Equipment for molding plastic in silicone molds. Equipment for plastic injection molding

Molding plastics under pressure is the most effective and widespread way of obtaining different products. Equipment for plastic casting - a wide range of devices that allow you to convert plastic and give it a certain shape.

Features of casting as a chemical process

When casting, plastic under pressure changes its viscous flow consistency to flow through the equipment channels. A certain form is prepared in advance, where the molten mass enters, where it becomes solid. Like the equipment for plastic casting, the material itself can be different - the choice depends on the mode in which the casting takes place and in what form.

Casting of plastics occurs most often at a pressure of 80-140 MPa. If it is higher, there is an opportunity to get products that will be characterized by high strength. In addition, ultra-high pressure allows you to accurately convey the dimensions of parts of the product. The pressure level is chosen depending on the degree of viscosity, melting of the plastic, the type of mold and the result to be achieved.

Types of casting

The equipment for injection molding of plastics is chosen depending on which type of casting will be taken as a basis. There are several of them:

1. Injection. With its help, products are obtained with a minimum thin or thickest walls, they give less shrinkage. The process itself is the injection of molten plastic into a mold that does not completely close.
2. Intrusion. This method is necessary for obtaining products with thick walls. At the heart of his work is the injection into the mold of less material than is required. The mold is filled with a fluid composition at low pressure. As soon as it is filled, a small amount of material is delivered under high pressure - it finally forms the product and compensates for its shrinkage.

Injection molding machines - basic equipment

The equipment for casting of plastics is used differently, but, as a rule, on its basis piece products are made. The advantages of high-pressure casting are:

1. The possibility of using different types of plastic.
2. The effectiveness of the equipment, which provides an automated process.
3. The possibility of producing details of complex geometry, which can not be done by other technologies.
4. The products created by the method of casting can be reinforced, be hybrid or hollow, multicolored and of expanded plastic.
5. The ability to form products of different weights - from several grams to several kilograms.

Technology features

Using equipment for casting plastic products, you can create different products. In this case the method itself is cyclical, and its essence can be reduced to the following:

1. First, the polymer is melted, which accumulates in the cylinder of the injection molding machine for further feeding into the mold.
2. The melt is transferred to a mold, which is uniformly filled with a polymer compound.
3. The melt solidifies, while the material cylinder is still closed with the mold system.
4. After the product hardens, the mold opens, the product is removed from it.

The equipment for plastic casting consists of the following elements:

• Block, which prepares the melt and feeds it to the mold (injection unit);
• Blocking the locking (and opening) of the mold, which is a press device with a slider (clamping unit);
• Drive unit: it provides all types of movement of mobile equipment and accessories;
• Control device injection molding machine: it is designed to provide important parameters for the work, so that the casting is performed qualitatively.

Thermoplastic automata are complex and rather expensive devices, in which modern technical solutions are embodied.

Types of machines

TPA is a modern equipment for the casting of plastics, presented in various modifications. Depending on the method of plasticization, they are single- or two-screw, piston or screw-piston ones. The plasticization itself can be combined or separate. The number of plasticizers is also different. The drive in the TPA can be electrical or hydromechanical. In addition, all injection molding machines are horizontal, vertical, angular - with a horizontal or vertical press part.

Corner equipment for injection molding of plastics allows the creation of large products that are difficult to remove from the mold, and vertical TPA, on the contrary, are good for the production of small products, including reinforced ones.

How does the injection molding machine work?

The operating principle of injection molding machines is simple. The raw material, which must be processed, is placed in the bunker of the plasticization unit, then it is removed into the cylinder, where the force of friction acts under the influence of the screw . As a consequence, the raw material is heated, plasticized, then fed with a homogeneous mass into the space. As the required amount of melt accumulates, the material is injected into the mold. The finished product is taken out of it, and the cycle is started again.

Equipment for molding plastic in silicone molds is used in several modes:

1. Manual, when operations are started by pressing the button and setting the final positions of moving the mobile nodes.
2. Semi-automatic. In this mode, the mobile security door opens and closes to perform one working cycle.
3. Automatic (photocell). In this case, the cycles follow one another, but the command for the next cycle is transmitted by the photosensors at the moment when the finished product falls between them.
4. Automatic (time) when the cycle is in automatic mode, and the next cycle starts after the time delay between them expires.

Protection systems

Any devices, including equipment for the casting of plastics in the home, should work on the basis of safety rules. Modern TPA is always equipped with systems that ensure the safety of personnel, working in emergency situations. All protective devices are electronic, mechanical, safety, and also as a protective cover for heating elements.

By means of electronic devices it is possible to protect the mechanism of the hydraulic system. In emergency cases, you can use the "emergency stop" button to disconnect the oil pump drive. Mechanical systems simply close the molds. With the protective cover of the heating elements, the safety of the equipment is ensured.

Main brands

Modern manufacturers offer a wide choice of injection molding machines, and the price for the equipment for plastic casting is very different and depends on technical parameters, capacity and other indicators. The most popular for today are Japanese, Chinese and South Korean brands. So, the new TPA series was released by the Japanese company Nissei. Features of these products are as follows:

1. The presence of 5-zone temperature control, including the heating of the loading port.
2. TPA can work not only from the network.

An interesting solution is offered by Sumitomo company: in its lineup there are 4 models, which have a direct drive of an auger on ball bearings. The model is highly accurate. The price created by the popular brand Toshiba for plastic injection is high, but it justifies the excellent quality of the systems. The distinctive features of the products of this brand are:

• A new control system that manages robots directly;
• Software packages can be downloaded over the Internet;
• The device can be configured for audio restrictions.

Nadem from Meiki

The Nadem model from Meiki has direct control, it is complemented by an injection compression system. This device is fully electric, operating at high speed. The JSW Plastics Machinery brand offers the same perfect unit: High speed TPA makes it possible to produce a wide range of products of different thicknesses. Under the Toyo brand, the largest injection molding equipment has been developed. The price of such equipment can reach one million rubles, while the machine is resistant to vibration, equipped with a special injection mechanism, which is associated with the balancing of columns.

On the basis of JONWAI injection molding machines, various automotive parts are manufactured. Initially, the company focused on the fact that they used recycled polymer materials. And the products of this brand are widely used by popular car manufacturers HYUNDAI, PEUGEOT, FORD, DACIA, FIAT. TPA are widely used in the molding of plastic bumpers. The manufacture of equipment for these processes is one of the activities of JONWAI.

Molding into silicone molds: what is the essence?

Vacuum molding in elastic forms involves the production of plastic, rubber, plastic products. This method is used for different purposes: when creating prototypes and prototypes, small batches of goods of varying degrees of complexity, shape and size. Forms are created on the basis of pouring silicone into the formwork, where the master model is located. The silicone polymerizes, after which it is molded into molds.

The equipment for molding plastic into silicone molds allows you to obtain products that perfectly reproduce the dimensions and surface texture of the master model. In addition, casting in vacuum prevents the appearance of porosity on the surface and defects on it. It is also important that silicone molds allow creating products of any complexity and configuration, which can not be achieved with the use of other technologies.

Rotational molding of plastics

Manufacture of equipment for rotational casting of plastic products is a difficult process, which allows to obtain products of large size. The peculiarity of their production is that there are no seams in this product, and its walls are equal in thickness. Rotoforming involves the absence of pressure on the material, so the finished products do not have internal stresses, which affects the greater strength. This type of molding consists of three stages of work:

1. First, polymeric material is poured into the mold.
2. The form is sent to the chamber where it is heated. It is this stage that is rotational molding.
3. At the last stage, the rotational form is cooled.