In the global market of household and industrial plastic products, there is a stable trend of active development. This fact is confirmed by the statistics given by the leading companies over the last few decades. Plastic injection molding

Industry leaders

Today in the world there are about a hundred large companies that produce equipment for molding plastics under pressure, raw materials and finished products. The geography of their placement is very extensive, even if their number is reduced, taking into account the formation of subsidiaries, merger and acquisition processes.

Today in the world there are several stably formed enterprises - market leaders. First of all, they represent the Asian part of the planet. Leading enterprises that produce equipment for molding plastics under pressure and finished goods, as well as supply raw materials, are located in China, Taiwan, South Korea, Singapore, and Japan. Their total share in total production volume is within 35-45%. Industry leaders are in the European region. The largest enterprises are located in Poland, Latvia, the Czech Republic, Italy, Portugal, and Germany. They account for about 25-30% of the production volume. Russia can be noted separately, given its geographical location. The country has several leading enterprises in this industry.

Electric injection molding equipment: advantages and disadvantages

The machines used today have a number of features that allow enterprises to significantly expand the scope of production and product range. Plastics casting is carried out using injection molding machines (TPA). Equipping machines with an electric drive has several advantages over hydraulics. In particular:

  1. Reduced consumption of energy. Savings in comparison with hydraulic injection molding machines is about 60%.
  2. The ability to set and operate the machines in the premises for production of sterile products (e.g. medical devices). Hydraulic injection molding machine is not suitable for such purposes due to the presence of a special system of lubrication.
  3. Easy operation and management. This advantage is achieved due to the presence of a smaller number of functional units.
  4. High precision electric injection molding machines. This is particularly important in the manufacture of small components for medical, optical or watch industry.
  5. Shortened injection interval This can significantly increase productivity.

Among the disadvantages of the aggregates with the help of which injection molding is carried out, one can single out their higher cost. However, the alignment of prices is achieved by launching mass production of machines.

Current trends in capacity improvement

In order to increase the productivity and the utilization rate of machines, on which injection molding of products from different materials is carried out, first of all, the cycle time is reduced. In addition, a number of changes are being introduced directly into the process itself. In particular, they improve the results of mass injection and plasticization. Such improvements are especially important in a number of industries. For example, in the manufacture of PET preforms, which require the shortest possible cycle. Major manufacturers are actively developing the introduction of complex technologies today. Recently there has been a gradual conversion to the production of basic units of modular type. In their design laid the opportunity for improvement.

Injection molds

These items always deserve special attention. The fact that the cost of molds often reaches the price of the machine itself. In this regard, strengthening the protection of these elements is one of the primary tasks of the enterprises. High-performance hybrid and electric units in which the casting of plastics under pressure, equipped with active systems of ultrasonic and piezoelectric sensors. This protection reduces the reaction time of the machine and allows you to monitor the condition of the parts with the utmost precision.

External product quality

To increase the attractiveness of the finished product technology, which carries out molding of plastics under pressure, constantly improving. In the production of periodically introducing new methods. Today, for example, a fairly widespread plant decoration, as well as multi-component injection molding of plastic under pressure. Particular attention is paid and the materials used for production, in particular, are less common in Russia. These include, for example, include thermoplastic elastomers used in the automotive industry, silicones, thermosets. Through the use of different technologies injection moulding is carried out with a minimum expenditure of time and material. Furthermore, innovative methods can significantly reduce the weight of the finished product.

Environmental safety and quality

These points equally apply to finished products and machines on which casting of plastics under pressure. The presence of ISO 9001 certification quality is of particular importance for enterprises-producers in the process of searching for large and major customers. In addition, important and the environmental standard ISO 14001. In the absence of these certificates the manufacturer will not deal with customers who are counting on long term cooperation.

Plastic injection molding is the most common production method. The essence of this method lies in the injection of molten material into the workpiece with subsequent cooling. Granulated thermoplastics are used as raw materials. Products made from them can be subsequently recycled. In addition, a common material is thermosetting powder. During its processing, irreversible reactions occur that lead to the formation of a non-fusible product. Its subsequent processing is impossible.

Technology

Plastic injection molding is carried out by feeding material through special channels. After filling the press blanks, cooling - crystallization occurs. Production of products can be divided into several stages:

  • Design and manufacture of forms.
  • Preparation and formulation of raw materials, the mixing of the material with dyes and additives. At this stage take into account the requirements to the finished product.
  • The choice of method of processing raw materials.
  • Directly injection molded.

Operation specifics

Die casting should be carried out strictly in accordance with the chosen technology. Of particular importance is the exact observance of time and temperature regimes. This, in particular, concerns the final stage of production - crystallization. Die casting is carried out using a different number of blanks. Their number will depend on the production plan of the enterprise, as well as the product range. After the raw material is fed, the finished product is removed by the ejection system. Temperature control is usually water. It is fed into the cooling channels.

The structure of the press blanks

The shape of the molding constitutes a device for the manufacture of objects of different configuration and complexity. In the model the workpiece is present in the matrix (stationary element) and the plug (moving part). The plane of these parts act as a negative imprint of the outer surface of the product. Manufacturers often use multiple blanks. They made a few parts at a time. Enterprise, professionally engaged in injection molding, must have some press pieces for the different parts. They should have diverse configurations and design. It should be noted that the process of manufacturing moulds is complex, and always individual.

Process Specifications

Injection molding, as was said above, is carried out with observance of a temperature mode. In particular, in the processing of raw materials press the workpiece thermostatic or heated. In the first case the operation is performed, if the material is thermoplastic. Temperature press the workpiece in this case should not be higher than the crystallization or glass transition. If a thermoset is used, the form is heated. Its temperature should be equal to the level at which the rejection occurs. Injection pressure will depend on the shape design, viscosity of the molten raw material, sizes of the finished parts and Gating system. In the process of filling cavities, it increases gradually. Pressure up to 500 MPA provides a reduction in residual stresses in the raw material, to increase the degree of orientation of the crystalline elements (polymers). This contributes to not only strengthening the strength of the material, but also more accurate reproduction of dimensions of the parts. Pressure is distributed along the length of the cavity unevenly. This is due to the high viscosity of the melt and sufficiently rapid buildup in the cooling process.

Material precompression

It is used to equalize the pressure in the casting. Pre-compression is carried out on the installation, the jet nozzle unit which is equipped with a crane. Close it and prepare raw materials. Compression of the melt takes place in the material cylinder to the pressure casting. Then the tap open and served raw in the cavity. The melt with a sufficiently high speed filling out forms, further heated under the influence of the friction force. In some cases it can cause mechanical destruction of the material. To prevent the feed rate of the melt limit. Due to the preliminary compression is reduction of the time of filling the cavity in 1,5-2 times. In addition, increases the path of the material prior to freezing. This, in turn, allows you to cast long and thin-walled products.

Metal products manufacturing

This production differs from the above described technical characteristics of machines, the composition of the material, the technologies used. Thus, aluminum casting under pressure is performed on piston machines. These units are equipped with extrusion chambers, which can be cold or hot. In the latter case, the element is located inside the crucible with a metal alloy. The cold chamber is separated from the material and is installed vertically or horizontally. Aluminum die casting is performed on fully automated machines. Machines are equipped with software control. The work of adjusting the efforts of closing the casting molds and the speed of pressing is automatically carried out. The machines also have a locking system in case of malfunctions.

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