Cutting metal and other materials with a high-pressure stream of water and abrasive grit generally has been the domain of specialty shops dedicated to this process or large plants with special needs—and deep pockets. A new abrasive waterjet machine from Flow International Corp. (Kent, Washington) makes this process as attainable as, let's say, wire EDM, or almost any other mainstream metalworking process.
The newly-introduced product is called Bengal 4 × 4, an abrasive waterjet machining center suited to machining and fabrication applications. This model features a 48 by 48-inch work table. This size, the developers say, makes it ideal for high-volume production of finished and near net parts, and machining prototypes and short run jobs involving a very wide range of materials.
The Bengal 4 × 4 looks a lot like a typical machining center in overall appearance. The enclosure opens and closes somewhat like a see-through roll-top desk rather than the typical cabinet-style doors found on many traditional CNC metal cutting machine tools. Otherwise, this machine follows familiar machine tool styling. Given the size of the work table, the machine takes up a surprisingly small amount of floor space.
The machine uses FlowMaster, the builder's PC-based control system, the Paser 3 abrasive waterjet, a 25-hp, 40,000 psi Cougar pump, and a cantilever-style X-Y motion system with an 8-inch motorized Z-axis. Linear accuracy of ±0.005 inch and repeatability of ±0.002 inch is attained, the company says. Workpieces up to 4 inches thick can be cut. An optional second cutting head can be added to double output for production applications. All machine components are enclosed and integral to the machine.
FlowMaster software is a Windows 95-based package. Users can create a part with the software's drawing functions, or download a DXF or CAD file. After selecting material type and thickness, users click on icons to execute waterjet commands. The software determines and controls optimum cutting parameters, including feed and speed rates, for the application. No special knowledge of abrasive waterjet machining is necessary, which is encouraging to first-time users. An optional FlowShift module allows users to scan drawings directly into the controller and convert them to a DXF file.
The Paser 3 abrasive waterjet system helps simplify operation and achieve "peak performance"—machining at the fastest speed and lowest cost. A monitor analyzes cutting conditions and signals any deviation from peak performance. Operators track conditions via the screen display. The monitor also measures tool wear and signals when tooling replacement is necessary.
The comparison to wire EDM made earlier is an apt one. Both processes are often used for cutting complex 2D parts out of flat stock, including stacks of thin materials. Although abrasive waterjet does not approach the extreme accuracies of wire EDM, waterjet leaves no heat-affected zone, needs no setups for flushing, and can cut non-conductive materials. Many shops will see abrasive waterjet as means of freeing up their wire EDMs for the jobs they do best.