ProductionSystemAlcrete uses a semi-automated production system in its 11,613sq m (125,000sq ft) plant at Arthurstown, Co Kildare.
It combines fully automated robots with skilled staff to produce enough structural components to build 4,500 to 5,000 "living units" a year.
Based on German-designed technology, the heavy plant allows an assembly line approach to house and apartment building.
Each wall unit comes complete with openings for doors, windows, electrical sockets, ducting and other services.
Conduits embedded in the concrete allow wires and central heating piping to be channelled through once lifted into place on the building's foundations. Floor/ceiling units also have all required service connections available for electricians or plumbers to hook up once the units are positioned.
Alcrete is able to deliver wall elements with prefinished stonework faces or interior walls already finished to the colours requested by the customer. All interior surfaces are smooth enough to be paint-ready as a matter of course.
Long before any robots come into play, Alcrete's designers work with the client to transport the original building designs into the company's computer- aided design and control systems. These ensure that the finished elements are delivered accurate to within 2mms of original specification.
All precast elements start the same way, with a blank metal box onto the surface of which workers and robots position electrical boxes, reinforcing bar, conduits and so forth. The flat boxes move around the plant on purpose-built rollers from assembly station to assembly station and right on into the "curing chamber" after the concrete is finally poured.
Robots begin the construction process by positioning the metal forms which mark out the outer edges of the wall unit. The forms use powerful magnets to attach themselves onto the box surface. Robots pre-form and lay in elements, including reinforcing bar and also apply paint marks onto the box indicating where doors, windows, ducting and other openings must be created.
Human workers position wooden window and door forms, wire up the rebar and other metal reinforcing and also position conduits, electrical boxes and duct openings. They also include metal lifting points for the cranes that will later hoist the wall and floor elements into place once on-site.
The flat box carrying the whole assembly eventually rolls up to the concrete pouring station. The mixer can produce three tonnes of ready-to-pour concrete in just 90 seconds. This is channelled through a specially designed chute with 15 doors that can be opened and closed to avoid pouring concrete into window or door openings.
The box and its concrete cargo can be vibrated as a unit to settle the concrete and drive off air pockets and the whole is then rolled across to the curing chamber where it remains in air heated to 55 degrees for a preset time before eventual transport to the customer.
