Making Plastic Injection Molds

The injection mold is used for the production of molding plastic products.  Standard molds consist of fixed half and movable half.

Features and steps of the injection molding process

Firstly, the process of molding plastic products is carried out in injection molding machines with CNC and includes the following steps:

1. Preparatory work:
2. Calculation of the proportions of the material;
3. Setting up equipment and molding programs;
4. Installation and fixing of molds;
5. Loading the raw material into the hopper.
6. Heating polymers to a molten state.
7. Moving the melt with a screw through the gating runners into the mold.
8. Cooling and extraction of finished parts.

Moreover, if necessary, mechanical refinement of products is carried out.

Injection mold manufacturer in China: where to start

Secondly, the development of a plastic business of injection mold should begin with the selection of a production facility and the selection of personnel.

Choosing the right location

Business premises are best rented. This contributes to the rapid start-up of the production line.
There are some requirements for premises for locating production of plastic injection:

• Remoteness from residential buildings;
• The presence of natural ventilation in the premises;
• Compliance with fire regulations;

Moreover, the minimum area of the production workshop is 50 square meters, and the warehouse space is 80 square meters.

We calculate the required area depending on the size and number of products produced and based on the business scale.

Recruitments

Thirdly, and most importantly, the success of the enterprise and the quality of products directly depend on the professional of the production manager or technologist who manages and monitors compliance with the molding technology.

The company must have the following staff:

• Designers;
• CNC machine operators;
• Mechanics for maintenance of mills and mechanisms;
• Product quality control specialists;
• Movers and laborers.

However, to service a small manufacturing enterprise, a staff of specialists and auxiliary workers in the amount of 6-8 people may be enough. In addition, you need to hire proven and reliable specialists with work experience and relevant qualifications.

Main types of raw materials for injection molding in China

The selection of polymer compositions for the manufacture of plastic parts is the most important stage in the preparation of production.

Moreover, thermoplastic and thermosetting polymers, foam plastics are suitable for production:

• Polystyrene;
• Polypropylene;
• Polyethylene terephthalate;
• Polyvinyl chloride;
• Polyethylene of high and low pressure, etc.

In addition, the materials have different structures, melting points, and plasticities. Moreover, when changing raw materials, the equipment reconfigures. Polymeric waste should be sorted and crushed, washed, and dried.

Basic molding technology methods

However, for molding plastics, the following methods are good:

1. Extrusion – performed by extrusion or extrusion through a shaping mold. Moreover, it is good at manufacturing hoses, cable products, and other molded products.
2. Injection, in which the molten polymer, under high pressure, is injected into the mold. In addition, it is good for the manufacture of thin-walled parts of complex configurations, plastic cases of power tools and equipment, children’s toys.
3. Blow – to create hollow products: plastic containers, bottles, cans, medicine containers, paints.
4. Thermoforming – plastic products come by pressing. Moreover, good for the manufacture of disposable tableware, containers, packaging.
5. The intrusion casting method is good for casting thick-walled parts. However, the raw material pumps by means of a rotating worm screw.

In addition, there are complex technologies for molding: co-injection, sandwich, casting into rotary or multi-component molds.

These methods are good to produce multi-layer, two-component, multi-colored parts, products with a clear distinction between colors or outer coatings.

Injection molding technologies: production of thin-walled products

In addition, injection molding technology allows the production of thin-walled products of various configurations with thermoplastic polymers.

Moreover, the process of creating plastic products in injection molding machines includes:

• Loading raw materials into the receiving hopper;
• Moving granules under their own weight into the screw zone;
• Moreover, melting polymers to a liquid state;
• Injection of the molten mass under pressure into the mold;
• Cooling of the product with a gradual decrease in pressure and removal from the mold cavity.

Similarly, the produced items could also be reinforced, hollow inside, and multi-colored.

Choosing the right injection molding machine in China

However, the choice of equipment depends on the type of goods being produced.

Injection molding machine: electric or hydromechanical drive

In addition, it is an injection molding machine with an electric or hydromechanical drive for the creation of plastic products under pressure.

Consists of the following structural units:

• Loading hopper;
• Blocks of plasticization and preparation of raw materials;
• Main body;
• Closure nodes;
• Control module.

The press mechanisms can be located horizontally, vertically, be angular with a horizontal or vertical press. For various products, individual parameters are set for injection volume, speed, melting temperature.

However, injection molding machines can be with separate or combined plasticization and have several closure nodes. There are one or two-worm, piston, and worm-piston.

Modules of a fixed half and movable half

Moreover, inside they have a cavity for the injection of molten polymers. It is designed to create serial parts.

Molds are manufactured according to the customer’s specifications. The molds exactly repeat the outlines of future molded parts. However, finished molds are attached to the clamping elements of injection molding machines, and the molten polymer is injected into the cavity.

Vacuum raw material loader

In addition, units for injection molding automatically supply polymer granules to injection molding machines or extruders. Moreover, they consist of receiving hoppers, vacuum pumps, automatic dosing modules, air cleaners leaving the unit. There is monoblock and separate.

However, the compact monobloc loaders are easy to be placed directly on the injection molding machine.

Powerful separate loaders can transport raw materials

Feeding of raw materials is carried out by the method of vacuum suction of the material into the receiving hopper, from where the air pumps out by a vacuum pump. Moreover, under the pressure of its own weight, it enters the loading module of an injection molded in China, an injection molding machine, or an extruder.

Refrigeration unit for finished products

Similarly, this is good for cooling finished products in multi-batch production in injection molding machines.

Moreover, it shortens the production cycle for the manufacture of plastic moldings from molten raw materials. In conclusion, the automatic control system provides exact temperature parameters.