Waterjet cutting creates a narrow slot whose width (the kerf) is not perfectly constant from the entry surface to the exit surface. The divergence of the high‑pressure jet causes the kerf to widen with depth, a phenomenon known as kerf taper. Understanding this effect is essential for tight tolerance parts and for nesting efficiency.
The amount of taper depends primarily on three variables: the material thickness, the cutting speed, and the nozzle diameter. A faster traverse gives the jet less dwell time on any point, allowing the jet to spread slightly before the material is fully penetrated, while a larger nozzle naturally produces a wider initial kerf.
A simple empirical relationship can be expressed as a taper angle theta, where tantheta = (K_{bottom} – K_{top}) / t. Here K_{top} is the kerf at the entry surface, K_{bottom} the kerf at the exit surface, and t the material thickness. This relationship lets engineers estimate the extra material that will be removed and compensate in the CAD model.
K_{bottom} = exit‑surface kerf (mm)
t = material thickness (mm)
What causes waterjet kerf taper?
How does cutting speed affect kerf taper?
What is the impact of nozzle diameter on kerf taper?
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What is the relationship between cutting speed and kerf width?
Results are for informational purposes only and do not constitute professional advice.