Abstract: This article introduces the company profile of Chengdu Push Automotive Mold Co., Ltd., systematically elaborates on the company's typical equipment and its application in automated manufacturing technology, and discusses several core technologies in detail.
The level of manufacturing reflects a country's industrialization and productivity, thus occupying a vital position in the national economies of major economies. The development level of mold manufacturing is one of the important indicators for measuring a country's manufacturing level. In recent years, with the rapid development of the automotive industry, the market has placed higher demands on automotive mold manufacturing enterprises. The demand for large-scale automated, intelligent, and high-speed molds has grown rapidly, and higher, more precise, more detailed, and more comprehensive mold manufacturing technologies have become the foundation for automotive mold manufacturing enterprises.
Currently, CNC machining methods for automotive molds have evolved from simple surface machining to fully digital three-dimensional machining of both surface and structural surfaces, and from low-to-medium speed machining to high-speed machining. In the automotive mold manufacturing field, advanced manufacturing technologies based on integration, digitalization, and networking, such as automated and intelligent machining, are being increasingly widely applied, significantly improving mold production efficiency and machining accuracy, and propelling mold manufacturing to a new level. Chengdu Push Mold Co., Ltd., based on high technology and large investment, focusing on modern management and an international strategy, leverages the regional advantages of the emerging automotive manufacturing industry, accumulating strength, coordinating overall development, and looking globally. It has now become a modern manufacturing enterprise integrating automotive body panel stamping dies, gauges, fixtures, and stamped parts.
The company has digested and absorbed the standards of major automakers, forming its unique "PWS" standard and cultivating an independent R&D team. It now possesses the capability to develop various mid-to-high-end molds. The company designs and manufactures various automotive body panels and structural components for clients such as Mazda (Japan), PSA (France), FAW-Volkswagen, FAW Car, Dongfeng Peugeot-Citroën Automobile, GAC Mitsubishi, Changan Mazda, and Changan PSA. Body panels include roof outer panels, hood inner/outer panels, door inner/outer panels, fenders, side panel inner/outer panels, and tailgate inner/outer panels. Structural components include front/rear floors, wheel arches, pillars, bumpers, and various reinforcing components. From the technical development of structural component molds to the technical improvement of high-strength steel plate and outer body panel molds, the company has developed proprietary production technologies and distinctive products, including proprietary technologies such as parametric assembly design and mold surface clearance design, as well as high-speed precision floating blanking molds, multi-station molds, automated molds, high-strength steel plate molds, and roof molds.
I. Mold processing equipment
Given the characteristics of automotive molds—large structural dimensions, complex shapes, and high surface quality requirements—the company is equipped with advanced production equipment to meet these requirements, including 3 five-axis machining centers (SORALOCE, RAMBAUDI, and MECOF), more than 20 five-sided machining centers, and more than 20 three-axis machining centers, CNC milling machines, and conventional machining centers.
(1) For some automotive molds with structures such as side cutting, side shaping and side flanging, the hole, contour or shaping accuracy requirements of the corner processing area are high. This requires a five-axis machine tool with good spindle rigidity and high precision. The SORALOCE machine tool (as shown in Figure 1) can fully meet the processing needs. The main parameters of the machine tool are as follows: fixed worktable size: 7000mm×2500mm; rotary worktable size: 2500mm×2500mm, front and back movement 1500mm; spindle: maximum extension 1025mm, vertical movement 3000mm; horizontal movement 3000mm, maximum speed 3000r/min; A-axis, B-axis and rotary worktable range: 0°～360°;
Figure 1 SORALOCE machine tool
(2) For automotive molds with large structural dimensions, complex shapes, and high surface quality requirements, high-speed machining can be carried out using a five-axis linkage machine tool, such as the RAM-speed-H45PLUS high-speed machining center from RAMBAUDI (as shown in Figure 2). The main parameters of this machine tool are as follows: machining range: 4500mm×2700mm×1500mm; positioning accuracy: X-axis 0.025mm, Y-axis 0.020mm, Z-axis 0.015mm, A/C axis P≤12”; repeatability: X-axis 0.010mm, Y-axis 0.010mm, Z-axis 0.010mm, A/C axis P≤8”; spindle power: 30kW, spindle speed: 24000r/min; spindle uses silicon nitride (Si3N4) ceramic ball bearings; tool magazine capacity: 30 tools; the column adopts a gantry frame structure, which has high precision and is particularly suitable for high-speed machining of large automotive molds.
Figure 2. RAMBAUDI RAM-Speed-H45PLUS high-speed machining center
II. Main Processing Technologies Currently Used in Mold Products
Mold automation manufacturing technology reflects the overall technical level of an enterprise's manufacturing. It is composed of many interconnected technical links. Several years ago, the company proposed a strategic goal of developing automated processing of automotive molds and formed a relevant technical research team. It has carried out a series of optimizations and improvements using TRITOP scanning technology, simulation, and online testing, and has achieved good results in the field of automated processing technology for automotive molds.
(1) TRITOP technology uses unique digital points and reference points to construct a complete coordinate positioning system. It utilizes optical imaging positioning technology and grating measurement principle to obtain a complete point cloud of complex workpiece surface in a very short time.
Technology. TRITOP technology is used to scan mold casting blanks, thereby obtaining the true state of the mold before processing, which ensures the safety of automated manufacturing of automotive molds.
(2) The structure of automotive molds is complex, with many molds involving side cutting, side shaping, and side flanging. To ensure the safety of automated manufacturing of automotive molds, it is necessary to simulate the machining process of the side cutting, side shaping, and side flanging parts. Currently, we have established a corresponding machine tool database based on the company's machine tool equipment parameters to ensure the safety of automated manufacturing of automotive molds.
(3) In the automated manufacturing process of automotive molds, the machining accuracy mainly depends on the measurement and accuracy compensation of the machining tools. The on-machine inspection system is a measurement method that uses a workpiece probe on the machine tool to inspect the workpiece. It monitors and compensates for the entire mold processing process, prevents human error, and ensures the accuracy of automated manufacturing of automotive molds.
1. Manufacturing technology of a typical molded product – the top cover
The roof is one of the largest stamped parts in automotive molds, and its quality directly affects the appearance of the car. Therefore, in addition to analysis, design, and debugging, the manufacturing process is also crucial. Our company has accumulated rich technical experience in the processing and manufacturing of roof parts, mainly in the following aspects:
(1) When machining the surface, use the circular arc approach and retraction method to improve the machining quality of the top cover, as shown in Figure 3.
(2) Point milling is used in the surface machining to reduce the wear of the cutting tool and increase the cutting speed. Finishing is carried out by tilting the spindle at 10°, as shown in Figure 4.
Figure 3 shows the use of a circular arc tool entry and exit method.
Figure 4 Point milling machining method
(3) In order to ensure the machining accuracy of the profile and reduce the wear of the cutting tool, the R of the quenched area is pre-finished by leaving 0.05mm before the profile is finished, and then the entire profile is finished, as shown in Figure 5.
Figure 5. Processing method of quenching zone
(4) In the subsequent mold processing of the top cover, in order to ensure the progress of the surface and the processing efficiency, the program was optimized to ensure that the spindle Z-axis did not lift the tool, and the feed value of the clearance area was set to the maximum speed, as shown in Figure 6.
Figure 6. Processing methods for processing areas and clearance areas.
2. Application of new equipment in mold processing and manufacturing
In the automotive manufacturing industry, the requirements of high-volume and high-precision production dictate that durability is a fundamental element of automotive molds. To improve the service life of automotive molds, surface treatment is essential. Flame hardening remains the primary surface treatment method for automotive molds, with most manufacturers in my country still operating on a manual hardening basis. Since the quality of flame hardening largely depends on the operator's experience, problems such as low hardness or cracking of the mold surface after hardening frequently occur. Therefore, finding a mold hardening method that delivers high-quality and stable hardening is crucial. CNC laser hardening machine tools, through program control, can not only effectively guarantee the requirements of mold surface hardening but also improve the efficiency of mold surface hardening. Currently, our company has entered the practical application stage of using laser hardening machine tools for mold hardening, and can now complete the hardening of non-deep drawing and non-deep cavity molds. When using laser hardening on the mold surface, the hardened layer is uniform, and the hardness and quality are significantly better than manual hardening, as shown in Figure 7.
Figure 7 shows the quenching of an automotive mold using a CNC laser hardening machine.
III. Conclusion
With the continuous improvement of automotive mold manufacturing technology, digitalization, integration, and automation are inevitable trends in the automotive mold manufacturing field. From the standardization and innovation of processing technology and processes, to the improvement and innovation of tooling and processing equipment, automation technology will comprehensively cover and systematically connect all aspects of production and manufacturing, improving quality, reducing costs, forming a complete and standardized manufacturing theory, and creating a number of high-yield, high-efficiency, and high-quality manufacturing enterprises. Looking to the future, with the progress and development of emerging science and technology, and accompanied by the wave of industrial upgrading in my country's manufacturing sector, various new theories and technologies will be applied to the automotive manufacturing industry. Digitalization, networking, and intelligence will gradually integrate with automation technology, complementing each other's advantages, and jointly exploring new areas in automotive mold manufacturing.
