What issues should be paid attention to in mold making?

P&M As a mold company that can provide ODM/OEM services, according to customers' ideas, we can provide products with high quality from the aspects of mold process analysis, product design optimization, mold design improvement, plastic parts production efficiency improvement, and defective parts improvement. We always adhere to the principles of quality first and time first. While providing customers with the highest quality products, try to maximize the production efficiency and shorten production time. Meanwhile, We promise: All customer-centric, never for short-term profit, and sell long-term benefits. As a professional mold manufacturer, what issues should be paid attention to in mold making?I will explain it in detail below：

1. Collect the necessary information

When designing a cold stamping die, the information to be collected includes product drawings, samples, design tasks and reference drawings, etc., and the following questions should be understood accordingly:

l) Know whether the product view provided is complete, whether the technical requirements are clear, and whether there are any special requirements.

2) Understand whether the production nature of the part is trial production or batch or mass production to determine the structural nature of the mold.

3) Understand the material properties (soft, hard or semi-hard), dimensions and supply methods (such as strips, coils or scrap utilization, etc.) of the parts in order to determine the reasonable gap for blanking and the feeding method of stamping.

4) Understand the applicable press conditions and related technical specifications, and determine the appropriate mold and related parameters according to the selected equipment, such as the size of the mold base, the size of the mold handle, the closing height of the mold, and the feeding mechanism.

5) Understand the technical force, equipment conditions and processing skills of mold manufacturing to provide a basis for determining the mold structure.

6) Understand the possibility of maximizing the use of standard parts in order to shorten the mold manufacturing cycle.

2. Stamping process analysis

Stamping processability refers to the difficulty of stamping parts. In terms of technology, it mainly analyzes whether the shape characteristics, dimensions (minimum hole edge distance, aperture, material thickness, maximum shape), accuracy requirements and material properties of the part meet the requirements of the stamping process. If it is found that the stamping process is poor, it is necessary to propose amendments to the stamping product, which can be modified after the product designer agrees.

3. Determine a reasonable stamping process plan

The determination method is as follows:

l) Perform process analysis according to the shape, dimensional accuracy, and surface quality requirements of the workpiece to determine the nature of the basic processes, namely blanking, punching, bending and other basic processes. Under normal circumstances, it can be directly determined by the drawing requirements.

2) Determine the number of processes, such as the number of deep drawing, according to process calculations.

3) Determine the sequence of the process arrangement according to the deformation characteristics and size requirements of each process, for example, whether to punch first and then bend or first bend and then punch.

4) According to the production batch and conditions, determine the combination of processes, such as composite stamping process, continuous stamping process, etc.

5) Finally, comprehensive analysis and comparison are carried out from the aspects of product quality, production efficiency, equipment occupancy, difficulty of mold manufacturing, mold life, process cost, ease of operation and safety, etc. Under the premise of meeting the quality requirements of stamping parts, Determine the most economical and reasonable stamping process plan suitable for specific production conditions, and fill in the stamping process card (contents include process name, process number, process sketch (semi-finished product shape and size), mold used, selected equipment, process inspection requirements, plate (Material specifications and performance, blank shape and size, etc.):;

4 Determine the mold structure

After determining the nature and sequence of the process and the combination of processes, the stamping process plan is determined and the structure of the die of each process is determined. There are many types of punching dies, which must be selected according to the production batch, size, precision, shape complexity and production conditions of the punched parts. The selection principles are as follows:

l) Determine whether to use simple mold or composite mold structure according to the production batch of the part. Generally speaking, the simple mold has a low life and low cost; while the composite mold has a long life and high cost.

2) Determine the type of die according to the size requirements of the part.

If the dimensional accuracy and cross-sectional quality of the parts are high, the precision die structure should be used; for the parts with general accuracy requirements, ordinary die can be used. The precision of the parts punched out by the compound die is higher than that of the progressive die, and the progressive die is higher than the single process die.

3) Determine the die structure according to the type of equipment.

When there is a double-action press during deep drawing, it is much better to choose a double-action die structure than a single-action die structure

4) Choose the die structure according to the shape, size and complexity of the part. Generally, for large parts, in order to facilitate the manufacture of molds and simplify the mold structure, single-process molds are used; for small parts with complex shapes, for ease of production, composite molds or progressive molds are commonly used. For cylindrical parts with large output and small external dimensions, such as semiconductor transistor casings, a progressive die for continuous drawing should be used.

5) Choose mold type according to mold manufacturing power and economy. When there is no ability to manufacture high-level molds, try to design a simpler mold structure that is practical and feasible; and with considerable equipment and technical strength, in order to improve the life of the mold and meet the needs of mass production, you should choose a more complex Precision die structure.

In short, when selecting the structure of the die, it should be considered from many aspects, and after a comprehensive analysis and comparison, the selected die structure should be as reasonable as possible. See Table 1-3 for the comparison of the characteristics of various types of molds.

5. Carry out necessary process calculations

The main process calculation includes the following aspects:

l) Blank unfolding calculation: It is mainly to determine the shape and unfolded size of the blanks for the bent parts and deep-drawn parts, so that the layout can be carried out under the most economical principle, and the applicable materials can be reasonably determined.

2) Calculation of punching force and preliminary selection of stamping equipment: calculation of punching force, bending force, drawing force and related auxiliary force, unloading force, pushing force, blank holder force, etc., if necessary, also need to calculate the punching work and Power in order to select the press. According to the layout drawing and the structure of the selected mold, the total punching pressure can be easily calculated. According to the calculated total punching pressure, the model and specifications of the stamping equipment are initially selected. After the general drawing of the mold is designed, check the equipment Whether the die size (such as closed height, worktable size, leakage hole size, etc.) meets the requirements, and finally determine the type and specification of the press

3) Pressure center calculation: Calculate the pressure center, and ensure that the mold pressure center coincides with the center line of the mold handle when designing the mold. The purpose is to prevent the mold from being affected by the eccentric load and affecting the mold quality.

4) Carry out layout and material utilization calculation. In order to provide a basis for material consumption quota.

The design method and steps of the layout drawing: generally consider and calculate the utilization rate of materials from the perspective of layout first. For complex parts, thick paper is usually cut into 3 to 5 samples. Various possible solutions are selected. Optimal solution. Nowadays, computer layout is commonly used and then comprehensively considers the size of the mold size, the difficulty of the structure, the mold life, the material utilization rate and other aspects. Choose a reasonable layout plan. Determine the overlap, calculate the step distance and material width. Determine the material width and material width tolerance according to the specifications of the standard plate (strip) material. Then draw the selected layout into a layout drawing, mark the appropriate section line according to the mold type and punching sequence, and mark the size and tolerance.

5) Calculation of the gap between the convex and concave molds and the size of the working part.

6) For the drawing process, determine whether the drawing die uses a blank holder, and carry out the drawing times, the die size distribution of each intermediate process, and the calculation of the size of the semi-finished product.

7) Special calculations in other areas.

6. Overall mold design

On the basis of the above analysis and calculation, the overall design of the mold structure can be carried out, and the sketch can be drawn, the closed height of the mold can be calculated preliminarily, and the outline size of the mold, the structure of the cavity and the fixing method can be roughly determined. Also consider the following:

1) The structure and fixing method of convex and concave molds;

2) The positioning method of the workpiece or blank.

3) Unloading and discharging device.

4) Guiding mode of the mold and necessary auxiliary devices.

5) Feeding method.

6) Determination of the form of the mold base and the installation of the die.

7) Application of standard mold parts.

8) Selection of stamping equipment.

9) Safe operation of molds, etc.