This article will talk about the commonly used materials in automotive molds and the knowledge points that should be paid attention to in design, as well as the commonly used materials in automotive molds and the corresponding points that should be paid attention to in design. It is hoped that this will be helpful to everyone.

         What should be noted in mold design?

         Mold is the basic process equipment of industrial production, known as the "mother of industry". In industrial production, it plays an important role, and in mold design, we need to pay attention to the following:

         1. The diagonal tip should be rounded off from the center of the mold

         2. The spacing between the support column (SP) and the foot pad should be kept equal, so that the mold is balanced.
 

         3. The KO hole is eccentric with the eccentricity of the injection port liner, and the maximum inclination angle of the injection port liner shall not exceed 15.

         4. For two and a half molds, the parting stroke between the upper fixed plate and the female template needs to be controlled by a mechanism. LP must have a guide sleeve on the male template, and generally, an LK shutter is also required.
 

         5. The method for handling the inner barb is generally to use slanted tips, inner sliders, and stripping plates (pushing out the middle plate). The pushing out tips should be avoided under the sliders as much as possible to avoid collision or interference.
 

         6. Generally, the mold core exceeds the finished product contour by 20-30mm and should be rounded off from the center of the mold. The template should be 20-30mm away from the mold core frame. If there is a slider, the template should be enlarged, and special attention should be paid to avoiding interference with the return pin.

         7. Generally, finished flat products should not be glued in the middle to prevent bending and deformation. Under normal circumstances, STP is directly below RP. When the mold seat is large, the spacing of STP is 150-200mm. The screw spacing for locking the upper and lower ejection plates is 150-200mm

         8. When there is a ejector pin below the slider or a diagonal tip is broken, the upper and lower ejector plates should be equipped with a forced return mechanism. The draft angle of the finished product is based on the reduction of adhesive. When designing waterways, it is advisable not to use a water pipe directly connected to the mold core, but to use a mold inlet pipe connected to the mold core using ORING. Try to maximize its diameter and arrange it below the projected area of the finished product. Three principles of cooling water path: A. Rapid cooling, B. Uniform mold temperature, C. Convenient processing

        What are the main considerations for mold design

        Guiding language: Below are some main precautions about mold design that I have compiled, hoping to help everyone!

        During the use of molds, mold design is indispensable. Mold design plays a very important role in manufacturing workpieces. In order to better carry out mold design, we need to pay attention to the following four major issues:

        Mold processing accuracy design:

        Ultrasonic welding heads should maintain a symmetrical design as much as possible to avoid uneven stress and lateral vibration caused by the asymmetry of sound wave transmission (the welding head used for welding utilizes the longitudinal transmission of ultrasonic vibration, which can cause heating and fracture of the welding head for the entire resonance system). The application of ultrasonic welding in different industries has different requirements for machining accuracy. For particularly thin workpieces such as the welding of lithium-ion battery electrodes and ears, and the coating of gold foil, the machining accuracy is very high. All machining equipment is equipped with CNC equipment (such as machining centers) to ensure that the machining accuracy meets the requirements.

       Mold frequency parameter design:

       Ultrasonic welding machines have a central frequency, such as 20KHz, 40KHz, etc. The working frequency of the welding machine is mainly determined by the mechanical resonance frequency of the transducer, amplitude converter, and welding head (Horn). The frequency of the generator is adjusted according to the mechanical resonance frequency to achieve consistency, so that the welding head works in a resonant state. Each part is designed as a half wavelength resonant body. The generator and mechanical resonance frequency both have a resonance operating range, such as the general setting of 0.5KHz, within which the welding machine can basically operate normally. When making each welding head, the resonance frequency is adjusted to ensure that the error between the resonance frequency and the design frequency is less than 0.1KHZ. For example, for a 20KHz welding head, the frequency of the welding head will be controlled between 19.90-20.10KHz, with an error of 5 ‰.

       Mold vibration node design:

       The welding head and amplitude lever are both designed as a half wavelength resonant body with a working frequency. In the working state, the amplitude of the two end faces is maximum and the stress is minimum, while the amplitude of the node in the middle position is zero and the stress is maximum. The node position is generally designed as a fixed position, but the thickness of the fixed position is usually greater than 3mm, or it is fixed with grooves, so the fixed position is not necessarily zero amplitude, which can cause some calls and some energy loss. For calls, rubber rings are usually used to isolate other components, or sound insulation materials are used for shielding. Energy loss is considered when designing the amplitude parameters of the mold.

       Design of amplitude parameters for molds:

       Amplitude is a key parameter for materials that need to be welded, equivalent to the temperature of ferrochrome. If the temperature is not reached, fusion cannot be achieved. If the temperature is too high, the raw material will be burnt or cause structural damage, resulting in a decrease in strength. Due to the different transducers they choose, the amplitude output by the transducers varies. By adapting amplitude changing rods and welding heads with different ratios, the working amplitude of the welding head can be corrected to meet the requirements. Typically, the output amplitude of the transducer is 10-20 meters, while the working amplitude is generally around 30 meters. The ratio of amplitude changing rods and welding heads is related to the shape of the amplitude changing rods and welding heads, as well as factors such as the ratio of front to back area. In terms of shape, such as exponential amplitude changing, functional amplitude changing The stepped amplitude has a significant impact on the transformation ratio, and the area ratio before and after is directly proportional to the total transformation ratio. If different welding machines are used, the simplest method is to make them according to the proportional size of the working welding head, which can ensure the stability of amplitude parameters.

       What are the processes and precautions for designing automotive stamping molds?

        Stamping process is a method of obtaining workpieces of certain size, shape, and performance by applying external force to the blank through a mold to cause plastic deformation or separation. Stamping process and mold design are important technical preparation processes for stamping. Stamping process and mold design should be combined with the actual situation of equipment, personnel, and other factors, comprehensively considering the quality, efficiency, strength, environmental protection, and safety of the parts, and selecting and designing technologically advanced, economically reasonable, safe and reliable process plans and mold structures, Below is a brief introduction to the process and precautions for designing automotive stamping molds:

       1、 Automotive stamping process design

      (1) Analysis of parts and their stamping process

      Based on the design drawings of stamping parts, analyze the shape characteristics, size, accuracy requirements, raw material size specifications, and mechanical properties of stamping parts, and combine the available stamping equipment specifications, mold manufacturing conditions, stamping batch size, and other factors to analyze the stamping process of parts. A good stamping process should ensure low material consumption, fewer processes, less equipment occupation, simple mold structure and high service life, stable product quality, and simple operation.

      (2) Determine the process plan

     On the basis of analyzing the stamping process, the main process parameters are calculated to identify the characteristics and difficulties of the process and mold design. Based on the actual situation, various possible stamping process plans are proposed, including process properties, number of processes, process sequence, and combination methods.

     (3) Determine process parameters

      Process parameters refer to the data based on which the process plan is formulated, such as various forming factors (drawing coefficient, bulging coefficient, etc.), part unfolding dimensions and punching force, forming force, material utilization rate of part layout, punching pressure center, workpiece area, bending or drawing forming force, complex part blank unfolding size, etc.

     (4) Select stamping equipment

      Based on the nature of the stamping process to be completed and the force and energy characteristics of various stamping equipment, the main factors required for stamping, such as deformation force, deformation work, mold closure height, and contour size, are considered. Combined with the existing equipment situation, the equipment type and tonnage are reasonably selected. Common stamping equipment includes crank press, hydraulic press, etc.

       2、 Stamping mold design

      Mold design includes the selection and design of mold structural forms, calculation of mold structural parameters, and drawing of mold drawings.

      (1) Selection and Design of Mold Structure Form

       Based on the proposed process plan, the structural form of the stamping die is selected and designed considering the shape characteristics, part size, accuracy requirements, batch size, mold conditions, and requirements for easy and safe operation of the stamped parts.

      (2) Calculation of Mold Structural Parameters

       After determining the structural form of the mold, it is necessary to calculate or verify the relevant parameters on the mold structure, such as the geometric dimensions of the mold parts (convex, concave molds, etc.), the strength and stiffness of the mold parts, the motion parameters of the mold moving parts, the installation dimensions between the mold and equipment, and the selection and calculation of elastic components.

       (3) Draw mold diagram

        The mold drawing is the ultimate embodiment of the stamping process and mold design results, and a complete set of mold drawings should include complete information about the mold and the mold used. The mold drawing consists of a final assembly drawing and a part drawing of non-standard parts.

        3、 Basic requirements for stamping materials

        The materials used for stamping should not only meet the technical requirements of the design, but also meet the requirements of the stamping process and subsequent stamping process.

        (1) Requirements for stamping forming performance

        In order to facilitate stamping deformation and improve the quality of the parts, the material should have good plasticity, low yield strength ratio, large plate thickness directionality coefficient, small plate plane directionality coefficient, and a small ratio of yield strength to elastic modulus of the material. For the separation process, it is not necessary for the material to have good plasticity, and materials with better plasticity are less likely to separate.

       (2) Requirements for material thickness tolerances

        The thickness tolerance of the material should comply with national standards. Because a certain gap between the molds is suitable for materials with a certain thickness, the thickness tolerance is too large, which not only directly affects the quality of the parts, but may also lead to damage to the molds and punching machines.

        4、 Selection of Precision Stamping Oil

       Stamping oil plays a crucial role in the stamping process, and its good cooling performance and extreme pressure and wear resistance have made a qualitative leap in the service life of molds and the improvement of workpiece accuracy. The performance of stamping oil varies depending on the material of the workpiece.

      (1) Selection of stamping oil for silicon steel plates

      Silicon steel plate is a material that is relatively easy to cut. Generally, in order to ensure the easy cleaning of the finished workpiece, low viscosity stamping oil is selected to prevent burrs during cutting.

     (2) Selection of stamping oil for carbon steel plates

     When selecting stamping oil for carbon steel plates, the first thing to pay attention to is the viscosity of the stretching oil. Determine the optimal viscosity based on the difficulty, stretching oil method, and degreasing conditions.

     (3) Selection of stamping oil for galvanized steel plates

     Due to the chemical reaction with chlorine based additives, when selecting stamping oil for galvanized steel plates, attention should be paid to the possibility of white rust caused by chlorine based stamping oil, while using sulfur based stamping oil can avoid rusting. However, degreasing should be done as soon as possible after stamping.

     (4) Selection of stamping oil for stainless steel plates

      Stainless steel is a material that is prone to hardening, requiring the use of tensile oil with high oil film strength and good sintering resistance. Generally, stamping oil containing sulfur chlorine composite additives is used to ensure extreme pressure processing performance while avoiding problems such as burrs and fractures on the workpiece.

How to improve the efficiency and accuracy of high-end precision automotive mold manufacturing?

     With the rapid development of China's automotive industry, the automotive manufacturing industry requires better quality, lower investment, and more importantly, manufacturing efficiency for automotive mold manufacturing. Modern industrial molds are mainly manufactured through CNC milling technology, which involves complex rotation using CNC milling machines. High speed rotating milling cutters are used to cut the required mold shape and features on fixed blanks.

      Improve the efficiency of high-end automotive precision mold manufacturing and ensure the quality of automotive parts:

      1、 Standardization of Automotive Mold Design

     Among the numerous precision molds for automobiles, when designing precision molds for automobiles, comprehensive consideration is given to the service life, occasions, process methods, and a series of possible problems that may arise during the process. From the source, the design of mold drawings has developed towards standardization and process standardization.

      2、 Manufacturing process optimization and formulation

     After the task of designing automotive mold patterns is completed, the next step is to develop the mold manufacturing process. The general process of mold manufacturing is as follows: cutting → rough machining → heat treatment → flat grinding → precision machining → fitter, etc. During the process, some technical difficulties may arise due to the significant differences between mold and general component manufacturing. Therefore, when formulating the process, not only should the rigidity, accuracy, and process travel of the machine tool be comprehensively considered, but also the coherence of the previous and subsequent processes, as well as whether the margin is reasonable. At the same time, we focus on the key details of the process when formulating the process, achieving a unified design benchmark, cutting benchmark, programming benchmark, measurement benchmark, and mold assembly benchmark to reduce accumulated errors.

      3、 Selection and matching of cutting machine tools

      The matching process of the machine tool is particularly important when cutting high-end precision molds. When using a simple and economical CNC machine tool to cut the surface and outer circle of precision automotive molds, there are always very obvious cutting marks. Usually, the accuracy of the machine tool cannot meet the precision size requirements of the drawing. Therefore, when cutting precision molds, special attention should be paid to the important parameters, performance, function, accuracy, etc. of the machine tool, which is more conducive to improving the efficiency of the mold process.

       4、 Machine Tool Selection and Matching

      The selection of cutting tools is very important when cutting precision automotive molds. We should consider the material of the cutting tools used to cut the mold parts, and combine the tool holder and matching blade information provided by the tool manufacturing enterprise to select reasonable cutting parameters. Commonly used non-metallic materials such as carbon steel, titanium alloy, aluminum, and composite materials should focus on improving efficiency during rough tooling, with appropriate back feed, high feed speed, and medium speed; When precision cutting automotive molds, the principles of high rotational speed, high feed rate, and low cutting allowance are important parameters that can be referred to in the recommended parameters provided by the cutting tool enterprise.

       5、 Programming device usage and matching

        With the rapid development of CNC machine tools and the improvement of programming intelligence, complex parts or high-end precision molds have put forward higher requirements for CNC machine tools and programming tools. From manual programming to automatic programming, software programming can accurately draw complex parts or molds, while also avoiding error rates. Nowadays, many automobile manufacturing enterprises are widely using specialized programming tools that are suitable for themselves. When cutting complex parts or molds, as long as you choose a suitable programming tool that you are proficient in, it is more conducive to improving cutting efficiency.

       6、 Performance and Selection of Cutting Oil

       Cutting oil is a lubricating medium that must be used in metal cutting processes. High precision mold cutting processes have higher requirements for the cooling, lubrication, penetration, and cleaning performance of cutting oil. When using waste engine oil, vegetable oil, etc. instead of specialized cutting oil, it is easy to encounter defects such as burrs, scratches, damage, and deformation, and the tool life will also be greatly reduced. Due to the use of non corrosive sulfurized extreme pressure anti-wear additives as the main agent, high-end cutting oil has strong adhesion to the oil film. The strong and tough oil film can effectively protect the cutting tools and improve the surface quality of the mold. At the same time, it can avoid problems such as rust and blackening of the workpiece and allergic reactions of workers.