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What is injection molding?

Most of our products in the buckets and cups categories are manufactured using the injection molding process.

This process allows precise and efficient production of complex plastic parts in large quantities. An injection molding machine mainly consists of a hopper, plasticizing screw, injection unit with nozzle, mold, ejector system, clamping unit, and control console.

The plastic granulate is fed into the screw via the hopper, where it is melted by frictional heat and heating elements (typically up to 200 °C, depending on the material). The molten plastic is then injected under high pressure into the closed mold cavity. The process takes place in two stages – the injection phase and the holding phase.

Inside the mold, the material cools and solidifies, taking the exact shape of the cavity. Once cooled, the mold opens, and the finished parts are ejected by the ejector mechanism.

The mold then closes again automatically, and a new cycle begins.

Injection molding is a precise, repeatable, and highly efficient manufacturing method ideally suited for packaging products that require tight tolerances and high surface quality.

It ensures uniform wall thickness, reliable sealing between container and lid, and smooth, hygienic surfaces essential for food packaging.

Injection Moulding Process – one of the most precise and efficient methods for manufacturing technical plastic components. It enables the serial production of complex geometries with tight tolerances and high repeat accuracy. Most of our buckets and cups are produced on modern 100-ton injection moulding machines.

Phases of the Injection Moulding Process

Phase Description Typical Parameters
1. Plasticising The plastic granulate is melted and homogenised inside the screw cylinder. Temperature: 180–240 °C · Screw speed: 80 rpm
2. Injection The molten material is injected into the closed mould under high pressure. Injection pressure: 800–1 200 bar · Time: 0.5–2 s
3. Holding Pressure Additional material compensates for shrinkage during cooling. Pressure: 400–800 bar · Time: 2–6 s
4. Cooling The part solidifies in the mould and gains its final dimensions. Cooling time: 5–20 s · Mould temp: 20–40 °C
5. Demoulding The mould opens and ejector pins release the finished part. Total cycle: 15–40 s (depending on article size)

Technical Data – Example of a 100 t Injection Moulding Machine

  • Clamping force: 1 000 kN (≈ 100 t)
  • Screw diameter: 35–45 mm
  • Max. injection volume: approx. 150 cm³
  • Max. injection pressure: up to 2 000 bar
  • Average cycle time: 20–30 s
  • Material: Polypropylene (PP) or Polyethylene (PE)

Advantages of the Injection Moulding Process

High dimensional accuracy, smooth surfaces, reproducible quality and very short cycle times. Ideal for packaging with strict hygienic requirements. The process is energy-efficient, fully automatable and allows the use of recycled materials (rPP).