Hardware mold design | Engineering planning, layout design and single-operation mold process arrangement

Engineering Planning

Engineering planning capability is the core capability of mold design. In a sense, the sum of a company's engineering planning capabilities constitutes its entire competitiveness. Layout design and single-operation mold process arrangement are its main manifestations in mold design. Below is a summary of our engineering planning experience:
Layout Design Process
Layout Design Principles
Layout design is the key to mold design. Excellent mold designers need rich spatial imagination and creativity, as well as extensive practical design experience and solid basic skills. Based on our twenty years of mold design experience and the knowledge and experience of predecessors, we have summarized the general principles of hardware mold layout design:

1) Plan the forming process according to the shape and precision requirements of the product. The process arrangement should facilitate material feeding, product output, and subsequent forming as the basic starting point of the design;

2) Processes should be dispersed as much as possible to optimize the mold structure, fully utilize the excellent physical properties of the mold material, improve mold life, and simplify the mold structure;

3) Production capacity should match the production batch. When the production capacity of one-to-one output is lower than the production batch, a comprehensive evaluation of the production increase methods of using double-row, multi-row, or single-stage molds should be conducted, striving to adopt double-row or multi-row molds. This simplifies mold manufacturing and extends mold life;

4) Progressive dies generally use automatic feeding mechanisms and precise spacing with guide pins. For higher precision requirements, side cutting edge spacing is added. To ensure accurate feed pitch and mold safety, guide holes are typically punched at the first station, guide pins are installed at the second station, and misfeed detection equipment is installed at the third station. Guide pins are prioritized at stations prone to runout;

5) During design, the main characteristics of stamped parts should be grasped, the shape of the stamped parts carefully analyzed, and the relationship between each station considered to ensure smooth stamping. For special parts with complex shapes and high precision requirements, necessary measures should be taken. Measures to ensure the machining accuracy of parts;

6) Strive to improve material utilization and minimize waste;

7) Appropriately set up empty workstations to ensure sufficient strength of the mold and avoid interference between parts during installation. This also facilitates process adjustments during trial molding and provides more space for subsequent mold modifications;

8) Verify the material feeding method to ensure smooth material feeding and product output during mold production;

9) When producing two or more products at a time, ensure that the flash direction of all products is consistent;

10) After the design is completed, be sure to verify the stamping forming process conditions and the mold strength, rigidity, and other requirements; 1) For forming stations that may cause sheet deformation, lateral and longitudinal correction mechanisms should be installed, such as marking (embossing) or pressing lines on the scrap;

12) When stamping products with thin materials (t=0.04~0.15mm), the overall die layout should be shortened as much as possible. The blanking stations are generally arranged closely within a short length to reduce cumulative feeding errors;

13) For dimensions that are easily changed, lateral fine-tuning mechanisms should be installed, mainly at the forming position (especially when the material is thin).

14) For features with very high requirements for positional relationships... Try to complete the blanking process in one step. If this is difficult, it can be completed in an adjacent step (for multiple reference holes in the product, or parts with high dimensional accuracy requirements);

15) For features that require no burrs in certain areas, the blanking and burr removal processes are generally arranged in adjacent steps. Edge overlap setting: Factors affecting the edge overlap value:

a. Material mechanical properties: Materials with good plasticity have larger edge overlap values; materials with high hardness and strength have smaller edge overlap values;

b. Material thickness: The thicker the material, the larger the edge overlap value;

c. Workpiece shape and size: The more complex the workpiece shape, the smaller the corner radius. d. Layout: The overlap value of a double-row layout is greater than that of a straight-row layout;

e. Feeding and blocking method: Manual feeding is used, and the overlap can be smaller for side-pressure guides. Die flash overlap requirements:

To improve material utilization, based on our current technology, we require:

1) Product flash value (A) ≥ 1 times material thickness, minimum 1.5mm;

2) Product-to-product flash value (B) ≥ 1 times material thickness, minimum 1.5mm;

3) Product side flash value (C) is generally 2~3mm, minimum 1.5mm (see the diagram below);

4) Manual feeding in compound molds. The overlap value of the continuous material should be at least one times the material thickness (including one times the material thickness), and the minimum should be 1.5mm when the material thickness is thinner;

5) For large products (one or two products from one sheet of material), the overlap value should be 5~10mm;

6) The edge of the guide pin should be at least 1.5mm away from the edge of the sheet material.

Theoretical data and selection of various overlap values

The overlap values ​​of commonly used materials are shown in the table below:

Empirical values ​​of overlap value a and continuous material value a1 (taking electrolytic material as an example)

Selection of overlap values ​​for other materials

For the overlap values ​​of other materials, simply multiply the above overlap values ​​by a correction factor, the correction factor values ​​are as follows:

Medium carbon steel: 0.9
High carbon steel: 0.8
Hard brass: 1~1.1
Hard aluminum: 1~1.2
Soft brass: 1.2
Aluminum: 1.3~1.4
Non-metals: 1.5~2 Process Layout Stamping Arrangement Principles:

1) The order of each process should be determined according to its complexity. Generally, it should be based on facilitating the next process to ensure the accuracy and correct geometry of the parts. For punched and blanked parts, punch the hole first, then complete the outer shape step by step;

2) When the distance from the hole to the edge is small and the hole accuracy is high, punch the outer edge first, then punch the inner hole to ensure the hole accuracy;

3) Complex-shaped punches should be avoided as much as possible, and holes with sharp convex corners, narrow grooves, and narrow waists should be avoided. Weak links, etc.;

4) For areas with strict requirements, especially those with high precision in shape and position, punching should be done at the same station as much as possible. If this is difficult, punching can be done continuously at adjacent stations;

5) For large sheet materials with segmented material removal, the strength of the sheet material is weakened by the punching process. Therefore, guides should be added in the width direction of the sheet material (generally, a balancing top piece can be added);

6) Sufficient strength and rigidity should be ensured at the connection between the strip carrier and the part. When the stamped part has holes of varying sizes or narrow ribs, the smaller holes (shorter ones) should be punched first. 7) The spacing of the punched contours on the die should be less than the minimum allowable thickness of the die, generally greater than 2.5t, but not less than 2mm.

8) Punching processes with large contour perimeters should be arranged in the middle station as much as possible.

9) From a precision perspective, simultaneous processing of multiple holes is beneficial to maintaining the precision of the holes on the product. Therefore, holes with precision correlation should be processed in one step as much as possible.

10) The priority order of punching processing is as follows: when the distance between adjacent holes is small and cannot be punched in one step, low-precision holes should be punched first, followed by high-precision holes; for holes adjacent to the outer edge, when L<2t, the outer shape should be processed first, followed by the hole.

11) When the product has multiple measuring reference holes, all reference holes must be processed in the same step.

12) Avoid single-sided punching as much as possible when flashing to prevent material pulling.

13) For high-precision feet, they must be punched out in one step. Bending Process Layout Principles

1) For punched and bent parts, punch holes first, then remove the waste material around the bending area before bending. 1) Bend the material and remove any remaining waste.

2) When holes near the bending point have precision requirements, bend first and then punch to prevent hole deformation during bending.

3) To ensure bending quality and considering the springback characteristics of the material after bending, and for ease of mold adjustment, bending designs often require breaking down 90° bends into two steps (pre-rolling and forming). The pre-rolling angle is generally 45°, but in special cases, it can be reasonably split according to process requirements.

4) For complex bending parts, do not arrange complex structures in one step based on imagination. Based on manufacturing feasibility and the characteristics of the rolling process, break down complex rolling into multiple simpler rolling processes to gradually complete the product forming and avoid significant losses.

5) For multiple rolling processes with dimensional relationships in the same product, try to arrange them in the same step. If this is difficult, they can be arranged in adjacent stations.

6) For spring-type products, carefully consider the requirements of the component drawing. To prevent tearing of the rolled parts and insufficient elasticity or even fatigue fracture, the grain direction of the material is generally arranged perpendicular to the bending line of the product. When there are multiple rolls, the bending line of each roll should be at an angle of 30-60 degrees to the grain direction.

7) The strength and rigidity of the mold should be considered during the design, and the rolling sequence should be arranged reasonably.

8) The rolling scheme should be evaluated during the design to ensure process feasibility, and space should be reserved for changes to designs that are not absolutely certain.

9) The stability of the dimensions after rolling should be fully considered during the design, and the phenomenon of material pulling should be effectively prevented. Single-sided rolling should be avoided as much as possible, and additional forming processes can be added if necessary.

10) The unloading, feeding, and product output after rolling should be carefully considered during the design, as well as methods to ensure the stability of the rolled dimensions. Types and design principles of cutting edges. Forms of cutting edges for segmented punching. In automatic molds, in order to ensure complete edge trimming and prevent secondary shearing at the interface, which would affect product quality, therefore, in production... Process cuts are often incorporated into the product design; these are commonly referred to as cutting edges. Common cutting edges used in metal molds include the following categories: In automatic mold design, arc-shaped cutting edges are used, and the following three specifications are commonly seen (see the diagram below): Cutting Edge Design Principles Cutting edges are merely process cuts, so the product's function should not be affected by them, and their impact on the product's appearance should be minimized. Therefore, the following principles should be followed when setting cutting edges:
1) The segmented punching of the cutting edge should simplify the mold structure, resulting in a simple, easy-to-process punch shape with sufficient strength;
2) The shape, size, precision, and usage requirements of the product parts should be guaranteed;
3) After decomposing the internal and external contours, the connections between the segments should be straight or smooth;
4) The number of cutting edges should be minimized, and their positions should avoid weak points and important parts of the product's shape (as indicated by special requirements on the drawings);
5) Straight edges with tolerance requirements and sliding edges should be used. 6) The mating edges should be punched in one go, not in sections, to avoid the accumulation of processing errors;

7) Complex shapes and parts with narrow grooves or slender arms are best decomposed, as are complex and large internal shapes;

8) When arranging the cutting edges, the flash method of the product should be considered to avoid making shearing cutters that cannot be processed (whether small punching cutters can be reinforced smoothly);

9) The design of the cutting edges must consider the impact on the product and the feasibility and processing cost of the die. Guiding Method Design Guiding Method Design Principles 1) At the first station of the sheet material layout, punch guide holes. The second station must have guide pins. Subsequent stations should have guide pins at appropriate intervals, prioritizing stations prone to movement.

2) The guide holes should be located on the reference plane of the strip material, generally on the cut or leftover material.

3) Guide pins should be placed before important processing stations.

4) If the location of the guide pins interferes with the layout process, guide pins may not be necessary.

5) The location of the guide pins must not interfere with the layout process. When working on the product, additional empty workstations can be added to provide space for the placement of guide pins;

6) Guide pins and floating pins should be placed as much as possible at the flash shearing point, with the floating pins in front and the guide pins behind (closer to the product).
Guide Pin (Pin) Design
The positioning of sheet metal is of great significance to product quality. Positioning refers to the actions of determining the accurate position of the material within the die before punching. There are various tools for sheet metal positioning, among which guide pins (pins) are the most commonly used and most effective precise positioning structure in automatic dies. The following are some common types of guide pins. See the diagram below for details: In mold design, we generally use pin type 1. In type 1, the assembly clearance between the pin and the die plate is 0.01mm (double-sided clearance), and the clearance between the pin and the pin hole in the lower die plate is 0.02mm (double-sided clearance). The pin hole in lower die plate 1 is 1mm larger than that in the lower die plate, and the pin hole in lower die plate 2 is 1mm larger than that in lower die plate 1. The pin hole in lower die base 2 is also 1mm larger than that in lower die plate 2. Pin type 2 is a floating pin, and should... This design is used when there is an inclined slider in the die-cutting plate. This design ensures the stability of the sheet material when the inclined slider is in action. Therefore, when there is an inclined slider in the die-cutting plate, some type 2 pins are arranged in the type 1 pins (and there can be a suitable number of type 2 pins). When the die is in a free state in type 2 pins, the dimension H2 in the figure is generally 5~6mm. Pin types 3 and 4 are used when there is insufficient space in the intermediate plate. When designing the pins, the distance between the edge of the pin hole on the sheet material and the edge of the sheet material is generally about 2~3mm. However, the minimum deviation should not be less than 1.5mm. To ensure guiding accuracy, after punching out the pin hole, the next step must be to set up a row of pins. The misfeed pins can only be installed after the third row. The general sequence is: punch pin hole --- fix pin --- misfeed pin --- fix/floating pin --- floating pin --- … --- fix pin. When punching the pin hole in the mold, the hole size should be 0.02mm larger than the pin. For example, when using a Φ3 pin, the pin hole size is Φ3.02mm. Pin Structure Design

1) Commonly Used Pin Specifications

2) Pin Exposure Standards on the Punching Surface
Material Guiding Method Design
Material Guide Pin (Dual-Purpose Pin) Arrangement Requirements

1) The arrangement of material guide pins should ensure stable and reliable feeding of the strip. Therefore, the material guide pins should be arranged as evenly and symmetrically as possible, with consistent floating material height, and the spacing should be flexibly selected according to the material width and thickness (the spacing is generally 30~70mm);

2) Avoid setting material guide pins in weak parts of the sheet material to prevent deformation of the sheet material and the product, affecting product quality;

3) Generally, one or two pairs of material guide pins should be symmetrically arranged before punching the pin holes to facilitate the introduction of the sheet material.
Floating Material Pin Structure Design
Commonly Used Specifications of Floating Material Components
Maximum Gap Between Sheet Material and Punching Plate

Due to the influence of machining accuracy, it is difficult for the floating material pin to make the sheet material and the punching plate fit perfectly when the top of the floating material pin touches the punching plate. Therefore, in actual production, there is a certain gap between the two (there should be no negative gap between the two). For the normal production of the mold, the gap between the two should not be too large and the following principles must be followed:

1) The assembly clearance between the floating pin and the lower mold plate is 0.04mm. The spring used for the floating pin is generally a TF light-load spring.

2) The design of the floating height H of the floating pin should follow the following principle: the floating height is generally around 20mm, ensuring that the lowest point of the sheet material is 3-5mm higher than the highest point of the lower mold insert protruding from the mold surface. When there is a contradiction between the two, the latter principle shall prevail.

3) The clearance of the floating pin head on the die is 2mm larger than the floating pin ΦA, and the clearance depth is H1+H2-t, where the height H2 of the floating pin head is generally 4-5mm. The width of the floating groove H1 is generally 1.5t, with a minimum of 1.2mm. t is the material thickness. (Screws, plug screws, cup head screws) Cup Head Screw Machining

Notes:
1) When using Φ5/16" screws in the automatic mold intermediate plate, the countersunk hole depth of the cup head is 9mm;

2) The countersunk hole depth of punching males, rolling males, and inserts should be below the mold surface of the cup head screw, and can be flexibly controlled without affecting the positioning;

3) The depth of the cup head screw in the table above is based on the principle that the mold surface is about 5mm higher than the top of the screw during mold assembly.

2) Commonly Used Mold Locking Cup Head Screw Specifications and Arrangement

3) Assembly Form of Cup Head Screw in the Mold

Ejector Screw Layout

1) Ejector Screw Machining

2) Ejector Screw Layout Requirements
Generally, equal-height sleeve components should be given priority. Ejector screws should only be considered when there is insufficient space in the mold.

Ejector Assembly Design

Ejector Pin Assembly Design
Ejector pins are often used at the final cutting point of the product, to blow out the product and to push the product away from the mold surface when rolling downwards at 90°. The size is generally... For Φ3 and Φ2 ejector pins, the product needs to be ejected 2-3mm away from the mold surface. See the following diagram for ejector pin design and assembly requirements: Ejector Block Component Design The ejector block design has the following basic requirements:
1) The float height H of the ejector pin is the same as the float height of the float pin;
2) Each ejector block uses two Φ8 TF or DF springs and M3/8" kilometre screws;
3) See the following diagram for specific requirements of ejector block component design and assembly. The diagram can be used as a reference during design;
4) The material of both the ejector block and the fastener is K460 oil steel;
5) Ejector block size specifications. Misfeed Component Design Misfeed detection equipment can effectively ensure the safety of the mold and is an indispensable piece of equipment in progressive dies. The following basic principles should be followed when designing misfeed detection equipment:
1) Misfeed detection equipment should be installed as early as possible, ideally in the third step after punching the positioning hole. Generally: punching the guide hole --- fixing the guide pin --- misfeed pin --- fixing or floating 1) Moving guide pin --- ... --- Fixed guide pin;

2) Misfeed detection equipment has the above two assembly methods. Our design should preferably use the upper mold mounting method, generally not the lower mold mounting method;

3) The misfeed detection spring is a yellow TF or DF light-load spring;

4) The H dimension in the diagram is 10~15mm;

5) The design and assembly requirements for the misfeed pin can be referred to the above diagram;

6) Other requirements for the design and assembly of the misfeed pin: According to the assembly form, it can be divided into the following two categories, see the following diagram for details. Air Blowing Design: In progressive dies, to smoothly deliver the product and save costs, we try to design the mold as a sheet material pushing the product out. When the product size is too small or the product structure is not easily pushed out by the sheet material, we can design it as a pneumatic conveying mode. We commonly use the following two specifications for air blowers: 4X6XΦ2 and 6X8XΦ3. The following are the basic requirements for air blower design. Principles:

1) The blower placement should be as close as possible to the product, with the blower nozzle perpendicular to the product's discharge direction. For larger products, two or more blowers can be used.

2) The impact on the product should be considered during blower placement. To avoid imprinting, the blowers should be placed in the scrap area of ​​the product, or in the lower mold insert, or outside the sheet material area.

3) The assembly clearance between the blower and the lower mold plate is 0.04mm (0.02mm on one side), and the assembly clearance between the blower and the lower mold pad 1 is 0.2mm (0.1mm on one side).

4) In the free state, the bottom of the blower nozzle generally protrudes 1mm from the mold surface. This should be flexibly adjusted according to the product structure and ejection method during design.

5) The specific structure and assembly form of the blower are shown in the following figure.

6) For product material thicknesses of 0.3mm or less (including 0.3mm), a product-push-product ejection method should be used. When using this method, a blower should also be designed to compensate for any failures in the product ejection process.

7) For products with a thickness of 0.8mm or more (including 0.8mm), when scrap is removed by shearing with a cutting blade, an insert should be designed in the ejector plate to prevent the cutting blade from pulling the material. The insert is used to laterally position the cutting blade. See the diagram below: Tube Position Design In single-operation dies, tube position design is a very important aspect of die design. The quality of the tube position directly affects the dimensional accuracy and stability of the product. The basic requirements for tube position design are: reliability, effective guarantee of product dimensional stability, easy assembly and disassembly, and quick adjustment. Tube Position Selection Principles 1) If internal tube positions can be designed, use internal tube positions as the primary method (at least two, and the distance between them should not be too close), and then add external tube positions. This allows for quick and accurate product positioning and higher production efficiency.

2) For general punching dies, round holes should be used for internal tube positions as much as possible, and locating pins should be used for external tube positions. Its advantages are good effect and low cost;

3) For the outer tube position of the forming die, use positioning blocks instead of positioning pins, and use square holes for the inner positioning as much as possible; (the reason is that positioning blocks are easier to adjust than positioning pins, and positioning pins cannot prevent material pulling.)

4) When arranging the tube positions, attention should be paid to preventing the product from turning backward. (Generally, anti-backward pins are set at holes or notches in the product.) Design Principles of Outer Tube Positions Outer tube positions are coarse tube positions, which are easy to standardize, convenient to handle, and easy and quick to adjust dimensions. However, the positioning accuracy of the tube positions is not as high as that of the inner tube positions, and the ability to ensure product dimensional stability is not as good as that of the inner tube positions. When designing outer tube positions, the following should be noted:

1) The tube positions should be effective and reliable, and the distance between tube positions should be as far as possible, arranged on the four sides of the product (generally 6-8 tube positions should be arranged);

2) To ensure product stability, the tube positions should be arranged as symmetrically as possible;

3) The arrangement of tube positions should not obstruct the flow direction of the material; 4) Tube positions should not be placed in areas where the cross-sectional dimensions of the shear cut are prone to change, such as edges affected by the stretching process;

5) Tube positions should not be placed in areas where the product has an internal extruded shape and the edges will deform, such as near pressure lines, chamfers, and pressure peaks;

6) Tube positions should not be placed in areas where the dimensions are unstable after forming, such as after bending;

7) Pay attention to preventing the product from turning backward;

8) Tube positions should not be placed in areas where the product's strength is weak. Internal Tube Position Design: Internal tube positions offer high material precision and strong ability to ensure product dimensional stability, but product handling is more difficult. They are often used for precise positioning in mold design. The following requirements apply to internal tube position design:

1) The distance between tube positions should be as far as possible to facilitate product dimensional stability;

2) Tube positions should ideally not be on the same line;

3) When punching positioning holes during the stretching process, holes should be punched in areas with minimal deformation, and an arc-shaped hole should be punched on the outside to separate the positioning and deformation areas, reducing the impact of stretching;

4) Tube... There should be no extruded shapes near the positioning point, such as pressure lines, pressure peaks, chamfers, etc.;

5) The positioning hole of large parts should be as close to the operator as possible;

6) Pay attention to preventing the product from being reversed. Based on the different characteristics of the inner and outer tube positions, the two types of tube positions are often used together in the design, with the outer tube position for coarse positioning and the inner tube position for precise positioning. Outer Tube Position Design Parameters Compound Mold Stop Component Design The following are the basic requirements for the design of the compound mold stop component:

1) In the mold open state, the height H of the stop pin protruding from the mold surface is 8mm;

2) The stop pin positions should be as dispersed as possible. The transverse stop pin B1 is generally not placed in the scrap area, and the distance C from the scrap edge is 5~15mm. When the product cutting size is large, more than two stop pins can be set in both the transverse and longitudinal directions;

3) The stop pin must be placed close to the edge of the sheet material;

4) The spring used for the stop pin is a black round wire spring;

5) Common specifications for stop components in compound molds:

6) The following figure shows the compound mold stop component design. The design and assembly requirements for the mold clamping and retaining components can be used as a reference during the design process.

Note: All retaining pins in compound molds are hung under the outer ejector plate. Internal Guide Pillar Component Arrangement and Installation: Commonly used internal guide pillars (GP guide pillars) are available in the following specifications: Φ10, Φ12, Φ14, Φ16, Φ18, Φ20, Φ25, Φ30. Basic principles for internal guide pillar arrangement:

1) The distance from the center of the internal guide pillar hole to the edge of the mold plate is generally 35mm, but for small molds using Φ10 or Φ12 internal guide pillars, it is generally 30mm, with a minimum of 25mm (when using a BB mold base);

2) The arrangement of internal guide pillars should not obstruct material feeding and product ejection during mold production;

3) The distance between internal guide pillars on the same side is generally above 100mm, typically between 100 and 200mm;

4) When arranging internal guide pillars, attention should be paid to mold anti-reverse measures. Asymmetrical arrangement and differences in the size of individual guide pillars are often used to prevent mold anti-reverse measures.

5) To ensure the guiding accuracy of the automatic mold, small guide pillars are often added to strengthen the mold's alignment, as shown in the diagram below.

In the diagram:
1) The inner guide pillar (GP guide pillar) L is the main guide pillar, generally a Φ16 straight rod oil groove type guide pillar. It is fixed to the male clamping plate by M1/4" cup head screws, tightly fitted with the male clamping plate (assembly clearance is ±0.01), and the assembly clearance with the intermediate plate is 2mm. Embedded guide sleeves are installed in the mold plate and the lower mold plate, and the guide sleeves are glued and fixed with 609 glue. Holes need to be drilled in the lower mold plate and the lower mold base to avoid gaps. The distance from the center of the guide pillar hole to the edge of the mold plate is generally 40~50mm, and the assembly clearance between the guide sleeve and the mold plate is 0.2mm (single-sided clearance is 0.1mm);

2) K is the mold alignment square edge pin, the commonly used size is 15X20;

3) N is the auxiliary small guide pillar (GP The guide pillar is generally a Φ13 straight rod with an oil groove, which is locked to the lower mold plate 1 by an M1/4" cup head screw. The guide pillar is tightly fitted with the lower mold plate (assembly clearance is ±0.01). An embedded guide sleeve is installed in the mold plate, and the intermediate plate is drilled to avoid gaps. Pin Placement and Assembly: Commonly used edge pins are Φ6, Φ8, Φ10, and Φ12. The following principles apply to edge pin placement:

1) In principle, the edge pin and the inner guide pillar should be aligned along the length of the mold;

2) The distance between the center of the edge pin hole and the center of the inner guide pillar hole is generally 25~30mm;

3) When selecting the size of the edge pin, choose the largest diameter possible if space allows;

4) The edge pin assembly is a tight fit, i.e., the assembly clearance with the mold plate is ±0;
5) The application range of the edge pin includes mold plate positioning, Fixing of V-rolled male, U-rolled male, and outer guide pillars (TUR guide pillars). Square edge pin specifications and layout assembly requirements:

1) Square edge pin specifications: The following specifications should be selected for the square edge pins in the mold design, with a height equal to the thickness of the template plus -1mm.

2) Square edge pin layout requirements:
To prevent template deformation during processing, the number of positioning square edge pins should not be excessive. Generally, a center-to-center distance of 150±10mm is sufficient.

3) Square Edge Nail Assembly Requirements:

To facilitate the assembly of square edge nails and ensure the strength of the template, the nails are beveled at C1 around their perimeter, and the square edge nail holes on the template are rounded with R1 fillets.

Spring Arrangement and Selection Principles:

1) Before arranging and selecting springs, the unloading force of the mold should be estimated. Based on the estimated value, a safety factor of 1.5~2.5 should be used to determine the unloading force;

2) Based on the number of springs, the size of the springs, and the working stroke of the springs, combined with the order size, determine the spring life (generally, we select a life of 500,000 cycles for each order), as well as the type and specifications;

3) Within the allowable position of the template... To reduce mold costs, and provided the compression amount meets usage requirements, use large-diameter, heavy-duty brown springs (TB/TD springs) to minimize costs. This reduces the number of springs and lowers overall mold cost.

5) To ensure the mold is under vertical stress and minimize lateral stress, the springs should be arranged symmetrically both horizontally and vertically. For areas with positional interference, adjust the springs accordingly.
6) To guarantee the unloading force of the ejector plate, the mold should be pre-compressed in its free state, with a pre-compression amount of 2... ~5mm, generally 3mm;

7) Basic principle of spring arrangement: Ensure balanced unloading force. Only balanced internal stress in the mold can guarantee the mold's service life and product quality;

8) Symmetry principle: Symmetrical arrangement of springs can better achieve balanced internal stress in the mold.

9) Where the mold position allows, springs can be added to the forming part of the product to increase local elasticity. Selection and Arrangement of External Guide Pillars (TUR Independent Guide Pillars) Commonly used external guide pillars (TUR guide pillars) mainly have the following specifications: Φ19, Φ25, and Φ31. The following principles apply to the arrangement of external guide pillars (TUR guide pillars). 1) TUR guide pillars are typically used in molds with 1 pair (2 pillars), 2 pairs (4 pillars), or 3 pairs (6 pillars). In automatic molds, at least 2 pairs of external guide pillars should be used for rough mold alignment. When the mold size is 1.3m x 0.5m or larger, 3 pairs (6 pillars) of external guide pillars are designed for rough alignment.

2) External guide pillars are installed on the upper and lower mold bases.

3) In small and medium-sized automatic molds, 2 pairs (4 pillars) of external guide pillars are generally used for rough mold alignment. In the diagram, dimension B is 1mm, and dimension A is generally 45~75mm. For large automatic molds (mold length over 1.3m), 3 pairs of external guide pillars are generally used for rough mold alignment. Dimension B is 1mm, and dimension A is generally 80~100mm; (see the figure below for details)

4) When using one pair of external guide pillars for rough mold alignment in a single-operation mold, the guide pillars are centered, and dimension B is 1mm. When there are no internal guide pillars inside the mold, the external guide pillars need to be designed to prevent reverse rotation; (see the figure below for details)

5) For single-operation molds with a width greater than or equal to 500mm, two pairs of external guide pillars (4 in total) are generally used for rough mold alignment. In the figure, dimension B is 1mm, and dimension C is generally 45~70mm.

Determination of Template Dimensions

Determination of Progressive Mold Template Dimensions

1) To ensure the dimensional accuracy of the template after heat treatment, the length and width of the template should be as small as possible. 1) For molds exceeding 500mm in length, when the mold design is too long, the mold can be grouped. The gap between groups should be 3mm. The unit digit of the template size should be 0 or 5, and the unit digit of the mold base length can be arbitrary.

2) To reduce processing costs, at least one of the template's length and width dimensions must match the template's specifications, and the thickness should match the template's thickness specifications.

3) When designing the template, the workstations should be arranged reasonably to shorten the mold as much as possible, avoid feeding errors, and reduce mold costs.

4) The template's length and width dimensions are generally determined by the following parameters:

B0----Pitch;

B----Material width;

a value, in In the design, the value of 'a' is generally 25-30mm, and the distance between the edge of the floating material pin and the edge of the template should be at least 20mm;

The value of 'a0' is generally 25-30mm between the final wire-cut edge of the mold and the edge of the template, and should not be less than 20mm;

The dimension 'C' is generally 55-90mm, with 60-70mm commonly used for small and medium-sized molds, and 70-90mm commonly used for large molds;

The template length L1 = n*B0 + a + a0, where the template length is estimated from the previous formula and rounded down, with the decimal point being 0 or 5;

The template width is B2 = B + 2C, where the template width is estimated from the previous formula and rounded down, with the decimal point being 0 or 5. However, at least one of the template's length and width dimensions must match the template's standard dimensions.

5) The distance between the edge of the template's wire-cut cut and the template's edge must be ≥50mm; the distance between the edges of wire-cut inserts, pipe positions, floating pins, etc., and the template's edge must be ≥20mm;

6) To prevent mold inserts or punching the bottom of the male base, the lower mold pad 1 and male clamping pad should be made of oil steel or K460;

7) To save costs and facilitate processing, the male clamping plate (or pin clamping plate) should be made of 45# steel;

8) When either the template's length or width dimension is greater than 400, avoid using a 17mm thick template to prevent bending and deformation during mold use.

Drill base dimensions determination (A, D dimensions determination)

1) The die base does not have external guide pillars (TUR guide pillars). The long side of the die base is 80mm wider than the long side of the template (single side + 40mm), and the short side of the die base is 50mm wider than the short side of the template (single side + 25mm). For compound dies and punching dies, when the upper die cannot be secured using the die-cutting holes on the die-cutting machine, the short sides of both the upper and lower die bases should be increased from the current 25mm per side to 40mm to facilitate the fixed assembly of the upper die.

2) Adding external guide pillars (TUR guide pillars) to the mold base:

a. When adding Φ19 external guide pillars, the long side of the mold base is 140mm wider than the long side of the mold plate (single side +70mm). The short side of the mold base is 50mm wider than the short side of the mold plate (single side +25mm);

b. When adding Φ25 external guide pillars, the long side of the mold base is 160mm or 150mm wider than the long side of the mold plate (single side +80mm or +75mm). The short side of the mold base is 50mm wider than the short side of the mold plate (single side +25mm);

c. When adding Φ31 external guide pillars, the long side of the mold base is 180mm wider than the long side of the mold plate (single side +90mm). The short side of the mold base is 50mm wider than the short side of the mold plate (single side +25mm). The mold base dimensions can be finely adjusted based on the mold base specifications after the initial determination above.

Note: When designing a mold for a 400T injection molding machine, the mold base dimensions should be adjusted accordingly. The U-groove on the upper mold base is 100mm wider than the U-groove on the upper cover plate to facilitate the locking of the mold with the injection molding machine. For single-operation mold base design, if the injection molding machine tonnage is greater than or equal to 60T, lifting screws must be designed on the upper mold base.

Cover Plate Dimensions: The cover plate dimensions are exactly the same as the mold base dimensions. The cover plate only has locking screws, lifting screws, external guide post through holes, and base screw through holes.

Common Mold Specifications (After Machining): To save costs, except for molds from CANON, EPSON, PHILIPS, and those with monthly orders exceeding 50,000, which use imported materials, all others use domestic materials (all mold bases, cover plates, and feet are made of iron). Specific design specifications and drawing annotation standards are shown in the table below: 1) Dimensions after machining of imported K460 oil steel.

Lower Mold Foot Design: General requirements for the design of the lower mold foot: 1) The length of the pad is equal to the template length, and the pad width is 50mm or 75mm. The material is A3 iron. The height of the pad is determined according to the thickness of the lower mold template and the standard height of the lower mold.

2) The lower mold pad is fixed to the lower mold base with Φ3/8" cup-head screws. There are 2-4 cup-head holes on the lower pad (the screw hole spacing does not exceed 150mm).

3) The pad should be as close as possible to the forming area of ​​the mold, preferably directly opposite it.

4) When designing the pad, be sure to reserve space for the forklift fork (forklift fork arm width 125mm, thickness 15-40mm).

5) The position of the air ejector rod should be as close as possible to the forming bending line. The pad should not block the air ejector hole of the injection molding machine.

6) When designing the pad, prevent the pad from blocking the drain hole. If this cannot be avoided, the drain hole should be designed according to subsequent requirements, and attention should be paid to the anti-reverse design of the pad. (Asymmetrical design of screw positions). Equal-height sleeve assembly design: Compared to plug screws, equal-height sleeve assemblies are easier to adjust and have higher guiding accuracy. Therefore, we generally choose equal-height sleeve assemblies when there is an assembly position. The structure and specifications of the sleeve assembly are as follows: Notes: 1) The bilateral clearance between the template and the equal-height sleeve is 2mm (the relevant templates mainly include: intermediate plate, male clamping plate, male clamping pad, and lower mold pad);

2) The bilateral clearance between the template and the equal-height sleeve pad is 3mm (the relevant templates mainly include: upper mold base, cover plate, and lower mold base);

3) When determining the height of the equal-height sleeve, firstly, ensure that the ejector plate is at least 1mm higher than the longest male in the free state of the mold; secondly, ensure that the ejector stroke is 5~6mm. Mold height design. Progressive mold height design. Notes: a. Dimensions marked with a box in the table are reference dimensions; B. When the mold height exceeds the standard, the die holder (the groove depth is 120mm long and the width is the distance from the edge of the template to the edge of the mold holder). Single-operation mold height and template thickness design

1) Single-operation mold height
Note: Data marked with a box in the table represents the preferred range for mold closing height.

2) Mold air ejector design parameters
Note: a. Data marked with a box in the table represents the preferred range for mold closing height.
B. Actual height of ejector pin protruding from the worktable + mold top plate thickness - 5mm = 3) For compound dies and punching dies, when the upper die cannot be secured using the designated die-cutting holes on the die-cutting machine, the die-cutting width (single-side width) of the upper and lower die bases should be increased from the current 25mm to 40mm to reliably fix the upper die, prevent accidental detachment during production, and ensure production safety. For die-cutting slots with positioning grooves, the slots must be properly machined.

4) When the die closing height is insufficient, a shim should be added to the upper die base. When the shim height exceeds 80mm, a 30mm thick cover plate should be added to the shim.