Lenton has completed an order for three custom-built furnaces
with fast cooling performance for
heat-treating powder injection moulded
components in controlled atmospheres at temperatures up to
1000°C.
The furnaces, which have been built for Singapore-based
Solid
Micron Technologies, are designed
for burning off binders in
injection-moulded components at between 400°C and 500°C and then
sintering them at approximately 1000°C. The accelerated cooling system has been included in
order
to reduce the complete processing cycle to eight hours and maximise
throughput.
The furnaces have cylindrical gas-tight stainless steel
retorts with capacities
of 170, 340 and 510 litres which are fed with
nitrogen gas throughout the heating process to prevent oxidisation of the
components. Three-zone heating control ensures uniform and consistent
temperatures throughout the retorts
After-burners are fitted to minimise exhaust emissions to
atmosphere, and all electrical equipment has been designed for operation in
ambient temperatures from 34°C to 40°C and relative humidity of 98 per
cent.
In order to accelerate the cooling phase of each cycle, Lenton has
supplied a heat exchanger that can be moved between the furnaces and used to
force-cool the hot nitrogen gas, which is then circulated within the retorts.
This system has reduced cooling times from about six hours (in the case of a
full load in the largest furnace) to about three hours, allowing a full cycle to
be completed in a single shift.