Fixed-table sliding gantry milling machine Four-Star SD series

The SD series by Four-Star is a range of fixed-table gantry milling machines with sliding columns for machining large, heavy workpieces. Unlike moving-table configurations, the SD series moves the gantry — columns, cross-rail, and spindle head — along the X axis over a stationary table, enabling machining of workpieces of virtually unlimited length and mass beyond the capacity of any moving-table design.

The structure integrates the column and slider as a single one-piece casting. The cross-rail is manufactured in box-in-box cast iron with an optimized bending section modulus for maximum rigidity and vibration damping under roughing loads. The RAM spindle head has a standard cross-section of 450×400 mm, with optional 550×550 mm and 650×650 mm versions (4 roller guideways). X-axis drive uses rack-and-pinion with dual synchronous servo control from 5 m of travel; on SD-48 and larger models, the Y axis also uses rack-and-pinion drive.

X-axis travel ranges from 6 to 36 m; Y-axis from 2,400 to 5,400 mm; and Z-axis from 1,100 to 1,500 mm. Column spacing covers 2,450 to 5,450 mm, with table widths from 1,600 to 4,600 mm and table length equal to X travel. The spindle operates at up to 6,000 rpm and 22/26 kW (continuous/30 min), driven by an H/L planetary gearbox. The 32-tool ATC magazine with random tool selection is standard equipment. Positioning accuracy is ±0.015 mm, with repeatability of ±0.003 mm.

The standard CNC is FANUC 0iMF, with optional Siemens and Heidenhain alternatives. The series supports 90° milling heads, 5-face and 5-axis simultaneous heads, automatic head changer (AHC), CNC rotary table, and mobile control room.

The SD series targets manufacturers of energy equipment, heavy machinery, marine components, and large metal structures that require machining workpieces whose size and weight exceed the capacity of moving-table configurations.