STV CNC Optimum 5

With a 5 ft x 5 ft cutting envelope, the STV CNC Optimum 5 is the square table for shops that buy 5 ft wide sheet. It is the servo-driven table at the top of the STV CNC range, with an enclosed welded frame and its own control computer. The extra foot of width over the smaller square table is what lets a 5 x 10 sheet be cut once across the middle and loaded as two halves, with nothing trimmed off the width.

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.

The table takes up about 7 ft x 8 ft x 5 ft. Its water pan holds about 68 gallons. At 1,450 lb it is a table to position once and leave. Because the envelope is as deep as it is wide, a part can be nested in either direction, and remnants from larger jobs elsewhere in the shop usually fit without trimming. What it will not do is take a long part: anything over 5 ft has to be cut in two setups or sent to a longer table.

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.