What is Injection molding?

What are the advantages of injection molding? The essence of this method lies in the fact that the molten metal is fed into a steel split mold under pressure. The working pressure on the melt is carried out directly by compressed air (gas) or by a piston, which moves under the action of compressed air (gas), emulsion, or oil.

The pressure can reach several hundred atmospheres, which ensures good filling of the mold and the production of castings of the 3-5th accuracy class and with a surface roughness corresponding to the 5-8th class. This provides great performance.

Injection molding is carried out on compressor and piston machines. Piston machines are made with vertical and horizontal pressing chambers. Chambers can be cold or hot.

The scheme of injection molding on a machine with a vertical chamber is as follows. Melt 2 is poured with a measuring spoon into the pressing chamber 3.

Moreover, the upper piston 1, descending, exerts great pressure on a portion of the melt, which transfers pressure to the lower piston 8. The piston, moving, open the gate channel 11, through which the melt fills the mold cavity.

The procedure of molding machine

a – with a cold vertical pressing chamber,

b – with a cold horizontal pressing chamber;

c – position before pouring,

d – during pouring,

e – after pouring

Moreover, the mold consists of two half-molds 4 and 5. After the melt solidifies, the half-mold 4 moves aside, and the casting 7 together with the sprue 10 pushes out by pushers 6. Excess metal 9, which has not entered the mold cavity, pushes out of the chamber by piston 8 and goes to the smelter.

Injection molding on a machine with horizontal chamber proceeds in the same sequence.

What are the advantages of injection molding?

Injection molding allows you to solve one of the most important tasks of foundry production: to bring the dimensions of the casting as close as possible to the dimensions of the finished part.

Moreover, castings obtained in metal molds have a clean and smooth surface, which significantly reduces the surface finish of parts (grinding, polishing, etc.). This method uses to cast critical parts with thin walls and complex configurations.

In addition, injection molding is used to connect several parts or to obtain castings with fittings from other metals. Castings obtained by injection molding have a fine-grained structure and high mechanical properties.

The most advanced methods for manufacturing castings

What are the advantages of injection molding? It is also economically advantageous that a large number of castings can produce in a single mold in a short time. The high productivity of this casting method and the minimum allowances reduce the cost of production both in the foundry and in the machine shops.

In addition, injection molding eliminates the use of sand, so sanitary production conditions are better than in conventional foundries.

Moreover, on the other hand, injection molding is a complex technological process that requires knowledge of alloy metallurgy, casting technology, special knowledge of tool production in the manufacture of molds, and, finally, mechanics in the operation of injection molding machines.

Injection molding has some drawbacks

Injection molding has some drawbacks, such as the appearance of small air pockets (porosity) in castings. The air in the cavity of the mold does not have time to completely go out and partially mixes with the melt.

The gases dissolved in the metal do not have time to leave the casting; due to the porosity of the casting, it is impossible to heat treat it, since swellings appear when heated. Moreover, it is difficult, and sometimes impossible, to cast a part with an undercut and internal cavity in this way.

The machines and molds that exist in modern production are suitable only for the manufacture of castings from alloys with a melting point below 1000 ° C. Special experimental casting machines and molds have been made for casting steel.

Die casting can produce castings, not from all alloys

The most suitable are zinc alloys, some aluminum, and brass. Moreover, it is more difficult to obtain parts from steel and cast iron in this way. Bronze parts are not cast under pressure.

The high cost of equipment and molds makes it not always profitable to produce small batches of castings by injection molding, so the injection molding method is widely used in serial and mass production.

The 6 advantages of plastic injection molding

Injection molding allows the production of large quantities of plastic products and components in a short time. Moreover, it guarantees the dimensional repeatability of the pieces and reduces production costs thanks to the automation of the production process.

What are the advantages of injection molding? The molding of plastic materials is one of the most widespread techniques in the transformation processes of plastic materials.

It is a procedure whereby the techno plastic material melts and injects at high pressure inside the closed molds. It opens once the material has solidified and the product is ready.

Moreover, the wide diffusion of this technique can explain by its important advantages. It brings in terms of production efficiency and cost reduction.

But that’s not all: there are numerous other advantages of plastic injection molding that make this technique a viable solution for the production of plastic components.

It is precisely for this reason that we use injection molding of plastic materials to provide its customers with quality products that best meet the needs of various companies.

The 6 advantages of plastic injection molding.

Injection molding of plastic materials means obtaining large quantities of products in a short time. Moreover, this advantage accompanies by the consequent possibility of reducing production costs. Thanks to the automation of the entire procedure.

Production of complex design components

The versatility of injection molding involves, among other advantages. The possibility of obtaining parts with complex geometries is impossible to obtain with different techniques. In this way, injection molding makes it possible to respond to any need, making possible a high degree of customization of the products.

Moreover, the experience and competence of the supplier certainly contribute to this advantage.

The strength and stability of the pieces produced

Thanks to their stability, the plastic components have excellent durability over time. Thus, contributing to the quality of the final product itself.

What are plastic injection molds?

What products are made from injection molding? Many injection molding machines are sold in the global market every year, which work with special molds (molding molds, forming equipment).

A mold is a metal device good to use for the production of plastic products by injection molding. They are good to use for mass production. Production should be supervised by experienced engineers who will develop design documentation for the manufactured product, as well as the device itself.

Let’s look at each option:

The application of the technology involves several stages

Initially, the matrix with the powder is exposed to high temperatures until it becomes plastic. What products are made from injection molding? Further, a special punch puts pressure on the plastic, due to which it acquires the necessary shape. Despite its simplicity, this technology has its drawbacks.

Models for direct pressing, designed to work exclusively with simple materials, allow the production of simple products. Another disadvantage is the high cost of production, which makes it unprofitable to produce large batches.

For injection molding

The mold has 3 plates and a more complex device, it is multifunctional. Here, the matrix and gates locate independently in relation to each other. What products are made from injection molding? This allows you to design parts of different sizes. Due to the multifunctionality, many companies produce injection molded products, while the production requires relatively low costs.

The operation is only possible for professionals

The operation of injection molding models is only possible for professionals, as they are difficult to work with, are not easy to maintain, as well as expensive to repair.

According to the number of parts produced at a time, the molds are single and multi-place. The use of the latest molds allows the production of many parts at the same time, thereby increasing productivity and reducing the cost of production.

Mold material for casting: aluminum alloys, various steel grades, zinc alloys, and copper alloys. Aluminum plastic injection molds are common and are affordable and also have excellent performance.

What products are made from injection molding? machine for plastic panels

All owners of modern offices, shops and cafes, exhibition halls, and restaurants would like to make their premises clean, beautiful, and comfortable, but they do not want or do not have the financial opportunity to do so.

Today, it is absolutely not necessary to buy expensive finishing materials, since there is a large amount of finishing materials on the market that will look great and even solid. The best option, in this case, is plastic panels, which produce on a modern injection molding machine. It is worth noting that this finishing material will look great on your insulated loggia or balcony.

What products are made from injection molding? Plastic panels are indeed the most economical and simple finishing materials at the moment, which can be good to use in rooms of various types. Such a panel produces on an injection molding machine from solid polyvinyl chloride and from a softener.

The finishing material does not contain any harmful substances

The plastic panel can be good to use for interior decoration of kitchens, corridors, bathrooms, and loggias, as well as swimming pools, cafes, and restaurants.

Such panels are advantageous for finishing the interior of an office and various cultural and leisure facilities, sports and recreation complexes, and so on.

What products are made from injection molding?

This finishing material is quite popular in the domestic building materials market, it is much cheaper than siding and, moreover, natural wood. However, the panels are easy to produce not only in the classic white color, the manufacturer today has production technologies to imitate the texture and color of natural precious wood.

It must be said that when carrying out finishing work, cladding with plastic panels is easy to attribute to the most “clean” ways of finishing rooms. After its installation, no dust, no dirt, no waste, and no other construction debris will remain in the room. During installation, there are no problems with sizing, it perfectly cuts both along and across with a fine-toothed saw.

Proportional valves

In the process of molding plastics, exact proportions of the base material to the additional one are sometimes required. This makes it possible to achieve the requirements for molded products flexibly, mixing primary material with secondary material. To make this process simple and economical, a proportional valve for injection molding machines is good to use. 

This equipment interacts with a vacuum loader and controls through a small controller. When using loaders of the SAL-U series, control occurs from the loader panel. It will make operation even more convenient.

Proportional valve operation

By means of the PV and PVN valve, a proportional loading of recyclables together with primary raw materials in certain proportions ensures. What products are made from injection molding? It is good to use with a vacuum loader. The proportional valve controls by its own control panel or vacuum loader.

When loading raw materials, while reaching a predetermined period of time, the supply of primary material is cut off by means of a pneumatic valve, after which the supply for recyclables opens. 

After the specified time for supplying the secondary material, the pneumatic valve switches, and the supply of primary raw materials resumes. At the moment of stopping the loading of raw materials, the proportional dispenser stops.

The operation of the valve is based on pneumatic switching

The operation of the valve is based on pneumatic switching by external sources of compressed air. What products are made from injection molding? To operate a proportional valve, a pressure of 6-8 atmospheres is most often required. In operation, one of the loading channels always remains open and the other closed. Among the advantages of the device:

• Loading with one vacuum loader of two different materials, which have different fluidity and bulk density.
• There is no need to install a separate dispenser for crushed materials.
• Dosing carries out proportionally

What products are made from injection molding? Due to the stable operation of the magnetic valve, the precise operation of the pneumatic cylinder ensures strict proportions maintained between new and recycled material.

How to reduce flash in injection molding? Plastic injection molding equipment is in demand in various industries. In addition, the casting method uses to produce toys and stationery, car parts, polymer pipes, various containers, and profiles for plastic windows..

Types of plastics and raw materials

The following materials are used for the production of plastics:

• Polyvinyl Chloride;
• Polyethylene of high and low pressure;
• Polyethylene Terephthalate;
• Polystyrene;

Plastic injection molding: readjusted with every change of raw material

One of the features of the material is the possibility of its processing and creation of a secondary product. In addition, the latest technologies used in the processing and disposal of industrial waste make it possible to turn recycled materials into new materials that are used in subsequent production.

The recycling of polyethylene makes it possible to obtain products with the same properties and technical characteristics as the material from primary granules.

How to reduce flash in injection molding? Production features

The raw material for the production of such a synthetic polymer is LDPE granules of the highest quality. In addition, on its basis, a film is made that complies with GOST. The product does not have an unpleasant odor, it is durable, elastic, and colorless. The only drawback compared to the secondary counterpart is the high cost due to the fact that the feedstock is more expensive.

Production technology

The production of plastic products is carried out in a certain sequence:

1. PVC materials for the production of plastic products crush and load into the hopper of the injection molding machine.
2. Solid polymers are heated to the required temperature. The screw feeds the melt into the plasticizing unit.
3. In addition, under high pressure, the polymer mass is injected into the injection mold. Plastic uniform layers cover the walls of the form, exactly repeating its shape.
4. During the cooling process, the pressure in the mold decreases, and the cooling parts are removed outside.

The speed and volume of injection, as well as temperature parameters, are set individually for each type of product.

There are different ways of molding plastics:

• Extrusion – the creation of plastic products by extrusion;
• Casting – molding products in injection molds;
• Compression molding, when the molten mass compresses under the action of mechanical loads;
• Blowing – a heated polymer blank acquires the exact shape of an injection mold by blowing;
• Compression molding occurs when injection molds compress.

Equipment for the production of plastic products

In addition, for the manufacture of plastic products, various machines, and equipment for injection molding use:

1. Extruders

Extrusion means extrusion or extrusion. The production of plastic products occurs by extruding the molten polymer mass through a matrix that forms a certain shape.

The extrusion method creates window profiles, polymer sheets and films, plastic roofing, and plastic pipes.

How to reduce flash in injection molding? The installation includes the following components and mechanisms:

• Extruder;
• Pneumo-loader;
• Inflating heads with a cooling system;
• Calibration mechanisms;
• Pulling and turning devices;
• Stacking and winding modules.

The operation of mechanisms is controlled automatically

In addition, they are injection molding machines for the production of mass-produced plastic parts in molds by injection under pressure.

They include various functional units:

• Plasticization module, where the raw material heats to the required temperatures;
• An injection mold for plastic injection, where polymers inject and products form;
• A locking unit that provides closing and opening of molds;
• A special pusher removes finished castings from the machine.

An automatic CNC unit with a foreign-language interface and an LCD display ensures the management and control of the production of all plastic products.

In addition, the operation of the mechanisms provides by an electric, hydromechanical or electromechanical drive.

Depending on the location of the polymer injection system, injection molding machines are divided into:

1. Vertical – with vertical injection and horizontal split molds.
2. Horizontal – with a horizontal injection system and vertically arranged connectors.
3. Corner – for products of complex configurations with the location of the injection in different places.

The production of plastic products in injection molding machines involves heating polymers to a liquid state, feeding them under high pressure into molds, cooling, and removing finished parts.

Blow molding machines

With the help of blow molding machines, various thin-walled containers produce canisters, bottles, and barrels.

In addition, the production of bottles from blanks (preforms) pre-made in injection molding machines is carried out in the following order:

1. The performs heat in a special oven.
2. Hot blanks are placed in a mold, where the bottles pull and inflate through a special rod.
3. When in contact with the metal of the injection molds, the polymer hardens and becomes rigid.
4. The mold opens, and the finished bottles remove using a special manipulator.

How to reduce flash in injection molding? Extrusion blow molding machines

 

In addition, devices are used for the manufacture of volumetric hollow products by blow molding.

Used in various industries:

• Food production – production of bottles, cans, and containers;
• Pharmaceuticals – containers for medicines;
• Mechanical Engineering – fuel tanks, pipes, bumpers;
• Construction – pet packaging, containers for paints, and varnishes.

Extrusion blow molding machines consist of several main components:

1. Extruder with a screw mechanism and heating generator.
2. Head with a mouthpiece for forming tubular blanks or sleeves. It can be single, multi-strand, direct-flow, or angular.
3. Metal molds for plastic injection molding.

How to reduce flash in injection molding? The receiving-inflatable device consists of several mechanisms:

• Moving blanks to the mold;
• Closing, opening, and locking forms;
• Billet blowing;
• Flash cutting;
• Ejection of finished products.

In addition, the complete set of the machine includes the compressor and a cooler.

Thermoforming machines

Devices for thermal molding of products made of polyethylene film of various thicknesses: disposable thin-walled cups, plates, and containers.

Machines are single or multi-position rotary, revolving, or belt types.

For simple products, belt-type machines are suitable; for products of complex configuration, turret or rotary machines are suitable.

How to reduce flash in injection molding? Optional equipment

Auxiliary equipment for the production of plastic products can reduce manual labor and facilitate the production process.

This category includes:

• Various conveyors and belt conveyors;
• Mixers, loaders, dispensers;
• Crushers and drying bins;
• Robotic manipulators.

Mini plastic injection molding machines

Desktop machines for the manufacture of plastic products are widely in demand in small industries in the manufacture of limited quantities of goods. In addition, they easily place in small workshops, laboratories, or service stations.

Mini plastic injection molding machines can be made by hand. For this you will need:

1. Steel rod with the piston.
2. Cylinder from a metal pipe trim.
3. The adapter is 0.5 inches.
4. Thermostat and heater for 600 watts.
5. Fitting and fasteners.

With little engineering skills and instructions on the internet, you can build a machine to make simple plastic shapes.