Injection Moulding

Linecross specialises in developing injection mouldings for low to medium applications, with the in-house ability to manage complex tooling programmes and offer extensive post-moulding assembly and finishing processes for series production.

What is Injection Moulding?

Injection moulding is a widely used manufacturing process for producing plastic parts in large volumes. It involves injecting molten plastic material into a mould cavity under high pressure.

Our range of injection moulding machines from 35 tonnes to 2,300 tonnes enables us to offer customers a first-class concept-to-production service.

This state-of-the-art KraussMaffei injection moulding machine is one of our most recent investments. It is fast, precise, energy-efficient and can handle a complete range of interior products from door panels to seat backs. The robotic arm even takes the part away!

The stages of Injection Moulding

Mould clamping: The two halves of the mould are closed and clamped together with high force to securely hold them in place during the injection process.

Injection: Molten plastic material, usually in the form of pellets, is fed into a heated barrel of an injection moulding machine. The material is then forced into the mould cavity through a nozzle and runner system using a reciprocating screw or a ram at high pressure.

Cooling: Once the mould cavity is filled, the plastic material is left to cool and solidify inside the mould. The cooling process can be accelerated using cooling channels within the mould.

Mould Opening: After the plastic has sufficiently cooled and solidified, the mould is opened, and the finished part is ejected from the mould cavity.

Ejection: The finished part is pushed out of the mould using ejector pins or other mechanisms.

Injection moulding is used to produce complex and precise parts with high dimensional accuracy and repeatability. It is widely adopted in various industries, including automotive, electronics, consumer goods, medical devices, and more.

Injection Moulding 900 900 85 s c1

Injection Moulding benefits

Injection moulding offers numerous advantages as a manufacturing process for producing plastic parts:

High production efficiency

Injection moulding is a highly automated process, allowing for fast and continuous production of parts at a high volume. The cycle times are relatively short, resulting in a rapid production rate.

Complex part geometries

The process can produce intricate and complex part designs with precision and consistency. It can incorporate features such as undercuts, threads, and thin walls, which may be challenging or impossible with other manufacturing methods.

High dimensional accuracy

Injection moulding provides tight tolerances and excellent dimensional stability, ensuring that the finished parts meet strict specifications and fit perfectly with other components.

Material variety

A wide range of thermoplastic materials can be used in injection moulding, offering flexibility in material selection to suit different applications and performance requirements.

Low material waste

Vacuum forming can produce transparent or translucent parts, which is advantageous for applications requiring visibility or light transmission, such as packaging or display cases.


Once the initial tooling is created, the per-unit cost decreases significantly for larger production volumes, making it an efficient choice for mass production.

Reduced labour requirements

Once the initial tooling is created, the per-unit cost decreases significantly for larger production volumes, making it an efficient choice for mass production.

Part consolidation

Injection moulding allows for the integration of multiple components into a single part, reducing assembly and improving the overall strength and reliability of the final product.

Surface finish and aesthetics

The process can produce parts with a smooth surface finish, reducing the need for additional finishing operations. Moulded parts can be moulded in various colours or textures without the need for secondary painting or coating.

Consistency and repeatability

Once the process parameters are set, injection moulding ensures a high level of consistency and repeatability, resulting in uniform parts throughout the production run.

Materials used for Injection Moulding.

Injection moulding is a versatile manufacturing process that can work with a wide range of materials, including thermoplastics, thermosetting plastics, and elastomers. However, the most used materials for injection moulding are thermoplastics due to their ability to be repeatedly melted and solidified. test

Some common materials used for Injection Moulding:


Polyethylene (PE)

Key Properties:

Including HDPE (High-Density Polyethylene) and LDPE (Low-Density Polyethylene), used for various products like bottles, containers, and toys.


Polypropylene (PP)

Key Properties:

Known for its strength, flexibility, and resistance to heat, used in automotive parts, food containers, and packaging.


Polystyrene (PS)

Key Properties:

Available in general-purpose (GPPS) and high-impact (HIPS) forms, used for consumer electronics, packaging, and household items.


Acrylonitrile Butadiene Styrene (ABS)

Key Properties:

A tough and rigid material used in automotive components, consumer goods, and toys.


Polycarbonate (PC)

Key Properties:

Known for its high impact resistance and optical clarity, used in safety equipment, eyewear, and automotive components.


Polyethylene Terephthalate (PET)

Key Properties:

PETG offers high clarity and impact resistance, making it suitable for retail displays, medical packaging, and protective covers.


Polyamide (Nylon)

Key Properties:

Known for its strength, abrasion resistance, and low friction, used in engineering components, gears, and bearings.


Polyoxymethylene (POM) or Acetal:

Key Properties:

Offering excellent mechanical properties, used in gears, bushings, and precision engineering components.


Polymethyl Methacrylate (PMMA) or Acrylic

Key Properties:

Known for its optical clarity and weather resistance, used in lenses, signs, and displays.


Thermoplastic Elastomers (TPE)

Key Properties:

A family of rubber-like materials with properties of both thermoplastics and elastomers, used in seals, gaskets, and soft-touch grips

These materials represent just a fraction of the many options available for injection moulding. The selection of the material depends on the specific requirements of the product, including mechanical properties, chemical resistance, environmental conditions, and desired aesthetics.

Get in touch

At Linecross we provide a complete ‘concept to production’ service from customised product development to assembly and sequenced supply. Find out more about how our range of processes can support your business.

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