In recent months, we have enjoyed an increasing
number of enquiries for not just our speciality of chrome-plated
automotive components, but injection moulded parts for a range of
projects. But one issue that has cropped up is our choice of
tooling material for injection
Although aluminium tools have attracted a lot of interest, it is
largely based on price, not necessarily on the results achieved. We
believe this is false economy given the long-term advantages
offered by steel tooling and the narrowing gap in pricing.
Steel has been the tool material of choice here at Borough, it's
what we know and what we have used for 50 years, because volume
parts require tools that are fully hardened.
We typically produce components for our automotive clients in
tens or hundreds of thousands and often millions, so we feel steel
gives us greater consistency throughout our long production
In our experience, steel tools do not wear
or bruise like aluminium, which can wear more excessively along the
Steel is also better for polishing, long-term dimensional
stability and avoids 'sinkage', which can be a problem with some
tools for some components.
Whilst some enquirers will ask us to consider using aluminium
tools for their projects, we would only consider using them to
produce a few hundred prototypes or very low production volumes -
otherwise for us it has to be steel.
Despite a lot of noise about the low cost for aluminium, there
is hardly any cost difference now, so we always recommend the
better option, steel. For Borough, the components we produce and
chrome-plate are typically highly visible 'trim' items under
intense visual scrutiny, for which quality and consistency of
replication is critical.
The Borough rule is OEM trim parts for automotive really do
require steel tools for injection moulding components,
particularly those that take advantage of our new 2-shot machine
that allows for selective chrome-plating of components.
For larger mouldings produced by vacuum-forming, like roof
linings and interior panels, it is possible to use aluminium tools,
which are much more cost-effective than steel when made on this
scale. Aluminium tools are also ideal for low quantity applications
such as signage, etc., or when upfront costs and short lead times
are critical to the success of a project.
Our more than 50 years' experience of moulding and plating shows
that aluminium tooling probably isn't right for every application.
It depends on the material, the part being produced, the volumes
involved, and the number and kind of secondary operations being
As with all mouldings to be chrome-plated, we would always
recommend involving our design team at the earliest stage. There
are critical differences required in the moulding of components
specifically for chrome-plating, like avoiding thickness changes
which will eliminate uneven cooling that could cause shrinkage and
Unfortunately, the nature of the beast is that mould tools need
complex precision mechanisms, with parts that constantly impact
each during production of the moulded components. And that is why a
steel mould tool is the most durable solution for projects with
expected long production runs - even if we're not chroming the
So, our advice will always be,
choose what works best, as production runs might exceed your
expectations and then the false economy of aluminium tooling will
really impact the quality and overall cost.