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Types and applications of plastics Molding processes

In the previous article we have briefly introduced a few plastic processing methods, now I would like to introduce more plastic processing methods.

Injection Molding-

The injection molding machine uses the nature of molten plastic to melt into liquid after heating to a specified temperature, injecting the molten liquid into the closed cavity with high pressure, cooling and shaping, then opening the mold and pushing out to get the desired plastic product.

Injection molding can be used for thermoplastics, thermosets, low-foam plastics, and also for center control plastic products, metal powder injection molded parts.


Extrusion molding

The material is heated and pressurized in the extruder to make it molten and flowing, and then it is continuously extruded from the mouth mold to form the plastic products.

Extrusion molding is used in the processing of thermoplastics and rubbers, which can be used for dosing, granulation, rubber filtration, and it can also be used for continuous production and manufacturing of various continuous products, such as pipes, profiles, sheets, films, wire and cable coverings, rubber tires, and so on.


Compression molding

Install the upper and lower molds between the upper and lower templates of the press, add the plastic material directly into the cavity, close the mold, the plastic will be filled with the cavity under heat and pressure, and the plastic part will be obtained after curing and shaping.

Molded ones are used to produce electrical equipment (plugs and sockets), pot handles, handles for tableware, bottle caps, toilets, unbreakable dinner plates (melamine), carved plastic doors, and so on. They are also used to produce reinforced plastic sheets, pipes, rods and model products.图片3

Transfer molding-

Transfer molding is the process of loading plastic pellets into the filling room of the mold. The molten plastic is heated and pressurized to fill the cavity through the pouring system at the bottom of the filling room of the mold, and then cured.

The requirements of transfer molding are that the plastic should have a large fluidity before reaching the curing temperature and a fast curing rate after reaching the curing temperature.It is only used for rubber products, inlay products.图片4

Solid-phase molding-

Solid-phase molding is to make plastic molding at molten temperature, there is no obvious flow state in the molding process.

It mostly used for secondary molding processing of plastic sheet, such as vacuum molding, compressed air molding and pressure molding, originally used for thin sheet parts, now used for thick sheet parts.


Blow Molding-

Thermoplastic resin obtained by extrusion or injection molding of tubular plastic, heated to a softened state, placed in the folio mold, immediately after closing the mold in the billet into the compressed air, so that the plastic billet blowing and clinging to the inner wall of the mold, after cooling off the mold, that is, to obtain a variety of hollow products.

Blow molding is used for bottles, barrels, cans, boxes and all containers, balls, bellows and toys for packaging food, beverages, cosmetics, pharmaceuticals and everyday products, fuel tanks, car shock absorbers, seat backs, center brackets, armrests and headrest covers.



Calendering is the process of extruding and stretching materials close to the viscous flow temperature through the gap of a series of parallel rollers rotating in opposite directions to become thin sheet products with a certain thickness and width.

Calendering is used for PVC film and sheet, man-made leather products.


Rotational Moulding

Rotational molding is to add the measured liquid plastic to the mold first, after the mold is closed, make it rotate along the two vertical rotation axis, while making the mold heated, the plastic materials in the mold under the action of gravity and heat, gradually and evenly coated, molten adhesion on the entire surface of the mold cavity, molding the same shape as the mold cavity, and then cooled and shaped, demolded to make the desired shape of the product.

Rotational molding is mainly used to manufacture medium, large or super large hollow products such as handling boxes, tipping hulls, sailboat hulls, clothing models, industrial tanks and storage tanks, etc. for processing seamless hollow products.


Dongguan Ditai Plastic Company -( ) have been engaged in the thermoforming industry for more than 11 years, and we have produced over 8,000 kinds of products.

If you have a project related to thermoforming process, you can contact me at any time, I believe we can give the most professional opinions and plans to realize your wild ideas :).

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