This standard specifies design requirements and methods for each system in injection mold design. This standard applies to design of injection molds (hereinafter referred to as molds) used for molding thermoplastic parts.

Following documents are indispensable for application of this document.
GB/T1299 Tool and Die Steel
GB/T 8846 Plastic Molding Mold Terminology
Injection Mold Material Selection Specification

Terms and definitions defined in GB/T 8846 apply to this document.

Structural types of injection molds are shown in Figures 1 and 2. Material selection for injection molds shall meet requirements.

 

Figure 1 Structural Type

 

Figure 2 Structural Type

5.1.1 Minimum distance requirement from product edge to mold edge is shown in Table 1 and Figure 3, factors such as sliders, ejectors, and product structure need to be considered.

Table 1 Minimum Distance from Product Edge to Mold Edge

 

Figure 3 Minimum Distance from Product Edge to Mold Edge
5.1.2 Minimum thickness requirement from product to bottom of cavity plate and core plate is shown in Table 2 and Figure 4, factors such as sliders, ejectors, product structure need to be considered.

Table 2 Minimum Distance from Product to Bottom of Cavity Plate and Core Plate

 

Figure 4 Minimum Distance from Product to Bottom of Cavity Plate and Core Plate
5.1.3 Strength Design Requirements for Important Part Molds
5.1.3.1 Bumper Mold Strength Requirements: See Table 3 and Figure 5
Reference dimensions for strength of inner parting mold of bumper (mm)

Note: When hood has an inner parting, value A should be selected based on value B.
Table 3 Reference Table for Strength Dimensions of Bumper Inner Parting Mold

 

Figure 5 Strength Requirements for Bumper Mold
5.1.3.2 Instrument Panel Mold Strength Requirements: See Table 4 and Figure 6
Instrument panel mold strength reference dimensions (mm)

 

Table 4 Reference Table for Strength Dimensions of Instrument Panel Mold
Figure 6 Strength Requirements for Instrument Panel
5.1.3.3 Sub-Instrument Panel Mold Strength Requirements: See Table 5 and Figure 7
Reference dimensions for strength of sub-instrument panel mold (mm)

Table 5 Reference Table for Strength Dimensions of Sub-Instrument Panel Molds

 

Figure 7. Strength requirements for instrument panel mold
5.1.3.4 Strength requirements for door panel molds are shown in Table 6 and Figure 8.
Table 6: Reference Table for Door Panel Mold Strength Dimensions
Reference Dimensions for Door Panel Mold Strength (mm)

 

5.1.4 For special types of molds (e.g., high-gloss, electroplated, deep-cavity, thin-walled, and coated molds), strength dimensions must be confirmed by Geely's mold engineers.
5.1.5 Standard distance between two products in a mold should be at least 80mm, and minimum distance affected by product shape should not be less than 40mm, as shown in Figure 9.

 

Figure 9: Joint distance between two products in a mold

5.2.1 Basic Requirements for Parting Surface Design
Basic requirements are as follows:
a) No sharp angle areas are allowed at any position on parting surface;
b) Width of parting surface used for sealing in large molds is (30~50) mm, width of parting surface used for sealing in medium and small molds is (20~25) mm;
c) Open surfaces in parting surface should be designed with a simple and straight shape;
d) Sealing surface must extend from product surface (except for textured surfaces and high-gloss surfaces);
e) Product surface and sealing surface should avoid being located at the highest point of mold. If this cannot be avoided, additional protection should be added.
5.2.2 Angle between interlocking surfaces in small molds should not be less than 3°, in medium molds not less than 5°, and in large molds not less than 7°. For interlocking surfaces with an angle less than 5°, height in mold opening direction cannot exceed effective mating length for precise mold positioning.
5.2.3 Venting grooves should be evenly distributed on smooth surface around parting line; refer to Figure 10 and Table 7 for form and dimensions of venting grooves.

 

Figure 10 Venting Groove Dimensions

Table 7 Venting Groove Dimensions
5.2.4 Fillets of all parting surfaces should be designed to be integers, ease of machining should be considered.
5.2.5 Mold clamping force is achieved by pressure plate. Sealing surface of mold should not bear pressure in principle. Formula for calculating required pressure plate area is: Clamping Force / Pressure Plate Area ≤ 80MPA (N/mm²). Pressure plate is usually placed above mold feet or support pillars, and support is required in direction of pressure, as shown in Figure 11.

 

Figure 11 Mold Support Position

5.3.1 Ribs with a depth exceeding 10mm require inserts; venting grooves should be added to sides and bottom of inserts. For ribs with a depth of 10-15mm, products with special shapes, areas prone to air trapping, and areas with relatively poor material flowability, insert positions need to be reserved.
5.3.2 For molded parts where dimensions may vary or where wear is likely (e.g., insertion points where height is three times or more than the width), insert structures are required.
5.3.3 For parting lines with stepped requirements (e.g., door panel, map pocket edges), inserts are needed to control parting line quality and allow for assembly positioning, cavity polishing, and texturing.
5.3.4 To allow one mold to form multiple products, interchangeable inserts should be designed first, considering ease of assembly and disassembly, and safety. Interchangeable inserts should have easily identifiable and error-proof markings.
5.3.5 Inserts with any side greater than or equal to 80mm require additional cooling channels.
5.3.6 Principle for rib insert assembly is to facilitate machining, polishing, and venting. To prevent burrs, rib inserts are generally placed in the middle of rib.

5.4.1 During mold closing, all four guide pillars must simultaneously enter guide bushings. Mating length between guide pillar and guide bushing should not exceed 1.5 times diameter of guide pillar.
5.4.2 Effective mating height of guide pillars must exceed product's mold opening direction height by at least 30mm. Before inclined guide pillar contacts slider, guide pillar and guide bushing must first mate by at least 20mm.
5.4.3 For deep-cavity molds (such as instruments), square guide pillars must be higher than product's mold opening direction height to prevent collisions between core and cavity caused by shaking during hoisting or mold opening and closing, as shown in Figure 12.
5.4.4 For medium and large molds, shoulderless guide pillars and guide bushings are preferred, and venting grooves should be designed on guide bushing holes.
5.4.5 Molds weighing over 15 tons must use square guide pillars. Square guide pillar material must be 3Cr2Mo (equivalent to P20) as specified in GB/T 1299 and nitrided. Matching wear-resistant plate should be made of a self-lubricating material.

 

Figure 12 Square Guide Post Height
5.4.6 Guide components should have anti-misalignment features, especially for molds with two cavities. Similar molds (e.g., high-low configurations) should also be differentiated.
5.4.7 Small and medium-sized molds use precision positioning at the center of all four sides; large molds use 8 sets of precision positioning blocks.

5.5.1 Mold reference angles should be chamfered or marked to identify direction. Reference angles of mold frame and mold core should be consistent. For molds with clamping blocks, mold core reference angle should be designed opposite clamping block.
5.5.2 For medium and large molds, sidewalls of parting surface around mold should be used as guide locks.
5.5.3 Wear-resistant plate of guide lock surface should use a hardened material with an oil reservoir on the surface, should be fixed within corresponding groove (at least 8mm deep).
5.5.4 An R-angle should be added to root of guide lock to increase strength and reduce stress concentration.
5.5.5 Guide lock should consider influence of lateral forces, avoiding parallel guide lock surfaces in same direction, must have sufficient strength to withstand clamping force and injection pressure. As shown in Figure 13, guide lock width (W) ≥ 1.2 * guide lock height (H).

 

Figure 13: Width and Height of Guide Lock

6.1.1 One-piece lifters should be avoided. If unavoidable, length should be controlled within 350mm, hardening and nitriding treatment should be performed.
6.1.2 Angle of lifter connecting rod should be within 18°; minimum diameter of lifter rod should be φ12mm, and length should be controlled within 350mm; lifter rod should be as large as possible, preferably larger than φ20mm.
6.1.3 For selection of single-rod guides and double-rod guides, refer to Figure 14 and Table 8.
α: Angle of lifter; β: Advance/Delay ejection angle; C: Ejection distance; D: Diameter of lifter rod.

 

Figure 14 Lifter guide style

Table 8 Selection of Single-Rod Guide and Double-Rod Guide
6.1.4 Advance/delay ejection angle (β) of lifter should not exceed 20°. If it does, a double-rod or cross-rod lifter mechanism must be used.
6.1.5 For lifter blocks with a length of 200mm or more, two lifter rods are required.
6.1.6 Angle on the back of lifter block needs to be at least 2° larger than angle of rod. Side slope of ejector block groove should be checked through alignment rod hole.
6.1.7 Lifter design should consider bearing or positioning area of bottom and sides. Mating surface should be regular and flat.
6.1.8 For lifters below product's exterior surface, an additional anti-rotation mechanism should be added near guide sleeve of connecting rod to increase stability and safety of lifter movement.
6.1.9 Guide sleeves for lifter pins are added to bottom of ejector block and bottom of core. Length of a single guide sleeve is 1.5 times pin diameter; self-lubricating standard parts should be used for guide sleeves.
6.1.10 Sliding feet should use an integral standard design.
6.1.11 Lifter block should be designed with a reference flat position to ensure calibration during machining, inspection, and mold repair.
6.1.12 Lifter block and pin should preferably be fixed using pressure blocks or front-mounted screws; if there is no space, use horizontal round pins for fixing to prevent pins from falling off during production.
6.1.13 During normal mass production, temperature difference between lifter block and core periphery should be within 5℃. Generally, any lifter block with a diameter greater than or equal to 50mm requires an additional cooling channel.
6.1.14 Movement distance of lifter should consider impact of product shrinkage before design. After design is completed, motion simulation checks should be performed to avoid interference risks.

6.2.1 Ejector blocks are preferred for mold ejection; however, impact of product shrinkage on ejector block must be considered.
6.2.2 Lateral slope of ejector block should generally be 3° or higher, for molds produced under high temperature and high pressure, it should be 5° or higher.
6.2.3 When an ejector block is designed on core side corresponding to product's outer surface area, an additional anti-rotation mechanism should be added near guide sleeve of connecting rod to increase stability and safety of ejector block's movement.
6.2.4 Ejector blocks longer than 150mm must use two ejector rods to ensure stability during ejection.
6.2.5 During normal mass production, temperature difference between ejector block and core periphery should be within 5°. Generally, ejector blocks with a length greater than or equal to 50mm on any side require an additional cooling channel.
6.2.6 Minimum distance (X) between ejector block and inner sidewall should be ≥0.2mm to ensure that core sidewall is not scratched during ejection, as shown in Figure 15.

 

Figure 15 Push Block Design Requirements

7.1 Mechanical sliders or core pulls should be preferred.
7.2 Sliders and core pulls with parting line requirements must be designed with combined positioning. Size of slider positioning boss and screws must be determined according to slider size to ensure consistency each time slider is fixed to mold cavity for adjustment, as shown in Figure 16; use of brackets for fixing is not allowed, as shown in Figure 17; material selection requirements for sliders, inserts, core pulls, etc., involving high-gloss, textured, or painted product surfaces must be consistent with steel material of other exterior surfaces of mold.

 

Figure 16 Slider assembly positioning

 

Figure 17 Slider bracket fixing
7.3 For molds with high-gloss product surfaces, bottom of slider must not use wear-resistant plates with oil grooves; brass and graphite wear-resistant plates can be used.
7.4 Maximum angle of inclined guide post is 25°. Angle of wedge block's inclined surface is 2°~3° larger than that of inclined guide post. Wedge block must be able to withstand sufficient injection pressure. Height (H) of wedge block needs to be determined with reference to molding area on slider and direction of injection pressure. As shown in Figure 18, thickness (T) of wedge block is at least 1.5 times its height (H).

 

Figure 18 Thickness and height of wedge block
7.5 Effective bearing surface height of wedge block must exceed the lowest point of product molding surface, i.e., A should not be less than 0mm. Height (B) of wedge block's positioning boss should not be less than 15mm. For interlocking wedge blocks, an anti-locking mechanism is required. Height (C) of anti-locking mechanism should not be less than 15mm, and anti-locking surface angle is usually 10°, as shown in Figure 19.

 

Figure 19 Interlocking Wedge Block
7.6 Slider on cavity side usually uses a mechanical locking method to balance injection pressure. If hydraulic locking is used, an anti-reverse structure must be added.
7.7 For circular core-pulling mechanisms, an anti-rotation mechanism needs to be installed on mold.
7.8 All core-pulling holes must be checked to ensure they do not interfere with product during ejection.
7.9 Slider must have reliable tapered guidance and positioning in forward direction. As shown in Figure 20: minimum guide slope of slider's front part is 2°.

 

Figure 20 Minimum slope of slider front guide
7.10 Slider dimension definition. See Figure 21 and Table 9.

 

Figure 21 Slider Dimensions
Table 9 Slider Dimensions

7.11 Length of slider's pressure bar guide is 1.5 times slider height, must exceed travel distance of slider's I-beam. Pressure bar should be positioned as close as possible to parting surface.
7.12 Large sliders should have guide bars added to bottom; extra-large sliders (width ≥ 600mm) should use two guide bars, utilizing outer side of guide bars for single-sided sliding.
7.13 Slider's wedge surface must have a wear-resistant plate and an oil reservoir on the surface, fixed within reservoir.
7.14 All sliders must be matched with a limit block that sinks into mold plate, and springs or other standard parts should be added to prevent slippage towards product. Springs with a stroke exceeding 30mm should have bushings or center rods added.
7.15 When a mechanical slider has an ejection structure at the bottom, a limit switch or a mechanical anti-collision structure should be added.
7.16 Avoid placing sliders on the top side of mold. If using mechanical sliders, spring must have sufficient force to support slider's weight under preload. Regardless of whether slider is mechanically or hydraulically driven, an additional anti-fall mechanism must be added.
7.17 When core-pulling distance is large, or when safety of slider sliding cannot be guaranteed during mold opening, consider using a hydraulic cylinder drive (see Table 10). Forward and backward movement of hydraulic cylinder requires limit switch control.

Table 10: Selection of Mechanical and Hydraulic Drives
7.18 Slider drive (such as position of inclined guide post or hydraulic cylinder) should be as close as possible to guide unit (such as pressure bar).
7.19 Inclined guide post should be bolted from front of parting surface, embedded at least 1.5 times diameter in length. Avoid using large inclined guide post mounting brackets. For sliders less than 100mm in height, a smaller inclined guide post can be used; for sliders wider than 200mm, use two posts (see Table 11 for values).
7.20 During normal mass production, temperature difference between slider or core puller and mold periphery must be within 5℃. Generally, for sliders or core pullers with a product molding surface greater than or equal to 50mm, additional cooling channels are required.

Table 11 Slider and Angled Guide Pillar Dimension Comparison Table

8.1 Specifications of mold base should first consider matching with equipment, especially center of locating ring, length, width, thickness of upper and lower base plates.
8.1.1 Mold size classification is shown in Table 12.
8.1.2 Minimum strength requirements for mold base are shown in Table 13.

Table 12 Mold Size Classification Table

 

Note 1: If length/width of ejector plate is small, it can be reduced by one size as needed;
Note 2: If there is early or delayed ejection, or if cut-off portion is large due to ejector block, ejector plate needs to be appropriately thickened;
Note 3: When mold needs to be used on an injection molding machine with a clamping force greater than 20000k, or for other special types of molds (such as high-temperature and high-pressure production), it is recommended to use 3Cr2Mo ejector plate.
Table 13 Mold Base Dimension Table
8.2 Ejector Plate Guide Pillars and Ejector Plate Guide Bushings
8.2.1 Ejector plate guide pillars must be aligned with ejection mechanism (ejection cylinder or injection molding machine ejector rod) to ensure smooth ejection.
8.2.2 For interlocking molds, ejector guide pillars should extend deep into core plate to a depth equal to one times diameter of ejector guide pillar. For integral molds, ejector guide pillars should extend deep into core, and wear-resistant plates should be added to ground-side mold foot surface for auxiliary support.
8.3 Reset Rods
8.3.1 Clearance between reset rod and core should be controlled within 0.5mm on one side. A limit pin should be present at the bottom, and an adjustment plate should be provided at corresponding position in cavity.
8.3.2 Each mold set should have at least 4 reset rods. When mold length exceeds 1200mm, 2 more rods are required.
8.4 Support Pillars
8.4.1 Support pillars should be evenly distributed throughout ejection system and positioned below product, nozzle, slide groove, etc. The total area of support pillars should account for more than 30% of ejector plate area.
8.4.2 Large-diameter support pillars should be preferred. In cases of space constraints, square support pillars should be considered. To enhance strength of ejector plate, adjacent support pillars should not be aligned in a straight line. (See Figure 22).

 

Figure 22 Schematic diagram of push plate support column
8.5 Limiting pin
Locating pins are evenly distributed throughout ejection and reset system, placed below and near reset rod, pull rod, hydraulic cylinder, and sliding foot, with a spacing of 5 to 8 times pin diameter.
8.6 Locking Screws
8.6.1 Length of locking screw should not exceed 10 times its diameter (e.g., for an M10 screw, length should be controlled within 100mm). For small molds, M16 locking screws are preferred; for medium molds, M20 is preferred; and for large molds, M24 is preferred. Screw spacing should be 10 times its diameter. If longitudinal spacing exceeds 20 times its diameter, an additional row of locking screws is required.
8.6.2 Locking screws are arranged near nozzle on cavity side. For medium and large molds, four mold feet are arranged on core side, and additional locking screws are added.
8.6.3 Locking screws are arranged in a straight line. When there are lifting eye holes on plane of moving and fixed mold fixing plates, locking screws and lifting eye holes must be aligned in a straight line.
8.7 Ejector Screws
For small molds, M10 ejector screws are preferred; for medium molds, M12 is preferred; and for large molds, M16 and above are preferred. Spacing should be 15-20 times screw diameter. When row spacing exceeds 400mm, add a row of connecting screws.
8.8 Pry Grooves
All mold plates secured by screws must have pry grooves added between them.

9.1 Basic Requirements for Ejection Systems
9.1.1 For mechanically ejected molds, ensure center of locating ring and center of ejector hole are aligned.
9.1.2 Prioritize shortening ejection stroke to ensure stability of ejection mechanism.
9.1.3 For injection molding machines of 500 tons or more, use hydraulic cylinder ejection; for injection molding machines less than 500 tons, use mechanical ejection with springs and a return rod for reset.
9.1.4 Large molds use four hydraulic cylinders to control ejection of "I"-shaped ejector plate. Number of hydraulic cylinders for medium-sized molds depends on number of ejection mechanisms.
9.1.5 Movement of hydraulic cylinders must be parallel to ejection direction, ensuring balanced ejection. Ejection deviation must not exceed 2mm; if it does, a distributor must be installed.
9.2 Ejector Rods and Ejector Tubes
9.2.1 All ejector rods with a shaped section at the front must have a limit stop; cut surface must be parallel to long side of ejector plate.
9.2.2 For ejector rods with a diameter of φ6mm or less, mating section with mold plate should be approximately 15mm; for ejector rods with a diameter of φ6mm~φ12mm, mating section should be approximately 25mm; for ejector rods with a diameter of φ16mm and above, mating section should be approximately 30mm; mating section of pull rod should be at least three times rod diameter.
9.2.3 When using stepped ejector pins (all ejector pins with a diameter of φ6mm or less must be stepped) and stepped ejector tubes, a clearance section must be designed on mold plate. Length of clearance section should be increased by 15mm to 25mm beyond ejection stroke.
9.2.4 Wall thickness of all ejector tubes should not be less than 0.8mm and should be controlled within standard length. For door panel molds, secondary ejection should be used to standardize length of ejector tube. For instrument molds, it is recommended to use extension sleeves of different heights to standardize length and specifications of ejector tube.
9.2.5 All molds must have ejection limit blocks, which should be close to axis of hydraulic cylinder or mechanical ejection hole. If ejector plate is longer than 1200mm, two additional limit blocks should be added.
9.3 Other Ejection Requirements
9.3.1 In areas where appearance requirements are required for all electroplated parts, ejector pins are not allowed. Ejector blocks can be used instead to avoid ejector pin marks on product surface.
9.4 Hydraulic Cylinder Circuit
9.4.1 Select appropriate hydraulic cylinder specifications based on working environment of hydraulic cylinder.
9.4.2 Selection of hydraulic cylinders should refer to standards of mold user. They can be fixed to core plate or push plate.
9.4.3 Hydraulic cylinders and connectors should not be installed on the top side of mold.
9.4.4 Hydraulic cylinder is connected to mold plate via a connector, which must have reliable anti-rotation, and width of contact surface should not be less than 6mm.
9.4.5 Cylinder diameter should be calculated as 1.2 to 1.5 times the total weight of push plate and structure fixed to it. There should be a minimum allowance of 10mm at the front and rear ends of ejection cylinder stroke.
9.4.6 Hydraulic circuit should be designed by drilling holes in mold to reduce use of hoses. Drilling in hydraulic system is allowed at corners (Figure 23), but intersections should be avoided (Figure 24); intersections of blind holes are difficult to clean and remove metal filings, easily damaging hydraulic cylinder.

 

9.4.7 Oil circuit should be evenly arranged, with similar lengths. A single oil circuit should avoid more than five bends. For large molds, it is recommended that oil circuit be designed on moving mold fixing plate, then connected to oil cylinder via hoses. High-temperature and high-pressure molds should avoid internal oil circuits.
9.5 Limit Switches
9.5.1 All moving parts driven by oil cylinders need to be designed with limit switches, which must be kept fixed.
9.5.2 It is recommended to route electrical wires through holes in mold feet or other components. Conduits should generally be Φ20mm or larger.
9.5.3 Electrical wires should avoid passing through multiple components simultaneously; they should be designed on a single component. Alternatively, sockets can be added between components for easy assembly and disassembly.

10.1 Runners and Gates
10.1.1 Runner cross-section should be designed as circular as possible. For small and medium-sized molds, Φ6mm or Φ8mm is recommended, and for large molds, Φ10mm. End of runner should be at least 1.5mm away from product. Venting should be provided in cold slug section of runner.
10.1.2 For multi-cavity molds, distance from main runner to branch runners of each product (molten plastic flipping design is recommended) should be same to ensure injection balance.
10.1.3 Gate thickness should be half product wall thickness, and overlap thickness should also be half product wall thickness.
10.1.4 All runner gates must undergo mold flow CAE analysis for parameter verification.
10.1.5 All gate locations must consider product appearance and assembly requirements to ensure that gate location does not affect appearance or installation of mating parts.
10.1.6 Electroplated or high-gloss parts must not use submarine gates (including submarine ejector pins) or horn gates to avoid formation of debris due to gate breakage affecting product surface quality. Gate design should consider factors such as easy filling, avoiding pressure loss, and ease of trimming. Direct side gates, angled ejectors, or slider-assisted bottom side gates are commonly used (as shown in Figure 25). Linear distance between gates should be less than 300mm to avoid residual stress after product molding.

 

Figure 25 Glue Dispensing Scheme
10.1.7 Main wall thickness of bumper is typically 2.5mm. Distance between sprues should be less than 450mm, and filling end should be within 300mm of the nearest sprue point (R) to avoid difficulties in holding pressure, which could lead to shrinkage and uncontrollable dimensional problems, as shown in Figure 26.

 

Figure 26 Requirements for Glue Application in Bumpers
10.1.8 Main wall thickness of outer sill is typically 2.8mm. Distance between sprues (A) should be less than 300mm, and filling end should be within 200mm of the nearest sprue point (B) to avoid difficulties in holding pressure, which could lead to shrinkage and uncontrollable dimensional problems, as shown in Figure 27.

 

Figure 27 Threshold Glue Injection Requirements
10.1.9 Main wall thickness of electroplated parts is typically 2.5mm. Distance between glue inlets (A) must be less than 250mm, and distance from filling end to the nearest glue injection point (B) must be within 120mm. This is to avoid difficulties in pressure holding, which could lead to uncontrollable shrinkage, dimensional, and deformation problems, as shown in Figure 28.

 

Figure 28 Glue Injection Requirements for Electroplated Parts
10.1.10 For molds requiring adjustable runner flow (such as multi-cavity molds, single-hot-nozzle multi-sprue molds, etc.), a flow control valve should be added to runner for quick adjustment of runner flow to achieve filling balance.
10.1.11 Parting surface at the front end of nozzle or sprue bushing should be designed as a plane.
10.1.12 Gate insert should be hardened. For injection molding materials with a glass fiber content of 20% or higher, a gate insert should be added. For ease of process adjustment, medium and large molds should be designed with two sets of gate inserts of different types.
10.1.13 Length of gate sleeve for cold runners should be less than or equal to 80mm.
10.1.14 Refer to Figures 29 and 30 for general gate parameters.

 

10.2 Locating Rings Locating rings should be designed on both moving and fixed mold sides of mold, and removal threads should be added. Contact height between locating ring and main nozzle should not exceed 2mm.
10.3 Hot Runner System
10.3.1 Selection of a hot runner system should be based on technical considerations, choosing the most suitable one. For molds in same project, a hot runner system from same supplier should be used.
10.3.2 Hot runner system should consider equipment matching: ball head radius, nozzle inner diameter, wiring type and location, valve needle drive type (air valve or oil valve), etc.
10.3.3 Cooling channel for needle valve type hot runner cylinder must be controlled separately to avoid series connection with cooling water circuit on cavity side.
10.3.4 Hot runner plate should preferably be a split type, easily formed by simple machining, and prioritize maximizing support area for cavity (at least 60% of cavity bottom surface area). Hot runner wire frame and manifold should be avoided from product projection position as much as possible.
10.3.5 Hot runner systems with more than two nozzles require four additional guide pillars.
10.3.6 An anti-expansion ring should be designed at nozzle tip; no cold material section should be left at the tip of valve-type nozzle.
10.3.7 Nozzles that directly inject glue onto product surface require a cooling jacket.
10.3.8 Carefully check distance between hot runner nozzle orifice and glue area (greater than 25mm) to prevent localized overheating of product surface.
10.3.9 Hot runner system needs to be designed with drainage grooves on underside of mold.
10.4 Shrinkage Lines
Two parallel lines, 0.2mm deep, need to be engraved on product surface of mold core, with a spacing of 500mm or 1000mm plus theoretical shrinkage value.

11.1 Principles of Water Channel Design
Purpose of water channel design is to achieve ideal molding cycle and maintain a consistent temperature on the surface of mold cavity.
11.2 Requirements for Water Channel Design
11.2.1 Center distance between water channels should be 3 to 5 times hole diameter; distance between edge of water channel hole and mold cavity should be controlled at 1.5 to 2.5 times water channel diameter, distance between water channel and mold cavity surface should be kept as uniform as possible; distance between edge of water channel hole and parting surface should be at least 8mm; distance between edge of water channel hole and ejector pin holes, insert holes, etc., should be at least 3mm for ultra-small molds, at least 5mm for small molds, at least 8mm for medium and larger molds, as shown in Figure 31.

 

Figure 31 Waterway Design Parameters
11.2.2 Included angle between two connecting water passages should be at least 35° to avoid drill bit breakage during machining, as shown in Figure 32.

 

Figure 32 Waterway Design Parameters
11.2.3 Center distance between water-turning holes should be 3 to 5 times diameter of water-turning hole. A maximum of 6 water-turning holes can be designed in one circulating waterway, as shown in Figure 33.
11.2.4 Water flow direction must be consistent with material flow direction.
11.2.5 For easily deformable products, corresponding water channels should be designed in conjunction with product deformation, i.e., adjusting mold temperature in different areas to improve product deformation.
11.2.6 Two-cavity molds require separate circuit designs to cool individual parts.
11.2.7 Separate water channels should be designed for mesh or patterned areas.
11.2.8 Separate cooling should be designed near each nozzle in hot runner.
11.2.9 Cooling inserts should be used for areas requiring particularly strict temperature control (such as instrument caps).
11.2.10 Clearly mark water circulation circuit groups on mold exterior, such as: IN1, OUT1; IN2, OUT2; use internal water channels to optimize arrangement of nozzles to ensure a clean appearance.
11.2.11 The total length of a single water circulation channel in mold should not exceed 2m, and a single circulation water channel should not have more than 5 bends; temperature difference between inlet and outlet water should not exceed 5℃; a flow meter should be installed at outlet of water circulation system to monitor flow rate.
11.2.12 Relative distance between center of water channel hole and mold's reference angle should be an integer.
11.2.13 Water channel direction should be designed according to direction of greater product shrinkage. Large molds should have cooling zones designed separately.
11.2.14 Water inlet and outlet interfaces should be located on reverse operation side, and water collectors should be located on ground side of reverse operation side.
11.2.15 Mold's water-blocking mechanism must be easily disassembled; welding or use of glue is not allowed.

12.1 Avoid placing angled ejectors, ejector blocks, or sliders in visible parting line area of ​​electroplated parts.
12.2 For sharp corner areas (R<3mm) of electroplated parts, protective corners must be designed in mold design, as shown in Figure 34.

 

Figure 34 Protective corner of electroplated part
12.3 When mold structure or molding pressure causes an imbalance in lateral forces on mold, locating blocks or other structures should be added to maintain a balance in lateral forces on mold, preventing uneven forces from affecting mold's positioning accuracy, as shown in Figure 35.

 

Figure 35 Schematic diagram of mold positioning block
12.4 Longitudinal dimension (A) of outer sill needs to be reserved by 1.5-2m on one side. A corresponding insert (B) should be made on core side, and a separate water channel should be added to ensure that dimension is adjustable after trial molding and appearance are locked, as shown in Figure 36.

 

Figure 36: Outer Sill Dimension Reservation
12.5 Hydraulic Cylinder Selection Requirements
12.5.1 When piston works in cylinder, a certain safety distance is required to ensure that piston will not collide with cylinder, as shown in Figure 37.
L: Piston stroke S: Required stroke A: Safety distance between piston and cylinder front end B: Safety distance between piston and cylinder rear end, L=S+A+B, A≥5mm, B≥5mm

 

Figure 37: Cylinder Dimension Requirements
12.5.2 Size of cylinder must be able to meet required pushing and pulling force during operation. When selecting a cylinder, pushing and pulling force of cylinder must be greater than or equal to force that cylinder needs to withstand multiplied by a safety factor (K), as shown in Figure 38.
P1: Maximum pressure during injection molding (slider forming area) A1: Projected area (projected area in direction of slider movement)
P2: Maximum oil pump pressure that injection molding machine can provide (usually taken as 14MPa) K: Safety factor (usually taken as 1.2~1.5) F3=P1*A1*Sinα F_cylinder thrust=3.1415926*(D/2)²*P2 F_cylinder pull=3.1415926*［(D/2)²-（d/2）²］*P2

 

Figure 38 Hydraulic Cylinder Calculation Parameters
12.6 Limit Switch
12.6.1 When limit switches need to control synchronous movement, multiple limit switches need to be connected in series, as shown in Figure 39.

 

Figure 39 Series Connection
12.7 Mold Insulation
12.7.1 To ensure stable mold temperature and prevent heat loss during injection molding, mold must meet insulation requirements specified in Table 14.
Table 14 Mold Insulation Requirements

12.8 Mold Structure Motion Simulation
12.8.1 To ensure reasonable mold structure design, all common lifters, sliders, core pullers, and product ejection require static simulation; all complex structures such as variable-track core pullers and multi-structure combined motion require animation simulation, such as front and rear bumper molds.
12.9 Mold Counter
12.9.1 All molds must use Geely-designated intelligent counters and install them on operator's side, as shown in Figure 40.

 

Figure 40 Installation location of smart counter

13.1 Reliable parking blocks must be installed under mold on both cavity and core sides. Surface area of blocks must be at least 3% of bottom surface area of mold.
13.2 Whether it is a complete mold or any half mold, position of lifting ring must be determined through theoretical calculations to ensure balance of mold during lifting.
13.3 All molds must have locking modules installed on both operating and reversing sides to ensure safety during handling. For molds weighing less than 5 tons, locking plates should be installed diagonally; for molds weighing 5 tons or more, locking plates should be installed at all four corners.
13.4 Parts weighing more than 10 kg on mold must be designed with lifting eye holes.