The fully automated homogenizing plant with integrated slab storage was developed foremost for rolling slab of AA 2xxx and AA 7xxx series alloys. Such hard AlCu/AlZn alloys are destined mainly for the aircraft industry.
Production and handling of these slabs is known to be somewhat hazardous. Due to the casting process severe inner tensions prevail in the slabs after casting. It is anytime possible that large pieces of slabs burst off, resulting in severe injury to bystanders or damage to surrounding equipment. To avoid such dangerous situations it was mandatory to design a fully automated operation, including all slab handling.
After casting, slabs are transported by fork truck to the entry/exit table of the Batch Homogenizing Plant. The fork truck driver enters the charge/slab number - all other relevant slab information is available from the Production Planning System (PPS).
The fork manipulator moves the slabs to the weighing platform, where they are measured, weighed and marked. Parameters from the PPS are verfied against the measured values for each slab. If ok, the slab is transferred by the fork manipulator into the storage area of 180 slabs capacity.
From there all production steps are automated.
According to production orders from the PPS the fork manipulator collects the relevant slabs from their storage positions and builds a stack inside a steel cage. The steel cages are designed to protect the furnace internals from bursting pieces of slab.
During stack building a spacer manipulator takes up spacers from the spacer magazine and positions them on the slabs, layer for layer. This routine is repeated in reverse order after homogenizing.
The charging machine picks up the completed stack together with its steel cage and moves it into the homogenizing furnace, later from there to the air cooling station and finally back into stacking position for destacking.
In the homogenizing furnace precise temperature regimes are followed, according to selected homogenizing recipes for the corresponding alloy. Predefined recipes can be modified any time to suit special customers requirements. Heating curves for standard 2xxx, 3xxx and 6xxx alloys as well as sophisticated curves with several temperature steps for 7xxx alloys are defined and stored in the database.
Following destacking after homogenizing, single slabs are either returned by the fork manipulator to the slab storage area or transferred directly to the inspection station (visual and ultrasonic) and further on to the down-stream slab saw.
Alternatively to the PPS configuration of a stack, the operator can assemble slabs himself. This process is supported by an optimization calculation, which automatically suggests suitable slabs to put together into a stack.
The plant fully meets the stringent quality requirements of the aircraft industry, including state of the art data recording, reporting and full integration into client’s database.