fastening & assembly solutions and technology - Approved Business

with the substrates being encapsulated
meaning, for example, that watertight
systems are readily created.
Beyond that, the grip on to PVC is
excellent, making them highly suitable
for sealing and anchoring cables. Also,
the resin bonds even to clean steel, solders
and other metals commonly encountered
in electronic modules.
When cool, Macromelt is tough,
retaining slight flexibility at low temperatures,
yet good rigidity to 130°C or even
higher temperatures with the appropriate
grade. Electrical insulation is excellent at
typically 1 x 1012 Ω*cm and dielectric
breakdown does not occur up to stresses
of 20kV/mm.
The process
The system consists of the moulding
product, the mould set, the machine, and
the melting unit.
Macromelt products melt and flow at
low viscosities (1,000 to 10,000 cps),
which is ideal for the low injection pressure
process. These hot melts cure quickly
by cooling, so there are no toxic fumes
and cycle times are short. The materials
are available in amber, black and custom
colours.
The mould set, which is usually made
from aluminium, facilitates the process to
trial stage. Aluminium is preferred as it
has a low injection pressure, better thermal
conductivity, and no abrasive ingredients,
such as fillers and glass fibres.
Steel can also be used as the material for
Connectors can be safely secured
using a hot melt resin
Security for wires and cabling is assured using a hot melt resin in grommets
the mould set, if the manufactured part
includes steel or hard glass filled components.
In the latter case, it is recommended
that steel inserts be used in the
area of the cavity.
There are many types of moulding
machines available, although they generally
fall into two categories. For smallscale
production the option is a manually
opened mould set. Where there are production
that call for high productivity and
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output, the machines come with a sliding
stage or rotary table for the mould set.
The melting unit is equipment used for
injection of the hotmelt resin into the
mould set.
So, all in all, the use of hotmelts for
encapsulation is good news for several
reasons.
First, Low Injection Pressure means
that fragile and/or delicate components
can be encapsulated without fear of damage.
In addition, improved productivity
can be achieved through fast cycle times
(in many cases just 10 to 15 seconds),
there is no chemical reaction, and the single-component
material means the process
is both simple and clean. Further,
the resin qualities mean that water-tight
encapsulation with adhesion is possible,
and there is excellent electric insulation
and water resistance. And depending on
their chemical basis, the moulding products
are resistant to petrol, oils, alcohols,
acids and alkalis. Beyond that, the technology
produces good thermal durability
characteristics, with temperature resistance
from -40°C to +150°C.
Finally, because the products are
based on non-toxic and renewable raw
materials, the technology is
environmentally compatible.
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