Injection mold and injection molding process for lamp strip of automobile tail lamp

Abstract

The invention discloses an automobile tail light bar injection mold and an injection molding process, and relates to the technical field of injection molding equipment, the automobile tail light bar injection mold comprises a light bar mold cavity, a center main sprue A, graded sprue groups symmetrically arranged in the length direction of the light bar mold cavity, and a sequence valve control system; the center main sprue A is positioned at the midpoint of the length direction of the light bar mold cavity and is coaxial with the axis of the light bar mold cavity; the sequence valve control system comprises driving execution mechanisms correspondingly connected with the graded sprue set and the A center main sprue, a sensing assembly used for collecting the flowing state of a sprue area in real time and a control module, and the control module triggers the corresponding driving execution mechanisms to open the sprue according to feedback signals of the sensing assembly. According to the invention, through segmented progressive filling, the pressure, temperature and cooling shrinkage stress of the melt are balanced synchronously.

Description

Technical Field

[0001] This invention relates to the technical field of injection molding equipment, and in particular to an injection mold for automotive taillight strips and the injection molding process. Background Technology

[0002] Automotive taillight strip injection molds are specialized molds used to process automotive taillight strips through injection molding. The core of the process is to construct a mold cavity that matches the shape of the taillight strip, and in conjunction with the gate, runner and control system, inject molten plastic into the cavity and cool and solidify it to obtain a molded product that meets the requirements of structural precision, appearance quality and weather resistance and heat resistance. It is a key piece of equipment for the mass production of automotive lighting components.

[0003] Existing automotive taillight strip injection molds mostly adopt a single master gate or a simple multi-gate layout design, lacking a targeted hierarchical layout and precise control mechanism. Single master gate molds only set a single gate at one end of the mold cavity or a fixed position, and the melt needs to extend from the gate to fill both ends of the long strip. Although simple multi-gate molds have multiple gates, they lack coordinated control logic, and most of them are opened simultaneously. Moreover, the gate layout lacks symmetry and hierarchical design, and the runner structure is not optimized for the characteristics of long strips.

[0004] Due to the long length of automotive taillight strips, existing technologies present several technological challenges: First, uneven melt flow occurs. A single main gate results in excessively long melt flow distances, causing pressure and temperature to decrease along the way. By the time the strip reaches the end, it cannot fully fill the cavity, leading to defects such as material shortages and shrinkage marks. Second, weld lines are a significant issue. When multiple gates are opened simultaneously, the low temperature and poor fusion of the melt streams result in wide weld lines with insufficient strength, which can easily become stress concentration points and cause breakage. Third, dimensional accuracy is difficult to control. Inconsistent cooling rates from the gate to the end, coupled with differences in pressure loss, lead to product bending, warping, and uneven wall thickness, failing to meet assembly tolerances. Fourth, production efficiency is low. To ensure filling and cooling, injection pressure needs to be increased, and holding and cooling times need to be extended, which increases mold wear and prolongs the molding cycle, contradicting the advantages of efficient mass production in injection molding. Summary of the Invention

[0005] This application provides an injection mold for automotive taillight strips and an injection molding process, which uses segmented progressive filling to simultaneously balance melt pressure, temperature and cooling shrinkage stress.

[0006] This application provides an injection mold and injection molding process for an automotive taillight strip, employing the following technical solution: An injection mold for an automotive taillight strip and an injection molding process are disclosed. The automotive taillight strip injection mold includes a strip cavity, a central main gate (A), a tiered gate group symmetrically arranged along the length of the strip cavity, and a sequence valve control system. The central main gate (A) is located at the midpoint of the strip cavity's length and is coaxial with the cavity's axis. The sequence valve control system includes drive actuators connected to the tiered gate group and the central main gate (A), a sensing component for real-time acquisition of the flow state in the gate area, and a control module. The control module triggers the corresponding drive actuator to open the gate based on feedback signals from the sensing component.

[0007] Preferably, the connection between the central main gate A and the lamp strip mold cavity is provided with a transition chamfer, the transition chamfer is a 1.5mm×45° inclined surface structure, the central main gate A is rigidly connected to the mold fixing plate by a positioning pin, and the coaxiality error of the positioning pin is ≤0.02mm.

[0008] Preferably, the graded gating group includes at least three symmetrically distributed gating units. The two gating units in each group are symmetrically arranged along the width direction of the lamp strip mold cavity. The horizontal spacing between adjacent gating units is consistent. The runner axis of the graded gating group is parallel to the length direction of the lamp strip mold cavity, and the distance between the center of the runner and the inner wall of the mold cavity is constant.

[0009] Preferably, the inlet end of the graded gating group is provided with a conical buffer cavity, the cone angle of the conical buffer cavity is 30-45°, and the inner wall of the conical buffer cavity is machined with a spiral guide groove with a lead of 8-10mm, the spiral guide groove rotating in the same direction as the melt flow direction.

[0010] Preferably, an elastic scraping component is provided at the end of the graded gate assembly near the outlet. The elastic scraping component includes a high-temperature alloy steel elastic pin, an arc-shaped guide tube, and a driving component. The elastic pin is movably inserted between the arc-shaped guide tube and the graded gate assembly, and the outer peripheral surface of the elastic pin is provided with equally spaced cuts.

[0011] Preferably, the arc-shaped guide tube is tangentially connected to the graded gate assembly, the arc-shaped structure of the high-temperature alloy steel elastic ejector pin is adapted to the curvature of the arc-shaped guide tube, and the cross-section of the elastic ejector pin gradually increases along its axial direction to form a tapered guide structure.

[0012] Preferably, the driving assembly includes an electric telescopic rod, an arc-shaped slider, and a multi-link hinge mechanism. The arc-shaped slider slides along the arc groove corresponding to the arc-shaped guide tube, and the multi-link hinge mechanism converts the linear thrust of the electric telescopic rod into the arc-shaped scraping motion of the elastic pin.

[0013] Preferably, a coaxial conduit is provided on one side of the arc-shaped guide tube, and a flexible scraper is embedded inside the conduit. The flexible scraper has a cross-shaped scraping opening in the middle and is coaxially arranged with the conduit. The edge of the cross-shaped scraping opening extends to the inner wall of the conduit.

[0014] Preferably, a guide plate is vertically connected to the bottom of the conduit outlet, the guide plate has an inclined guide groove inside, a waste recycling box is provided directly below the guide groove, and the inclination angle of the guide groove matches the flow direction of the residual melt.

[0015] Preferably, an injection molding process for automotive taillight strips, using the aforementioned injection mold, includes the following steps: initially, only the A central main gate is opened to inject the melt; when the pressure sensor detects a specified pressure threshold, the two symmetrical graded gate units on both sides are opened simultaneously; the opening of subsequent gate units is triggered by the current unit pressure signal and a time delay is set, the delay time being adjusted according to the melt viscosity characteristics; after filling is completed, pressure holding and cooling are performed.

[0016] In summary, this application has the following beneficial effects: 1. This problem is solved through a centrally symmetrical multi-gate hierarchical layout structure. This structure uses the central gating gate A in the middle of the lamp strip mold cavity as the initial injection point, and symmetrically arranges multiple hierarchical gating gates (B1 / B2, C1 / C2, D1 / D2) on both sides along the length of the lamp strip, forming a stepped layout of "main gating foundation - progressive supplementation by hierarchical gating groups". This structure significantly shortens the flow distance of a single melt stream, making the melt flow path uniform along the length of the lamp strip. Pressure and temperature attenuation are effectively controlled, ensuring that the melt still has sufficient pressure and suitable temperature when it reaches the corners of the cavity, achieving full filling and avoiding defects such as insufficient material and shrinkage marks.

[0017] 2. This is addressed through a coordinated solution using a sequential valve precision control system and a multi-gate, progressively opening structure. The sequential valve control system is equipped with seven independently controlled relays and direct-acting electric cylinders, employing a dynamic control logic of "melt flow front triggering" rather than fixed-time interval opening: when the melt from the central gate A extends to position B1 / B2, that gate opens synchronously, and then gates C1 / C2 and D1 / D2 open sequentially as the melt flows. This structure ensures stable temperature and pressure when multiple melt streams converge, resulting in full molecular chain fusion. This reduces the number and width of weld lines, significantly improves the mechanical strength of the weld joint, and eliminates the risk of breakage.

[0018] 3. This problem is solved through a combination of a centrally symmetrical multi-gate layout and a sequential valve control structure. The centrally symmetrical layout ensures balanced melt pressure transmission, avoiding uneven wall thickness caused by pressure loss differences during flow; the sequential valve control structure, which opens as needed, ensures even melt filling within the mold cavity, significantly reducing internal stress generated during cooling and shrinkage. At the same time, the symmetrical layout makes the cooling rate of each part from the gate to the light strip more consistent, effectively suppressing bending and warping deformation, and ensuring that the product's dimensional accuracy meets the assembly tolerance requirements of automotive lights.

[0019] 4. The integrated optimized structure, combining a multi-gate symmetrical layout with precise sequential valve control, solves the problems of insufficient filling and uneven cooling at their root. It eliminates the need to increase injection pressure, extend holding time, or extend cooling time to ensure product quality, restoring the molding cycle to a reasonable level. Simultaneously, the stability of the symmetrical layout and sequential valve control reduces mold wear. Combined with automated operation, this significantly improves batch production efficiency, reduces production costs, and restores the core advantage of injection molding: "high-efficiency batch production."

[0020] 5. To further address the problem of air bubbles being difficult to expel during the injection of high-viscosity melts, thus affecting the density of the product structure, this invention further optimizes the process by setting a spiral guide groove with a lead of 8-10 mm and a rotation direction consistent with the melt flow on the inner wall of the conical buffer cavity. This is used to disperse pressure using the spiral shearing effect while simultaneously gathering microbubbles with centrifugal force and expelling them with the melt, significantly improving the density of the product's internal structure and avoiding bubble defects.

[0021] 6. To further address the issues of incomplete cleaning of residues after scraping by the elastic ejector pin and easy deformation of the scraper, this invention further optimizes the design by incorporating a high-temperature resistant flexible scraper with a "thin scraping opening and thick outer ring." The scraping opening in the center is cross-shaped and coaxial with the guide tube, enabling a wrap-around scraping of the entire circumference of the ejector pin and the cut gaps to thoroughly remove residual melt. At the same time, the thick outer ring ensures the stability of the scraper structure, while the thin scraping opening improves the adhesion accuracy and avoids secondary adhesion.

[0022] 7. To further optimize the process of driving the elastic ejector pin, the present invention also includes a drive assembly consisting of an electric telescopic rod and a multi-link hinge mechanism, as well as an arc groove and an arc-shaped slider coaxial with the ejector pin. This enables the efficient conversion of linear thrust into arc-shaped scraping force, reducing transmission loss by 15%-20%, while precisely constraining the ejector pin's movement trajectory, preventing uneven wear and jamming, and extending the life of the drive components.

[0023] 8. To address the issues of high-viscosity melt residue easily adhering to the flow channel, repeated deformation of the ejector pin leading to breakage, and dead corners in scraping, this invention further optimizes the design by incorporating an elastic ejector pin made of high-temperature alloy steel, featuring an arc-shaped adaptable structure, an axially gradually changing cross section, and equally spaced cuts. This enables stable reciprocating scraping under high-temperature conditions, thoroughly removing residual melt from the inner wall of the flow channel, avoiding deformation breakage and scraping dead corners. Simultaneously, the dual action of "extrusion-scraping" removes residue from gaps, extends the service life of the ejector pin, and ensures a scratch-free surface on subsequent products.

[0024] 9. To further optimize the invention, the present invention also features a tapered guide structure with a cross-section that gradually increases in size along the axial direction and equally spaced slits. This achieves uniform stress distribution to prevent pin breakage. When the slits close, they form "micro-scraping teeth" to enhance the cutting force. When the slits retract, they open to release internal stress, ensuring thorough scraping and long-term stable use of the pin. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the LED strip injection mold in this embodiment; Figure 2 This is a schematic diagram of the internal structure of the graded gating assembly in this embodiment; Figure 3 This is a schematic diagram of the connection structure between the graded gating assembly and the arc-shaped guide tube in this embodiment; Figure 4 This is a schematic diagram of the overall connection structure between the limit box and the drive assembly in this embodiment; Figure 5 This is an internal cross-sectional view of the catheter in this embodiment; Figure 6 This is a schematic diagram of the internal structure of the driving component in this embodiment; Explanation of reference numerals in the attached drawings: 1. Lamp strip mold cavity; 2. A-center main gate; 3. Staged gate assembly; 301, B1 gate; 302, B2 gate; 303, C1 gate; 304, C2 gate; 305, D1 gate; 306, D2 gate; 4. Heating and detection assembly; 5. Sequence valve control system; 501, Relay assembly; 502, Direct-acting electric cylinder; 6. Spiral guide groove; 7. Arc-shaped guide tube. ; 8. Ejector pin; 9. Cutting edge; 10. Guide tube; 11. Scraper; 12. Scraping edge; 13. Guide plate; 14. Waste recycling bin; 15. Limiting box; 16. Drive assembly; 1601. Second connecting rod; 1602. Electric telescopic rod; 1603. Arc groove; 1604. Arc slider; 1605. First connecting rod; 1606. Push block; 1607. Mounting block; 1608. Third connecting rod. Detailed Implementation

[0026] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content. Example 1

[0027] This invention discloses an injection mold and injection molding process for automotive taillight strips. It addresses the injection molding production of long, U-shaped automotive taillight strips with a length of 1158mm, a cross-section of 2.8mm, and a wall thickness. The aim is to solve technical problems in existing technologies such as insufficient melt filling, increased weld lines leading to decreased strength, difficulty in controlling dimensional accuracy, and prolonged molding cycles. An optimized combination of "multi-gate symmetrical layout + precise sequence valve control" is adopted, using PC / ABS alloy plastic as the injection molding material. Specifically, as shown... Figure 1 As shown, this is an injection mold for automotive taillight strips; it includes a strip mold cavity 1, a central main gate 2, a graded gate assembly 3, and a heating and detection assembly 4.

[0028] like Figure 1 As shown, the central main gate 2 is coaxially positioned at the midpoint of the length of the lamp strip mold cavity 1. The central main gate 2 adopts a conical runner design with an inlet diameter of 4mm, an outlet diameter of 3.5mm, a runner length of 12mm, and an inner wall roughness Ra≤0.02μm. A 1.5mm×45° transition chamfer is provided at the connection between the central main gate 2 and the lamp strip mold cavity 1 to avoid turbulence during melt flow. The outer side of the central main gate 2 is fixed to the mold fixing plate by 4 M6 locating pins with a positioning accuracy of ±0.01mm, ensuring that the main gate is always in the center of the mold cavity and providing a stable reference for segmented filling.

[0029] like Figure 1 As shown, the maximum flow distance of a single melt stream is precisely controlled to not exceed 300mm, effectively suppressing the attenuation of melt pressure and temperature along the flow direction, and ensuring sufficient filling pressure and suitable temperature at the corners of the cavity.

[0030] like Figure 1 and Figure 2 As shown, with the axis of the central main gate 2 of A as the axis of symmetry, three sets of graded gate groups 3 are symmetrically arranged on both sides along the length of the light strip. The graded gate group 3 includes gate B1 301, gate B2 302, gate C1 303, gate C2 304, gate D1 305, and gate D2 306; respectively B1 gate 301 / B2 gate 302, C1 gate 303 / C2 gate 304, and D1 gate 305 / D2 gate 306. The structure of each set of graded gate groups 3 is completely identical: all adopt cylindrical runners with a diameter of 3mm and a runner length of 10mm, and the inner wall of the runner is also polished.

[0031] The symmetrical layout and precise positioning design ensure that the melt flow paths on both sides are completely consistent, avoiding uneven filling caused by layout offset, and reducing defects such as material shortage and shrinkage marks from the source.

[0032] like Figure 2 and Figure 3 As shown, specifically, the spacing between adjacent gates strictly follows the following standards: the horizontal spacing between the A center main gate 2 and B1 gate 301, and between the A center main gate 2 and B2 gate 302 is 180mm; the horizontal spacing between B1 gate 301 and C1 gate 303, and between B2 gate 302 and C2 gate 304 is 168mm; the horizontal spacing between C1 gate 303 and D1 gate 305, and between C2 gate 304 and D2 gate 306 is 168mm; the horizontal spacing between D1 gate 305 and the left end of the light strip, and between D2 gate 306 and the right end of the light strip is 63mm; each group of graded gates 3 is positioned with the mold cavity plate by two M5 locating pins, and the coaxiality error of the symmetrical gates on both sides (such as B1 and B2) is ≤0.02mm.

[0033] like Figure 2 and Figure 3 As shown, the runners of the central main gate 2 and each group of graded gate groups 3 are all integrally formed from hard alloy material. The connection between the runners is made of arc transition (radius R5mm), with no right angle dead corners, reducing melt flow resistance. The runner axis of all gates is parallel to the length direction of the lamp strip mold cavity 1, and the distance between the center of the runner and the inner wall of the mold cavity is constant at 8mm, ensuring that the pressure transmission is direct and uniform when the melt is injected.

[0034] The chamfered transitions and rounded connections of the runner reduce melt flow resistance, minimize turbulence and bubble generation, and improve melt filling smoothness. The constant spacing between the runner and the mold cavity creates conditions for a symmetrical layout of the subsequent cooling system, contributing to improved cooling uniformity and further controlling product deformation.

[0035] like Figure 1 and Figure 2 As shown, the automotive taillight strip injection mold is included; it also includes a sequence valve control system 5, which is based on "independent control + dynamic triggering" and optimizes the feasibility of hardware configuration and control logic, as detailed below: like Figure 1 and Figure 2As shown, the sequence valve control system 5 includes a relay assembly 501, a direct-acting electric cylinder 502, and a heating and detection assembly 4. The relay assembly 501 uses seven HH52P electromagnetic relays, which correspond one-to-one with the A central main gate 2 and the three-group tiered gate groups 3 (B1 gate 301 / B2 gate 302, C1 gate 303 / C2 gate 304, D1 gate 305 / D2 gate 306). The relay coil voltage is DC24V, and the contact capacity is AC220V / 5A, ensuring stable driving of the direct-acting electric cylinder 502. The seven relays are integrated and installed in a dedicated control box, which is fixed to the outside of the mold and connected to the mold wiring via an aviation plug for easy maintenance and replacement.

[0036] like Figure 1 and Figure 2 As shown, seven independent relays enable individual control of each gate, avoiding overall production stoppages caused by linkage failures and improving system reliability.

[0037] like Figure 1 and Figure 2 As shown, each gate is equipped with one ES08-20 direct-acting electric cylinder 502, with a stroke of 5mm, rated thrust of 80N, response time ≤0.01s, and repeatability of ±0.005mm. The piston rod end of the direct-acting electric cylinder 502 is fixed to the gate valve core by a threaded connection. The valve core is made of tungsten-cobalt alloy, and the clearance between the valve core and the flow channel is controlled at 0.01-0.015mm to ensure tight sealing when the gate is closed and smooth flow when it is opened.

[0038] The high-precision response of the 502 direct-acting electric cylinder and the precise matching of the valve core ensure that the gate opening / closing action is accurate and in place, avoiding melt leakage or poor flow.

[0039] like Figure 1 and Figure 2 As shown, the heating and detection component 4 includes a nickel-chromium alloy heating wire wound around the outer wall of each gate runner. The heating wire has a diameter of 0.5 mm, a winding density of 5 turns / cm, and a rated power of 500W. The heating wire is wrapped with a ceramic insulation layer to prevent leakage and heat loss. A PT100 temperature sensor is embedded in the inner wall of the cavity corresponding to each group of graded gates 3. Pressure sensors (range 0-200MPa, accuracy ±0.5%FS) are embedded in the cavities corresponding to the A central main gate 2 and the D1 gate 305 and D2 gate 306. The sensor data is transmitted to the control module in real time via a data cable.

[0040] The dynamic control logic triggered by the pressure sensor can adapt to the melt flow state in real time compared to fixed timing control, avoiding disorderly merging of multiple melt streams and reducing weld lines.

[0041] In addition, the coordinated control of the heating wire and temperature sensor ensures that the melt at the gate is always kept in a molten state, avoiding cooling blockage, reducing the frequency of mold cleaning, and improving production continuity.

[0042] like Figure 1 and Figure 2 As shown, the injection mold for automotive taillight strips also includes a control module. The control module uses a PLC controller of model S7-200SMART, which is pre-programmed with a "melt flow front trigger" control program. It achieves precise control of the gate opening timing through data feedback from temperature and pressure sensors. The programmable design of the PLC controller makes it easy to fine-tune the gate opening interval according to different raw material characteristics (such as melt index), thereby improving the adaptability of the solution to the production of light strips made of different materials.

[0043] like Figure 1 and Figure 2 As shown, in the initial state, all A-center main gates 2 and graded gate groups 3 are in the closed state, and the heating wires are preheated to 230-250℃ and kept at a constant temperature. After injection molding starts, the PLC controller sends a signal to the corresponding relay, which only turns on the direct-acting electric cylinder 502 of A-center main gate 2, opens the valve core, and injects the melt into the mold cavity.

[0044] When the pressure sensors corresponding to gates B1 301 and B2 302 detect a pressure value of 55 MPa, it is determined that the melt flow front has extended to this position. The PLC controller synchronously sends a signal to the relays corresponding to gates B1 301 and B2 302 to open the two-stage gate groups 3.

[0045] When the pressure sensors corresponding to gates C1 303 and C2 304 detect a pressure value of 50MPa, the PLC controller sends a signal to open gates C1 303 and C2 304 after a delay of 0.03s.

[0046] When the pressure sensors corresponding to gates D1 (305) and D2 (306) detect a pressure value of 45 MPa, the PLC controller sends a signal to open gates D1 (305) and D2 (306) after a delay of 0.02 seconds, until the entire mold cavity is filled. The filling time is preset to 3.748 seconds through Moldflow simulation, and can be finely adjusted by the PLC controller in actual production.

[0047] The real-time monitoring function of sensor data can promptly report abnormal pressure / temperature fluctuations, making it easier for operators to quickly troubleshoot, reduce scrap rates, and improve process stability.

[0048] like Figure 1 and Figure 2As shown, the interior of the lamp strip mold cavity 1 is provided with symmetrical cooling channels. The cooling channels are arranged along the length of the lamp strip and located on both sides of the cavity. The distance between the axis of the cooling channel and the inner wall of the cavity is 15mm, and the diameter of the cooling channel is 8mm. Ethylene glycol aqueous solution is introduced into the cooling channel as coolant. The flow rate of the coolant is controlled at 2.5m / s. The heat of the cavity is removed by the circulation of the coolant, ensuring that the cooling rate of the melt from the gate to the end of the lamp strip is uniform and consistent, and reducing the difference in cooling shrinkage stress.

[0049] like Figure 1 and Figure 2 As shown, during the injection molding process, basic process parameters need to be set. Specifically, the temperature of the front section of the barrel is first set to 220℃, the temperature of the middle section of the barrel is set to 235℃, and the temperature of the rear section of the barrel is set to 225℃ to ensure that the PC / ABS alloy plastic particles are fully melted and plasticized to form a uniform melt.

[0050] The initial injection pressure was then set to 120 MPa, and the holding pressure was set to 80 MPa to avoid mold damage and flash caused by high pressure, while also preventing shrinkage marks and material shortages caused by low pressure.

[0051] The temperature of the molten material is maintained at 230-240℃ through the coordinated control of barrel heating and gate heating wire; pressure is held for 15 seconds to compensate for the shrinkage of the molten material in the mold cavity and ensure the product structure is dense; cooling for 30 seconds allows the molten material in the mold cavity to be fully cooled and solidified. Example 2

[0052] Based on the aforementioned automotive taillight strip injection mold, the injection molding process of this automotive taillight strip adopts a dynamic control logic of "melt flow front triggering". The melt flow state is monitored in real time by a pressure sensor built into the mold cavity, and the opening timing of each gate is triggered by the pressure signal fed back by the pressure sensor. The specific process is as follows: Phase 1: After injection molding starts, the direct-acting electric cylinder 502 of the A-center main gate 2 is activated only by the corresponding electromagnetic relay to open the A-center main gate 2. The molten melt is injected into the mold cavity from the A-gate under the high pressure of the screw, preferentially filling the central area to form a stable melt flow front and accumulate initial pressure. When the pressure sensor detects that the melt flow front extends to the corresponding cavity positions of B1 gate 301 and B2 gate 302, and the feedback pressure reaches 60MPa, the second phase begins.

[0053] The second stage: The electromagnetic relay synchronously controls the action of the direct-acting electric cylinder 502 of gates B1 301 and B2 302, opening gates B1 301 and B2 302. The melt is injected from gates B1 301 and B2 302 to supplement the melt pressure and flow, and to push the melt smoothly towards gates C1 303 and C2 304. When the pressure sensor reports that the pressure reaches 55MPa, it is determined that the melt flow front has extended to the corresponding cavity position of gates C1 303 and C2 304, and the third stage begins.

[0054] The third stage: Following the sequence of "first C1 gate 303 / C2 gate 304, then D1 gate 305 / D2 gate 306", the corresponding direct-acting electric cylinders 502 are controlled sequentially by electromagnetic relays to open C1 gate 303 and C2 gate 304. After an interval of 0.05s, D1 gate 305 and D2 gate 306 are opened to continuously replenish the melt to the far end area of ​​the light strip. According to Moldflow simulation monitoring, the time for the entire mold cavity to be completely filled is 3.748s. After filling is completed, the pressure holding stage is entered. After the pressure holding stage is completed, the cooling stage is entered. After cooling is completed, the mold is opened and the molded product is removed. Example 3

[0055] Major automotive parts manufacturers employ a 24-hour continuous production line to mass-produce U-shaped taillight strips with a length of 700-800mm. The raw material is high-viscosity PC / ABS alloy plastic with a melt flow index of 0.3-0.8g / 10min (220℃ / 10kg). The melt is injected into the mold after being heated to 220-240℃ in the barrel, with a required production capacity of over 120 pieces per hour. While the "centrally symmetrical multi-gate + sequence valve control" method in the above embodiment shortens the melt flow distance, the high-viscosity melt experiences a sudden pressure surge from 0.8-1.2MPa to 1.8-2.2MPa when the graded gate group 3 opens, causing localized impact. Furthermore, after 4 hours of continuous production, a 0.1-0.3mm thick layer of residual melt easily accumulates at the mold cavity and gate connection, resulting in strip-like scratches on the surface of subsequent products and affecting the appearance qualification rate.

[0056] Specifically, when the high-viscosity melt (melt index 0.3-0.8 g / 10 min) is dynamically opened in the graded gate group 3, the local pressure change superposition generates instantaneous pressure peaks, resulting in flash defects of 0.05-0.1 mm at the product edge. At the same time, in continuous batch production, the residual melt at the connection between the gate and the mold cavity cannot be cleaned in real time. After accumulating, it scrapes the subsequently injected melt, causing scratches on the product surface. There are pressure buffering issues of high-viscosity melt and self-cleaning issues at the mold cavity-gate connection, which affect the product qualification rate and batch production stability.

[0057] like Figure 2 and Figure 3As shown, in this embodiment 3, a conical buffer cavity is added at the runner inlet of the graded gate group 3. The cone angle of the buffer cavity is designed to be 30-45°, the length is 15-20mm, and the inner wall is machined with a spiral guide groove 6 with a lead of 8-10mm. The spiral direction of the guide groove is consistent with the melt flow direction, so that the high viscosity melt enters the mold cavity and flows spirally in the guide groove. The pressure smoothly transitions from the initial 1.8-2.2MPa to 1.2-1.5MPa, avoiding flash caused by sudden pressure changes.

[0058] like Figure 2 and Figure 3 As shown, specifically, the conical buffer cavity initially buffers the initial high pressure of the high-viscosity melt by expanding the flow channel space, and the spiral guide groove 6 on the inner wall guides the melt to flow in an orderly spiral. The spiral shearing effect is used to disperse the instantaneous impact force, so that the melt pressure smoothly transitions from 1.8-2.2MPa to 1.2-1.5MPa, thus avoiding the flash defects caused by sudden pressure changes at the source.

[0059] The centrifugal force generated by the spiral flow can gather tiny bubbles in the melt and push them toward the center of the flow channel, where they are discharged synchronously with the melt, significantly reducing internal bubble defects in the product and improving structural density.

[0060] like Figure 3 and Figure 4 As shown, an arc-shaped guide tube 7 is provided at the end of the graded gating group 3 near its outlet. The arc-shaped guide tube 7 and the end of the graded gating group 3 near its outlet are tangentially connected. A high-temperature alloy steel elastic ejector pin 8 is movably installed inside the arc-shaped guide tube 7. The high-temperature alloy steel elastic ejector pin 8 passes through the arc-shaped guide tube 7 around the corresponding center. At the junction of the arc-shaped guide tube 7 and the graded gating group 3, it is guided into the interior of the graded gating group 3 by its own deformation. Each time the gating is closed, the stroke of the high-temperature alloy steel elastic ejector pin 8 scrapes the residual melt along the inner wall of the flow channel of the graded gating group 3 axially, realizing the real-time discharge of the residual melt and ensuring that there is no risk of scratches in the next filling.

[0061] like Figure 3 and Figure 4 As shown, the arc-shaped guide tube 7 is tangentially connected to the graded gate assembly 3 to ensure that the movement trajectory is smooth; the high-temperature alloy steel elastic ejector pin 8 is adapted to the curvature of the arc-shaped guide tube 7, and smoothly enters the straight runner of the graded gate assembly 3 through its own elastic deformation at the junction; when the gate is closed, the ejector pin 8 makes an axial stroke along the inner wall of the runner to directly scrape off the attached residual melt; thus avoiding product scratches caused by residue accumulation from the source.

[0062] Moreover, the repeated axial scraping of the inner wall of the flow channel by the ejector pin 8 will create a slight "polishing effect", continuously reducing the roughness of the inner wall of the flow channel, further reducing the probability of melt adhesion. After long-term use, the residual problem is easier to control, and the mold cleaning cycle is extended.

[0063] like Figure 4 and Figure 5 As shown, the high-temperature alloy steel elastic ejector pin 8 has an arc-shaped structure. The arc-shaped structure of the high-temperature alloy steel elastic ejector pin 8 is precisely matched with the arc of the arc-shaped guide tube 7, ensuring that the ejector pin 8 moves along the preset trajectory of the guide tube without jamming or uneven wear, providing a smooth movement basis for its smooth entry into the straight staged gate group 3 flow channel. The cross-section of the ejector pin 8 increases uniformly from one end inserted into the arc-shaped guide tube 7 to the other end. Its core functions are reflected in two aspects: First, when the ejector pin 8 undergoes elastic deformation at the junction of the arc-shaped guide tube 7 and the staged gate group 3, the stress is evenly distributed along the gradual change direction of the cross-section, avoiding the fracture or permanent deformation of the ejector pin 8 caused by local stress concentration, and ensuring structural stability. Second, the gradual cross-section makes the contact pressure between the ejector pin 8 and the inner wall of the flow channel linearly distributed along the axial direction. The small cross-section of the insertion end facilitates smooth entry into the flow channel, while the large cross-section of the end can provide sufficient scraping pressure, ensuring that when scraping the residual melt along the inner wall of the flow channel axially, the pressure is uniform, the scraping is thorough, and there are no dead corners.

[0064] The tapered guide structure formed by the gradient cross section can guide the high-viscosity melt to flow smoothly along the gradient surface of the ejector pin 8 when the ejector pin 8 is stationary in the runner (gating opening and filling stage), reduce the impact friction between the melt and the surface of the ejector pin 8, avoid the generation of turbulence and vortex, indirectly reduce defects such as bubbles and shrinkage marks inside the product, and improve the uniformity of melt filling.

[0065] During the scraping process, the large cross-section of the ejector pin 8, which has a uniformly enlarged cross-section, exerts a slight squeezing effect on the residual melt at its end, pushing the viscous residual melt adhering to the inner wall of the flow channel away from the wall. Then, it is completely peeled off by axial scraping, forming a dual cleaning effect of "squeezing-scraping". This avoids high-viscosity residual melt adhering to the gaps in the flow channel and further reduces the risk of scratches on the product surface.

[0066] like Figure 4 and Figure 5 As shown, the upper surface of the high-temperature alloy steel elastic ejector pin 8 is provided with several equally spaced slits 9. When the ejector pin 8 enters the straight graded gate group 3 flow channel from the arc-shaped guide tube 7, the constraint of the inner wall of the flow channel causes the ejector pin 8 to undergo radial contraction deformation, and the equally spaced slits 9 close simultaneously, ensuring that the outer peripheral surface of the ejector pin 8 is in close contact with the inner wall of the flow channel, providing uniform contact pressure for axial scraping of residual melt and avoiding scraping dead corners.

[0067] When the ejector pin 8 retracts to the arc-shaped guide tube 7, the flow channel constraint is released, the ejector pin 8 elastically resets, and the cut 9 naturally opens. On the one hand, this releases the internal stress accumulated during the deformation process, preventing the ejector pin 8 from undergoing permanent deformation or breakage due to long-term repeated deformation; on the other hand, the opened cut 9 reduces the contact area between the ejector pin 8 and the inner wall of the arc-shaped guide tube 7, and disperses the contact points, avoiding wear on the inner wall of the guide tube caused by rigid friction, and extending the life of key components of the mold.

[0068] When the cut 9 is closed, evenly distributed micro protrusions are formed on the edge of the cut 9. These protrusions are equivalent to "micro-scraper teeth", which can enhance the cutting force on the stubborn residue on the inner wall of the flow channel, solve the problem of incomplete scraping by the smooth ejector pin 8, and the consistent spacing of the protrusions ensures uniform cleaning intensity throughout the entire flow channel.

[0069] The equidistant design ensures that the stress of the ejector pin 8 is evenly distributed along the axial direction when it deforms, preventing local stress concentration caused by the offset of the cut 9 position, and ensuring the accuracy of the ejector pin 8's movement trajectory and structural stability. If the cut 9 does not close evenly after the ejector pin 8 enters the flow channel, it indicates that the ejector pin 8 has experienced local wear or deformation fatigue. This can be indirectly judged through equipment operating parameters (such as changes in scraping resistance) without disassembling the mold, making it easy to replace the ejector pin 8 in advance and avoid scratch defects in batch products due to ejector pin 8 failure.

[0070] like Figure 4 and Figure 5 As shown, a conduit 10 is fixedly installed on one side of the arc-shaped guide tube 7. The conduit 10 and the arc-shaped guide tube 7 are coaxially and arc-shaped, and the outlet of the conduit 10 faces the inlet of the arc-shaped guide tube 7.

[0071] The catheter 10 and the arc-shaped guide tube 7 are designed to be coaxial and arc-shaped, precisely matching the arc-shaped movement trajectory of the high-temperature alloy steel elastic pin 8. This ensures that the pin 8 can smoothly enter the catheter 10 when it retracts, without jamming or uneven wear, thus counteracting the lateral force generated when the pin 8 deforms and resets. At the same time, the outlet of the catheter 10 faces the inlet of the arc-shaped guide tube 7, forming a continuous channel of "pin 8 retraction - residual entrainment - catheter 10 receiving", ensuring that the movement trajectory of scraping off residual residue is consistent each time.

[0072] like Figure 4 and Figure 5As shown, the inner ring of the guide tube 10 is provided with a scraper 11, and the scraper 11 is coaxially arranged with the guide tube 10. The coaxial arrangement of the scraper 11 and the guide tube 10 ensures that the central cross-shaped scraper 12 is always precisely aligned with the movement trajectory of the high-temperature alloy steel elastic ejector pin 8, avoiding cleaning dead corners caused by scraping deviation; the scraper 11 is made of high-temperature resistant flexible material. The selection of high-temperature resistant flexible material can not only adapt to the arc structure of the ejector pin 8 and the opening and closing action of the cut 9, but also tightly fit the outer peripheral surface of the ejector pin 8 (including the gap of the cut 9) through its own deformation, while avoiding rigid contact that could cause scratches or wear to the ejector pin 8; and the scraper 11 The scraper 11 has a cross-shaped structure in the middle, through which the high-temperature alloy steel elastic pin 8 passes. The cross structure can form a wrap-around scraping on the surface of the pin 8 from four directions, covering the entire circumference of the pin 8 without any omissions, while allowing the pin 8 to pass through smoothly. The thickness of the scraper 12 is less than the thickness of the outer ring of the scraper 11 itself, forming a mechanical structure of "thin scraper 12 + thick outer ring". The thin scraper 12 enhances the fit with the pin 8 and improves the scraping accuracy. The thick outer ring ensures the overall structural stability of the scraper 11, avoids deformation of the scraper 11 due to long-term reciprocating motion, and ensures the consistency of the scraping action.

[0073] like Figure 4 and Figure 5 As shown, the flexible material of the cross-shaped scraper 12 will elastically deform with the opening and closing state of the cut 9 of the ejector pin 8 when the ejector pin 8 passes through. The edge of the scraper 12 can be embedded in the gap of the cut 9 of the ejector pin 8 to scrape off the viscous residual melt attached to the gap (it is difficult for the ejector pin 8 to clean the dead corner of the gap by self-scraping alone), so as to achieve all-round residue cleaning of "surface + gap" and completely eliminate the risk of secondary adhesion of residue.

[0074] like Figure 4 and Figure 5 As shown, when the scraping edge 12 of the flexible scraper 11 comes into contact with the ejector pin 8, it generates a slight elastic buffer force to counteract the inertial impact force when the ejector pin 8 retracts, reduce the rigid collision between the ejector pin 8 and the guide tube 10 and the guide tube, and extend the service life of the moving components of the ejector pin 8; at the same time, the coaxially arranged scraping edge 12 forms a slight radial constraint on the ejector pin 8, which can calibrate the slight trajectory deviation caused by the long-term movement of the ejector pin 8 and ensure the accuracy of scraping and filling.

[0075] like Figure 4 and Figure 5As shown, a guide plate 13 is vertically installed at the bottom of the outlet of the conduit 10. A guide groove is provided inside the guide plate 13, and a waste recycling box 14 is installed directly below the bottom of the guide groove. The guide plate 13 is vertically installed at the bottom of the outlet of the conduit 10, and its internal guide groove is precisely aligned with the outlet of the conduit 10, forming a closed-loop channel of "conduit 10 outlet - guide groove diversion - recycling box collection". The guide groove provides a directional guidance path by adapting to the flow characteristics of the residual melt, avoiding splashing, adhesion or scattering of the residual melt at the outlet of the conduit 10. The recycling box is located directly below the guide groove, accurately receiving all the residual melt diverted by the guide groove, realizing the centralized collection of the residual melt.

[0076] like Figure 4 and Figure 6 As shown, a limiting box 15 is fixedly installed on one side of the graded gating assembly 3. Inside the limiting box 15 is a driving assembly 16 for driving the high-temperature alloy steel elastic ejector pin 8. The driving assembly 16 includes a second connecting rod 1601, an electric telescopic rod 1602 fixed to the limiting box 15, and an arc groove 1603 formed inside the limiting box 15. The arc groove 1603 is coaxially arranged with the high-temperature alloy steel elastic ejector pin 8. An arc-shaped slider 1604 is slidably arranged inside the arc groove 1603. The arc slider 1604 is fixedly connected to the other end of the high-temperature alloy steel elastic ejector pin 8, and the inner end of the arc slider 1604 is fixed... A first connecting rod 1605 is connected. One end of the first connecting rod 1605 is connected to the inner end of the arc-shaped slider 1604, and the other end of the first connecting rod 1605 is hinged to the center of the arc groove 1603. The output end of the electric telescopic rod 1602 is connected to a push block 1606. The push block 1606 is slidably connected to a mounting block 1607. One end of the second connecting rod 1601 is hinged to the mounting block 1607. The middle part of the second connecting rod 1601 is rotatably connected to the limiting box 15. The other end of the second connecting rod 1601 is hinged to the middle part of the first connecting rod 1605 through a third connecting rod 1608.

[0077] The electric telescopic rod 1602 outputs linear thrust, which is transmitted to the slidingly connected mounting block 1607 through the push block 1606, driving the second connecting rod 1601 to rotate around the hinge point between its middle part and the limiting box 15; the rotational motion of the second connecting rod 1601 is transmitted to the first connecting rod 1605 through the third connecting rod 1608, causing the first connecting rod 1605 to rotate around the arc center corresponding to the arc groove 1603.

[0078] The first connecting rod 1605 is fixedly connected to the arc-shaped slider 1604, while the arc groove 1603 is coaxially designed with the high-temperature alloy steel elastic ejector pin 8. Ultimately, the arc-shaped slider 1604 is driven to make a precise arc-shaped slide along the arc groove 1603, driving the ejector pin 8 to complete the reciprocating scraping action of adapting to the flow channel.

[0079] The multi-link articulated transmission structure and the coaxial positioning of the arc groove 1603 and the ejector pin 8 ensure that the movement trajectory of the ejector pin 8 is perfectly matched with the arc-shaped guide tube 7 and the graded gate assembly 3, without deviation or jamming, thus achieving precise and controllable scraping of residue.

[0080] The multi-link transmission structure can efficiently convert the linear thrust of the electric telescopic rod 1602 into the arc-shaped scraping force of the ejector pin 8, resulting in low transmission loss. At the same time, the support of the arc groove 1603 on the slider offsets the lateral friction force during the movement of the ejector pin 8. Compared with the direct drive method, the load of the electric telescopic rod 1602 is reduced by 15%-20%, which saves energy and extends the service life of the drive components, meeting the cost control requirements of high-capacity production.

[0081] Working principle: First, before the mold starts, the preliminary preparation work needs to be completed: the heating component heats the barrel and each gate runner to 230-250℃ in advance and maintains a constant temperature to ensure that raw materials such as PC / ABS alloy plastic can be fully melted and plasticized; the control module of the sequence valve control system 5 is initialized, the A center main gate 2 and the graded gate group 3 are both in the closed state, the temperature sensor and pressure sensor are activated and transmit data in real time, and the waste recycling box 14 is in place to ensure that the residual melt recycling channel is unobstructed.

[0082] Then, the injection molding process officially starts. The control module sends a signal to the corresponding relay, which only activates the direct-acting electric cylinder 502 of the A-center main gate 2. The valve core opens, and the molten plastic is injected into the lamp strip mold cavity 1 from the A-center main gate 2 under the high pressure of the screw. It first fills the central area of ​​the mold cavity, forming a stable melt flow front and accumulating initial pressure. At this time, the 1.5mm×45° transition chamfer at the connection between the A-center main gate 2 and the mold cavity avoids turbulence in the melt. The positioning pin ensures the accurate position of the main gate and ensures the stability of the melt flow base.

[0083] Subsequently, when the pressure sensor corresponding to gate B1 / B2 302 detects that the pressure has reached the set threshold and determines that the melt flow front has extended to this position, the control module simultaneously sends a signal to activate the direct-acting electric cylinder 502 of gate B1 / B2 302. The melt is then injected from this group of gates to supplement the pressure and flow, and to push the melt smoothly towards gate C1 / C2 304. During this process, the conical buffer cavity at the inlet end of the staged gate group 3 and the spiral guide groove 6 on the inner wall guide the high-viscosity melt to flow in an orderly manner, avoiding the generation of flash due to sudden pressure changes.

[0084] Next, when the pressure sensor corresponding to gate C1 / C2 304 reports that the pressure has reached the set value, the control module triggers gate C1 / C2 304 to open after a time delay set according to the melt viscosity characteristics. Subsequently, when the pressure sensor corresponding to gate D1 / D2 306 detects that the pressure has reached the target, gate D1 / D2 306 is opened after a set time delay, continuously replenishing the melt to the far end area of ​​the light strip until the entire mold cavity is filled. The constant spacing design between the runners of the graded gate group 3 and the mold cavity ensures uniform melt pressure transmission and further guarantees filling consistency.

[0085] After filling, the mold enters the pressure holding stage. The control module maintains the set pressure holding for 15 seconds to compensate for the shrinkage of the melt in the mold cavity, ensuring the product structure is dense and avoiding shrinkage defects. At the same time, ethylene glycol aqueous solution is circulated in the symmetrical cooling channel. The heat in the cavity is evenly removed through circulation, allowing the melt to gradually cool and solidify. The cooling time is set to 30 seconds. The symmetrical layout of the cooling channel ensures that the cooling rate of each part of the light strip is consistent, suppressing deformation.

[0086] During the pressure holding and cooling process, the sequence valve control system 5 continuously monitors the temperature and pressure data of each area. If any abnormality occurs, it will promptly provide feedback and adjust the parameters. After cooling is completed, the mold is opened. At this time, the elastic scraping component at the end of the graded gate group 3 is activated. The drive component 16 converts the linear thrust into the arc scraping motion of the elastic ejector pin 8. The elastic ejector pin 8 scrapes away the residual melt along the inner wall of the flow channel axially. The equally spaced cuts 9 on the ejector pin 8 close to form "micro-scraping teeth" to ensure thorough cleaning.

[0087] Finally, when the elastic ejector pin 8 retracts to the arc-shaped guide tube 7, the cut 9 opens to release internal stress. The ejector pin 8 passes through the flexible scraper 11 inside the coaxial guide tube 10. The cross-shaped scraper 12 of the scraper 11 is embedded in the gap of the ejector pin 8 cut 9 to further clean the surface residue. The residual melt is discharged through the guide tube 10 and flows into the waste recycling box 14 along the inclined guide groove of the guide plate 13 to achieve centralized recycling. Then the mold is reset to prepare for the next injection cycle. Through the coordinated work of each component, high-quality automotive taillight strips are continuously and stably produced.

[0088] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An injection mold for automotive taillight strips, characterized in that, The system includes a lamp strip mold cavity (1), a central main gate (2), a tiered gate group (3) symmetrically arranged along the length of the lamp strip mold cavity (1), and a sequence valve control system (5). The central main gate (2) is located at the midpoint of the length of the lamp strip mold cavity (1) and is coaxial with the axis of the lamp strip mold cavity (1). The sequence valve control system (5) includes a drive actuator connected to the tiered gate group (3) and the central main gate (2), a sensing component for real-time acquisition of the flow state in the gate area, and a control module. The control module triggers the corresponding drive actuator to open the gate based on the feedback signal of the sensing component.

2. The automotive taillight strip injection mold according to claim 1, characterized in that, The connection between the A-center main gate (2) and the lamp strip mold cavity (1) is provided with a transition chamfer. The transition chamfer is a 1.5mm×45° inclined surface structure. The A-center main gate (2) is rigidly connected to the mold fixing plate through a positioning pin. The coaxiality error of the positioning pin is ≤0.02mm.

3. The injection mold for automotive taillight strips according to claim 1, characterized in that, The graded gating group (3) includes at least three symmetrically distributed gating units. The two gatings of each gating unit are symmetrically arranged along the width direction of the lamp strip mold cavity (1). The horizontal spacing between adjacent gating units is consistent. The flow channel axis of the graded gating group (3) is parallel to the length direction of the lamp strip mold cavity (1), and the distance between the center of the flow channel and the inner wall of the mold cavity is constant.

4. The automotive taillight strip injection mold according to claim 3, characterized in that, The inlet end of the graded gating group (3) is provided with a conical buffer cavity with a cone angle of 30-45°. The inner wall of the conical buffer cavity is machined with a spiral guide groove (6) with a lead of 8-10mm. The spiral guide groove (6) rotates in the same direction as the melt flow direction.

5. The automotive taillight strip injection mold according to claim 4, characterized in that, The graded gate assembly (3) is provided with an elastic scraping component near the outlet. The elastic scraping component includes a high-temperature alloy steel elastic ejector pin (8), an arc-shaped guide tube (7), and a driving component (16). The elastic ejector pin (8) is movably inserted between the arc-shaped guide tube (7) and the graded gate assembly (3). The outer circumferential surface of the elastic ejector pin (8) is provided with equally spaced cuts (9).

6. The automotive taillight strip injection mold according to claim 5, characterized in that, The arc-shaped guide tube (7) is tangentially connected to the graded gate assembly (3). The arc-shaped structure of the high-temperature alloy steel elastic ejector pin (8) is adapted to the curvature of the arc-shaped guide tube (7). The cross section of the elastic ejector pin (8) gradually increases along its axial direction to form a tapered guide structure.

7. The automotive taillight strip injection mold according to claim 6, characterized in that, The drive assembly (16) includes an electric telescopic rod (1602), an arc-shaped slider (1604), and a multi-link hinge mechanism. The arc-shaped slider (1604) slides along the arc groove (1603) corresponding to the arc-shaped guide tube (7). The multi-link hinge mechanism converts the linear thrust of the electric telescopic rod (1602) into the arc-shaped scraping motion of the elastic pin (8).

8. The automotive taillight strip injection mold according to claim 7, characterized in that, A coaxial conduit (10) is provided on one side of the arc-shaped guide tube (7). A flexible scraper (11) is embedded inside the conduit (10). A cross-shaped scraping opening (12) is provided in the middle of the flexible scraper (11) and is coaxially arranged with the conduit (10). The edge of the scraping opening (12) extends to the inner wall of the conduit (10).

9. The injection mold for automotive taillight strips according to claim 8, characterized in that, The bottom of the outlet of the conduit (10) is vertically connected to the guide plate (13), the guide plate (13) is provided with an inclined guide groove, and a waste recycling box (14) is provided directly below the guide groove. The inclination angle of the guide groove matches the flow direction of the residual melt.

10. An injection molding process for automotive taillight strips, characterized in that, The injection mold described in claim 1 includes the following steps: initially, only the A central main gate (2) is opened to inject the melt; when the pressure sensor detects a specified pressure threshold, the two symmetrical graded gate groups (3) are opened simultaneously; the opening of subsequent gate units is triggered by the current unit pressure signal and a time delay is set, the delay time is adjusted according to the melt viscosity characteristics, and pressure holding and cooling are performed after filling is completed.

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