Cast and Peel

Peeling machine replaces expensive extrusion operations for cost effective production of high quality aluminum cylindrical bars.

The recently newly developed BÜLTMANN high-performance peeling machines for aluminum bars, which successfully replace the extrusion of bars, are now well established with various customers, for example with one of the leading European suppliers of aluminum products and semi-finished products. With the help of the BÜLTMANN peeling machine, round billets are turned into homogeneous precision bars with high surface quality.

The new line is here part of a state-of-the-art plant producing semi-finished products, special bars for automotive forging and billets for extruding. The peeling machine operates in a diameter range of 50 – 203 mm with material lengths of 3 - 7 m and feed speeds up to 0,5 m/sec.

With precisely controlled cutting depths of 1 - 5 mm the inverse segregation zone is reliably removed to ensure compositional uniformity through the entire cross section.


Moreover, a smooth surface finish of Rz 4 μm is quickly achieved with excellent roundness and a dimensional accuracy of, e.g., IT9, thus eliminating the need for separate sizing operations. The peeling machine is part of a production line provided by BÜLTMANN, including automatic visual inspection by digital cameras, color marking, and barcode embossing. The peeled bars are then automatically sorted according to the inspection results and individually stacked in transport stands or wooden slats for shipping or transfer to downstream operations.

This new peeling process offers key benefits over extrusion. The machine is compact and the associated material handling is streamlined. By contrast, an extrusion operation is larger, capital intensive, complex, and burdened by substantially higher operating costs associated with billet preparation, heating, extruding, controlled cooling, material handling, production scheduling, and increased work in progress (WIP). Moreover, extrusion does not remove the harmful inverse segregation layer at the billet surface.

The peeling machine is accompanied by an emulsion system, fume exhaust system, and chip conveyor with a sorting system to maintain alloy segregation. BÜLTMANN has initiated regular production of this new peeling machine to convert horizontally and vertically cast aluminum billets to high quality bars. It goes without saying that BÜLTMANN peeling machines operate fully automatically, which allows for the minimum use of personnel. As usual, customer satisfaction is our goal and we are pleased to have once again lived up to this claim.

Please contact us for further information.