Tolerances

Parts cut on an abrasive waterjet are generally made with a tolerance of 0.005 inches (5/1000 of an inch). This means that you should not depend upon features to be more accurately placed than 0.005 inches. Holes may be up to 0.01 inches smaller or larger than your specification.

Kerf

Kerf is the cutting width of the tool used to make your parts. We typically cut parts with an abrasive waterjet with a nozzle width of 0.040 inches. Features smaller than this size may be lost. Also, inside corners have to be able to accommodate the width of the nozzle, as seen in the picture below.

Taper

Parts will have a slight taper along the cut edge of the part, typically between 0.007 inches and 0.0005 inches.

Parts cut using ordinary waterjet cutting will have a slight taper along the cut edge of the part, typically between 0.007 inches and 0.0005 inches. Our low-taper waterjet cutting service eliminates this taper for an extra charge.

You can see the effect in the photo below. Both parts are made from aluminum 6061, but the one on the right is made using our low-taper waterjet cutting process.

Surface Finish

Please also see our FAQ on surface finishing options.

Our abrasive waterjet cut parts have a slightly rough surface finish on the areas where they are cut. You can see this effect on this part, cut from 0.25 inch thick Aluminum 6061 alloy:

Close up:

All parts are cut at "Quality 3", which is good enough for most purposes.

Note that clear plastics made on the waterjet will have a frosted appearance along cut edges, which can be removed with appropriate chemical cleaning and polishing, if desired. Note that laser cut parts have much smoother edges. Here is what 0.125 inch thick clear polycarbonate plastic looks like after being cut with a waterjet:

Waterjet entry/exit points

Tabs

Your part may have a small tab where the part was held to the stock material. You can remove this tab with a file or a similar tool.

Tolerances

Parts cut on a laser are generally made with a tolerance of 0.005 inches (5/1000 of an inch). This means that you should not depend upon features to be more accurately placed than 0.005 inches. Holes may be up to 0.01 inches smaller or larger than your specification.

Kerf

Kerf is the cutting width of the tool used to make your parts. We typically cut parts with a laser beam width of 0.01 inches. Features smaller than this size may be lost. Also, inside corners have to be able to accommodate the width of the laser beam.

Melting of plastic materials of charring of wood may also affect accuracy.

Taper

Parts will have a slight taper along the cut edge of the part, typically approximately 0.01 inches.

Surface Finish

Laser cutting plastics produces a fairly smooth surface, particularly when compared with waterjet cutting. Here is what 0.118 inch thick clear acrylic plastic looks like after being cut with a laser:

A closeup of the above image:

Tabs

Your part may have a small tab where the part was held to the stock material. You can remove this tab with a file or a similar tool.

Currently, Big Blue Saw makes all parts using either abrasive waterjet or laser cutting technology.

For more about waterjets, visit The Waterjet Web Reference or see our FAQ on waterjets.