Cutting Stacked, Perforated Aluminum Sheets

We stacked 5 sheets of thin aluminum sheets that were perforated with tens of thousands of small holes.  We wanted to see the effect of raising the nozzle to be 1/8”, ¼” and ½” above the surface of the material.  We expected the small perforated holes to have more of an effect on the integrity of the lower sheets, but as you can see, the damage was minimal.  We cut the sheets at 60,000 psi with a 10/30 orifice / nozzle combination at 100 ipm.  We also stacked 10 sheets thick and cut at 50 ipm, but we did see serious degradation of the quality of the cut through to the bottom.  Higher speeds of course are achievable, but this application does not allow higher than 100 ipm for various reasons.

Rich