Nine Core Steps Of Stamping Mould Design

Obtain the necessary information

(1)Obtain the product parts drawing with specific technical requirements. Understand the shape, size and accuracy requirements of the workpiece. Size (size and location) of keyholes, and key surfaces, analyze and determine the datum of the workpiece.

 The various processability requirements for stamped parts are not absolute. Especially under the current rapid development of stamping technology, according to the actual needs and possibilities of production, it is necessary to comprehensively apply various stamping technologies, reasonably select the stamping method, and correctly carry out the formulation of the stamping process and the selection of the mould structure to meet both the technical requirements of the product and the conditions of the stamping process.

(2) Collect the process cards of workpiece processing. From this, it is possible to study the interrelationship between its front and back processes and the processing process requirements and assembly relationships that must be mutually assured between each process.

 (3)Understand the production lot of the workpiece. The production of the part plays a decisive role in the economy of the stamping process. For this reason, it is necessary to decide the type, structure, material and other related matters of the mould according to the production lot of the part and the quality requirements of the part, and thus analyze the economy of the mould processing process and the rationality of the public production, and depict the outline of the stamping work step.

 

(4)Determine the specifications of the raw material of the workpiece and the condition of the wool (such as plate, strip, coil, scrap, etc.), understand the nature and thickness of the material, determine whether to use less scrap-free shot samples according to the processability of the part and initially determine the specifications and precision level of the material.

(5) analysis of the design and process requirements for the direction of the material fibre and the direction of the burr.

(6)Analyze the technical capacity and equipment conditions of the tooling workshop for manufacturing moulds and the standard parts of moulds that can be used.

(7)Familiar with the equipment information or situation of the stamping workshop.

(8)Study and digest the above information, and conceive the structure plan of the mould initially. If necessary, the established product design and the process can be modified so that the product design, process, mould design, and manufacture can be better integrated to achieve perfect results.

Determination of process scheme and mould structure type

 Determining the process scheme is the most important part of the process analysis of stamping parts. It includes.

 1) Process analysis according to the requirements of shape characteristics, dimensional accuracy and surface quality of the workpiece to judge its main attributes and determine the nature of the basic process. What are the basic processes such as falling, punching, bending, drawing, flanging and expanding? List the single processes required for stamping, which can be directly determined from the product part drawing requirements in general.

 (2) according to the process calculation, determine the number of processes. For drawing parts, you should also calculate the number of deep drawings. Bending and parts, punching parts should also be based on their shape, size and accuracy requirements, etc., to determine whether it is a time or several processing.

 (3) according to the processing of the deformation characteristics, size and accuracy requirements and the requirements of the convenience of operation, to determine the sequence of the process arrangement. Such as using first punching after bending or first bending after punching.

 

 (4) According to the production volume, size, precision requirements and mould manufacturing level, equipment capacity and other factors, the single process has been initially arranged in sequence to the possible combination of processes, such as composite stamping process, continuous stamping process, etc. Usually, single-process production with simple mould is suitable for thick material, low precision, small batch and large size punching parts; continuous production with progressive mould is suitable for thin material, small size and large batch punching parts; and composite mould is suitable for punching parts with high precision of type position.

 After determining the nature and sequence of the process and the combination of the process, the process scheme of stamping is determined. In other words, the structure type of each processed mold is decided.

Performing the necessary process calculation

 

(1)Design the material layout and calculate the blank size.

2) Calculate the punching force (including punching force, bending force, drawing force, flanging force, expanding force, unloading force, pushing force, pressing force, etc.), and if necessary, calculate the punching work and power.

(3) Calculate the centre of pressure of the mould.

(4) Calculate or estimate the thickness of each main part of the mould. Such as the thickness of the concave mold, the fixed plate of the convex mold, the cushion plate and the free height of the unloading rubber or spring, etc.

(5)Decide the clearance of the convex and concave molds, and calculate the size of the working part of the convex and concave molds.

(6) For the drawing process, it is necessary to decide the way of drawing (crimping or not) and calculate the number of drawing times and the size of semi-finished products in the intermediate process.

The overall design of the mold

Based on the above analysis and calculation, the overall design of the mold structure is carried out (at this time, it is generally only necessary to sketch out the sketch), the closing height of the mold is calculated initially, and the shape size of the mold is set out roughly.

The main parts of the mold structure design

 (1) Parts of the workpiece. Such as convex mold, concave mold, convex and concave mold structure design, and fixed form of choice.

 (2) positioning parts. In the mold, the commonly used positioning device has many types. An adjustable positioning plate, fixed stopper pin, movable stopper pin and fixed distance side edge, etc., must be selected and designed according to the specific situation.

(3)Unloading and pushing the device. Such as the choice of rigid or elastic, spring and rubber selection and calculation.

 (4) guide parts, such as the choice of guide pillar, guide sleeve guide or guide plate guide, the choice of intermediate guide pillar, side and rear guide pillar or diagonal guide pillar, the use of sliding guide sleeve or ball guide sleeve with steel balls, etc.

 (5) support and clamping parts, fastening parts. Such as mold handles and upper and lower mold base structure selection.

Selection of stamping equipment

The selection of stamping equipment is an important element of process design and mold design. The reasonable selection of equipment has a significant impact on the quality of the workpiece, the improvement of productivity and the safety of the operation, and also brings convenience to the design of the mold.

 The selection of stamping type mainly depends on the process requirements and production lot.

 The specification of stamping equipment depends mainly on the process parameters and mold structure size.

Drawing the general diagram of the mold

 The drawing of a general drawing of the mold (including the drawing of parts and workpieces) is in strict accordance with the drawing standards (GB/T4457~ GB/T4460 and GB/T131-1993). At the same time, in the actual production, combined with the operational characteristics of the mold and the need for installation and adjustment, the layout of its drawing forms a certain habit.

The general drawing of the mold includes the following.

 (1)Main view. Draw the section view of the mold in the working position. Generally, one-half of the drawing shows the situation when the blank is placed before the start of punching (when the punch ram is in the upper stop position). The other half shows the state when the punch ram is in the lower stop position after the end of punching, and the workpiece has been formed (or separated).

 (2)Top view. Usually, the lower half of the top view and the other half of the top view is drawn. Sometimes, the top view’s lower half is also drawn completely.

(3)Side view, elevation view and partial section view, etc. When necessary, the side view of the working position of the mold must be drawn. Sometimes in the upper right corner of the drawing, the upper part of the mold elevation view and local section, etc.

 (4) Workpiece diagram. General workpiece drawing in the upper right corner. For the work done by several sets of molds, in addition to drawing the workpiece diagram of this process, you also need to draw the workpiece diagram of the previous process.

(5) Layout diagram. For the progressive mold, it is necessary to draw the pattern arrangement, the sequence of process arrangement and the stamping content completed by each work step; the work step spacing, the lap value and the strip size should be marked. The layout diagram of the punching mold should show the layout, the size of the strip and the size of the lap value.

 

 (6) list the parts list, indicating the material and quantity. All standard parts should be selected specifications.

 

 (7) technical requirements and instructions. Technical requirements include punching pressure, the type of equipment selected, the overall line position tolerance of the mold and assembly, installation and commissioning, mold closure height, mold clearance and other requirements.

Draw each non-standard part of the parts diagram

The part diagram should indicate all the dimensions, tolerances and fits, form tolerances, surface roughness, materials used and their heat treatment requirements, and other technical requirements.

Fill in the mold record card and prepare the stamping process document.

 For small batch production, a detailed list of process routes should be filled in, while for large batch production, process cards and procedure cards should be made for each part.

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