Parameters of water jet cutting
Due to the cutting process the shape and position deviation, cutting angle, edge geometry, entry and exit
points as well as roughness are influenced.
Shape and position deviation
Machine capability and cutting process influence the shape and position deviation. The results are
measured based on profiles.
Shape and position tolerances according to SN EN ISO 9013 chapter 5.
Cutting angle errors
The cutting angle error u (perpendicularity or inclination) is mainly influenced by cutting speed, material
type and thickness and to a small extent also by the diameter of the cutting media and the machine
Figure 1 — Cross-sectional view of the workpiece
The cutting angle error results from the process parameter change of the cutting gap top
down. The profile is relevant for the workpiece contour (shape and position tolerance). The cutting angle
error u is separately determined (figure 1)
Contour errors are the edge error j, corner radius rE, cutting start and cutting end error t1/t2. These are
mainly influenced by cutting speed, material type and thickness, the diameter of the cutting media and to a
small extent also by the machine technology.
Figure 2 — Workpiece bottom view
Contour errors mainly occur due to the cutting material flow.
1.4.1 Edge geometry
The corner error j defines contour deviations on the bottom side of the workpiece (figure 6).
1.4.2 Cutting start and end
The cutting start and end errors t1/t2 can be generally reduced by appropriate starting and ending
strategies. Starting and end points should be positioned in areas where they aren’t distracting (figure 7).
Figure 3 — Workpiece bottom view
The roughness of the cutting surface is mainly influenced by the cutting speed, material type and
thickness, and to a small extent by the cutting media and the process management.
l3Area of greatest roughness
b)Roughness measuring line