Quality Waterjet Newsletter

Quality Waterjet Newsletter – 8/2/2005

Abrasive Waterjet (AWJ) Cutting of Aerospace Materials

This short article will highlight some results of abrasive waterjet cutting of aerospace materials from a research study by Conner et al. *

The subject materials in their study include: 1.6 mm thick Inconel 718 and Titanium alloy (Ti6Al4V); 4 mm thick Aluminum 7075-T6; and 4 to 5 mm thick Graphite/Epoxy composite (3501-6 resin and 65% IM-6 fibers). These materials are examples of aerospace materials used on aircrafts such as B-2 “Stealth” Bombers. These materials are difficult to machine with traditional machining methods because they cause high temperature rises, rapid tool wear, or fracturing and delamination (for composites). Abrasive waterjet cutting has some great advantages in machining these materials. The experimental study by Conner et al. was aimed to establish empirical relationships between process parameters and cutting performance. One of the applications is to predict kerf taper for nozzle tilting compensation.

Among their findings, the typical cutting speeds of these materials are as follows:

In terms of surface roughness and kerf taper, the aluminum, titanium, and Inconel 718 alloys follow typical trends for metals. That is, increasing cutting speed will produce a rougher kerf surface and a smaller bottom kerf width. Increasing abrasive size will likely increase the surface roughness, but will have less effect on bottom kerf width. For fiber reinforced plastic(FRP) composites, fabric type composite was compared with the tape type. Surface roughness in fabric material is greater than that of tape material. Empirical equations for kerf width and surface finish of FRP composites cut with AWJs were also included in their paper.

* Conner, I., Hashish, M., and Ramulu, M., “Abrasive waterjet machining of aerospace structural sheet and thin plate materials,” Proceedings of the 2003 WJTA American Waterjet Conference, Houston, Texas, August 17-19, 2003.

Beyong High Pressure

· Call for participation: WJTA American Waterjet Conference will be held on August 21-23, 2005 at the Marriott Westchase Hotel in Houston, TX, focusing on advances in HP waterjet technology, new techniques & applications, systems/supplies/ equipment. For details, visit www.wjta.org or call (314)241-1445.