How to... reduce plastic packaging
wall thickness by 25% using injection
compression moulding
Sumitomo (SHI) Demag’s UK packaging
expert Kevin Heap talks through the
commercial and ecological benefits of
injection compression moulding and how
the technique compares to traditional
moulding of ultra-thin plastic packaging.
What is injection compression
moulding?
Why is it beneficial to packaging?
Global forecasts for rigid plastics, which
is the category thin walled containers sits
in, is predicted to rise at an annual rate of
3.7% from 52.9 million tonnes in 2017 to
63.4 million tonnes in 2022, according to
research by Smithers Pira*.
The value of materials used to produce
The method of pressing material in a rigid plastic packaging is also forecast to
mould is quite a common industrial grow across the same period at an annual
process, typically using rubber and resin rate of 3.9% to reach $202 billion.
and a combination of heat and pressure
to mould products.
PE is projected to be the largest-
growing segment during this forecast
It has generally been used to produce period. Light-weighting and consumer
thicker sectioned parts on slower convenience are important factors in
cycle times, for example, optical lens this expansion, with the combination
or thermoset applications. However, of environmental pressures and high
the technique hasn’t been applied to polymer prices placing increasing
the mass-production of polypropylene pressures on packaging manufacturers.-
packaging applications, until recently.
20 FDPP - www.fdpp.co.uk
Most companies operating in the
competitive arena produce millions of
packaging containers every year. Volume,
raw material waste and precision are
fundamental to each company’s financial
viability, with many facilities operating
20+ machines to meet supplier demand.
By applying injection compression
techniques to stack moulds, packaging
moulders can now reduce the wall
thickness of containers and lids from
0.45mm to 0.35mm. This saves around
25% in raw polypropylene materials
compared to the standard injection
moulding process, while maintaining
comparable mechanical properties.
Given the dominant role that materials
play in low cost, mass-produced
disposable food packaging containers
and with packaging converters striving