Subtracting material from a cylinder of wood or any circular piece of wood requires the 4th axis in CNC router machining. The aim of the 4th-axis is to index continuously such as engraving cylinders or stair columns. For decorative embellishments of columns the 4th-axis performs flawlessly. The YouTube video (https://www.youtube.com/watch?v=V5gzAh1LKVU) is an excellent example of indexing by the rotary movement of the 4th-axis which is the major difference when compared to a 3-axis CNC router. It requires a strongly built gantry such as the OMNICNC 1325 model. Even the frame of the OMNI 1325 is tubular steel welded with ribs for extra stability. The ATC (automatic tool change) magazine is a key feature of the router, and the spindle is air-cooled.
OMNI 4-Axis 1325 Model
The spindle is Italian make, and the 9 kW frequency spindle has programmable speeds up to 24,000 rpm (revolutions per minute) The ATC holds 8 tool units and take the shortest path between two tools which means that quick change times are possible. The program operates continuously without the need to stop at any time for frequent tool changes.
Positioning systems are accurate due to linear motion by rack and pinion system on the X and Y-axis. The Z-axis operates on a ball screw arrangement. The brushless AC servomotors on all the axes operate on the digital platform which means low maintenance. Due to the strong gantry an optional drill bank and saw aggregates speed up production. Also optional are pop up pins for precise locating of the object. The pins do not hamper the cutting operation as they swing away.
Apart from the above quality components, the 1325 OMNI model bears the OMNI signature of high quality. The control system is PC platform based, and is in a waterproof enclosure.