How accurate are Waterjet machines?

Part accuracy depends on many factors;

Firstly, it will depend on the accuracy of the Waterjet machines motion control. When the linear encoder feedback system is included on a Techni machine, we can achieve positional accuracy of 0.02mm (0.001”) per axis.

  • However, there are a number of other factors which will determine the accuracy of the part being produced;
  • The size and consistency of the kerf. Kerf is the amount of material removed during the cutting process. Because waterjet is an erosion process, the amount of time the stream sits in 1 position will affect the amount of material being removed, or the width of the kerf. Therefore, Techni waterjets software automatically adjusts the kerf width to suit the speed, material, and other relevant factors. This minimises any reduction in part accuracy due to the varying nature of a waterjet kerf width.
  • The stand-off distance between the cutting head and the workpiece. As the nozzle gets closer to the workpiece, it increases the kerf and as it gets further away it reduces the kerf. Therefore, the more consistent the stand-off height can be maintained, the more accurate the part will be. Therefore Techni has developed a number of options, including Laser Mapping and Touch Probing to help produce accurate parts.

Generally speaking, Waterjet machines will consistently produce parts which within +/- 0.25mm (+/-0.010”), and can produce parts down to +/-0.05mm (+/-0.002”) if an accurate standoff and consistent kerf are maintained.