STV CNC Optimum 4

The STV CNC Optimum 4 is a 4 ft x 4 ft CNC plasma table, the servo-driven table at the top of the STV CNC range, with an enclosed welded frame and its own control computer. It is the smallest full-size table in its series: the square cutting envelope takes half of a 4 x 8 sheet at a time, which suits brackets, gussets, signs and one-off repair parts more than long nested runs.

The mechanical parts are a step up from the stepper tables in every row of the maker's comparison. Three servo motors drive through 5:1 planetary gear reduction onto helical rack and pinion, the linear guides are hardened heavy-duty units, and the gantry is machined metal instead of extruded aluminum. Stated motion accuracy is about 0.001 in per 12 in, with a step resolution of plus or minus 0.00008 in. Gantry clearance is 6.75 in and Z travel 5.5 in. The enclosed tubular frame is welded, the single welded water pan is 4 in deep, and plate capacity is 2 in of steel. Motors sit in housings and full-length shields cover the guides against splash.

Floor space is the argument for this size. STV CNC gives the occupied area as about 6 ft x 7 ft x 5 ft, so it fits a bay where a full-sheet table would block the aisle. The water table holds about 43 gallons, a small enough volume to drain and clean in one go. The table weighs 1,350 lb. Sheets have to be sheared or cut down to 4 ft before loading, so the nearest steel supplier's cut-to-size service matters more here than on a 4 x 8 machine.

The control is Optimum CNC, running on a Linux mini PC that comes with the table and talks to it over Ethernet; the buyer adds a monitor, mouse and keyboard. Because the PC is dedicated to the table, an operating system update on an office laptop cannot stop production. The software reads .dxf and G-code files and has 80+ editable shape templates. Four proximity sensors handle homing and gantry alignment. Torch height control, a magnetic breakaway with a cable catch and a collision switch are standard, and the plasma cutter is sold separately.