Plastic mold and using method thereof

Abstract

The invention belongs to the technical field of plastic processing, and particularly relates to a plastic mold and a using method thereof. The plastic mold comprises a lower bottom mold which is arranged on a workbench, and a shaping mold is fixed on the upper surface of the lower bottom mold; the upper top die is arranged on the lower bottom die in a lifting mode, and a fixed cavity is formed when the upper top die abuts against the lower bottom die; a runner communicated with the shaping cavity is formed in the upper top mold; the cold material structure is arranged on the shaping mold in a lifting manner and is positioned below the runner; when the upper top die abuts against the lower bottom die, the cold material structure abuts against the outlet end wall of the runner. When the shaping cavity is filled with the materials in the hot melting state, the cold material structure moves downwards, and the contact area between the materials in the cold material structure and the formed workpiece is extruded. Through the arrangement of the cold material structure, when the shaping cavity is filled with the material in the hot melting state, the cold material structure moves downwards and extrudes the material in the cold material structure, so that the contact area between the material and a formed workpiece is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic processing, specifically relates to injection molding, and particularly relates to a plastic mold and its use method. Background Art

[0002] During the injection molding process of plastic products, the main function of the cold slug well is to store the cold slug formed at the initial stage of injection due to low temperature, and prevent it from entering the cavity, which may cause cold slug marks, uneven gloss or performance defects on the surface of the product. For example, when the molten material flows through the nozzle or the runner, the front material forms a cold slug due to rapid cooling, and the cold slug well can intercept and store it.

[0003] In the related art, the cold slug well is mostly arranged below the outlet of the nozzle or the runner, and the molten material in the hot melt state at the initial stage of injection directly flows into the cold slug well to achieve the effect of isolating the cold slug.

[0004] However, if the diameter of the cold slug well is set too large, the contact area between the material in the cold slug well and the formed workpiece will be too large, which is not conducive to post-treatment.

[0005] Therefore, how to solve the problem that the diameter of the cold slug well is too large, resulting in the difficulty of separating the material in it from the formed workpiece is a technical problem that needs to be solved in this field.

[0006] It should be noted that the above information disclosed in this background art section is only used to understand the background art of the concept of this application. Therefore, the above description is not considered to constitute the information of the related art. Summary of the Invention

[0007] The embodiments of the present disclosure at least provide a plastic mold and its use method.

[0008] In a first aspect, the embodiments of the present disclosure provide a plastic mold, including: A lower bottom mold, which is arranged on the workbench, and a shaping mold is fixed on its upper surface; An upper top mold, which is arranged to be lifted and lowered on the lower bottom mold, and forms a shaping cavity when it abuts against the lower bottom mold; A runner communicating with the shaping cavity is formed on the upper top mold; A cold slug structure, which is arranged to be lifted and lowered on the shaping mold and is located below the runner; Wherein, when the upper top mold abuts against the lower bottom mold, the cold slug structure abuts against the end wall of the outlet of the runner; When the shaping cavity is filled with the molten material, the material pushes the cold slug structure to move downward, squeezing the cold slug in the cold slug structure to deform, so as to reduce the contact area between the cold slug in the cold slug structure and the formed workpiece.

[0009] In an alternative embodiment, the sizing die is axially provided with a collecting hole, and the cold material structure is vertically arranged in the collecting hole; The upper surface of the sizing die is provided with a positioning groove; Wherein, when the cold material structure retracts into the positioning groove, the surface of the cold material structure is coplanar with the upper surface of the sizing die.

[0010] In an alternative embodiment, the cold material structure includes: a cold material well, which is vertically arranged in the collecting hole and has an upper end protruding from the surface of the sizing die; A positioning ring, which is vertically fixed to the upper end of the cold material well; Two receiving openings are radially formed in the cold material well near the positioning ring, and each receiving opening is hinged with a pressing piece, and the outer wall of the pressing piece abuts against the inner wall of the collecting hole; Wherein, when the cold material well moves downward, the inner wall of the collecting hole presses the pressing piece to turn inward; The two pressing pieces turn inward synchronously to squeeze the cold material in the cold material well, so as to reduce the contact area between the cold material therein and the formed workpiece.

[0011] In an alternative embodiment, the outer wall of the pressing piece is conical, and the outer diameter of the pressing piece gradually decreases from top to bottom.

[0012] In an alternative embodiment, the inclination angle between the conical surface of the outer wall of the pressing piece and the horizontal plane is: 60 - 80°.

[0013] In an alternative embodiment, a horizontal through hole is formed in the lower bottom die, and an adjusting rod is slidably arranged in the horizontal through hole, and the adjusting rod is located below the cold material well; Wherein, when the adjusting rod moves horizontally towards the cold material well, it pushes the cold material well upward to facilitate demolding.

[0014] In an alternative embodiment, the end of the adjusting rod is provided with an inclined surface, and the horizontal height of the inclined surface gradually decreases from the end close to the adjusting rod to the other end; Wherein, when the adjusting rod moves towards the cold material well until the inclined surface abuts against the bottom wall of the cold material well, and the adjusting rod continues to move, the inclined surface pushes the cold material well and the formed workpiece upward to separate from the sizing die.

[0015] In an alternative embodiment, a convex block is arranged on the adjusting rod, and a guiding surface is arranged on the side wall of the convex block, and the guiding surface gradually increases in horizontal height from the end close to the cold material well to the other end.

[0016] In an alternative embodiment, a cut-off film is arranged on the bottom wall of the cold material well, and the cut-off film is a flexible part; When the adjusting rod moves towards the cold slug well, the convex block presses the cut-off film to deform upwards, so that the material in the cold slug well detaches from the cold slug well.

[0017] In an alternative embodiment, the thickness of the positioning ring is the same as the grooving depth of the positioning groove, and the outer diameter is the same as the inner diameter of the positioning groove. In a second aspect, the embodiments of the present disclosure further provide a method for using a plastic mold, and the method includes: The upper top mold moves downwards until it abuts against the lower bottom mold, and the cold material structure abuts against the outlet end wall of the runner; The cold material structure is adapted to collect the cold material in a hot melt state at the initial stage of injection to prevent the cold material from flowing into the shaping cavity; When the shaping cavity is filled with the material in a hot melt state, the material pushes the cold material structure to move downwards. When the cold material structure moves downwards, it squeezes the cold material inside it to deform, so as to reduce the contact area between the cold material in the cold material structure and the formed workpiece.

[0018] The beneficial effect of the present invention is that the present invention provides a plastic mold and a method for using the same. Through the arrangement of the cold material structure, during the process of the shaping cavity being filled with the material in a hot melt state and gradually solidifying, the cold material structure moves downwards and shrinks into the collection hole, the inner wall of the collection hole squeezes the two extrusion pieces to turn inwards, and the extrusion pieces squeeze the material in the cold slug well to deform, so as to reduce the contact area between the material and the formed workpiece.

[0019] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention are achieved and obtained by the structures specifically pointed out in the specification and the drawings.

[0020] To make the above objectives, features, and advantages of the present invention more obvious and understandable, specific preferred embodiments are hereby given, and in conjunction with the accompanying drawings, the following detailed description is provided. Description of the Drawings

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the related technical solutions. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 Isometric view of the unfolded state of the plastic mold provided by the embodiments of the present disclosure; Figure 2 Isometric sectional view of the unfolded state of the plastic mold provided by the embodiments of the present disclosure; Figure 3Cross-sectional perspective view of the cold material structure provided by the embodiments of the present disclosure; Figure 4 Partial cross-sectional view of the adjusting rod and the cold material structure provided by the embodiments of the present disclosure; Figure 5 Perspective view of the adjusting rod and the cold material well provided by the embodiments of the present disclosure; Figure 6 Schematic diagram of the deformation state of the material in the cold material well extruded by the extrusion sheet provided by the embodiments of the present disclosure; Figure 7 Schematic diagram of the connection state between the formed workpiece and the material in the cold material well provided by the embodiments of the present disclosure; Figure 8 Schematic diagram of the connection state between the formed workpiece and the material in the cold material well in the prior art..

[0023] In the figure: 1. Upper top die; 10. Shaping cavity; 11. Runner; 2. Lower bottom die; 20. Shaping die; 21. Collection hole; 22. Positioning groove; 23. Through hole; 24. Adjusting rod; 25. Inclined surface; 26. Convex block; 3. Cold material structure; 31. Cold material well; 32. Positioning ring; 33. Extrusion sheet; 34. Cut-off film; 4. Workpiece; 40. Cold material. Detailed implementation manners

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0025] In this document, when it is mentioned that the first component is located on the second component, this may mean that the first component can be directly formed on the second component, or a third component can be inserted between the first component and the second component. In addition, in the drawings, for the effective description of the technical content, the thickness of the components can be exaggerated or reduced.

[0026] In this document, the exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0027] The terms used herein are for describing specific exemplary configurations only and are not intended to be limiting. As used herein, the singular articles "a", "an", and "the" may also be intended to include the plural forms, unless clearly stated otherwise in the context. The terms "comprising", "including", and "having" are inclusive, thus specifying the presence of the specified features, steps, operations, elements, and / or components, but not precluding the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as the order of performance. Additional or alternative steps may be employed.

[0028] As used herein, phrases such as "in one embodiment", "according to one embodiment", "in some embodiments", etc. generally refer to the fact that the specific feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a specific feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example", "exemplary", etc. are used "as an example, instance, or illustration. Any embodiment, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other embodiments, aspects, or designs. Instead, the use of the terms "example", "exemplary", etc. is intended to present concepts in a specific manner.

[0029] It has been found through research that in the related art, cold slug wells are mostly arranged below the nozzles or the discharge ports of the runner channels, and the hot melt state materials at the initial stage of injection directly flow into the cold slug wells to achieve the effect of isolating cold materials.

[0030] However, if the diameter of the cold slug well is set too large, it will lead to too large a contact area between the materials in the cold slug well and the formed workpiece, which is not conducive to post-treatment.

[0031] Therefore, how to solve the problem that the diameter of the cold slug well is too large, resulting in the difficulty of separating the materials therein from the formed workpiece is a technical problem that the art continues to solve.

[0032] Regarding the defects and their causes of the above solutions, they are all the results obtained by the inventors through practice and careful research. Therefore, the process of discovering the above problems and the solutions proposed in this disclosure by the present disclosure for the above problems should all be the contributions made by the inventors during the process of this disclosure.

[0033] It should be noted that: Similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] The following will describe in detail some embodiments of the present invention with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0035] As Figures 1 to 8 shown, at least one embodiment provides a plastic mold, including: a lower bottom mold 2, which is arranged on a workbench, and a shaping mold 20 is fixed on the upper surface; the shaping mold 20 is detachably arranged on the lower bottom mold 2, and the shaping mold 20 is in the shape of the workpiece 4 after molding to adapt to the requirements of workpieces 4 of different specifications and models. An upper top mold 1, which is arranged to be lifted and lowered on the lower bottom mold 2, and forms a cavity 10 when abutting against the lower bottom mold 2; a material injection port is formed on the upper top mold 1, and the material injection port is communicated with the runner 11, and the material in a hot-melt state flows to the shaping cavity 10 through the material injection port. A runner 11 communicated with the shaping cavity 10 is formed on the upper top mold 1; the runner 11 is adapted to guide the material in a hot-melt state to flow into the shaping cavity 10. A cold material structure 3, which is arranged to be lifted and lowered on the shaping mold 20 and is located below the runner 11; wherein, when the upper top mold 1 abuts against the lower bottom mold 2, the cold material structure 3 abuts against the end wall of the outlet of the runner 11; at this time, the cold material structure 3 abuts against the bottom wall of the upper top mold 1 to prevent the cold material at the initial stage of injection from flowing into the shaping cavity 10. In this embodiment, the cold material 40 refers to the material in a hot-melt state with a relatively low temperature. Since the temperature in the runner 11 is still relatively low during the process of injecting it into the runner 11, the temperature of the material in a hot-melt state at this time is slightly lower than the normal required temperature, and the material in this state cannot be directly used to mold the workpiece 4. When the shaping cavity 10 is filled with the material in a hot-melt state, the material in the shaping cavity 10 pushes the cold material structure 3 to move downward to squeeze the cold material inside the cold material structure 3 to deform, so as to reduce the contact area between the cold material inside the cold material structure 3 and the workpiece 4 after molding. Through the setting of the cold material structure 3, during the process that the shaping cavity 10 is filled with the material in a hot-melt state and gradually shaped, the cold material structure 3 moves downward and shrinks into the collection hole 21, and the inner wall of the collection hole 21 squeezes the two extrusion pieces 33 to turn inward, and the extrusion pieces 33 squeeze the cold material in the cold material well 31 to deform, so as to reduce the contact area between the cold material and the workpiece 4 after molding. In this embodiment, the material is a plastic material recycled from waste materials, which is re-melted into a hot-melt state after classification and cleaning.

[0036] Referring to the attached Figure 8 drawings, in the related art, the diameter of the cold material well 31 is mostly 1.5 - 2 times the diameter of the runner 11. The relatively large diameter of the cold material well 31 can prevent the cold material 40 in the runner 11 from flowing into the shaping cavity 10. However, for the cold material well 31 with a relatively large diameter, after the workpiece 4 is demolded from the shaping mold 20, the contact surface between the cold material 40 and the workpiece 4 is too large, which is not conducive to separating the cold material 40 from the contact surface, and even after separation, a relatively large trace will be left.

[0037] Referring to the attached Figure 2, the shaping die 20 is axially provided with a collecting hole 21, and the cold material structure 3 is arranged to move up and down in the collecting hole 21; when the upper top die 1 and the lower bottom die are engaged in contact, the positioning ring 32 of the cold material structure 3 abuts against the outlet end wall of the runner 11. At this time, the upper end of the cold material structure 3 protrudes from the shaping die 20. A positioning groove 22 is provided on the upper surface of the shaping die 20; the inner diameter of the positioning groove 22 is larger than the inner diameter of the collecting hole 21. Among them, when the cold material structure 3 shrinks into the positioning groove 22, the surface of the cold material structure 3 is coplanar with the upper surface of the shaping die 20.

[0038] Reference appendix Figure 3 , the cold material structure 3 includes: a cold material well 31, which is arranged to move up and down in the collecting hole 21 and its upper end protrudes from the surface of the shaping die 20; an adjusting groove is axially provided on the inner wall of the collecting hole 21, a sliding block is arranged on the outer wall of the cold material well 31, and the sliding block is slidably arranged in the adjusting groove. A return spring is arranged in the adjusting groove, the upper end of the return spring is fixed on the sliding block, and the return spring is adapted to push the cold material well 31 upward to move. So that the positioning ring 32 can abut against the outlet end wall of the runner 11. A positioning ring 32, which is vertically fixed at the upper end of the cold material well 31; the thickness of the positioning ring 32 is the same as the grooving depth of the positioning groove 22, and the outer diameter is the same as the inner diameter of the positioning groove 22; when the positioning ring 32 and the cold material well 31 are pushed downward by the molten material and shrink into the collecting hole 21, the upper surface of the positioning ring 32 is coplanar with the upper surface of the shaping die 20 to ensure the smoothness of the inner wall of the thermoplastic molded material. Two accommodating openings are radially provided at the position where the cold material well 31 is close to the positioning ring 32, and an extrusion piece 33 is hinged in each accommodating opening. The extrusion piece 33 is arc-shaped, and the outer wall of the extrusion piece 33 abuts against the inner wall of the collecting hole 21; a torsion spring is sleeved on the outer wall of the hinge shaft of the extrusion piece 33 and the accommodating opening, and the torsion spring is adapted to push the extrusion piece 33 to turn outwards. Among them, when the cold material well 31 moves downward, the inner wall of the collecting hole 21 squeezes the extrusion piece 33 to turn inwards; the two extrusion pieces 33 turn inwards synchronously to squeeze the cold material 40 in the cold material well 31 to deform, so as to reduce the contact area between the cold material 40 in the cold material structure 3 and the formed workpiece 4.

[0039] Continue to refer to appendix Figure 3 , the outer wall of the extrusion piece 33 is conical, and the outer diameter of the extrusion piece 33 gradually decreases from top to bottom. As the cold material well 31 moves downward and shrinks into the collecting hole 21, the inner wall of the collecting hole 21 gradually squeezes the two extrusion pieces 33 to turn inwards synchronously, and the two extrusion pieces 33 turn inwards to gradually squeeze the cold material 40 in the cold material well 31 to make its outer diameter smaller, so that the contact area between the cold material 40 in the cold material well 31 and the workpiece 4 in the shaping cavity 10 is reduced. Thus, it is more convenient to remove the cold material 40 in the cold material well 31 from the formed workpiece 4 at the rear end. Preferably, the inclination angle between the conical surface of the outer wall of the extrusion piece 33 and the horizontal plane is: 60 - 80°.

[0040] Reference appendix Figure 4 A horizontal through hole 23 is formed in the lower bottom die, and an adjusting rod 24 is slidably arranged in the horizontal through hole 23. The adjusting rod 24 is located below the cold material well 31. When the adjusting rod 24 moves horizontally towards the cold material well 31, the cold material well 31 is pushed upward to facilitate demolding.

[0041] Reference appendix Figure 5 An inclined surface 25 is arranged at the end of the adjusting rod 24, and the horizontal height of the inclined surface 25 gradually decreases from one end close to the adjusting rod 24 to the other end. When the adjusting rod 24 moves towards the cold material well 31 until the inclined surface 25 abuts against the bottom wall of the cold material well 31 and the adjusting rod 24 continues to move, the inclined surface 25 pushes the cold material well 31 and the formed workpiece 4 upward to separate from the shaping die 20. A convex block 26 is arranged on the adjusting rod 24, and a guiding surface is arranged on the side wall of the convex block 26, and the horizontal height of the guiding surface gradually increases from one end close to the cold material well 31 to the other end. A cut-off film 34 is arranged on the bottom wall of the cold material well 31, and the cut-off film 34 is a flexible part. The cut-off film 34 is a high-temperature resistant fluororubber (temperature resistance 320 °C, Shore hardness 60A), with a thickness of 1.2 mm, and is in direct contact with the hot melt state material. When the adjusting rod 24 moves towards the cold material well 31, the convex block 26 squeezes the cut-off film 34 to deform upward, so that the cold material 40 in the cold material well 31 is separated from the cold material well 31.

[0042] At least one embodiment provides a method for using a plastic mold, and the method includes: The upper top die 1 moves downward to abut against the lower bottom die 2, and the cold material structure 3 abuts against the outlet end wall of the runner 11; The cold material structure 3 is adapted to collect the hot melt state material at the initial stage of injection to prevent the cold material 40 at the initial stage of injection from flowing into the shaping cavity 10; When the shaping cavity 10 is filled with the hot melt state material, the material pushes the cold material structure 3 to move downward. When the cold material structure 3 moves downward, the cold material 40 inside is squeezed and deformed to reduce the contact area between the cold material 40 in the cold material structure 3 and the formed workpiece 4.

[0043] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional 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, and therefore should not be construed as a limitation to the present invention. In addition, terms such as "first", "second" and other numerical terms used herein do not imply order or sequence unless explicitly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer or section discussed above may be referred to as the second element, component, region, layer or section.

[0045] Based on the above revelation of the ideal embodiments of the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A plastic mold, characterized in that: include: A lower bottom mold (2) is arranged on a workbench and has a shaping mold (20) fixed on its upper surface; An upper mold (1) is lifted and arranged on the lower mold (2) and forms a certain cavity (10) when it abuts against the lower mold (2); The upper mold (1) is provided with a flow channel (11) which is in communication with the molding cavity (10); A cold material structure (3) which is lifted and arranged on the shaping die (20) and is located below the flow channel (11); When the upper mold (1) abuts against the lower mold (2), the cold material structure (3) abuts against the outlet end wall of the flow channel (11); When the molding cavity (10) is filled with hot-melt material, the material pushes the cold material structure (3) to move downward, and when the cold material structure (3) moves downward, it squeezes the cold material (40) therein to deform, thereby reducing the contact area between the cold material (40) in the cold material structure (3) and the formed workpiece (4).

2. The plastic mold according to claim 1, characterized in that: The shaping die (20) is provided with a collecting hole (21) along the axial direction, and the cold material structure (3) is lifted and disposed in the collecting hole (21); The upper surface of the shaping mold (20) is provided with a positioning groove (22); When the cold material structure (3) shrinks into the positioning groove (22), the surface of the cold material structure (3) is coplanar with the upper surface of the shaping mold (20).

3. The plastic mold according to claim 2, characterized in that: The cold material structure (3) comprises: a cold material well (31), which is arranged in a lifting manner in the collecting hole (21) and has an upper end protruding from the surface of the shaping mold (20); A positioning ring (32) is vertically fixed to the upper end of the cold material well (31); the cold material well (31) is provided with two receiving openings in a radial direction near the positioning ring (32), each receiving opening having an extrusion sheet (33) hingedly connected therein, and the outer wall of the extrusion sheet (33) abuts against the inner wall of the collecting hole (21); When the cold material well (31) moves downward, the inner wall of the collecting hole (21) squeezes the extrusion sheet (33) to turn inward; The two extrusion plates (33) are synchronously turned inward to extrude the cold material (40) in the cold material well (31) to deform, thereby reducing the contact area between the cold material (40) in the cold material well (31) and the formed workpiece (4).

4. The plastic mold according to claim 3, characterized in that: The outer wall of the extrusion sheet (33) is tapered, and the outer diameter of the extrusion sheet (33) gradually decreases from top to bottom.

5. The plastic mold according to claim 4, characterized in that: The inclined angle between the conical surface of the outer wall of the extrusion sheet (33) and the horizontal plane is 60-80°.

6. The plastic mold according to claim 3, characterized in that: The lower bottom mold (2) is provided with a horizontal through hole (23), an adjusting rod (24) is slidably arranged in the horizontal through hole (23), and the adjusting rod (24) is located below the cold material well (31); When the adjusting rod (24) moves horizontally toward the cold material well (31), the cold material well (31) is pushed to move upward, so that the formed workpiece (4) can be demoulded from the forming mold (20).

7. The plastic mold according to claim 6, characterized in that: An inclined surface (25) is provided at the end of the adjusting rod (24), and the level of the inclined surface (25) gradually decreases from one end close to the adjusting rod (24) to the other end; The adjusting rod (24) moves toward the cold material well (31) until the inclined surface (25) abuts against the bottom wall of the cold material well (31), and the adjusting rod (24) continues to move, and the inclined surface (25) pushes the cold material well (31) and the formed workpiece (4) to move upward to separate from the shaping mold (20).

8. The plastic mold according to claim 7, characterized in that: The adjusting rod (24) is provided with a protrusion (26), and a side wall of the protrusion (26) is provided with a guide surface, wherein the horizontal height of the guide surface gradually increases from one end close to the cold material well (31) to the other end.

9. The plastic mold according to claim 8, characterized in that: The bottom wall of the cold material well (31) is provided with a stop film (34), and the stop film (34) is a flexible member; When the adjusting rod (24) moves toward the cold material well (31), the protrusion (26) squeezes the cut-off membrane (34) to deform upward, so that the material in the cold material well (31) is separated from the cold material well (31).

10. The plastic mold according to claim 2, characterized in that: The thickness of the positioning ring (32) is consistent with the groove depth of the positioning groove (22), and the outer diameter of the positioning ring (32) is consistent with the inner diameter of the positioning groove (22).

11. A method for using a plastic mold, characterized in that: Using the plastic mold according to any one of claims 1 to 10, the method of using comprises: The upper mold (1) moves downward until it abuts against the lower mold, and the cold material structure (3) abuts against the outlet end wall of the flow channel (11); The cold material structure (3) is suitable for collecting the cold material (40) at the initial stage of injection, so as to prevent the cold material (40) at the initial stage of injection from flowing into the molding cavity (10); When the molding cavity (10) is filled with hot-melt material, the material pushes the cold material structure (3) to move downward, and when the cold material structure (3) moves downward, it squeezes the cold material (40) therein to deform, thereby reducing the contact area between the cold material (40) in the cold material structure (3) and the formed workpiece (4).

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