Vertical Turret Lathe Product

Overview

A vertical turret lathe (VTL) is a large-spindle production machine used for facing, boring, and turning flat or cylindrical parts up to 600 mm diameter and 600 mm height. The spindle is vertical, and the workpiece clamped horizontally into a power chuck that can exert 50–500 kN of clamping force. Unlike a horizontal engine lathe where the spindle is in the operator's line of sight, a VTL keeps the operator at a safe distance and allows more mass and rigidity in the frame. A rotary tool turret — typically with 4–6 stations — automatically indexes cutting tools into position, so the operator or a simple control loop can complete a sequence of facing, boring, and radius operations without manual tool changes. A Hydraulic System provides the clamping and infeed pressure, and a Main Drive Unit with a gearbox selects from 4–8 discrete spindle speeds, each matched to the job and material.

Spindle and chuck

The Spindle Assembly is a vertical shaft mounted in the Main Column, supported by large tapered-roller or cylindrical-roller Ball Bearing pairs rated for the full workpiece weight plus cutting forces. The shaft itself is typically 80–150 mm in diameter and made from alloy steel. A hydraulically actuated Spindle Chuck — usually a three-jaw power chuck — clamps the part on centerline. When powered, the chuck exerts force that grows with the clamping area; a 300 mm chuck holding a 100 kg workpiece at 100 bar hydraulic pressure delivers roughly 150 kN. The Spindle Drive Gear meshes with the main drive, transmitting torque at the selected speed. Most machines provide 4–8 speeds: 10, 25, 50, 100, and 200 rpm are typical, covering both heavy-feed roughing and fine finishing.

Rotary table and indexing

The Rotary Table (Workbed) is a large-diameter ductile iron disc that rotates about the vertical centerline. The Spindle Assembly is fixed to it, so rotating the table rotates the entire spindle and chuck. This Rotary Table Drive, powered by a hydraulic motor or stepper motor, allows the operator to index workpieces or reposition the spindle relative to a fixed tool turret. Some machines allow 360° indexing for multi-sided parts; others offer fixed 90° indexing. Once positioned, the table locks via a Rotary Table Casting locking pin to prevent rotation during cutting.

Tool turret

The Tool Turret Assembly is a fixed or radial carousel mounted on the Crossrail Assembly, positioned above and around the spindle. Each Tool Station Block holds a cutting tool — a facing bit, boring bar, radius tool, or thread-chasing head — ready to engage. The Turret Plate rotates (usually hydraulically or by stepper motor via a Turret Indexing Gear), and a Turret Latch Solenoid-engaged latch stops it at each position. Most turrets have 4–6 stations; large machines may have 8. The Vertical Ram with Quill quill is the tool-holding member; it descends vertically onto the workpiece under controlled Infeed Hydraulic Cylinder pressure.

Ram and infeed mechanism

The Vertical Ram with Quill is a vertical quill that extends downward from the turret head toward the spinning workpiece. Its Quill Shaft is guided by a Ram Sleeve mounted on the Crossrail Assembly, and the entire ram is locked by a Spindle Lock Clamp while spinning (to prevent chat and tool breakage). Infeed is controlled by a Infeed Hydraulic Cylinder, typically connected to a foot pedal or an automatic control circuit. Feed rate is usually 1–10 mm/rev depending on tool and material; coarse feeds in roughing (3–5 mm/rev) and fine feeds in finishing (0.1–0.5 mm/rev) are typical. Many machines use a simple "rapid down, infeed automatically until depth reached, rapid retract" cycle.

Column and frame

The Main Column is the main vertical ductile iron or nodular iron casting that anchors the spindle Ball Bearing blocks and resists all cutting forces. The Column Casting is typically 4–6 m tall and weighs 8000–25000 kg for large machines, providing the mass needed to damp vibration. The Bearing Saddle is a precision-machined pocket on the column top that receives the spindle bearing block. The Hydraulic Manifold Block is integrated into or bolted to the column, distributing pressure to the chuck and ram cylinders via solenoid-actuated Directional Control Valve spools.

Drive motor and gearbox

The Main Drive Unit is a 15–50 kW three-phase motor coupled to a Speed Gearbox that provides the 4–8 discrete spindle speeds. The gearbox is typically a fixed-ratio unit operated by a manual lever (older machines) or solenoid-switched transmission (modern units). Speed selection is essential: too fast and tool life drops and the part can be damaged; too slow and feed rate becomes uneconomical. The motor output drives the spindle via Drive Belt V-belts (or gears on larger machines) and a Drive Pulley. A Hydraulic Pump is often belt-driven from the same motor to supply the Hydraulic System, so hydraulic pressure is available whenever the machine is running.

Hydraulic circuit

The Hydraulic System is simple but critical. A Hydraulic Pump (typically 5–10 cc/rev gear pump) draws from the Hydraulic Reservoir and pressurizes the circuit. A Main Relief Valve set at 150–200 bar protects the system. A Directional Control Valve — solenoid-actuated or manually controlled — directs flow to the chuck or ram. When the operator presses the foot pedal, the solenoid valve extends the infeed cylinder, lowering the tool onto the workpiece. A Pressure Sensor monitors the circuit for overload and can trigger an emergency stop if pressure exceeds a limit. Hydraulic Hose Assembly connects pump, manifold, and cylinders with high-pressure hose (3/8" or 1/2" bore, rated 210 bar minimum).

Typical facing cycle

The operator loads the workpiece into the chuck, selects the appropriate spindle speed (say 100 rpm for a 300 mm facing operation in cast iron), and engages the turret to position a facing bit. The spindle starts, the foot pedal is pressed, and the ram descends automatically, taking a 2–3 mm depth of cut with automatic infeed control. Once the tool reaches depth, the operator lifts the foot pedal and the ram retracts. The turret is indexed to the next station (perhaps a boring tool), and the cycle repeats. With a well-designed turret sequence, one part per minute is achievable for moderate sizes. The Electrical System system provides automatic solenoid switching for turret and ram, often controlled by a simple mechanical cam or a PLC on modern machines.