The rapid development of mold manufacturing skills has become an important component of modern manufacturing techniques. Such as CAD/CAM skills for molds, laser rapid prototyping skills for molds, fine forming skills for molds, ultra-fine machining skills for molds, dynamic simulation skills for activities, cooling, and heat transfer processes using finite element method and gap element method in mold design, CIMS skills for molds, DNM skills for molds already under development, and CNC skills, they cover almost all modern manufacturing skills.

 

Modern mold manufacturing skills are moving towards accelerating information driven, advancing manufacturing flexibility, sensitive manufacturing, and systematic integration.

 

1、 High speed milling: the third generation of mold making skills

 

High speed milling not only has high processing speed and excellent processing accuracy and appearance quality, but also has a lower temperature rise (only 3 ℃ increase in workpiece processing) and smaller thermal deformation compared to traditional cutting, making it suitable for processing temperature and thermal deformation sensitive materials such as magnesium alloys; Also, due to its low cutting force, it is suitable for machining thin-walled and poorly rigid parts; Reasonable selection of cutting tools and cutting parameters can achieve a series of advantages such as hard material (HRC60) processing. Therefore, high-speed milling machining skills were still a hot topic at that time, and it has been developed towards higher sensitivity, intelligence, and integration, becoming the third generation of mold making skills.

2、 Electric discharge milling and; Green” Product Skills

 

From the perspective of foreign electric machining machines, they have reached a moderately high level in terms of functionality, process indicators, intelligence, and proactivity. The new trend abroad is the research and development of electric discharge milling machining skills (electric discharge generative machining skills), which is a new skill that replaces the traditional use of formed electric machining cavities. It is a three-dimensional or two-dimensional summary machining (similar to CNC milling) using high-speed rotating simple tubular electric machines, so there is no longer a need to manufacture messy formed electric machines. This is obviously a serious development in the field of electric discharge forming machining.

 

Recently, Mitsubishi Corporation of Japan has launched the EDSCAN 8E electric discharge machining machine tool, which has made new developments. This machine can perform active compensation for electrical losses. A dedicated CAM system developed for this machine on Windows 95 can be linked with general CAD tools such as AutoCAD and can perform online precision measurement to ensure high-precision machining. In order to acknowledge the presence of abnormalities or damages in the processed shape, the CAM system can also perform simulation machining.

 

Along with the advancement of electrical discharge machining skills, the safety and protection skills of electrical discharge machining are increasingly being emphasized, and many electrical machining machines have considered safety protection skills. Now the European Community has stipulated that there is no; CE” The marked machine tools cannot enter the European Union market, and the world market is increasingly emphasizing the requirements of safety and protection skills. Nowadays, the primary issue with electric discharge machining machines is radiation disturbance, as it has a significant impact on safety and environmental protection, and is increasingly being emphasized in the global market; Green” In the case of products, as the leading equipment for mold processing, electrical discharge machining machines are used; Green” Product skills will be a necessary challenge to be addressed in the future.

 

3、 New generation mold CAD/CAM software skills

 

Nowadays, mold software developed by universities and research institutes in countries such as the UK, US, Germany, and China has the characteristics of intelligence, integration, and mold manufacturability evaluation of the new generation of mold CAD/CAM software.

 

The new generation of mold software should be based on many common sense summarized from mold design practice. These common sense have been systematically and scientifically organized, stored in a specific method in the engineering common sense database, and can be easily called by molds. Under the support of intelligent software, mold CAD is no longer an imitation of traditional design and calculation methods, but under the guidance of advanced design theory, and by making full use of the rich common sense and successful experience of experts in this field, its design results must be reasonable and progressiveness.

 

The new generation of mold software designs mold structures with three-dimensional thinking and intuitive feelings, and the generated three-dimensional structural information can be easily used for mold manufacturability evaluation and CNC machining. This requires mold software to reach an appropriate level of perfection and high integration in three-dimensional parametric feature modeling, molding process simulation, CNC machining process simulation, and information exchange, arrangement, and processing. To measure the level of software integration, it is not only necessary to consider whether the functional modules are complete, but also whether these functional modules share the same data model, whether they form a dynamic database in a consistent manner, and whether they complete the information summarization, processing, and sharing to support the entire process of mold design, manufacturing, installation, inspection, testing, and production.

 

The function of evaluating the manufacturability of molds is very important in the new generation of mold software. It requires selecting multiple plans, evaluating the rationality and economy of the mold design process, and providing correction basis for mold designers.

 

In the new generation of mold software, manufacturability evaluation primarily includes budgeting for mold design and manufacturing costs, mold installability evaluation, mold part manufacturing process evaluation, mold structure and forming function evaluation, etc. The new generation of software should also have device oriented functionality, as the functionality of the mold can only be expressed through its device structure. After adopting the device oriented design method, the mold device is no longer a simple assembly of individual parts. Its data structure can not only describe the function of the mold, but also define the device characteristics of the interrelationships between mold components, completing the association of components. Therefore, it can effectively ensure the quality of the mold.

 

4、 Advanced rapid mold manufacturing skills

 

1. The rapid development of laser rapid prototyping technology (RPM) has reached a world-class level in China and is gradually being commercialized. The most commercially available rapid prototyping processes in the world are SLA (stereolithography), LOM (layer by layer manufacturing), SLS (selective laser sintering), and 3D-P (three-dimensional printing).

 

Tsinghua University has long introduced the SLA250 (stereolithography or photosensitive resin laser curing) equipment and skills from the American 3D company and conducted development and research. After several years of hard work and repeated improvements, the university has perfected and launched the "; M-RPMS - Multi functional Rapid Prototype Manufacturing System; (with layered solid manufacturing SSM and melt kneading molding MEM), this is a system with two independent intellectual property rights and two rapid prototyping processes in China (national patent), which has a good functional price ratio.

 

2. The moldless multi-point forming technology is another advanced manufacturing technique that uses highly adjustable punch heads to replace traditional molds for sheet metal surface forming. The moldless multi-point forming system uses CAD/CAM/CAT skills as the primary means to quickly and economically complete active forming of three-dimensional surfaces. Jilin University of Technology has undertaken the national key scientific and technological research project on mold free forming, and has independently designed and manufactured a high-level mold free multi-point forming equipment.

 

5、 On site mold inspection skills

 

The development of fine molds requires increasingly high measurement standards. Fine coordinate measuring machines have been rarely used in production sites due to environmental limitations for a long time. The new generation of three coordinate measuring machines fundamentally have temperature compensation and selection of anti vibration data, improved dust prevention measures, enhanced environmental adaptability and operational reliability, making them easy to install in the workshop for on-site measurement.

 

6、 Mirror polishing mold surface engineering skills

 

Mold polishing skills are an important component of mold surface engineering and a crucial post-processing technique in the mold manufacturing process. Now, domestic molds are polished to Ra0.05μ The polishing equipment, grinding tools, abrasives, and processes of m can fundamentally meet the needs, and it needs to be polished to Ra0.025μ The mirror polishing equipment, grinding tools, abrasives, and processes of m are still in the exploratory stage. With the large-scale use of mirror injection molds in production, mold polishing skills have become a key issue in mold production. Due to certain problems in domestic polishing technology skills and materials, a large part of injection molds such as point and shoot camera lens injection molds, CD, VCD discs, and injection molds with high transparency requirements still rely on imports.

 

It is worth noting that the polishing of the mold surface is not only affected by the polishing equipment and process skills, but also by the mirror finish of the mold data. This has not received sufficient attention, which means that the polishing itself is constrained by the mold data. For example, when using 45 # carbon steel for injection molding, polish to Ra0.2μ At m, there are significant drawbacks visible to the naked eye, and continuous polishing can only add brightness, while roughness has no hope of improvement. Therefore, imported mold materials are often used in the production of mirror molds in China, such as Sweden's Yishengbai 136 and Japan's Datong PD555, which can achieve satisfactory mirror finish.

 

The material of mirror mold is not only a matter of chemical composition, but more importantly, a series of advanced processes such as vacuum degassing, argon gas maintenance of ingots, vertical continuous casting and rolling, and flexible forging are required during smelting, so that the mirror mold steel has a series of advantages such as fewer internal defects, fine impurity particle size, high dispersion degree, fine metal grain size, and good uniformity, in order to meet the requirements of polished mirror mold steel.

 

Article sourced from SMC molded products manufacturer www.jmlicheng.com