STV CNC Optimum 10

The STV CNC Optimum 10 cuts a 10 ft x 5 ft envelope, enough for a full 5 x 10 sheet or for a 4 x 8 sheet with room left beside it for a remnant. It is the servo-driven table at the top of the STV CNC range, with an enclosed welded frame and its own control computer. Of the standard sizes this is the one bought for throughput: more parts per load and fewer sheet changes.

Under the covers this is a different machine from the stepper tables. The frame is an enclosed welded tubular structure and the gantry is machined metal, with 6.75 in of clearance. Hardened heavy-duty linear guides and helical rack and pinion carry gantry and table, behind full-length shields. Three servo motors with 5:1 planetary gear reduction provide the motion, and STV CNC states an accuracy of about 0.001 in per 12 in and a step resolution of plus or minus 0.00008 in. The Z axis has 5.5 in of travel on a precision ground ball lead screw. Plate capacity is 2 in of steel over a single welded pan 4 in deep, and rollerballs for sliding material on are fitted along the table edge.

That capacity has a cost in water and floor. The pan holds about 136 gallons, which is a real job to drain and clean. The table occupies about 12 ft x 8 ft x 5 ft. It weighs 2,000 lb. A 5 x 10 sheet of plate cannot be manhandled, so overhead lifting or a forklift with a sheet lifter belongs in the plan along with the table.

Optimum CNC, the maker's own control, comes installed on a palm-sized Linux mini PC that is included and linked by Ethernet through a port on the front of the table. A monitor, wireless mouse and keyboard have to be added. The software accepts .dxf, .gcode, .nc and .tap files and includes 80+ editable shape templates, so simple parts can be drawn at the machine. Homing uses a kit of 4 proximity sensors, one of them for gantry alignment. Torch height control, an E-stop, a magnetic breakaway with cable catch and collision and material detection sensors are standard; the plasma cutter is a separate purchase.