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Brunk

Capabilities

Rapid Prototyping

Waterjet

Waterjet

Rapid Prototyping

Low Volume

Rapid Prototyping

Low Volume

Waterjet Cutting for Precision Metal Prototype Components

Waterjet cutting is a cold-cutting process that uses a high-pressure stream of water mixed with abrasive garnet particles to cut through metal and other materials without generating heat. Because the process does not produce a heat-affected zone (HAZ), it is well suited to materials where thermal input would alter microstructure, mechanical properties, or residual stress state. This makes waterjet cutting a preferred method for prototyping components in titanium, nitinol, stainless steel, and other alloys used in medical device and high-tech manufacturing applications where the metallurgical condition of the cut edge is relevant to part performance. 

How Waterjet Cutting Works

In abrasive waterjet cutting, water is pressurized to between 40,000 and 90,000 psi and forced through a small orifice to create a high-velocity jet. Abrasive garnet is introduced into the jet stream at the cutting head, and the combined kinetic energy of the water and abrasive particles erodes the material along the programmed cut path. The kerf width produced by waterjet cutting is typically between 0.03 and 0.05 inches, depending on the nozzle configuration and material being cut. Cut accuracy on well-fixtured flat stock is generally within ±0.005 inches, which is sufficient for most prototype validation purposes though secondary finishing operations are sometimes required where tighter edge tolerances are specified. 

Cutting speed varies with material type and thickness. Waterjet is capable of cutting material thicknesses that laser processing cannot practically address, and is particularly effective on stock between 0.25 and 4 inches thick. For thinner materials, laser cutting is often faster and produces a finer edge condition, so the choice between the two methods at Brunk is made based on material, thickness, and the downstream requirements of the prototype part.

Applications at Brunk

Waterjet cutting at Brunk is used primarily for two categories of prototype work. The first is flat-pattern blanks in exotic alloys where heat input from laser cutting would be problematic. Nitinol, for example, is highly sensitive to thermal processing because its phase transformation temperatures determine its functional behavior. Cutting nitinol blanks by waterjet preserves the as-received material condition and avoids the need to re-characterize the alloy after cutting. Titanium and certain stainless steel grades used in implantable device applications are also commonly processed this way for the same reason. 

The second category is thicker-section components that would require multiple laser passes or are outside the practical thickness range of Brunk’s laser cutting equipment. For these parts, waterjet provides a single-pass cut path with no thermal input and acceptable dimensional accuracy for prototype evaluation.

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Submit your drawings or CAD files to discuss material, thickness, and tolerance requirements for waterjet cut prototypes.

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Frequently Asked Questions

Does waterjet change material properties, and how does laser cutting compare?

Laser cutting creates a heat-affected zone whose depth depends on material and parameters. For many sheet metal parts, the HAZ is small and acceptable. If you must preserve hardness, microstructure, or minimize distortion, waterjet is recommended.

How small can internal features be?

Laser can produce very small features; the minimum size depends on material and thickness but is often on the order of the beam diameter plus allowances. Waterjet minimum hole size is typically 1.2–1.5 times the jet diameter; extremely small holes may be better drilled or cut with a fine laser head.

Is taper an issue with waterjet?

Conventional waterjets produce some taper, more noticeable in thicker materials or at higher speeds. Dynamic heads and taper compensation greatly reduce taper, resulting in near-vertical edges for many parts.

What about part warping?

Laser can introduce heat that may cause slight warping in thin materials; fixturing and tuned parameters mitigate this. Waterjet is a cold process and does not cause thermal warping, making it ideal for thin or heat-sensitive parts.