The car industry’s search for higher productivity when machining parts has spurred development of a novel design of machine tool with four times the machining capacity and flexibility of a typical machining centre.
As its name suggests, the 4-Cut machining centre has four spindles. The unusual arrangement of the these upright spindles, which are carried in pairs on independent slides below an overhead workpiece, has led to the nickname ‘upside down’ machining.
The arrangement is particularly suited to unmanned machining, since swarf and chips fall away automatically under gravity.
Developed in Germany by Hulle Hille of Ludwigsburg part of the Thyssen Production Systems group that includes Giddings &Lewis the 4-Cut is undergoing trials for would-be customers in the German automotive industry.
Components being machined include suspension parts, brake callipers, end machining of crankshafts, inlet and exhaust manifolds, conrods, water and fuel pump housings.
First seen at the Metav and IMTS shows earlier this year, the prototype HSK 100 4-Cut was put through its paces machining parts mounted in a twin or multi-setup pillar fixture held in a 500mm x 630mm pallet carrier. The pillar fixture is presented horizontally to the spindles. Each pair of spindles can work simultaneously, but independently, on each side of the pillar. Alternatively, all four spindles can work on the underside pillar face.
Five-axis machining can be performed on an individual workpiece. The pallet carrier has a rotary axis for indexing or providing a full fourth B-axis. It is mounted on a vertical slide, on a column, to form the Z-axis.
The pallet carrier column traverses on the Y-axis. The column rides on a massive T-bed. Mounted on the front of the bed are two cross rails, each carrying a twin spindle head providing two X-axis traverses.
The standard tool magazine has two twin semi-circular magazines carrying up to 180 quick-release taper tools. Tool changing takes 2 seconds.
All swarf and chips drop into a pair of swarf conveyors. When a machining cycle is complete, the pallet can be spun at up to 200rpm under a jet of coolant to fling off any remaining chips.
The pallet changer swaps 500mm x 630mm pallets sideways in the work area, taking 12 seconds to complete the changeover so that the finished pallet returns to the front of the machine in the conventional upright position. The configuration provides ready access to finished work and to the machining area.
The 4-Cut comes in two versions, the HS 63 and HSK 100. These have 32/45kW and 13/20kW spindles, with speeds up to 16,000rpm and 12,000rpm respectively.
Rapid traverses are 75m/min in the X-axis and 50m/min in the Y-axis, with acceleration speeds of 10m/s2 and 7m/s2.
Chip-to-chip times are 4.9 seconds on the HS63 and 5.1 seconds on the HS100. Optionally, the work pallets can be fitted with a fifth C-axis in the form of trunnion-type or rotary table unit work holders.
The HSK 100 will cost around £330,000.