Injection mold machining method and injection mold

Abstract

The invention provides an injection mold processing method and an injection mold, relates to an injection mold processing technology, and particularly discloses a method for processing the outline of a mold by adopting a numerical control processing machine tool to obtain a mold blank; the mold blank is fixed through a clamp, radial parting lines are marked on the mold blank, and then the mold blank is equally cut to form block workpieces capable of being assembled; the parting surfaces of the block workpieces are machined, and the assembled parting surfaces of the four block workpieces are matched with one another after the four block workpieces are assembled in sequence; a mold body spliced by four block workpieces is clamped by a clamp, after the bottom of the mold body spliced by the four block workpieces is turned by a numerical control machine tool, a preset structure is installed in the mold body spliced by the four block workpieces to form an injection molding cavity, and the whole mold is divided into units capable of being spliced; the machining face of each block workpiece is in an open state, and tool interference is eliminated; and the key matching surface is secondarily processed after assembly, so that the overall precision is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of injection mold processing, in particular to an injection mold processing method and an injection mold. Background Art

[0002] In the field of precision plastic mold manufacturing, rotating body products (such as bottle caps, gears, decorative parts, etc.) often need to be molded from multiple workpieces. Traditional processing methods usually use a split mold structure, that is, each workpiece that makes up the cavity is first processed separately, and then assembled and integrated. After the multiple workpieces are assembled, it is difficult to ensure strict concentricity and roundness, resulting in a decrease in the geometric accuracy of the final molded product, affecting assembly or performance. The connection between parts is prone to discontinuity, forming obvious joint lines or uneven areas on the product surface, seriously affecting the product's appearance quality and finish (surface roughness). Especially for products requiring high gloss or mirror finishes, the sharp corners, edges, or delicate structures of individual workpieces are prone to bruises, deformation, or wear during the independent processing, handling, and assembly process, reducing the mold life and affecting product details. Summary of the Invention

[0003] The object of the present invention is to provide an injection mold processing method and an injection mold, which can solve the problems raised by the above background technology in view of the shortcomings of the existing technology.

[0004] The technical solution of the present invention is achieved as follows: The invention provides an injection mold processing method, comprising the following steps: using a CNC machine tool to process the outer contour of the mold to obtain a mold blank; Fix the mold blank with a fixture, mark four radial dividing lines at intervals of 90 degrees along the radial direction of both ends of the mold blank, and then cut the mold blank into equal parts to form assembled block workpieces; Processing the parting surfaces of the divided workpieces so that the parting surfaces of the four divided workpieces match each other after being assembled in sequence; A mold body assembled from four divided workpieces is clamped with a fixture, and the bottom of the mold body assembled from the four divided workpieces is turned using a CNC machine tool. A predetermined structure is installed in the mold body assembled from the four divided workpieces to form an injection molding cavity.

[0005] In some technical solutions of the present invention, the mold body assembled from four divided workpieces has an overall truncated cone-shaped structure.

[0006] In some technical solutions of the present invention, a through hole communicating with the injection molding chamber is provided on the small diameter end of the mold body, which is assembled from four divided workpieces.

[0007] In some technical solutions of the present invention, two guide grooves are machined on the outer side walls of the divided workpieces by using a CNC machine tool, and the opposite guide grooves on the two oppositely arranged divided workpieces are coaxial.

[0008] In some technical solutions of the present invention, the four block workpieces include two first block molds and two second block molds. The two first block molds are symmetrically arranged with the two second block molds as the symmetry axis. The parting surface located on the first block mold matches the parting surface located on the second block mold. The first block mold and the second block mold both include internal surfaces, end faces and parting surfaces assembled with each block workpiece.

[0009] In some technical solutions of the present invention, blind holes are provided on the opposite side walls of the two first segment molds or on the opposite side walls of the two second segment molds.

[0010] In some technical solutions of the present invention, oblique guide column holes are provided on the side walls of the first segment mold or the second segment mold.

[0011] In some technical solutions of the present invention, the inner surfaces of the first segment mold and the second segment mold are both machined with predetermined pattern structures using an electric spark machining machine.

[0012] An injection mold is characterized by comprising an injection mold structure processed by an injection mold processing method.

[0013] Compared with the prior art, the present invention has at least the following advantages or beneficial effects: solving the processing difficulties of deep cavity molds through block processing strategies. The overall mold is divided into assembleable units so that the processing surfaces of each block workpiece are in an open state, eliminating tool interference; after assembly, the key matching surfaces are secondary processed to ensure overall accuracy. The block workpieces can be processed in parallel, shortening the processing cycle; after assembly, only the key parts need to be fine-machined, reducing the overall processing time. Each block includes an inner surface (cavity), an end face (mold surface), and a parting surface (assembly surface), forming a standard modular structure, realizing standardized block types, reducing programming and tool change times, and symmetrical parting surfaces form a wedge-shaped force lock to enhance the rigidity of the assembly. The block workpiece can be replaced later to support local modification of the cavity to adapt to multi-specification production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the three-dimensional structure of the movable mold after assembly in the present invention.

[0015] Figure 2 It is a schematic diagram of the three-dimensional structure of the main body cavity formed after the movable mold is assembled in the present invention.

[0016] Figure 3 It is a schematic diagram of the three-dimensional structure of a single movable mold in the present invention.

[0017] Figure 4 for Figure 3 Schematic diagram of the upward-looking structure.

[0018] Figure 5 for Figure 3 Schematic diagram of the right view structure.

[0019] Figure 6 It is a schematic diagram of the three-dimensional structure of the movable mold and the fixed mold in the present invention.

[0020] Figure 7 This is a structural diagram of the injection molding chamber formed by combining the movable mold and the fixed mold of the present invention.

[0021] Figure 8 It is a schematic cross-sectional structural diagram of the movable mold and the fixed mold in the present invention.

[0022] Figure 9 It is a schematic diagram of the three-dimensional structure of the fixed mold in the present invention.

[0023] Figure 10 It is a schematic diagram of the top structure of the fixed mold in the present invention.

[0024] Figure 11 for Figure 10 Schematic cross-sectional view along the AA direction.

[0025] Figure 12 for Figure 10 Schematic cross-sectional view along the BB direction.

[0026] Reference numerals: 1. Moving mold; 2. Oblique guide hole; 3. Guide groove; 4. Oblique guide column; 5. Gate mold; 6. Mounting seat; 7. Fixed mold; 8. Fixed seat; 9. Guide strip; 10. Split mold; 12. Catheter structure; 13. Cavity structure; 14. Parting surface. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of 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. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0029] Example The present invention provides an injection mold processing method, such as Figures 1-12 As shown, the process includes the following steps: using a CNC machine tool to process the outer contour of a cylindrical / truncated cone-shaped blank, so that the outer contour of the mold is gradually formed to obtain a mold blank; Fix the mold blank with a fixture, mark four radial dividing lines at 90° intervals along the radial direction of the mold blank by laser scribing or engraving, forming four independent block workpiece areas (such as 1 / 4 sector blocks), and then cut the mold blank into equal parts along the dividing lines by wire cutting or band sawing to form assembled block workpieces; Each workpiece is clamped separately, and the parting surfaces 14 of the workpieces are precisely milled using a CNC machine tool to ensure the flatness, roughness and angular tolerances (e.g., ±0.01mm) of adjacent parting surfaces 14 to achieve seamless matching assembly. Finally, the four workpieces are assembled in sequence so that their assembled parting surfaces 14 match each other. The parting surfaces 14 are machined separately to eliminate cumulative errors, with an assembly clearance of ≤0.02mm, reducing the risk of mold flash.

[0030] The four block workpieces are clamped and locked with a ring-shaped fixture to assemble a complete mold body. The bottom end face of the mold body assembled from the four block workpieces is turned by a CNC machine tool to form an injection cavity, and the rotation center of the four block workpieces is ensured to be coaxial with the axis of the injection cavity. Subsequently, a predetermined structure is installed in the mold body assembled from the four block workpieces to form an injection cavity. The predetermined structure is a core / insert, which is used to form the injection cavity structure 13. This technology solves the processing difficulties of deep cavity molds through a block processing strategy. The overall mold is divided into assembleable units so that the processing surface of each block workpiece is in an open state to eliminate tool interference; after assembly, the key mating surfaces are secondary processed to ensure overall accuracy. The block workpieces can be processed in parallel to shorten the processing cycle; after assembly, only the key parts need to be fine-machined to reduce the overall processing time.

[0031] In some technical solutions of the present invention, the inner cavity of the mold body, which is assembled from four component parts, has a truncated cone-shaped structure. This cone-shaped taper design utilizes inclined sidewalls to provide a natural demolding slope, reducing ejection resistance of the molded part. The larger diameter end of the assembled mold body serves as the ejection port, while the smaller diameter end serves as the injection port. The tapered surfaces enhance the assembled structure's shear resistance and extend the mold's life.

[0032] In some embodiments of the present invention, a through-hole is provided on the smaller diameter end of the mold body, which is assembled from four separate components, to communicate with the injection chamber. This through-hole provides a passage for subsequent injection molding material to enter the injection chamber. It also provides a mounting area for the subsequent gate mold 5, ensuring that the axis of the gate mold 5 is coaxial with the axis of the injection chamber.

[0033] In some technical solutions of the present invention, two guide grooves 3 are machined on the outer wall of each segmented workpiece using a CNC machine tool, and the guide grooves 3 opposite to each other on the two oppositely arranged segmented workpieces are coaxial. During assembly, the guide grooves 3 on the symmetrically arranged segmented workpieces are aligned, and radial limiting is achieved by inserting guide pins or under the constraints of other clamping structures. The guide grooves 3 are used to form an assembly positioning reference for four segmented workpieces to constrain the radial displacement of the four segmented workpieces.

[0034] In some technical solutions of the present invention, the four segmented workpieces include two first segmented molds and two second segmented molds. The two first segmented molds are symmetrically arranged with the two second segmented molds as the axis of symmetry. The parting surface 14 on the first segmented mold matches the parting surface 14 on the second segmented mold. The symmetrical segmented design reduces processing complexity, and the matching parting surfaces 14 achieve force closure and self-locking. The first segmented mold and the second segmented mold both include internal surfaces, end surfaces, and parting surfaces 14 assembled with the respective segmented workpieces. Each segmented workpiece includes an internal surface (cavity), an end surface (mold closing surface), and a parting surface 14 (assembly surface), forming a standard modular structure, achieving standardized segmented types, reducing programming and tool change times, and the symmetrical parting surfaces 14 form a wedge-shaped force lock, enhancing the rigidity of the assembly. Subsequent replacement of the segmented workpieces is used to support local cavity modification and adapt to multi-specification production.

[0035] In some technical solutions of the present invention, blind holes are provided in the opposing side walls of the two first segment molds or the opposing side walls of the two second segment molds. Blind holes are machined into the inner side walls of the symmetrical segmented workpieces for inserting ejector pins or retaining plates. These blind holes serve as mounting locations for positioning and securing mechanisms during machining, thus avoiding the weakening of the segmented workpieces that would be caused by the provision of through holes.

[0036] In some technical solutions of the present invention, four holes for inclined guide posts are formed on the sidewalls of the first or second segment mold. These holes provide dynamic centering to compensate for thermal expansion differences. The inclined holes are machined in the segment sidewalls at an angle to the parting surface 14. The inclined guide posts are inserted after assembly. The segment positions are automatically corrected during mold opening and closing, as well as during parting surface 14 machining, preventing undercutting. The preload of the inclined guide posts suppresses vibration and improves stability during high-speed injection molding.

[0037] In some technical solutions of the present invention, a predetermined pattern is machined onto the interior surfaces of both the first and second segmented molds using an EDM. Patterns (e.g., leather or wood grain) are engraved on the interior surfaces using EDM while the molds are segmented. EDM also mitigates tool interference issues with complex curved surfaces, preventing texture loss in negative angles inaccessible to CNC milling cutters and reducing costs.

[0038] An injection mold is characterized by comprising an injection mold structure processed by an injection mold processing method. The movable mold is a divided workpiece.

[0039] The injection mold structure includes: a mounting seat 6 and a fixed mold 7, the fixed mold 7 is mounted on the side wall of the mounting seat 6, and a plurality of movable molds 1 are arranged around the outer wall of the fixed mold 7, and the plurality of movable molds 1 are arranged around the outer side of the fixed mold 7 along the circumference of the fixed mold 7. The plurality of movable molds 1 assembled in sequence are in a truncated cone structure, and the circumference of the movable mold 1 is distributed on the outer wall of the fixed mold 7 and the four movable molds 1 are separated synchronously by using a guide structure, thereby avoiding the difficulty of demolding due to the complex structure of the traditional mold. The truncated cone structure fits tightly when closed, reducing the flash of the injection molded product and improving the dimensional stability of the product; the truncated cone structure has a feed port on the side away from the mounting seat 6, and a main body cavity is provided in the truncated cone structure. The fixed mold 7 is partially embedded in the main body cavity and the bottom of the main body cavity is closed. A secondary body cavity connected to the main body cavity is opened on the top of the fixed mold 7, and a guide structure for guiding the synchronous movement of the plurality of movable molds 1 is provided on the mounting seat 6. By arranging four movable molds 1 circumferentially around the fixed mold 7 to form a frustum-like structure, and using a guide structure to achieve synchronous radial movement of the four movable molds 1, a closed injection cavity is formed when the mold is closed, and the movable mold 1 is quickly separated to take out the product when the mold is opened. In the mold closing stage: the movable mold 1 slides along the guide groove 3 of the mounting seat 6 toward the center of the fixed mold 7 to form a frustum-like structure, and the top of the fixed mold 7 is embedded in the bottom of the main cavity to form a closed injection space composed of the main cavity and the auxiliary cavity; Injection stage: the molten material is injected into the main cavity from the feed port, filled into the auxiliary cavity, and cooled to form; In the mold opening stage: the guide structure guides the movable mold 1 to slide outward synchronously, the frustum-like structure is separated, the molded part is exposed, and then the product is ejected.

[0040] In some technical solutions of the present invention, a gate mold 5 is detachably provided on the top of the frustum-like structure, a portion of the gate mold 5 is embedded in the feed port, and the gate mold 5 is connected to the main body cavity. The gate mold 5 and the frustum-like structure are detachably designed, and the gate mold 5 is embedded in the feed port to achieve the connection between the pouring system and the main body cavity, and allows for quick replacement; during specific operation, the gate mold 5 is installed on the top of the frustum-like structure, and its lower end is embedded in the feed port to form an injection channel. After the injection is completed, the gate mold 5 is removed separately to clean the residual material or replace it with a different type (such as a point gate, a side gate). By replacing the gate mold 5 or adjusting the pattern of the movable mold 1, different product requirements can be adapted.

[0041] In some technical solutions of the present invention, an ejection channel is defined along the axial direction of the fixed mold 7, communicating with the auxiliary body cavity. A push rod is inserted into the channel. After the mold is opened, the push rod moves upward along the channel, contacts the bottom of the product, and applies a thrust, causing the product to escape from the auxiliary body cavity. After separation, the follower mold 1 is allowed to freely fall or be grasped by a robotic arm. During the process of the push rod ejecting the molded part from the auxiliary body cavity through the axial ejection channel of the fixed mold 7, the push rod is propelled by a servo push rod structure, ensuring uniform thrust, thus preventing deformation or damage to the product caused by manual ejection. This structure enables automated demolding, and the use of mechanical ejection reduces manual operation and improves production efficiency.

[0042] In some technical solutions of the present invention, a duct structure 12 is provided on the outer wall of the ejector pin, and a chamber structure 13 for cooling is provided between the outer wall of the duct structure 12 and the inner wall of the ejection channel. A channel structure connected to the chamber structure 13 is provided on the outer wall of the fixed mold 7. The duct structure 12 and the ejection channel form a sealed chamber, which is connected to the cooling / exhaust system through an external channel to achieve mold temperature control or exhaust, realize directional cooling, improve heat dissipation efficiency, and shorten the molding cycle of the product. The specific operation is divided into a cooling stage and an injection stage. During the cooling stage, the cooling medium is injected into the chamber through the channel structure, flowing around the duct, accelerating the heat dissipation of the fixed mold 7. During the injection stage, the chamber structure 13 can be connected to a vacuum pump to extract the gas in the main chamber, reduce bubble defects, and improve the density of the product.

[0043] In some technical solutions of the present invention, a patterned structure is provided on the inner surface of the movable mold 1. The patterned structure on the inner surface of the movable mold 1 directly forms a texture or logo on the product surface. During injection molding, the molten material fills the patterned structure, and after cooling, the corresponding texture is replicated on the product surface. After the mold is opened, the pattern is automatically released when the movable mold 1 is separated, eliminating the need for subsequent processing. The patterned structure on the inner surface of the movable mold 1 is processed using an electric discharge machine to form complex patterns.

[0044] In some technical solutions of the present invention, a fixed seat 8 is sleeved on the outer wall of the fixed mold 7, and the fixed seat 8 is a sleeve-shaped structure. The side wall of the mounting seat 6 is provided with a mounting opening adapted to the fixed seat 8. The fixed mold 7 is embedded in the mounting opening of the mounting seat 6 through the outer fixed seat 8 to prevent the fixed mold 7 from shaking and deflecting. When the mold is closed, the radial force applied by the movable mold 1 to the fixed mold 7 is dispersed from the fixed seat 8 to the mounting seat 6, preventing the fixed mold 7 from shifting and ensuring that the fixed mold 7 maintains position accuracy during high-pressure injection molding. The modular design of the fixed mold 7 and the fixed seat 8 allows for quick disassembly and replacement of the fixed mold 7.

[0045] In some technical solutions of the present invention, the guide structure includes a guide groove 3 corresponding to a plurality of the movable molds 1. The guide groove 3 is arranged on the side wall of the mounting seat 6 along the radial direction of the fixed mold 7. The movable mold 1 is slidably arranged in the guide groove 3. Two guide bars 9 are installed in the guide groove 3. Both sides of the movable mold 1 are provided with limit grooves adapted to the guide bars 9. The guide groove 3 cooperates with the guide bar 9 to limit the movable mold 1 to slide only along the radial direction of the fixed mold 7, prevent the movable mold 1 from deflecting, and ensure the alignment accuracy of the four movable molds 1 after alignment. The limit grooves on both sides of the movable mold 1 are interlocked with the guide bars 9 provided in the guide groove 3. When sliding, the guide bars 9 provide linear constraints, so that the multiple movable molds 1 move synchronously in the guide groove 3 under the drive of the mold opening structure. When closing, a tight frustum-like structure is formed under the constraint of the mold opening structure. The guide bars 9 are in surface contact with the limit grooves to improve wear resistance.

[0046] In some technical solutions of the present invention, an oblique guide hole 2 is provided in the split mold 10. The angle formed by the reverse extension line of the oblique guide hole 2 and the axis of the fixed mold 7 when intersecting is acute. A matching oblique guide post 4 is provided in the oblique guide hole 2. A through-hole is provided on the side wall of the mounting seat 6. The oblique guide post 4 extends outward after being provided in the through-hole. The oblique guide post 4 cooperates with the oblique guide hole 2. When the mold is opened, the oblique guide post 4 slides in the oblique guide hole 2, causing the movable mold 1 to move outward. The oblique guide post 4 causes the axial component force generated by the movable mold 1 to gradually separate the product from the inner surface of the movable mold 1, reducing the risk of adhesion between the product and the inner surface of the movable mold 1, and assisting in avoiding obstructions caused by complex textures or undercut structures when the product is separated from the mold, thereby reducing demolding resistance.

[0047] Two mounting grooves are symmetrically provided on the outer side wall of the fixed mold 7, and a split mold 10 is detachably provided in the mounting groove. When the injection molding material is demoulded, the split mold 10 is first withdrawn from the mounting groove to reduce the contact area between the injection mold and the fixed mold 7, which is convenient for the later demoulding process.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for processing an injection mold, characterized in that: The following steps are involved: The outer contour of the mold is processed by a CNC machine tool to obtain a mold blank; Fix the mold blank with a fixture, mark four radial dividing lines at intervals of 90 degrees along the radial direction of both ends of the mold blank, and then cut the mold blank into equal parts to form assembled block workpieces; Processing the parting surfaces of the divided workpieces so that the parting surfaces of the four divided workpieces match each other after being assembled in sequence; A mold body assembled from four divided workpieces is clamped with a fixture, and the bottom of the mold body assembled from the four divided workpieces is turned using a CNC machine tool. A predetermined structure is installed in the mold body assembled from the four divided workpieces to form an injection molding cavity.

2. The method for processing an injection mold according to claim 1, wherein: The mold body, which is assembled from four sub-workpieces, has an overall truncated cone structure.

3. The method for processing an injection mold according to claim 2, wherein: A through hole communicating with the injection molding chamber is provided on the small-diameter end of the mold body, which is assembled from four divided workpieces.

4. The method for processing an injection mold according to any one of claims 1 to 3, characterized in that: Two guide grooves are machined on the outer side walls of the divided workpieces by using a numerical control machine tool, and the opposite guide grooves on the two oppositely arranged divided workpieces are coaxial.

5. The method for processing an injection mold according to claim 1, wherein: The four block workpieces include two first block molds and two second block molds. The two first block molds are symmetrically arranged with the two second block molds as the symmetry axis. The parting surfaces on the first block molds match the parting surfaces on the second block molds. The first block molds and the second block molds both include internal surfaces, end faces and parting surfaces assembled with each block workpiece.

6. The method for processing an injection mold according to claim 5, characterized in that: Blind holes are provided on the opposite side walls of the two first segment molds or the opposite side walls of the two second segment molds.

7. The method for processing an injection mold according to claim 5, characterized in that: An oblique guide column hole is provided on the side wall of the first segment mold or the second segment mold.

8. The method for processing an injection mold according to claim 5, characterized in that: The inner surfaces of the first segment mold and the second segment mold are both machined with predetermined pattern structures using an electric spark machining machine.

9. An injection mold, characterized in that: The invention comprises an injection mold structure processed by the injection mold processing method according to any one of claims 1 to 8.

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