In recent years, with the rapid development of China's economy, people's living standards are also greatly improved, and various industries are gradually developing and expanding. The car, as a means of transportation, plays an increasingly important role in people's lives, the demand for cars is also increasing, which promotes the booming development of China's automobile manufacturing industry.
Automotive stamping die as a more important part of the automotive manufacturing field, and the development of the automotive manufacturing industry has an inseparable relationship. Stamping molds applied in the manufacture of automotive parts, can effectively improve the efficiency of automotive production, and targeted solutions to some of the problems existing in the traditional mold manufacturing technology, can further enhance production efficiency and improve product quality.
Automotive stamping mold design technology
Design Ideas
Mold design is divided into three parts: stamping process design, mold surface design and structural design. In the various stages of mold design, mold stamping process design should be based on the product drawing requirements, in order to meet the product quality characteristics of the premise, we should consider minimizing the cost of molds, material costs, shorten the manufacturing cycle. And we should consider the machinability of the mold, but also consider the operability of the mold automated production. For example, the design of the gap between the concave and convex mold, the designers need to use simulation and analysis software combined with the actual mold debugging experience, repeated calculations, and strive to be accurate, in order to reduce the mold later debugging to produce a large number of surface product problems and accuracy problems (Figure 1). The following ideas can be referred to in the design.
(1) Analyze the benchmark car.
(1) the benchmark car samples to analyze, check the traces of the parts, to determine the manufacturing process, such as the traces of the parts appeared in the stretching traces, traces of trimming, flanging traces and so on.
② Combined with its own process conditions, reasonable adjustment of the process program.
(2) The investigation of similar parts.
① Understand the products of the same series of models, to understand what problems exist in the development process of this part.
② Find a reference part and collect information about it. Check the process plan, product number molds, molded process parts and finished parts.
③Find out the mold debugging report, mold modification record sheet, production report, and other relevant information related to the part from the beginning of the mold design to the final delivery of the mold.
④ Understand the actual production situation.
● What is the formability? What are the molding difficulties (which parts are good and which parts are bad)?
● Understand the production schedule, the number of processes, and the parts that are prone to necking.
● How to transport the boxes and how to place the parts on the boxes.
● Understand equipment parameters.
● The grade of the material being processed.
Design process
Regarding the design process of automobile stamping mold, designers should pay attention to the following points.
(1) improve the material utilization rate: for high-volume automobile production, improve the utilization rate of the material is one of the most important work of the mold process design. As long as the material utilization rate to improve a few percentage points, you can save a large amount of material costs, the car cost reduction plays a huge role.
(2) reduce the stamping process: mold design trend is the merger of parts, symmetrical pieces of left and right mold (such as the front door, rear door, etc.), inside and outside the board mold (such as the front hood inside and outside the board), the upper and lower plate mold (such as luggage compartment cover plate up and down section), etc., the original two or even more pieces of a piece of a piece of the original, different pieces of the combination of a set of molds, molds more and more, the number of single piece of the process greatly reduces the number of the entire car molds The number of less and less, which plays a key role in reducing the cost of stamping.
(3) stamping automation: in order to adapt to the full automation of the stamping line, the mold must be considered robotic loading and unloading, the automatic discharge of waste, pneumatic automatic sensor devices are commonly used and so on.
(4) the use of computers for simulation and analysis, focusing on the production process of previous models of problems. Grasp the dimensional accuracy requirements for parts with mating relationships on the part. For easy rebound parts (such as aluminum door inner plate, wing plate, longitudinal beam, etc.) must be rebound calculations, and develop a reasonable rebound compensation program, rebound compensation needs to be controlled within tolerance, in order to minimize the later part of the mold debugging time and reduce the risk of reopening the mold scrap. Take flanging rebound compensation as an example: according to the product structure, determine the direction of its rebound, and give the process rebound angle in the design of the process program. General θ = 3 °.
Automotive stamping mold manufacturing technology
Nowadays, the most commonly used key technologies in China's automotive stamping die manufacturing industry include CAE stamping analysis and processing technology and high-precision CNC programming machining technology.
China's large-scale mold manufacturing usually apply CAE stamping analysis processing technology to carry out simulation analysis of stamping parts forming, this technology has a fairly high core value, and often use this technology to analyze all kinds of problems during the forming of stamping parts around the clock, which can effectively reduce the mold later surface product problems and precision problems. This technology is used in conjunction with the actual production conditions of China's automobile industry. For example: the rapid introduction of new models, resulting in a serious shortage of mold development cycle, which brings technical difficulties and great challenges to the automotive mold industry, while the design and manufacturing cycle of the mold has also put forward higher requirements. Due to the introduction of SE analysis technology, the mold design can be updated quickly. Using SE analysis technology to analyze the formability of the new model cover parts from different angles and levels to reduce the later mold debugging time, which greatly shortens the development cycle of the mold and improves the development efficiency of the stamping mold.
The high-precision CNC programming machining technology of the mold is mainly embodied in such aspects as: improving the machining accuracy of the mold surface, improving the degree of machining in place, and realizing the fine design of the mold surface. High-precision machining in addition to machine tool accuracy and tool management, mainly by the improvement of programming technology to achieve. Through high-precision machining, the precision of the mold reaches the goal of less clamping of the mold face, and also greatly reduces the debugging time of the mold and shortens the mold development cycle.
Maintenance strategy of automotive stamping die
Repair strategy of chipping edge
Chipping is a kind of fault often faced in the repair of stamping dies, and it is also an important maintenance point in the repair of stamping dies. There are many reasons for its triggering, but whichever reason will have an adverse effect on the quality and performance of the mold and parts. When the degree of chipping is very small, you can directly use manual grinding machine for manual welding and grinding processing, when the degree of chipping is very large, it is necessary to replace the new insert. Die welding, but also to choose the appropriate mold welding electrode, generally with a welding rod directly for die welding.
Burr repair strategy
In the stamping die production, due to poor clearance between the edge, it is easy to processed parts of the edge burr is too large and other quality problems. Edge gap is bad, respectively, according to the size of each type of mold gap width and other factors to make some corresponding adjustments to try to ensure that the internal gap of each mold is reasonable.
Flanging bad maintenance strategy
In the stamping die flanging process for parts flanging, due to poor flanging clearance, easy to cause flanging surface waves, wrinkles, but also cause the dimensional accuracy on the overshoot, affecting the assembly accuracy of the car. For bad flanging gap, the gap between the concave and convex molds should be checked, the location of the problem should be clarified, and then the gap should be adjusted to be reasonable and even through the mold research.
Cracking repair strategy
In stamping production, part cracking is a serious quality problem that affects vehicle performance and safety and must be avoided. Cracking problems, can be adjusted by adjusting the die stretching rib, balance block, reduce the crimping force and other means of controlling the inflow of sheet material, if the mold surface roughness is not enough to cause parts cracking, the mold can be polished to reduce the resistance of the material inflow in order to eliminate the cracking defect.
Wrinkle bad maintenance strategy
In stamping production, part wrinkling is also a serious quality problem, especially the exterior surface of the outer covering, which seriously affects the appearance quality of the vehicle and must be avoided. When the wrinkling problem occurs, the inflow of sheet material can be controlled by adjusting the drawing rib of the mold, balancing block, increasing the crimping force and other means to increase the resistance of material inflow in order to eliminate the wrinkling bad.