Composite materials, particularly those that are laminated, posed a challenge for a small waterjet cutting job shop on the West coast. After testing several waterjet systems, the job shop discovered that the machines were unable to pierce the materials without delaminating them. The shop owner was determined to find a solution, so he contacted waterjet manufacturer Wardjet Inc. (www.wardjet.com).
Wardjet recommended its Pneumatic Drill mounted next to the abrasive waterjet cutting head on a Wardjet Z-613 waterjet cutting system. This pneumatic drill lets the job shop automatically drill holes through laminated materials at specific offsets from the waterjet cutting head without damaging the material. Once a hole is drilled, the waterjet then automatically starts cutting from inside the pre-drilled hole diameter. As a result, the shop doubled its production capabilities without having to purchase an additional waterjet system, saving over $150,000.
The job shop selected a pneumatic drill model that runs at 1,850 rpm and on 25-cfm at 90 psi compressed air. A CAD/CAM program, IGEMS, automates the entire drilling process.
Also on its Wardjet system, the job shop opted for a second set of bearings added to the machine's cross beam. This gives them the freedom to add an independent second cutting head, along with a second pneumatic drill, at any time in the future.
The system's circuit board within Wardjet's Z-Carriage makes this possible. Machine owners simply plug in new items using 8 unused wires supplied with every Z-Carriage. If the job shop gets a second Z-Carriage, it comes shipped with all the options and ready to be installed on the waterjet machine's second set of bearings.
The extra bearings do not get in the way when running the Z-613 because the machine provides an extra 12 in. of space in its Y axis. According to Wardjet, on many other waterjet systems, mounting a second set of bearings in advance would limit the machine's travel until the second cutting head was installed. Then both heads would be used to reach the full Y-axis travel.
Another feature on the job shop's waterjet machine is a height sensor that allows operators to maintain a constant nozzle height above workpiece materials, regardless of any warping. There is no risk of nozzle breakage, and keeping the head close to material surfaces at all times ensures the best cuts possible.
Also on the machine is the Variable Speed Mini-hopper, a system that automates changing abrasive waterjet flow rates through software. When low-pressure piercing, for example, the Mini-hopper automatically reduces abrasive flow rate, then increases the quantity when the machine starts the remainder of the cut at regular operating pressure.