Page 52 - Plastics News April 2024

INTERNATIONAL NEWS

sign and processing parameters This will affect what press size is As concerns about sustainability
for injection moulding? needed to mould the component in grow, how can the use of ther-
production. moplastics be integrated into the
Shrinkage affects the physical size of injection moulding process while
the mould form and is a key consid- maintaining part quality and per-
eration when designing a mould tool. formance?
Even within the same range of poly- By working with experienced mould
mers they can vary due to different tool manufacturers such as us, sus-
factors one such factor being addi- tainability in plastic injection moulding
tives, or fillers. Fillers such as Talc and starts with mould tool design. Mould
Glass fibre are common in materials tool design is a complex area and by
and much like clamping force the working with experienced and expert
shrinkage of materials can vary greatly tool designers your tool can be de-
so it is important to know not only signed with minimised waste in mind
the polymer that is to be moulded, at every stage of the manufacturing
but the specific material grade as well. process.
Due to the chemical construction of Considering optimal cavitation, cool-
some polymers and the additives, the ing, and ejection systems that best
tool designer may need to choose align with the product material speci-
specific grades of tool steel for con- fication will mitigate the generation of
struction of the inserts to maximise plastic waste in the moulding process.
the life of the tooling. Polymers such With the continuing advancements in
as PolyVinyl Chloride (PVC) release recycled polymers and their improv-
Properties of thermoplastics are a corrosive gasses during processing ing compatibility with the plastic injec-
key factor when designing an injec- which can chloride steels with low- tion moulding process there is tangible
tion mould tool and the tool designer er chrome content (non-stainless). ethical progress for the plastics sec-
must take into consideration multiple While some materials require high tor. Here at Pentagon, we are excited
factors that can vary greatly from pol- hardness tool steels due to the abra- to be taking this journey in the next
ymer to polymer. The main ones to sive properties or those of fillers that chapter of plastics processing and its
consider are camping force require- are added. contribution to wider environmental
ments, shrinkage, corrosive or abra- and economic sustainability.
sion properties, and mould tempera- Processing properties of the polymer
ture. dictate what temperature the tool
needs to maintain during moulding.
Depending on the chosen polymer Some polymers require very cold
and size of product the clamping force tools, this is achieved by running
required to successfully mould the chilled water through the tool and in-
component can vary greatly, materi- serts, while others can require heating
als such as Low-Density Polyethylene over 200°C, which is often achieved
require low force, while Polyether with hot oil or sometimes on smaller
Sulphones and Polysulfones could re- tools electrical heaters built in.
quire 13 times more clamping force.

54 PLASTICS NEWS April 2024