Concentrating water into a high-pressure stream and shooting it from a waterjet at 60,000 psi can work wonders. At this force level, water can cut and shape a wide variety of materials like cloth, foam, glass, plastic, and rubber as quickly as 100 ft. per minute. Water can even cut through harder materials like wood, granite, stone, aluminum, and steel, and is sometimes mixed with abrasive chemicals to get the job done. Another application of waterjet cutters is to carve designs into artificial turf and carpets. CNC Machines International (CNCMI), Raleigh, N.C., makes a VLF series high performance waterjet cutter to do just that.
To ensure cutter precision and speed, CNCMI uses DMC-2153 5-axis Ethernet motion controllers from Galil Motion Control, Rocklin, Calif. Waterjet cutters like the VLF system must keep the water stream tangent to the material for precise cuts. The machine even allows a bevel cut to 45°. Bevel cutting is useful in carpet cutting when fitting a logo cutout into the base, as straight edges would allow the logo to fall straight through the base material.
The DMC-2153 XY axes control linear and circular patterns (rack and pinion), the Z-axis controls waterjet height, and the Y-axis controls two motors for gantry function. The fifth or rotary axis controls stream motion by keeping it in tangent to XY motion. In addition to tangential motion, the DMC-2153 handles constant velocity, slaving, and linear and circular interpolation.
As is common with computer numerical control (CNC) machines, the VLF reads G-codes to enact motion. To accommodate this, CNCMI specified the Mach3 graphical user interface from ArtSoft to translate the G-codes into motion commands for the Galil controller. The software performs all calculations for precise control of up to six simultaneous axes using a trajectory planner that feeds the Galil controller a series of linear interpolation commands that are 4 msec apart. The Mach3 software also comes with ready-made drivers for Galil controllers, resulting in reduced set-up time.
The CNCMI VLF works at speeds of up to 1,200 in./min over carpet areas as large as 16 x 96 ft. with positioning accuracy to 0.010 in. An added bonus: Because waterjet cutting doesn’t generate heat, it cuts without damaging or distorting surrounding material, as opposed to traditional methods like die pressing. For more information, visit Galil Motion Control.