FOUNDRY & MACHINING

Iron Foundry

In 1973, a British engineering firm designed and installed a large continuous iron foundry in an African workshop. The firm closed operations 20 years later leaving the workshop with no engineering support. Later, the sand cooling system completely failed, interrupting the re-processing of the foundry sand and necessitating manual work. The workshop invited DIAK to solve the problem. It was clear that there was no point in recreating the same system since the technical process was inaccurate and relied on obsolete components. Instead DIAK designed and assembled a complete replacement system built onto framework sections exactly to match the mounting of the original. This would permit the old system to be hoisted out from above the sand conveyor on the overhead gantry, and the new system to be dropped in with no further work for the user apart from wiring the main power connection.

The new systems used Siemens EPROM logic chips which were programmed with the entire system operation. The volume of sand passing by on the conveyor was measured by fibre-optic sensors, and the temperature and moisture content by a dielectric capacitance "surface-ski" float. The EPROM calculated the sand condition and instantaneously controlled pressurised water jets in the next zone into which the sand conveyor passed. The sand then dropped into a rotating mixer and back to the foundry shop floor ready for use. Each part of the system was protected against the hostile environment- the fibre-optic units were continuously cleaned by air jets, the EPROM sealed in a IP65 cabinet, and the condition of the float continuously monitored. The EPROM controlled alarms to alert operators on the ground of such faults as failure of the sand supply to arrive, and it also performed controlled shut-down procedures. The system worked first time and needed no user intervention thereafter.

One year later, DIAK performed a 2nd major project in the foundry when a new 2 ton shake-out machine was installed together with the sand transport- a screw augur conveyor, vibratory feeder, moving belt and rotating feed hopper. All other conveyor belts were also replaced.

The 3rd phase and the end of the basic overhaul was completed one year later in cooperation with David Brown Engineering when all of the gearboxes and drives were rebuilt for each stage of the foundry, followed by a full overhaul of the jolt squeeze machines.

Engineering Workshop

In 1970, a major engineering workshop in Africa acquired a centre lathe, a large 18 inch capacity machine, which has since seen good service for many years. The UK manufacturer closed a few years after the delivery, but solid engineering design kept the machine running for many years. However a sudden fracture in the drive gearbox wrecked several gears and the clutch, leaving the user with no apparent alternative but to seek a new machine.

An on-site inspection by DIAK resulted in a proposal to collect the broken parts and airfreight them to the DIAK U.K. works. There the parts were examined and tacked back together for CNC dimensions to be taken and gear formations to be mapped. DIAK then machined complete new replacement parts to match the broken items. A current production clutch was adapted and shipped with the new parts. The lathe returned to full service at a repair cost less than 10% of the replacement price of a new machine.