As an automatic lathe, the multi-spindle screw machine allows multiple tools to cut multiple pieces of material simultaneously. Usually configured in 4, 5, 6 or 8 spindle models, each spindle is attacked by a cross-slide and end-slide tool effectively making each spindle a 2-axis lathe. As CNC is applied to some or all slides on these historically cam actuated machines, their ability to machine complex and high accuracy parts has grown significantly. Numerous attachments are available for use on one or more stations for specific metalworking operations.
The multiple spindles are carried in a precision machined drum that rotates in a horizontal orientation. In production, the operations needed to be performed on a part are divided among the number of spindles. Because each spindle station is being machined simultaneously, when the drum indexes from one station to the next a complete part is produced.
In other words on a six-spindle multi, six parts are completed with one full rotation of the drum. While the cycle time on a single spindle machine is additive--it’s the sum of the operations performed—because the multi-spindle is cutting six parts simultaneously its cycle time is simply whichever is the longest single operation performed.
Multi-spindles are either automatic bar or chucker depending on the raw stock being used. Bar machines uses a drum feeder that aligns the machine’s spindle number. On a chucker the first station is loaded externally using a feeder system and increasingly, a robot or gantry loader. Bar machines usually employ collets to hold the raw stock while chuckers use either collets or external chuck to secure the workpiece.
Multi-Spindle Trends:
Individually programmable spindle motors
Linear axis motors on tool slides
Internal gantry load/unload and palletization
In-process gaging and sensing
Quick change tooling
Closed loop feedback for tool compensations
Compound slides for single point turning
Robotic loaders