Mold making technology has developed rapidly and has become an important part of modern manufacturing technology. These include CAD/CAM technology for molds, laser rapid prototyping technology for molds, precision prototyping technology for molds, ultra-precision machining technology, mold design using the finite element method, flow technology with boundary elements, cooling, dynamic simulation heat transfer process. technology, CIMS technology for molds, DNM technology for molds and CNC technology, which cover almost all modern manufacturing technologies.
Modern mold manufacturing technology is evolving towards faster information-based manufacturing, greater manufacturing flexibility, more agile manufacturing and systematic integration.
1. The 3rd generation of mold technology High-speed milling
High-speed milling is not only characterized by high speed and excellent machining accuracy and surface quality, but also has low temperature (the workpiece heats up to only 3°C) and small thermal deformation compared with traditional cutting machining, making it o Suitable for processing temperature-sensitive materials (magnesium alloys, etc.). Due to the low cutting force, it is also suitable for processing rigid and thin-walled parts. The tool selection and cutting consumption are reasonable, and the processing of hard materials (HRC60) has a series of advantages. Therefore, high-speed milling technology is still a hot topic today. It has evolved towards greater agility, intelligence and integration and has become a third generation modeling technology.
2. Erosive milling and “GREEN” product technology
From a foreign perspective, electrical discharge grinding (EDM) technology has reached a very high level in terms of performance, process indicators, intelligence and automation level. The current new trend abroad is the research and development of EDM milling technology (EDM processing technology), which is an alternative to traditional cavity-forming electrode processing technology, using high-speed rotation of simple to three-dimensional tubular electrodes or two-dimensional. dimensional contouring (such as CNC milling). It is therefore an important development in the field of EDM without the need to produce complex shaped electrodes.
With the advancement of EDM technology, more and more attention has been paid to EDM safety protection technology, and many electrical machines are considered safety protection technology. At present, the EC has stipulated that machines without “CE” marking are not allowed to enter the EC market, while the international market also pays more and more attention to technical safety requirements.
More and more attention is being paid to “green” products on the international market. In this case, EDM machine tools, as the dominant mold processing equipment, need to solve this problem in the future.
3. New generation mold CAD/CAM software technology
Mold software currently under development in the UK, USA, Germany and other countries, as well as in some of our universities and research institutes, is characterized by the intellectualization, integration and evaluation of mold manufacturability with a new generation of software CAD/CAM mold.
The new generation of mold manufacturing software must be based on a summary of mold manufacturing practice. The knowledge was systematized and scientifically organized to store the technical knowledge base in a specific way and can be easily retrieved by making molds. With the support of intelligent software, mold manufacturing CAD no longer imitates traditional design and calculation methods. Instead, under the guidance of advanced design theory, it will make full use of the specialized knowledge and successful experience in this field, and the result of its design will inevitably be reasonable and progressive.
The new generation of mold software designs the mold structure with stereoscopic thinking and intuitive feeling. The three-dimensional structural information generated can be easily used to evaluate mold manufacturing by CNC machining, which requires three-dimensional modeling of parameterized features, simulation of molding processes, numerical simulation of machining processes, and information exchange. The organization and management have reached a considerable degree of perfection and present a high level of integration. Measuring the degree of software integration depends not only on whether the functional modules are complete, but also on whether these functional modules use the same data model, whether a unified global dynamic database is formed, to provide integrated management and information sharing for support the entire process of achieving mold design, manufacturing, assembly, inspection, testing and commissioning.
The mold manufacturability evaluation function is very important in the new generation of mold software. It should not only filter many programs, but also evaluate the rationality and economics of the mold design process and provide mold designers with a basis for making changes.
Manufacturability assessment includes estimation of mold design and manufacturing costs, assessment of mold assembly, assessment of the manufacturing process of mold parts, and assessment of mold structure and performance. The new generation of software must also have an assembly-oriented function, because the form function can only be embodied by its assembly structure. After the introduction of the assembly-oriented design method, mold assembly is no longer simply assembled from parts. The data structure can not only describe the shape function, but also define the relationship between parts and components to effectively achieve shape quality.
4. Advanced Manufacturing Technology Rapid Tooling
1) With the rapid development of Laser Rapid Prototyping (RPM), China has reached the international level and gradually commercialized it. The main rapid prototyping processes sold worldwide are SLA (Stereolithography), LOM (Layered and Separated Manufacturing), SLS (Selective Laser Sintering) and 3D-P (3D Printing).
Tsinghua University was the first to introduce the American company 3D's SLA250 (stereolithography or photosensitive resin laser hardening) equipment and technology and carried out research and development. After years of hard work and many improvements, the “M-RPMS Multifunctional Rapid Prototyping Manufacturing System” (with LOM-SSM, Melt Extrusion MEM) was launched, the only system in the world with independent Chinese intellectual property rights (national patent ) with two rapid prototyping processes and a better price-performance ratio.
2) Multipoint formless molding technology is another advanced manufacturing technology that uses a highly customizable punch group instead of a traditional mold. Automatic 3D surface forming is performed quickly and cost-effectively by CAD/CAM/CAT technology as the main means of the shapeless multi-point forming system. Jilin Industrial University carries out the national major scientific and technological project on shapeless forming and has independently developed and manufactured the world's leading shapeless multi-point forming equipment.
Compared with the Massachusetts Institute of Technology (MIT), the University of Tokyo (Japan) and the Tokyo Institute of Technology (Japan), China's technology occupies a leading position in the practical application of theoretical research and is currently in the field of popularization and driven application. .
3) The resin stamping die was successfully used in the test production of domestic cars for the first time. FAW Mold Manufacturing Co., Ltd. designed and manufactured 12 sets of resin molds to test the new prototype car. The 12 sets of molds are for luggage, hood, front and rear fenders and other large and complex interior and exterior panel designs. The main features are: The mold surface is based on the main CAD/CAM processing model; Swiss Ciba high-strength resin mold is used; the distance between convex and concave shape is controlled by imported special wax plates; mold dimensions are highly accurate; the manufacturing cycle can be reduced by half to two-thirds, and the manufacturing cost can be saved by 10 million yuan (12 sets of molds). This opened a new path for small car test production and is a pioneer in China. The experts at Swiss Ciba are convinced that these will be international standards for 90 years.
5. Field-based mold testing technology
With the development of precision molds, measurement requirements are becoming greater and greater. The three-coordinate accurate measuring machine, which was limited by the environment for a long time, was rarely used in production. The new generation of three-coordinate measuring machine basically has the characteristics of temperature compensation and anti-vibration materials and anti-dust measures to improve environmental adaptation and reliability, so it can be easily installed in the workshop to achieve the measuring characteristics in the local .
6. Mold surface mirror polishing technique
Mold polishing technology is not only an important part of mold surface engineering, but also an important process in the mold manufacturing process.
At present, domestic polishing tools with polishing performance of Ra0.05μm and abrasives and processes can basically meet the needs. However, with the introduction of mirror polishing devices with polishing performance of Ra0.025 μm, abrasives and processes are still in the development phase.
At present, commercial polishing equipment, grinding tools and technologies, and abrasives that can achieve ultra-fine surface roughness of Ra0.05μm can basically meet the needs. However, achieving an ultrafine surface roughness of Ra0.05 μm is still in the development phase.
With the large-scale application of mirror injection molds in production, mold polishing technology has become a key issue. Since there are still some problems with polishing technology and materials in China, such as: In some cases, such as lenses, injection molds, CDs, VCD discs and high transparency tools, a large proportion of injection molds still rely on imports.
It is important to note that the polishing of the mold surface is affected not only by the polishing equipment and technology, but also by the mirror quality of the mold material, which has not received enough attention. In other words, the polishing itself is limited by the mold material. For example, with 45# carbon steel as the mold, polishing to Ra0.2m, visible defects and additional polishing can only increase the gloss, while there is no hope of improving the roughness. Therefore, the current domestic production of mirror molds often uses imported mold materials such as ASSAB 136 from Sweden, Datong PD555 from Japan, etc. to obtain a satisfactory mirror.
Mirror molding materials are not just about the chemical composition of the material. More important are the requirements of vacuum degassing in melting, argon shielding ingot, vertical continuous casting and rolling, smooth forging and a series of advanced technologies to make mirror mold steel with fewer internal defects and impurities, fine grain size , high degree of dispersion, fine grain metal size, good uniformity and a series of advantages to meet the requirements of mirror polished steel.
7. Modern mold manufacturing is developing in unlimited quantities
In this competitive industrial world, all things are becoming more modern and innovative than ever. The future is unlimited and unpredictable, as is the development of modern forms.
