plate of the tool (called the top bolster). In such cases the threaded cylinder called shank is not attached to the tool. The clamps are either mechanical (manually operated using spanners) or air operated varieties. Turret type punch press machines have a table or bed with brushes or rollers to allow the sheet metal workpiece to traverse with low friction. Brushes are used where scratches on the workpiece must be minimized, as with brushed aluminium or high polished materials. The punch press is characterized by parameters such as: Frame type Mechanism of delivering power to the ram (mechanical, electro-mechanical or hydraulic) Size of working area (e.g., 2500 x 1250 mm) Single or multiple station Force rating (for example, 20 tons) The type of tool shop and its capacity (e.g., store revolving type, capacity 34 tool) Speed or productivity (typically characterized by the speed of strokes with a step movement of 25 and 1 mm) Speed of movement without shock (speed-load displacement) Maximum weight of workpiece Safety features Power consumption The type of software Punch presses are usually referred to by their tonnage and table size. In a production environment a 30-ton press is mostly the machine used today. The tonnage needed to cut and form the material is well known, so sizing tooling for a specific job is a fairly straightforward task. According to the requirement the tonnage may even go up to 2000 to 2500 ton presses. Die set A die set consists of a set of punches (male) and dies (female) which, when pressed together, form a hole in a workpiece (and may also deform the workpiece in some desired manner). The punches and dies are removable, with the punch being attached to the ram during the punching process. The ram moves up and down in a vertically linear motion, forcing the punch through the material into the die. Axis The main bed of most machines is called the 'X' axis, with the 'Y' axis being at right angles to that and allowed to traverse under CNC control. Dependent on the size of the machine, the beds, and the sheet metal workpiece weight, the motors required to move these axis tables will vary in size and power. Older styles of machines used DC motors; however, with advances in technology, today's machines mostly use AC brushless motors for drives. CNC-controlled operation To start a cycle, the CNC controller commands