This article was written by Andrew Rankin of Sovrin
Plastics and Peter Manser of Battenfeld UK. This is Page
1 of 3.
'Micro Moulding Techniques are allowing the industry to create
a host of exiting new miniature products. This article describes
one micro moulding process and its benefits'.
Getting down to Size
As medical techniques have developed, the need
for finer and smaller structures has accelerated to such an extent
that a whole new industry is evolving with levels of accuracy and
quality control never dreamed of before. This has come about as
a result of a number of improving and enabling technologies such
as computers, machining centres, moulding machines and vision inspection
systems, all coming of age simultaneously during the past ten years.
There is a wide range of perceptions as to what
constitutes a micro-component. In simple terms, a micro component
is something that weight less than 1g. The weight of a micro component
is in the milligram range. The weight of a nanocomponent would be
in the submilligram range and falls outside the scope of the technology
described in this article.
Selecting the Right Process
When more than one component is required, economics
demand that some form of mass production must be employed. For straightforward
geometric shapes, machining can be employed and automated machining
techniques are valid for tens, hundreds or even thousands of parts.
More complicated three dimensional profiles would in the past, have
been made by creating a model pattern from which a mould would be
created for casting with a suitable resin. This was time consuming,
and without sophisticated vacuum techniques the results were variable
in quality. More recently the use of rapid prototyping using lasers
and ultraviolet curing resins has allowed single or small-batch
production of intricate profiles using computer-aided design programs.
As numbers of parts reach hundreds of thousands and beyond, the
manufacturing process requires much higher output rates and consistency
of components. This is where injection moulding becomes the favoured
solution. Although high standard injection moulds are expensive,
the cost per component reduces as quantities increase.
Higher volume and complex structures require the
injection moulding of polymers, powder metals or ceramics (Figure
1).
