Plastic Molding

plastic moldsA combined plastic mould for compression molding, extrusion molding, injection molding, blow molding and low foam molding, which mainly comprises a variable concave die and a variable convex die. While concave die composed of a concave die composite substrate, a die module, a die combined board, And Convex die composed of a punch composite substrate, a punch module, a punch combined card plate, a cavity truncation module and a side intercepting plate. Coordinated changes in the mold convex, concave and auxiliary forming systems can process series of plastic parts of different shapes and sizes. Matched with plastic molding machines, Plastics processing industry give plastic products a complete configuration and precise dimensions. Due to variety of plastics, processing methods, structure of plastic molding machines and plastic products is complicated, so types and structures of plastic molds are also diverse.

The tools and products we use in daily life, range from base of the machine tool, outer casing of the machine, to a small screw, button and case of various household appliances, all of which have a close relationship with molding. The shape of mold determines shape of these products, and quality and precision of molding determines quality of these products. Because of different materials, appearance, specifications and uses of various products, molding is divided into casting molds, forging dies, die-casting dies, stamping dies and other non-plastic molds, as well as plastic molds. In recent years, with the rapid development of plastics industry and continuous improvement of strength and precision of general and engineering plastics, application range of plastic products is also expanding, such as: household appliances mould, instrumentation mould, construction equipment mould, automotive mould. The proportion of plastic products is increasing rapidly. A well-designed plastic part can often replace multiple traditional metal parts. The trend of plasticization of industrial products and daily-use products is on the rise.

Mold design and manufacturing are closely related to plastic processing. The success or failure of plastic processing depends to a large extent on the mold design effect and mold manufacturing quality, while the plastic mold design is based on the correct plastic product design.

Structural elements to be considered in the design of plastic mould are:

1, Parting surface. That is contact surface where concave and convex cooperate when molding is closed. The choice of its position and form is influenced by factors such as product shape and appearance, wall thickness, forming method, post-processing process, molding type and structure, demolding method and molding machine structure.

2, Structural parts. That is sliders, inclined tops, straight top blocks of complex molding. The design of structural parts is very critical, which is related to life of mold, processing cycle, cost, quality of product, etc. Therefore it has higher requirements to designer’s comprehensive ability for designing complex mold core structure, pursuing as simple as possible, more durable and more economical.

3, Mold accuracy. That is fine positioning, guide columns, positioning pins etc. Positioning system is related to appearance quality of product, quality and life of molding. According to different mold structure, different positioning methods are selected. The positioning precision control mainly depends on the processing. The internal mold positioning is mainly for a more reasonable and adjustable positioning way that designers must fully consider.

4, Pouring system. That is feeding channel from nozzle of injection molding machine to cavity, including main channel, runner, gate and cold hole. In particular, location of gate should be selected to facilitate filling of molten plastic in a well-flowing cavity, the solid-state flow path and gate cold material attached to the product are easily ejected from molding and removed during mold opening (except for hot runner mold).

5, Plastic shrinkage and various factors affecting dimensional accuracy of product, such as mold manufacturing and assembly errors, molding wear and so on. In addition, when designing compression molding and injection molding, matching of process and structural parameters of molding machine should also be considered. Computer-aided design techniques have been widely used in plastic molding design.

plastic mouldingsAn injection mold is a part that imparts shape and size to a plastic item during molding. Although structure of molding may vary depending on type and performance of plastic, shape and structure of plastic product, and type of injection machine, basic structure is uniform. Molding is mainly composed of a casting system, a molding part and a structural part. The gating system and molded part are in direct contact with plastic and vary with plastic and product. It is the most complicated and most varied part of molding, and requires the highest degree of smoothness and precision.

The gating system refers to part of flow path before plastic enters cavity from nozzle, including main channel, cold material hole, shunt channel and gate. Molded parts refer to various parts that make up shape of product, including moving molds, fixed molds and cavities, cores, forming rods, and exhaust ports.

In Hafo Mould, which has 20 years of production experience in injection mold, we will meet the needs of customers with more stringent requirements:

  1. Higher mold accuracy

With continuous improvement of living and production levels, requirements for product structure are also constantly increasing, which requires molding have higher ornamental and more sophisticated functional design. Traditional mold processing method has high dependence on the operator’s personal technology, use of various tools and complex, and processing cycle is relatively long, which can not meet the requirements of plastic molding manufacturing. Therefore, high-precision three-dimensional structural molding become a new growth demand point, and we will be in the direction of precision, three-dimensional, high-efficiency and rapid.

  1. Higher plastic molding life

Life of plastic molding is an important parameter of molding, which is related to quality of  product and overall cost of product. At present, service life of molding is above 1 million plastic cycles, and for higher requirements, imported steel with higher quality will be selected while material cost and processing cost are also increased accordingly.

  1. Shorter Mold manufacturing cycle

Current market is fiercely competitive, and speed of product replacement is fast. How to make products appear faster and better in front of consumers is the key to success. Therefore, product is required to be controlled from the design to finished product in a very short period of time; and many products are assembled from a variety of structures and material combinations, often requiring plastic parts to be designed and efficiently formed in a short period of time. As a result, shorten manufacturing cycle of the plastic mold, and higher production processes and production efficiencies are required to meet entire production demand.

  1. More clear design and manufacturing division of labor

At present, a detailed and professional form of cooperation in the design and manufacture of plastic molds has been formed in China. When product requirements are put forward by customers, Hafo Mold R&D team proposes a design plan after 3D modeling. After solution is determined, Our engineers will carry out mold manufacturing. Finally finished mold will be transferred to injection department for plastic production or customers. These links have been specialized, scaled and completed through a professional team, and manufacturing features are geographically differentiated and more detailed.

  1. Factory will develop into a specialized segmentation

Plastic mould usually only need to manufacture one or several sets to meet production requirements. They are produced in single products, but there are many accessories that make up the mold. From the largest mold base to the smallest thimble, it is vital that each one Accessories affect the final product quality, so quality of each accessory must meet very high precision and quality requirements. At Hafo Mould, requirements for subdivision and specialization of accessories have been improved. Only by focusing on professionalism can we produce higher quality products.

In recent years, development of plastic molding in China has been quite fast. At present, plastic molds account for about 30% of entire mold industry. With rapid development of China’s automotive mould, home appliances mould, electronic communications mould, and various building materials, it is expected that in the future mold market, proportion of plastic mold in total molding will gradually increase, and development speed will be faster than other molds. Taking automotive industry as an example, with rapid growth of automobile production and sales, potential market for automotive molding is huge. According to reports, in the production of automotive, all kinds of functional parts must be molded by molding. More than 200 pieces of interior parts mould are needed to make a normal car. While the large and medium-sized plastic mould such as bumper mould, instrument panel mould, fuel tank mould, steering wheel mould meet only about 50% from production capacity of molding industry currently. In the field of construction, replacement of traditional materials by plastic building materials is also a general trend. It is expected that penetration rate of plastic doors and windows and plastic pipes in China will reach 40% to 60%, and market share of plastic drainage pipes will exceed 60%, which will greatly increase demand for molding. It should be said that application potential of plastic molding cannot be underestimated. Experts predict large, precise and well-designed injection mold will be widely welcomed by market.

plastic moldingIt is expected that in the future mold market, development speed of plastic molds will be higher than other molds, and proportion in the mold industry will gradually increase. Among them, the plastic mold processing technology generally presents the following development trends:

1, The increasing size of mold-forming parts and high productivity of parts require multiple cavities, resulting in larger mold. Large-scale mould with large tonnage can reach 100 tons, and a few hundred cavities and thousands of cavities require mold processing equipment. Large workbench, increased y-axis z-axis travel, large load-bearing, high rigidity, high consistency.

2, Mold steel material processed by molding has high hardness, and mold processing equipment is required to have thermal stability and high reliability.

3, For complex cavity and multi-functional composite mold, with complexity of shape of workpiece, it is necessary to improve design and manufacture level of mold. A variety of grooves and materials are formed or assembled into a set of mold. Functional composite molds require a large amount of machining programming procedures, high cutting depth and high stability, and high processing difficulty.

4, It will be more attractive to makes the compounding and high efficiency of processing equipment through the refinement of mold processing. High-speed milling has many advantages such as high-hardness materials that can be processed, smooth processing, small cutting force, and small temperature rise and deformation of workpiece, which makes mold companies pay more and more attention to high-speed machining.

5, High dynamic accuracy. The static performance introduced by machine tool manufacturer does not reflect the actual machining situation when molding is three-dimensionally machined. High-precision machining of three-dimensional surface of molding also requires high dynamic precision performance, high-speed and high-precision matching high rigidity, thermal stability, high reliability and high-quality control system of machine tool.

6, The popularization of mold integrated manufacturing unit and its technology. In addition that molding has the functions of automatic feeding, stamping forming, lamination metering, thickness grouping, iron core combination and product output, hinge assembly connection, and complex motion structure, in-mold heating, Forging, local heat (tissue) control, in-mold welding, tapping, partial injection molding, in-mold cutting, in-mold testing and other process combinations also appeared in molding. It is particularly worth mentioning that new technologies such as internal hot die cutting of plastic and boron steel sheets, and variable edge cutting of motor pen-shaped iron cores have created a new era of integrated mold manufacturing units. Mold products continue to develop in the direction of large, sophisticated, high performance, integrated manufacturing units.

8, Wide application of 3D printing in the mold manufacturing. 3D printing application production mold cavity is a new trend in the development of cavity mold. The metal additive-reduced material combination manufacturing technology is an important direction in the field of 3D printing. At present, high-precision manufacturing of complex metal parts is realized by 3D layer-by-layer additive forming, combined with high-speed milling of layer thickness profile and material reduction.

9, The intelligentization of the mold. At present, in the plastic molding and die-casting mold industry, it has presented some kinds of mold that cavity pressure, temperature, flow, cooling process be intelligent controlled. In addition, intelligence of mold processing equipment is also rapidly advancing intelligent manufacturing of mold.

10, Lightweight new materials, presentation and optimization of large-scale plastic molds. With development of lightweight vehicles, lightweight new materials emerge in an endless stream. China mold factory have begun to cope with this change, and have launched lightweight new materials for car cover mold and large-scale development of composite data mold.

11, Maturity of large-scale progressive die technology, high-speed and high-reliability has become an important feature of fine-level progressive die. At present, large-scale progressive stamping parts are everywhere, parts are getting larger and larger, shapes are more and more complex, show large scale progressive die technology entered the mature stage. The high-precision precision progressive die has higher and higher requirements for stability and reliability of production, and has become an important means of competition for mold manufacturing enterprises. Obviously, mold design and manufacturing technology of super large-sized formed parts and small ultra-precision parts has become a hot spot for molding factory.

12, Mold standard parts tend to be refined. In recent years, with improvement of mold types and requirements, mold standard parts have become an important condition for mold company to participate in international competition. The variety and classification are the main trends of current mold standard parts. There are more and more traditional standard parts, and quality requirements are getting higher and higher. New functional structure standard parts with more manufacturing flexibility are also becoming more and more important, becoming a new direction for new technologies and innovations to enhance competitiveness.