One of the great things about a waterjet is how economically it makes its cuts. Unlike regular saws, it removes and pulverizes far less material, known as “kerf,” from whatever it is you are cutting.
For example: if you cut a board with a saw, part of the board (the kerf) is turned into sawdust. That sawdust represents the amount of material lost – usually about the width of a saw blade – which has been removed during cutting.
With a waterjet, the amount of material removed is much less than with a saw blade. Waterjet kerf will be about 0.020” to 0.060” (0.5 mm to 1.5 mm), depending on the nozzle and the horsepower of the pump.
To measure the kerf on your waterjet, make a part with a known dimension, such as a one-inch square, and then carefully measure the actual width. If your one-inch square is actually 0.96 inches, then your kerf is 0.04 inches. Once you’ve adjusted for this kerf, you should be able to create a one-inch square that is exactly 1.00 inches.
If, however, you have a project that requires precision down to tenths or hundreths of an inch, then you’ll need to take into account the following factors:
Metals expand and contract with temperature. Even plastic will show some change in size depending on the temperature. Remember that your tank will usually be warmer than the outside air as you cut, so let your material sit in the water until it reaches a constant temperature.
Invest in a set of high precision calipers and treat them gently. When you measure the kerf, take several measurements at different locations on the part and average them since kerf varies with the nozzle speed.
Cut a facsimile of the actual part you will make using the specific material to be used in the final product and measure the kerf on it. This will let you adjust for variations in kerf between different features of the part.
TechMoon makes state-of-the-art, affordably-priced precision waterjets that are among the best you’ll find anywhere. For waterjets that won’t pulverize your budget, contact TechMoon today!