Amada AC 255NT

Auto-index rotation allows individual turret stations to rotate to any angle under CNC control. On a standard turret, tools are fixed at whatever angle they were loaded — to punch a feature at 45 degrees requires a separate tool loaded at 45 degrees, consuming a turret station. Auto-index stations rotate the tool holder to any programmed angle, allowing a single punch to produce slots and cutouts at any orientation without additional tooling. The AC 255NT has 16 auto-index stations — slots, oblong holes, and shaped cutouts in any direction are punched with one tooling setup. This dramatically reduces the number of tools required to produce complex part geometry.

Amada's Multi-Tool holder mounts multiple small punches (typically 8–32 punches per holder) in a single turret station. A standard 48-station turret becomes a turret with effective capacity of hundreds of punch positions — ideal for parts requiring many small holes in a pattern (perforated sheet, ventilation patterns, electronics chassis). Each punch in the multi-tool set is individually selectable by CNC-controlled index rotation. Multi-tool reduces setup time on parts with repetitive hole patterns and eliminates the need to dedicate multiple turret stations to the same punch size in different locations.

The Amada EM series uses a servo-electric drive (no hydraulics) for all punch motions — a servo motor directly drives the ram through a ball screw or belt transmission. The AC series uses servo-controlled hydraulics. Servo-electric drives are quieter, more energy efficient, and require less maintenance (no hydraulic fluid management). The EM 2510NT has a 20-ton punching capacity in a servo-electric design. The AC 255NT has a 25-ton capacity with servo-hydraulic drive — providing more punching force for thick material and heavy forming tools. For shops regularly punching 5–6 mm steel or using heavy lance/form tools, the AC's higher force is an advantage.

The AC 255NT punches mild steel to 6.35 mm (0.25 in), stainless steel to 4.5 mm (0.178 in), aluminum to 6.35 mm (0.25 in), copper to approximately 3 mm, and pre-finished/coated materials using no-mark repositioning. Material selection affects tool clearance requirements — mild steel typically uses 20–25% of material thickness as punch-to-die clearance; stainless uses 15–20%; aluminum uses 10–15%. Amada provides clearance recommendations in their tooling catalog. Punching galvanized, pre-painted, and decorative coated materials is possible with no-mark repositioning and ground or polished workholding to prevent surface damage.

CNC punch press is faster and lower consumable cost for parts with many identical small holes — punching 200 holes in a chassis takes seconds vs minutes on laser. Laser cutting is faster for complex profile cutting, handles any contour shape, and requires no tooling investment. Punch presses produce formed features (louvres, bridges, dimples, tapped extrusions) that laser cannot — laser can only cut, not form. For high-volume chassis production with many punched holes and formed features, a punch press is the economical choice. For flexible job-shop cutting of varied outlines with few holes, laser is more versatile. Many shops run both: punch for hole-intensive parts, laser for profile cutting.