Injection stretch blow moulding

Robust, high clarity packaging popular in many market sectors

ISBM edited image

Centred on our Madrox site in Poland, the addition of injection stretch blow moulding (ISBM) technology was largely prompted by growing customer demand for lightweight, glass clear containers.

This process also guarantees consistently accurate neck finish profiles. The majority of our output is in the form of screw threaded bottles, but we can also produce preforms for conversion by our customers.

Quick Guide

infographic - stretch blow moulding

This process has two main variants – single-stage and two-stage. In both variants the plastic is first injection moulded into a preform, which defines the neck finish of the final bottle. The single stage process involves producing a preform and stretch blowing the bottle in the same machine.

These preforms are heated over their glass transition temperature, then blown using high pressure air into bottles using special blow moulds. At the same time the preform is stretched with a core rod to enhance its rigidity. Robinson offers both single-stage and two-stage options, predominantly using PET material but also PP where appropriate.

The key advantages of ISBM are:

  • Flexibility to make smaller runs
  • Preform wall thickness can be varied to allow blowing of rectangular and non-round shapes
  • Good O2 and CO2 barrier properties for PET bottles
  • Reduced weight containers
  • Dimensionally accurate neck finishes
  • High breakage resistance

Explore case studies

60ml segment shaped bottle

60ml segment shaped bottle

Working with the Tomil brand Dr Devil to manufacture a 60ml segment shaped bottle

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2 stage PET bottles

2 stage PET bottles

A versatile preform suitable for APC and fabric conditioner markets

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500ml waisted PET bottle

500ml waisted PET bottle

Handwash packaging for Pollena Ostrzeszów’s brand Biały Jeleń

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