves upward The end face of the piston rod 51 can press against the moving block 4 to push the moving block 4 to move upward along the guide groove 21. When the piston rod 51 moves downward, the end face of the piston rod 51 can separate from the moving block 4. A return spring 46 is provided between the moving block 4 and the casting insert 2. When the oil cylinder 5 pushes the moving block 4 to move upward, the cutter 3 moves upward to block the gate 23 and the return spring 46 is compressed at this time. When the piston rod 51 moves downward, the return spring 46 pushes the moving block 4 to move downward to drive the cutter 3 to reset.

[0030] A fixed limiting insert 6 is embedded in the upper end of the casting insert 2, and the upper end surface of the casting insert 2 is flush with the upper end surface of the limiting insert 6. The upper end surface of the casting insert 2 and the upper end surface of the limiting insert 6 are both provided with runners. One end of the runner on the casting insert 2 is aligned and connected with one end of the runner of the limiting insert 6, and the other end of the runner of the limiting insert 6 is a through end. The runners on the casting insert 2 and the limiting insert 6 form the above-mentioned casting runner 22, and the through end of the runner of the limiting insert 6 is the above-mentioned gate 23. The through end of the runner of the limiting insert 6 is in a trumpet shape, and the cutter 3 passes between the limiting insert 6 and the casting insert 2.

[0031] The lower end of the casting insert 2 is located on one side of the guide groove 21 and a limiting groove 24 is provided. The limiting block 7 is fixed in the limiting groove 24. The movable block 4 is provided with a positioning groove 41 on the side close to the limiting groove 24. One side of the limiting block 7 extends into the positioning groove 41. When the movable block 4 moves downward to the lowest position, the limiting block 7 abuts against the bottom surface of the positioning groove 41.

[0032] The upper end of the movable block 4 is provided with four mounting slots 43, which surround the cutter 3. Each of the four mounting slots 43 houses the aforementioned return springs 46, with the upper ends of the return springs 46 resting against the bottom surface of the guide slot 21. Adjustment bolts 44 are threaded onto the bottoms of two symmetrical mounting slots 43. Abutment plates 45 are fixed to the inner ends of the adjustment bolts 44, which rest against the inner ends of the corresponding return springs 46. The adjustment bolts 44 can be used to adjust the position of the abutment plates 45 within the mounting slots 43, thereby adjusting the position of the return springs 46, thereby adjusting the compression of the return springs 46 and, consequently, the elastic force of the return springs 46.

[0033] The cutter 3 comprises an upper cutter section 31, a clearance section 32, and a lower connecting section 33. A clearance groove is defined on the sidewall of the limiting insert 6 located on one side of the gate 23. The upper cutter section 31 passes between the clearance groove and the casting insert 2. The clearance section 32 has a concave, arc-shaped clearance surface on the side facing the limiting insert 6. The thickness of the clearance section 32 gradually increases from the upper cutter section 31 to the lower connecting section 33. The lower connecting section 33 is fixedly connected to the movable block 4. The movable block 4 has an L-shaped connecting groove 42, and the lower connecting section 33 is L-shaped and snaps into the connecting groove 42. A clearance slope 61 is defined on the lower edge of the clearance groove.

[0034] When the injection molding is completed, the oil cylinder 5 pushes the moving block 4 to move upward, and the moving block 4 moves upward with the cutter 3. The upper end of the cutter 3 moves upward to block the gate 23, thereby blocking the connection between the casting runner 22 and the molding cavity, and achieving the purpose of cutting the gate 23. At this time, the return spring 46 is compressed. After the plastic part is molded, the oil cylinder 5 is depressurized, and the moving block 4 can be reset downward under the action of the return spring 46. The return spring 46 can generate enough elastic force to overcome the resistance encountered when the cutter 3 is reset, ensuring that the cutter 3 is completely reset. Since the return spring 46 is used to achieve the reset of the cutter 3, the oil cylinder 5 only needs to provide a one-way output, and the one-way drive oil cylinder 5 can be used. The oil circuit structure is simple, and the cost of the oil cylinder 5 is lower, which makes the overall structure of the mold simple and the cost lower, and the stability is higher.

[0035] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

Claims

1. A mold-in-mold gate structure for a plastic part mold, the plastic part mold comprising a casting insert (2) fixed on a lower mold base (11), a casting runner (22) being provided on the casting insert (2), one end of the casting runner (22) being a gate (23), characterized in that: The in-mold gate cutting (23) structure comprises a cutter (3), a moving block (4) and an oil cylinder (5), wherein the cutter (3) is telescopically arranged in the casting insert (2) and the upper end of the cutter (3) is aligned with the gate (23), the lower end of the casting insert (2) is provided with a guide groove (21), the moving block (4) is arranged in the guide groove (21), the oil cylinder (5) pushes the moving block (4) to move upward along the guide groove (21), the lower end of the cutter (3) is fixedly connected to the moving block (4), a return spring (46) is provided between the moving block (4) and the casting insert (2), and when the oil cylinder (5) pushes the moving block (4) to move upward, the cutter (3) moves upward to block the gate (23) and the return spring (46) is compressed at this time.

2. The in-mold gate structure of the plastic part mold according to claim 1, characterized in that: The oil cylinder (5) includes a piston rod (51), the end surface of the piston rod (51) is a plane, and when the piston rod (51) moves upward, the end surface of the piston rod (51) can abut against the moving block (4), and when the piston rod (51) moves downward, the end surface of the piston rod (51) can separate from the moving block (4).

3. The in-mold gate structure of the plastic part mold according to claim 1, characterized in that: A fixed limiting insert (6) is embedded in the upper end of the casting insert (2), the upper end surface of the casting insert (2) and the upper end surface of the limiting insert (6) are flush, and the upper end surfaces of the casting insert (2) and the upper end surfaces of the limiting insert (6) are both provided with flow channels, one end of the flow channel on the casting insert (2) is aligned and connected with one end of the flow channel of the limiting insert (6), and the other end of the flow channel of the limiting insert (6) is a through end, and the flow channels on the casting insert (2) and the limiting insert (6) form the above-mentioned casting flow channel (22), and the through end of the flow channel of the limiting insert (6) is the above-mentioned gate (23).

4. The in-mold gate structure of the plastic part mold according to claim 3, characterized in that: The through end of the flow channel of the limiting insert (6) is in a trumpet-shaped shape.

5. The in-mold gate structure of the plastic part mold according to claim 1, characterized in that: The lower end of the casting insert (2) is located on one side of the guide groove (21) and further has a limiting groove (24), a limiting block (7) is fixed in the limiting groove (24), and a positioning groove (41) is provided on the side of the movable block (4) close to the limiting groove (24), one side of the limiting block (7) extends into the positioning groove (41), and when the movable block (4) moves downward to the lowest position, the limiting block (7) abuts against the bottom surface of the positioning groove (41).

6. The in-mold gate structure of the plastic part mold according to claim 1, characterized in that: Four mounting grooves (43) are provided at the upper end of the moving block (4), and the four mounting grooves (43) are arranged around the cutter (3). The above-mentioned return springs (46) are respectively installed in the four mounting grooves (43), and the upper ends of the return springs (46) are in contact with the bottom surface of the guide groove (21).

7. The in-mold gate structure of the plastic part mold according to claim 6, characterized in that: The bottoms of the two symmetrical mounting grooves (43) are screwed with adjusting bolts (44), and the inner ends of the adjusting bolts (44) are fixed with abutting pieces (45), which abut against the inner ends of the corresponding return springs (46).

8. The in-mold gate structure of the plastic part mold according to claim 3, characterized in that: The cutter (3) comprises an upper cutter section (31), a clearance section (32) and a lower connecting section (33); a clearance groove is provided on the side wall of the limiting insert (6) on one side of the gate (23); the upper cutter section (31) passes between the clearance groove and the casting insert (2); the clearance section (32) is provided with a concave arc-shaped clearance surface on one side facing the limiting insert (6); the thickness of the clearance section (32) gradually increases from the upper cutter section (31) to the lower connecting section (33); and the lower connecting section (33) is fixedly connected to the moving block (4).

9. The in-mold gate structure of the plastic part mold according to claim 8, characterized in that: A lower edge of the relief groove is provided with a relief slope (61).

10. The in-mold gate structure of the plastic part mold according to claim 8, characterized in that: An L-shaped connecting groove (42) is provided on the moving block (4), and the lower connecting section (33) is L-shaped, and the lower connecting section (33) is snap-connected in the connecting groove (42).

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