One of the critical factors for efficient water-jet cutting is the height of the jet nozzle from the workpiece. That's where Water Jet Sweden focused its attention with its new height-sensor setting system. WJS supplies profile cutting equipment in various sizes for different applications.

If the gap between the cutting nozzle and the material is too large or too small, cutting efficiency will be reduced, and as a result operating speed will be lessened, too. Another result is that the quality of the profiled edge deteriorates, requiring remedial or even product rejection.

The critical distance between the nozzle and the material should be just a few millimeters, but WJS says the new sensor is able to maintain this distance within a tolerance of +/- 0.1 mm. This ensures a position of 2.5-3.0 mm across the whole working area, which can be extended up to 4×12 meters.

For users, this brings benefits in greater cutting efficiency and cleaner edges at no extra cost.

When this operation is carried out through the CNC system, several functions are involved. The operator enters any desired figure for the distance that is to be held between the material and the cutting head. The measurements can be set on-line or, at specific time intervals e.g., every 10 seconds. The head will follow these instructions reliably throughout the cutting operation.

In addition, the new height sensor system can be fully-integrated with a new WJS anti-collision monitoring device. At the conclusion of each operating cycle the cutting system will automatically raise the head clear of the surface as a safety measure to help protect the expensive jet nozzle from accidental damage during workpiece retrieval.

The new system brings advantages to users who process profiles from large sheets of material. Such materials may have significant bows and buckles across their width or length, which significantly complicate the profiling process. Processors of smaller profiles also benefit from the system because it cuts down on the initial set-up time, improves productivity and reduces the need for skilled operator oversight of the cutting process.

New installation

A recent application of Water Jet Sweden's cutting technology is at ThyssenKrupp Materials International's Logistics Center in Dortmund, Germany, a stainless steel and nonferrous materials processing center. The operators there invested in new WJS cutting technology to increase throughput and lower operating costs.

The Dortmund plant processes up to 1,900 metric tons/day of material. It's described as a “first-stage processing center” for manufacturers and fabricators of stainless steel and nonferrous metals. It operates three shifts/day with up to 300 work cells arrayed over more than 50,000 m². Available processes for finished or semi-finished parts include sawing, flame cutting, laser cutting, grinding, water-jet cutting, tubing laser, and foiling. All shapes and sizes of tubes, steel bars and sheets of stainless steel and nonferrous materials are processed.

Marcus Raback, Logistics Center Dortmund works director, explains that the plant “executes a significant portion of the total added value manufacturing in the whole of Germany in this sector.”

Traditionally, parts cutting has been done by sawing, or laser or plasma cutting. However, the rapid adoption of water-jet cutting throughout manufacturing over the past 10 years (since the first machines were widely installed), prompted ThyssenKrupp Materials to look at the comparatively new technology for heavy-duty cutting.

After reviewing bids from several water-jet cutting machine builders, ThyssenKrupp chose Water Jet Sweden based on its technical ‘know-how' and engineering skills, and for its demonstration of the ways that water-jet cutting could improve productivity and lower costs at Dortmund.