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.

Features of injection molding

How does a plastic injection molding machine work? The principle of operation of injection molding machines for the production of plastics is to melt granular polymer material to a liquid state. Feed it under high pressure into a closed injection mold. Moreover, the product acquires the exact outlines of the internal cavity of the mold.

In addition, various types of raw materials can be good to use in production: polyethylene, polystyrenes, polyethylene terephthalates, polyvinyl chlorides, and polypropylenes.

However, machines are configured for certain parameters:

• Consistency;
• Degree of viscosity;
• Melting parameters.

The main criterion for choosing a material is the melt flow rate.

How does a plastic injection molding machine work? In addition, the strength, quality, and accuracy of product parameters depend on temperature and pressure values, which should be in the range of 80 to 200 MPa.

Moreover, it is important to strike the right balance, as low pressure can lead to cavities or underfilling, while too high pressure can lead to flashing.

Varieties of plastic injection molding methods

The determining factor in the choice of equipment is the melting methods, which are injection or intrusion.

1. The injection method is suitable for creating parts of complex configurations with walls of various thicknesses: from very thin to thick-walled. Moreover, a popular method is characterized by minimal shrinkage. However, the ability to use multi-cavity molds for plastic injection, and work with any polymers.
2. The intrusion method is suitable for creating three-dimensional parts with thick walls. In addition, by rotating the screw, the molten mass is fed into the injection mold and fills it. Then, under pressure, another small amount of solution is injected, filling all the cavities of the casting mold and compensating for the shrinkage of the cooling melt.

Stages and features of the process

Moreover, the creation of plastic products in injection molding machines takes place in several stages:

1. The polymer raw material is loaded into the receiving hopper of the injection molding machine.
2. Under the influence of their own weight, the granules enter the screw zone, where they are melted under the influence of high temperatures.
3. In addition, under high pressure, through the mouthpiece of the plasticizing module, the molten mass injects into the molds.
4. In the process of cooling, the pressure in the molds gradually decreases, and the products are taken out.
5. However, the entire casting process takes from a few seconds to 10 minutes. Moreover, it depends on the starting material, wall thickness, dimensions, and configuration of the parts.

In addition, plastic parts for cars, various containers, stationery, toys, household items, components for electronics, medical equipment, and other products are created by injection molding machines.

How does a plastic injection molding machine work? Types of molding equipment

 

The choice of mechanisms and equipment for plastic injection depends on the type, configuration, and dimensions of the manufactured parts.

In addition, machines operate in automatic, semi-automatic, or manual modes.

Extruders

Good to use for the production of sheet products, polymer films, plates, pipes, and window profiles.

Moreover, the raw material load into the mechanism and squeeze out under pressure through molds with predetermined proportions.

Machine tools include:

1. Pneumatic loading mechanisms;
2. Extruders with a filter system;
3. Blowing heads with coolers;
4. Calibration mechanisms;
5. Pulling and turning devices;
6. Stacking and winding modules.

In addition, extruders control automatically using special programs.

Injection molding machines

Good to use for injection molding of all types of products under pressure from polymeric materials. Moreover, in injection molding machines, parts of various shapes and configurations with walls of different thicknesses, hybrid, hollow or multi-colored products can create.

In addition, the production technology consists of the melting of polymeric raw materials and injection under high pressure into special molds.

Machine tools include:

• Loading bins
• Preparation and plasticization modules;
• Press forms;
• Closure nodes;
• Automatic control units.

By design, injection molding machines are:

• Electrical, electromechanical, and hydromechanical;
• With combined or separate plasticization;
• Piston, worm-piston, one- or two-worm.

How does a plastic injection molding machine work? In addition, they can have one or more options for plasticization and a different number of mold closure nodes.

Blow molding machines

Good to use for the manufacture of polyethylene containers and containers with thin walls: bottles, canisters, barrels up to five thousand liters.

Moreover, blow molding machines heat up polymer raw materials and create products by blowing them into molds of certain sizes.

Extrusion blow molding lines

They produce products by combining the methods of extrusion and blowing, which expands the possibilities and range of products.

In addition, extrusion blow molding machines produce:
Fuel tanks and bumpers for cars, various bottles, bottles for the cosmetic and medical industries, chairs, buckets, and toys.

Moreover, machines differ in the type of extrusion heads, the number of streams and posts, including:

• Extruders that heat up and prepare the polymer mass
• Molds with a closing mechanism for molding products;
• Heads of angular or direct-flow configuration, single or multi-strand, for forming sleeves or pipes;
• Blowing elements supplying compressed air at high pressure to molds with blanks.
• Extrusion blowing lines are equipped with compressors and coolers.
• Thermoforming complexes
• Good to use to create disposable plastic utensils or containers with thin walls.

In addition, the production technology consists in blowing products from a polymer film heated to a temperature of about 140 ° C, with a thickness of more than 100 microns. Moreover, finished products are punched out of the plate and packaged.

The process is controlled semi-automatically or manually.

Additional accessories

The production of plastics is equipped with various auxiliary devices:

• Dryers;
• Dispensers
• Mixers
• Conveyors
• Crushers;
• Loaders;
• Conveyors.

Mini machines for highly specialized enterprises

In addition, for the production of small batches of plastic products or experimental batches of goods, there are mini-machines on the market suitable for use in small, highly specialized enterprises.

Moreover, compact machines do not require large production areas and can be placed on a regular table. Craftsmen make such machines with their own hands to organize production at home.

1. The technique for plastic injection is characterized by the high precision of products and other advantages:
   The possibility of manufacturing products of any geometric shapes and sizes of impeccable quality.
   2. Use of any polymers.
   3. Mass production of identical parts.
   4. Lack of additional refinement of cast products.
   5. Profitability and quick payback of production.

Moreover, by injecting the molten mass under high pressure, the molds are evenly filled, including the smallest details and holes.