At the beginning of reform and opening up, household appliances carried people's longing for a better life, which is one of important signs of family's material living standards. In 40 years since reform and opening up, development of home appliance manufacturing industry has experienced rapid development from being unable to be self-sufficient, relying on ticket supply, to localization, challenging international home appliance giants, meeting people's high-end demand, and making China the world's largest home appliance manufacturing country.
Home appliance molds, as supporting technology and equipment for home appliances, also experienced a development process from small to large and weak to strong. Whether China's home appliance industry is just starting or is challenging international home appliance giant, home appliance molds are shouldering responsibility of pioneering road.
Since most parts of home appliances are produced by molds, appearance shape and structure reflect complexity of molds. Changes in home appliances depend on level of R&D and manufacturing of home appliance molds. Appearance and structure of home appliances have undergone 4 stages: the first stage is simple appearance and structure stage; the second stage is complex curved surface and deep cavity stage; the third stage is appearance differentiation stage; the fourth stage is customization stage centered on user needs. Each stage is achieved through technological revolution with mold as core to achieve leapfrogging between these 4 stages. Therefore, development of home appliance mold technology has always focused on meeting needs of users, constantly breaking barriers of technology and concepts, pushing home appliance industry forward.

 

(A) Refrigerator

 

(B) Liner and door lining adsorption mold

Figure 1 The first stage of household appliances and molds

The first stage represents primary stage of development of home appliance industry, and home appliance molds mainly rely on imports. Due to limitation of mold design and manufacturing level, appearance of home appliances is mainly flat and rounded, which is convenient for product structure design, mold design and manufacturing. At that time, there was a huge gap between technical level of domestic mold industry and foreign developed countries. Domestic mold companies mainly used manual drawing. Due to occlusion of technical information in industry, it was difficult for technicians to obtain high-level mold technical information. Domestic mold companies mainly used ordinary machine tools such as turning, milling, planing and grinding to process mold parts, which have poor accuracy and low efficiency. The most automated equipment is mainly fast-moving wire cutting and electric discharge machine tools, manufacturing capacity of complex mold parts is weak. Therefore, appearance of home appliances on the market is basically unchanged, as shown in Figure 1.

The second stage is driven by replacement of software and hardware with computer-aided technology and numerical control processing technology to solve complex surface and deep cavity mold development problems. Due to increasing output of home appliances, users have increasingly higher aesthetic needs for appearance of home appliances. Products with curved surfaces and deep cavity designs are favored by consumers. Upgrading demand of home appliance industry has put forward new requirements for home appliance mold technology. Under historical opportunity of reform and opening up, home appliance mold companies have more and more opportunities to communicate with mold developed and regional enterprises. Advanced mold technology and management concepts have been introduced, absorbed and transformed to form core technology competitiveness and management mode of China's mold enterprises. For example, Haier Mold, in the early days of its establishment, borrowed from Japan and Hong Kong's mold technology and management experience, through coordinated development with enterprises in Guangdong, Zhejiang and other regions where mold industry developed earlier, it took the lead in forming scale and technological innovation capabilities.

 

A. Washing machine

 

B. CNC machining center

 

C. Deep cavity mold

Figure 2 Second-stage home appliances and machine tools, deep cavity molds

At this stage, leading companies in the industry took the lead in adopting CAD / CAE / CAM computer-aided technology for mold design, simulation, and programming of machining programs. A large number of mold parts are processed by CNC machining tools, such as CNC milling, CNC turning machining centers, CNC EDM machines, CNC wire cutting machine tools, etc. Application of industrial software and CNC equipment has enabled company's design and manufacturing capabilities to achieve a huge leap. At the same time, it has played a very good role in demonstration, promoted upgrade of software and hardware technology in entire mold industry, as shown in Figure 2.

 

A. Mold CAD

 

B. Mold CAM

 

C. Mould CAE

Figure 3 Mold CAD \ CAM \ CAE technology

Complex surface of product can be designed by CAD software. Mold structure design is efficiently completed by CAD software. CAE software is used to simulate and analyze molding process. Not only can it predict defects of molded product intuitively, but it can also guide optimization of part structure and design of mold gating system. Complex surface of mold cavity can be quickly programmed by CAM software, CNC machining machine is driven to automatically complete machining process, as shown in Figure 3. After mold technology change at this stage, complex appearance of home appliances, difficulty of molding caused by deep cavity structure, complexity of mold structure, and long injection cycle were effectively solved, which promoted appearance and structural design of home appliances into a prosperous period. Home appliance companies have introduced new products with different shapes, which has achieved domesticization of China's main home appliance products.
At this stage, informatization management technology of mold enterprise has begun to sprout. Due to increasing number of backbone enterprises in the industry, traditional management methods cannot meet needs of large-scale and discrete manufacturing of molds. Leading enterprises in the industry have begun to use information systems for enterprise management, professional information promotion departments have been established within enterprise. Enterprise management level has been greatly improved.

The third stage is appearance differentiation stage promoted by new materials, new processes and new technologies. At the beginning of this stage, Japan, South Korea, Europe, and other home appliance companies maintained a leading position in the field of high-end home appliances. New materials, new processes and new technologies for home appliances were widely used in high-end home appliances to satisfy users. Among them, representative mold technologies, such as high-gloss spray-free coating, two-color dual-material injection, and in-mold transfer, have long been monopolized by Japanese, Korean, and European and American home appliance companies. For example, leading domestic appliance company in Korea has applied two-color and two-material injection technologies to flat-screen TVs. Its beautiful appearance and quality make its’ sales of color TV dominate international market. Material injection technologies is applied to flat-panel TV products. The beautiful appearance quality makes the brand's sales of color TV dominate the international market. At the same time, it has signed a competition agreement with injection molding equipment manufacturers to achieve a technological monopoly in the field of home appliances.
At this stage, after nearly 10 years of rapid development of China's home appliance mold technology, mold design and manufacturing capabilities of large-scale backbone mold enterprises in the industry have approached level of developed countries in the world, some aspects have also surpassed, such as development of design standards and knowledge databases, design and processing of molds with complex structures. However, in general, gap between technical level of home appliance molds and developed countries is mainly concentrated in the development and application of three new technologies, which is also key to achieving surpass in China's home appliance industry.

 

A. High-end refrigerator with two-color trim technology

 

B. Complete solution for two-color trim technology

Figure 4 The third stage of home appliances and three new technologies

In order to build international competitiveness of home appliance molds, some large-scale backbone enterprises in the industry focus their strategic focus on development and application of three new technologies. For example, Haier Mould established Mould Technology Research Institute to carry out research, development, and application of three new technologies. At the same time, it carried out industry-university-research cooperation in mould industry, strengthening technological exchanges and demonstrations. This not only formed core competitiveness of enterprise, but also promoted technological progress of industry. At this stage, Haier Mould has mastered more than 10 mold technologies such as high-gloss spray-free, large two-color injection, in-mold transfer, and large laminated molds, promoted its application on Haier home appliances, supporting Haier's strategy to create the world's first brand of home appliances, as shown in Figure 4.
It can be seen from biannual China Mould Industry Association's "fine mold award" winners list that three new mold technologies such as high-gloss spray-free coating, laminated injection, two-color dual-material injection, and color plate stamping have been listed for the first time, Many technologies have been upgraded iteratively in the next awards.

 

A. PDM

 

B. SAP

 

C. MES

Figure 5 PDM \ SAP \ MES information system

At this stage, with localization of information system, technology is becoming increasingly mature. At the same time, informatization management of backbone mold companies has played a good demonstration role. Information technology of home appliance mold industry has been fully promoted in enterprises above designated size, and industry management level has been greatly improved, as shown in the figure. 5 shown.

The fourth phase is customization phase of user needs oriented by intelligent mold manufacturing and industrial ecological interconnection. In Internet era, home appliance industry has entered era of product customization, users no longer satisfy product experience. Instead, they hope that their personalized needs will be followed and adopted, and reflected in the products they purchase, to achieve the best experience for products. Therefore, personalized customization of home appliance users poses new challenges to technology of home appliance molds.

 

A. Transfer customized air conditioner on-hook

 

B.3D printing air conditioner on-hook

Figure 6 Custom technology for user needs

Customized mold transfer technology can meet personalized needs of product appearance patterns. Pattern printed on diaphragm can be derived from user's photo and specified pattern, transferred to surface of product appearance part through mold. User purchases his own exclusive home appliances. At the same time, this technology enables a pair of molds to produce products with multiple appearances, reducing number of molds and achieving rapid product iteration. Customized mold transfer technology is integration of multiple professional technologies such as film manufacturing, printing, automatic film feeding, mold structure, and injection. Industrialization requires collaborative manufacturing of industrial ecology to achieve. Industrialization of additive manufacturing technology also requires industrial ecological interconnection and coordination to achieve. Rapid development of additive manufacturing technology has greatly reduced production cost of small batches of products, surface quality of products has also improved greatly. In the future, users will experience their own creative "3D printing" home appliances. Metal additive manufacturing technology is applied in the field of mold parts manufacturing, which realizes conformal cooling of small and medium-sized mold parts, solves deformation problem caused by difficult cooling of hot parts of part, can meet needs of product function customization, and has broad market prospects. ,As shown in Figure 6.