Handle and injection molding process thereof
By using integral injection molding and vertical ejection molding technology, the seam problem of split handles has been solved, achieving efficient and stable handle production and usage results.
Patent Information
- Application Number
- CN202611364018.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-04
- Publication Date
- 2026-11-03
AI Technical Summary
Traditional injection molding processes for split handles suffer from discontinuous and uneven seams, high mold investment and costs, long production cycles, and unstable bonding between the soft rubber layer and the hard rubber skeleton, resulting in a limited service life.
Using an integral injection mold, the upper and lower shells are assembled into an integral skeleton. Through one-time overmolding, a seamless soft rubber layer is formed. Combined with a multi-point physical locking structure, the ejector pin assembly is used to eject the molding in the vertical direction.
It achieves a seamless, smooth-looking coating with a comfortable grip, high bonding strength, short production cycle, reduced mold and equipment requirements, high product yield, and long service life.
Smart Images
Figure CN123025436A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of product injection molding, specifically to a handle and its injection molding process. Background Technology
[0002] Injection molding is a processing method in which molten plastic material is injected into a mold cavity, and after cooling and solidification, a molded product is obtained. Overmolding injection molding involves injecting a soft plastic layer onto the outer surface of a pre-formed hard plastic skeleton (or metal insert), giving the product both the structural strength of hard plastic and the comfortable grip of soft plastic. It is widely used in the production of handles, grips, and other products. For handles with a split design, the traditional method is to first injection mold multiple hard plastic parts, then overmold each part individually, and finally assemble the overmolded parts into a complete handle product. This "separate overmolding and reassembly" process has the following drawbacks: First, seams are unavoidable between the overmolding layers of each component. These seams are neither continuous nor smooth, severely affecting the product's appearance and grip. Second, each component requires a separate overmolding mold and injection molding process, resulting in a large number of molds, high costs, and the need for multiple injection molding machines, leading to a long production cycle and low efficiency. Third, the soft rubber layer is only bonded to the hard rubber frame using adhesive or physical bonding methods, which can easily lead to loosening, slippage, and detachment after long-term use, resulting in a limited product lifespan.
[0003] Therefore, it is necessary to provide a handle and its injection molding process. Summary of the Invention
[0004] The present invention provides a handle and its injection molding process, which effectively solves the problems of poor finished product quality, high cost and low cancellation efficiency faced by existing split handle injection molding.
[0005] The technical solution adopted in this invention is: The handle is manufactured using an injection molding process. The injection mold includes a front mold assembly and a rear mold assembly. The rear mold assembly includes a rear mold core and ejector pin assemblies. The front mold assembly includes a front mold core and several side core-pulling slider assemblies. The side core-pulling slider assemblies, front mold core, rear mold core, and ejector pin assemblies form a cavity. The rear mold core is provided with a support portion for supporting the lower housing, and the support portion has grooves. The process includes the following steps: S1, opening the mold; S2, placing the lower shell on the rear mold core and fixing it; S3, placing the upper shell on the lower shell, thus fixing the lower and upper shells; S4, closing the mold; S5, injection molding, injecting colloid into the cavity; S6, opening the mold after injection molding, separating the side core-pulling slider assembly from the handle, and the ejector pin assembly lifting the handle from the rear mold core to remove the material. The handle is composed of the lower shell, the upper shell, and the injection molding layer.
[0006] Furthermore, in step S5, the injected colloid is a thermoplastic melt.
[0007] Furthermore, in step S6, the ejector pin assembly lifts the handle from the rear mold core in the vertical direction.
[0008] Furthermore, the injection temperature in step S5 is 180℃-320℃, and the injection pressure is 80-200MPa.
[0009] A handle, injection molded using the aforementioned injection molding process, includes a lower housing, an upper housing, and an injection-molded layer.
[0010] Furthermore, an annular step is formed between the lower housing and the upper housing, and the injection-molded layer is connected to the annular step.
[0011] Furthermore, the lower housing and the upper housing are fixedly connected by snaps, threads, or adhesive.
[0012] Furthermore, the lower end of the lower housing has a positioning structure that engages with the groove for positioning.
[0013] Furthermore, a groove is also provided on the upper end face of the upper housing.
[0014] Furthermore, the cross-sectional shape of the first groove is rectangular and irregular, with the opening narrowing upwards.
[0015] Beneficial effects of the invention: This application first assembles the upper and lower shells into an integral frame, and then completes the integral molding of the soft rubber layer by applying a rubber coating to the outer surface of the upper shell in one go. Molten TPC material flows continuously and solidifies on the outer surface of the frame. The rubber coating layer is seamless, has a smooth appearance, and is comfortable to hold, avoiding the uneven seam problem caused by traditional separate rubber coating and assembly.
[0016] This application involves a four-step process during injection molding: the soft rubber simultaneously fills the embedded groove and wraps the outer surface. After curing, it forms a multi-point, multi-directional physical locking structure with a bonding strength far exceeding that of traditional adhesive or socket methods. It does not loosen or fall off during long-term use, effectively extending the product's service life.
[0017] This application requires only one overmolding mold and one injection molding machine to complete the overmolding of the entire handle. There is no need to develop molds for each component separately, nor is it necessary to occupy multiple injection molding machines. At the same time, it eliminates multiple overmolding and intermediate turnover steps, greatly reducing mold investment and equipment occupation, significantly shortening the production cycle, and effectively controlling the overall manufacturing cost.
[0018] This application achieves a stable composite skeleton before injection molding by positioning and fitting the lower shell with the rear mold core groove and pre-fixing the upper shell with the lower shell (using snaps, threads, or adhesive). The skeleton does not shift or loosen during mold closing and injection molding, effectively ensuring the uniformity of the injection layer thickness and positional accuracy. At the same time, the ejector pin assembly ejects smoothly in the vertical direction, avoiding deformation or tearing of the product due to uneven force during demolding. The overall process consistency is good, the product yield is significantly improved, and it is suitable for large-scale stable production. Attached Figure Description
[0019] Figure 1 A flowchart of the handle injection molding process provided for an embodiment of this application.
[0020] Figure 2 This is an overall schematic diagram of the injection mold used in the injection molding process provided in the embodiments of this application.
[0021] Figure 3 A cross-sectional view of the injection mold used for the injection molding process provided in the embodiments of this application for the injection molding of the handle.
[0022] Figure 4 This is a schematic diagram of the lower housing of the handle provided for an embodiment of this application.
[0023] The markings in the diagram are: 1. Front mold core; 2. Side core-pulling slider assembly; 3. Ejector pin assembly; 4. Rear mold core; 11. Lower shell; 12. Upper shell; 13. Injection layer; 110. Annular step. Detailed Implementation
[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0025] like Figure 1 and Figure 2 as well as Figure 3As shown, the first embodiment provided in this application is a handle injection molding process using an injection mold. The injection mold includes a front mold assembly and a rear mold assembly. The rear mold assembly includes a rear mold core 4 and an ejector pin assembly 3. The front mold assembly includes a front mold core 1 and several side core-pulling slider assemblies 2. The side core-pulling slider assemblies 2, the front mold core 1, the rear mold core 4, and the ejector pin assemblies 3 form a cavity. The rear mold core 4 is provided with a support portion for supporting the lower housing 11. The support portion is provided with... The groove is provided, and the following steps are included: S1, opening the mold; S2, placing the lower shell 11 on the rear mold core 4 and fixing it; S3, placing the upper shell 12 on the lower shell 11, so that the lower shell 11 and the upper shell 12 are fixed; S4, closing the mold; S5, injection molding, injecting colloid into the cavity; S6, after injection molding, opening the mold, the side core-pulling slider assembly 2 disengages from the handle, and the ejector pin assembly 3 pushes the handle off the rear mold core 4 to remove the material. The handle is composed of the lower shell 11, the upper shell 12 and the injection molding layer 13.
[0026] In the above design, after assembling the upper shell 12 and the lower shell 11, the outer surface of the upper shell 12 is coated with rubber. Compared with the traditional method of coating each hard plastic part separately for a split handle, this application eliminates multiple coating and intermediate turnover steps, significantly shortening the production cycle of a single product and improving the output efficiency per unit time, which is particularly suitable for mass production scenarios. Furthermore, the traditional solution requires developing a separate coating mold for each split part, resulting in a large number of molds, high investment, and the need to occupy multiple injection molding machines for simultaneous or time-sharing production, leading to low equipment utilization. This application only requires one coating mold to complete the overall handle coating molding, significantly reducing mold development costs. At the same time, it only occupies one injection molding machine, significantly reducing equipment investment and production line footprint, effectively saving manufacturing costs. In addition, the traditional method of coating and then assembling the parts inevitably results in seams between the coating layers of each component. These seams are neither continuous nor flat, seriously affecting the product's appearance and grip feel. This application uses an integral skeleton placed into the cavity for one-piece encapsulation. Molten TPC material flows continuously and solidifies on the outer surface of the skeleton. The encapsulation layer is continuous and seamless, with a smooth and beautiful appearance and a comfortable grip. Especially for products such as handles that require frequent gripping and operation, the improved grip directly affects the user experience and satisfaction.
[0027] Specifically: In step S5, the injected colloid is a thermoplastic melt.
[0028] In the above design, the thermoplastic melt has good fluidity and filling performance at the injection temperature, which can fully fill the tiny spaces in the cavity, ensuring that the injection layer 13 after molding is tightly bonded to the lower shell 11 and the upper shell 12, and at the same time has sufficient structural strength and surface quality after cooling.
[0029] Specifically: In step S6, the ejector pin assembly 3 lifts the handle from the rear mold core 4 in the vertical direction.
[0030] In the above design, the ejector pin assembly 3 is specifically configured to lift the handle from the rear mold core 4 in the vertical direction. Through the vertical ejection force, the handle can be smoothly separated from the surface of the rear mold core 4, avoiding handle deformation or surface scratches caused by tilted ejection, thereby effectively ensuring the molding accuracy and appearance integrity of the product.
[0031] Specifically, the injection temperature in step S5 is 180℃-320℃, and the injection pressure is 80-200MPa.
[0032] In the above design, the injection temperature is controlled within the range of 180℃ to 320℃, and the injection pressure is controlled within the range of 80MPa to 200MPa. By controlling the injection temperature and pressure within the above-mentioned preferred range, it is possible to ensure that the colloid has sufficient fluidity to smoothly fill the cavity, and to avoid thermal deformation or positional displacement of the lower shell 11 or upper shell 12 due to excessive temperature or pressure, thus ensuring stable and reliable molding quality of the injection-molded layer 13.
[0033] like Figure 3 and Figure 4 As shown, the second embodiment of this application is a handle, which is injection molded using the aforementioned injection molding process, and includes a lower housing 11, an upper housing 12, and an injection-molded layer 13.
[0034] During actual assembly, the lower shell 11 and the upper shell 12 are first assembled into a skeleton and placed in the mold cavity. During injection molding, the molten colloid flows and solidifies on the outer surface of the skeleton and in the gaps between the skeletons, forming an injection-molded layer 13 on the upper shell 12.
[0035] In the above design, by setting the injection molding layer 13 on the upper end surface of the upper housing 12, the upper end surface of the upper housing 12 can be covered, improving the feel of the handle when the user uses the handle of this application (the palm mainly contacts the corresponding area of the upper housing 12).
[0036] Specifically: an annular step 110 is formed between the lower housing 11 and the upper housing 12, and the injection-molded layer 13 is connected to the annular step 110.
[0037] In the above design, the injection molding layer 13 is supported by the annular step 110, so that the outer surface of the injection molding layer 13 can be flush with the outer surface of the lower shell 11.
[0038] Specifically, the lower housing 11 and the upper housing 12 are fixedly connected by snaps, threads, or adhesive.
[0039] In the above design, the snap-fit connection has the advantages of quick assembly and no need for auxiliary tools, making it suitable for large-scale rapid assembly; the threaded connection has the advantages of stable connection and good disassembly; and the adhesive connection has good sealing performance. All three methods can be flexibly selected according to actual production needs to ensure that the lower housing 11 and the upper housing 12 have formed a reliable pre-fixed structure before injection molding.
[0040] Specifically: the lower end of the lower housing 11 has a positioning structure that engages with the groove for positioning.
[0041] In the above design, the positioning structure forms a positioning fit with the groove on the support part of the rear mold core 4. In the step of placing the lower shell 11 before injection molding, the convex-concave fit between the positioning structure and the groove enables the lower shell 11 to be quickly and accurately positioned on the rear mold core 4, avoiding positional displacement of the lower shell 11 during mold closing and injection molding, thereby ensuring the uniformity of the injection layer 13 thickness and the overall molding accuracy.
[0042] Specifically, the upper end face of the upper housing 12 is also provided with a groove.
[0043] In the above design, by setting the No. 1 groove, it can be filled or partially covered by the injection molding layer 13 during the injection molding process, or it can be used as a functional structure reserved on the finished handle to meet specific assembly requirements or design requirements such as weight reduction and reinforcement.
[0044] Specifically, the cross-sectional shape of the first groove is a rectangle with an upward-sloping, irregular shape.
[0045] In the above design, the cross-sectional shape of the first groove is designed to be rectangular, which is simple to process and easy to cooperate with other components; while the irregular shape with an upward opening and narrowing can form an undercut or locking effect during the injection molding process, which helps to form a more solid mechanical locking structure between the injection molding layer 13 and the first groove, further improving the overall bonding strength of the handle.
[0046] In further detail, it should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. The handle is injection molded using an injection mold, which includes a front mold assembly and a rear mold assembly. The rear mold assembly includes a rear mold core (4) and an ejector pin assembly (3). The front mold assembly includes a front mold core (1) and several side core-pulling slider assemblies (2). The side core-pulling slider assemblies (2), the front mold core (1), the rear mold core (4), and the ejector pin assemblies (3) form a cavity. The rear mold core (4) is provided with a support portion for supporting the lower housing (11). The support portion is provided with a groove. Its features are: The process includes the following steps: S1, opening the mold; S2, placing the lower shell (11) on the rear mold core (4) and fixing it; S3, placing the upper shell (12) on the lower shell (11) to fix the lower shell (11) and the upper shell (12); S4, closing the mold; S5, injection molding, injecting colloid into the cavity; S6, opening the mold after injection molding, separating the side core-pulling slider assembly (2) from the handle, and the ejector pin assembly (3) lifting the handle from the rear mold core (4) to remove the material. The handle is composed of the lower shell (11), the upper shell (12) and the injection layer (13).
2. The handle injection molding process according to claim 1, characterized in that: In step S5, the injected colloid is a thermoplastic melt.
3. The handle injection molding process according to claim 1, characterized in that: In step S6, the ejector pin assembly lifts the handle from the rear mold core (4) in the vertical direction.
4. The handle injection molding process according to claim 1, characterized in that: The injection temperature in step S5 is 180℃-320℃, and the injection pressure is 80-200MPa.
5. A handle, injection molded using the handle injection molding process described in claim 1, characterized in that: It includes a lower housing (11), an upper housing (12), and an injection-molded layer (13).
6. The handle according to claim 5, characterized in that: An annular step (110) is formed between the lower housing (11) and the upper housing (12), and the injection molding layer (13) is connected to the annular step (110).
7. The handle according to claim 5, characterized in that: The lower housing (11) and the upper housing (12) are fixedly connected by snaps, threads or adhesive.
8. The handle according to claim 5, characterized in that: The lower housing (11) has a positioning structure at its lower end that engages with the groove for positioning.
9. The handle according to claim 5, characterized in that: The upper end face of the upper shell (12) is also provided with a groove.
10. The handle according to claim 9, characterized in that: The cross-sectional shape of the first groove is rectangular and irregular, with the opening narrowing upwards.