Plastics News Europe - July/August 2019 - 20

thermoforming

in good shape
swissplast AG, a custom thermoformer with locations in Germany and Switzerland, specialises
in producing 'unusual' products. In the past, parts formed by the company have even made it
onto a special series of Swiss postal stamps. By Karen Laird

postal stamp issued by the
Swiss Post in 2013 to commemorate a century of using
electric vehicles to deliver the mail depicted the Kyburz DXP electric
three-wheeler, the vehicles that today
make up bulk of the mail carrier delivery fleet. The trikes are sturdy, with a
robust design and feature 8 different
parts made by swissplast, including
the highly visible bright yellow leg
covers and the battery housing. A
quiet point of pride for a company
that has taken on a considerable
number of thermoforming challenges
in the almost three decades since its
inception.
Founded in 1990, swissplast started life as a Swiss custom thermoforming company named Blumer
Kunststoffe. The company was acquired in 2011 by Barac Bieri who renamed it swissplast AG in 2013.
Through organic growth and acquisitions, the company now has locations
in Gotha, Ichenhausen and Diedorf,
Germany, and one in Sargans, Switzerland.
swissplast is a 'one-stop shop',
offering the entire spectrum of services from development through
production. The importance of this
capability should not be underestimated, according to Stephan Zwahlen, managing director of the swissplast site at Sargans. "Especially for
the many customers who are switching technologies and coming to thermoforming for the first time. They
have no experience and tend to be
quite surprised when they discover
the possibilities thermoforming can
offer."

The eRod, a road legal electric sports car with a range of up to 140km,
for which swissplast produces a total of 12 different casing parts from
cooled aluminum series tools

A brief look at
thermoforming
While thermoforming may seem to
be a relatively simple and straightforward process, this is a technology
that has over the years evolved to enable the complex geometries and
tight tolerances needed for today's
technical and industrial parts. Considerable investment, too, is required:
the big machines carry a price tag of
around €800,000.
However, as with all technologies,
in thermoforming, too, using the
right tool, selecting the right material
for the part being formed and getting
the processing parameters right are
crucial to producing quality parts.
The process offers several advantages over, for example, injection

The fully automatic Jorns double bending machine JDB is configurable in lengths from 3.2
to 12.2 metres and with a bending capacity of up to a maximum of 3mm of sheet steel

moulding or over other plastic forming processes. In the first place, thermoforming allows large parts to be
produced more economically than
other methods. Second, thermoforming moulds, which are often made
from aluminium because of this metal's favourable thermal conductivity,
are far less expensive than those used
in other processing technologies.
Wood, plaster, steel, cast phenolic
and cast filled epoxy resins are also all
materials used to construct moulds.
Another major difference with
other processing technologies is that
in thermoforming, the plastic material is not melted, but merely softened
through heating. Basically, it is a manufacturing process where a plastic
sheet is heated in an oven until pliable, then stretched into or over a
mould, trimmed and ejected as a
product. A single-sided male or female tool is used, which means that
the cosmetic side of the part should
always face the tool. Parts can be produced with a class A surface and colour as per customer requirement.
Two very commonly applied thermoforming techniques are vacuum
forming and pressure forming.
In vacuum forming, vacuum is applied to draw the plastic sheet onto
the mould. In some cases, pressure is
added, by using a pressure box to
pump compressed air onto the surface of the sheet or film being

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Plastics News Europe - July/August 2019

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