Terrain Following Capabilities for High-Angle Waterjet Cutting

Oct. 6, 2010
OMAX combines two cutting technologies for more effective, cost-saving material processing

OMAX engineers combined their Terrain Follower capability and A-Jet tilting waterjet head for a new cutting tool that detects changes in workpiece material surface heights and automatically adjusts the nozzle to maintain proper standoff throughout the cutting process.

Engineers at OMAX Corp. have accomplished what they claim is the first successful adaptation of terrain-following technology to a high-angle tilting waterjet head. The systems was demonstrated for the first time at IMTS 2010, with a waterjet cutting system that the developer describes as “definitively more compact and streamlined than any other previous industry attempts, yet robust to endure the rigors of the waterjet cutting process.”

“Terrain following” is a term borrowed from aircraft navigation, referring to a guidance system that provides a pilot or autopilot with climb or dive signals so that the aircraft will maintain as closely as possible a selected height above a ground contour in a vertical plane.

For their waterjet cutting application, OMAX engineers combined two of their established products, the Terrain Follower functionality and the A-Jet tilting waterjet head. The combination allows the A-Jet to detect changes in workpiece material surface heights and automatically adjust its nozzle to maintain proper standoff throughout the cutting process. These functions are accomplished with no additional machine programming necessary, OMAX emphasizes.

Machine shops and fabricators have adopted the A-Jet for cutting beveled edges, to prepare parts for welding and cutting parts with complex geometries. Terrain-following capabilities are particularly important in these situations because changes in the work material’s height due to warped surfaces and stress-relieving can alter intended cut lines.

With terrain following capability, operators can cut and bevel warped and uneven workpiece surfaces with no concern for dragging the A-Jet’s mixing tube on high spots or uneven surfaces. This means they can begin cutting without having first to locate material high points, and as a consequence reduce production cost, downtime, and workpiece damage. “The challenge in combining the two technologies was the limited space involved with the A-Jet’s compact design. Our engineers had to drastically shrink the terrain sensing circuitry and devise a way to accommodate for the low clearance at the material when the mixing tube is at maximum tilt,” explained OMAX engineering designer Rick Marks.

“At large tilt angles, changes in material height need to be detected a lot closer to the mixing tube than with conventional near vertical waterjet cutting. With a conventional large-diameter sensing foot, the system would sense high spots in the material before the mixing tube even encountered them, causing the machine’s Z-axis to rise up too far above the material at inappropriate times,” said Marks. “To overcome the problem, we developed a special small diameter, low profile detection ring. This new ring design, or sensor foot, detects material height changes as close to the mixing tube as possible, but still allows room for the tilting motion of the A-Jet head.”

The A-Jet nozzle cuts accurate beveled edges at angles determined by the machine operator or by the part program, and is capable of a positioning accuracy of ±0.09 degrees (±6 arc minutes), making the accessory the most accurate articulated cutting jet of its kind in the industry. With a compact design to accommodate tight cutting situations, the A-Jet integrates two motion axes to allow tilting of the nozzle over a range of 0° up to 60° from the vertical position.

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