Twin-Column Vertical Turret Lathe

Overview

A twin-column vertical turret lathe turns very large, heavy rotational parts that cannot practically be held in a horizontal lathe. The workpiece sits face-up on a rotary table, gravity helps hold and center it, and the cutting tools come down from above and in from the side. Parts include wind turbine bearing rings, gas and steam turbine casings, large gears and flanges, mining mill shells, and pressure vessel heads, often weighing tens of tonnes and measured in metres. The twin-column layout puts a column on each side of the table, joined by a Cross Rail, so the structure forms a rigid portal around the part. That stiffness is what lets the machine take heavy cuts on the outer diameter of a large ring without chatter.

Bed, Base and Table Bearing

The Bed & Base is a large Base Casting in grey cast iron, anchored to a deep foundation and set level on twelve Leveling Pad points. The heart of the base is the Hydrostatic Table Bearing, a hydrostatic bearing that floats the rotary table on a film of pressurized oil delivered to several Hydrostatic Pad elements and watched by Pressure Sensor feedback. A hydrostatic bearing carries enormous axial load with almost no friction and no metal-to-metal contact, which is essential when the table plus workpiece can exceed a hundred tonnes.

Rotary Worktable

The Rotary Worktable is the C axis of the machine. A heavy Faceplate is rotated through a large Table Gear Ring ring in case-hardened alloy steel, driven by two Drive Pinion gears off twin Servo Motor drives in an anti-backlash arrangement. Twin pinions let the control preload the gear mesh from both sides so positioning stays tight even under interrupted cuts. The workpiece is held by four Self-Centering Jaw units; each Jaw Body is driven in or out by a Jaw Clamping Screw to grip a wide range of diameters and recentre the part.

Columns and Cross Rail

The two Column members are tall castings, each with Linear Guide Rail ways and a Ball Screw driven by a Servo Motor to raise and lower the Cross Rail. Lowering the rail to suit a short part shortens the unsupported reach of the tooling and raises rigidity. The Cross Rail Casting spans the columns and carries the vertical tool heads; once positioned, Rail Clamp Block units lock the rail to the columns so it does not move under cutting force.

Vertical Ram Heads

Each Vertical Ram Head is a complete machining station. A Tool Ram slides vertically on Linear Guide Rail ways driven by a Ball Screw and Servo Motor, giving the Z axis. At its lower end is a Indexing Turret, an indexing Turret Disc that presents the next tool. The turret is locked by a Curvic Coupling, a face gear that delivers high indexing accuracy and clamps with great rigidity, and it is rotated by a Index Motor running on Ball Bearing supports. Several Turret Tool Holder pockets carry boring bars, facing tools, and grooving tools so a full sequence runs without operator changes.

Side Head and Cutting Strategy

The Side Turret Head mounts on a column rail and reaches in from the side. Its Side Slide carries a Side Turret on a Ball Screw and Servo Motor axis, and it is used for outside diameter turning while a ram head works the face or bore at the same time. Running a ram head and a side head together cuts cycle time on big parts, because two surfaces are generated in one rotation of the table. The control coordinates feed rates so the cutting loads stay balanced and the part does not deflect.

Control, Hydraulics and Coolant

The CNC Control System system runs five to eight axes. A CNC Unit coordinates the table C axis and every slide through one Servo Drive per axis, fed by redundant Power Supply units, with the operator working at a Operator Console built on an LCD Panel. Auxiliary circuits switch through banks of Relay devices, and field signals run on a Wire Bundle terminated in Connector blocks.

The Hydraulic & Lube Unit unit serves the hydrostatic table bearing, the rail clamps, and way lubrication, with a Hydraulic Pump feeding a Valve Manifold and a separate Way Lubrication Pump metering oil to the ways. Cutting large steel parts makes heavy swarf, so the Coolant & Chip System system pairs high-flow Coolant Pump units with a Chip Conveyor and a Coolant Filter.

Variants and Use

Single-ram machines suit shops that turn one feature at a time, while twin-ram machines with a side head are bought for high throughput on large bearing rings and gear blanks. Larger tables and taller columns extend the envelope into power generation and heavy mining components. Across the range, the defining traits are the portal stiffness from the Column pair and the load capacity of the hydrostatic Hydrostatic Table Bearing, which together let the machine hold tight tolerance on parts that no horizontal lathe could carry.