Waterjet Cutting

Waterjet cutting uses a high‑pressure abrasive jet to cut almost any material thickness with no heat‑affected zone and excellent edge quality.

Overview

Waterjet cutting (abrasive waterjet) uses a high‑pressure stream of water mixed with abrasive to cut virtually any material, including metals, composites, stone, glass, and plastics. It cuts by erosion rather than heat, so there is no heat‑affected zone, microcracking, or change in material properties. Typical kerf width is about 0.03–0.05", with clean edges and minimal burr.

This process excels for flat parts from thick or difficult materials, especially where you care about base material properties, finish, or tight nesting from plate. It handles very thick stock (over 4") and stacked sheets, and it does not care about reflectivity or thermal conductivity. Tradeoffs: cutting speed is slower than thermal processes, especially in thick plate; cost per part is higher for simple, high‑volume shapes; and small holes or ultra‑tight tolerances may still need secondary machining. For prototypes, low to medium volumes, and complex 2D profiles in demanding materials, waterjet is a strong choice.

Common Materials

  • Aluminum 6061
  • Stainless steel 304
  • Mild steel (A36)
  • Titanium Grade 5
  • Carbon fiber composite
  • G10/FR4

Tolerances

±0.003" to ±0.010" depending on thickness and cut quality setting

Applications

  • Thick plate brackets and base plates
  • Titanium and stainless profiles from plate
  • Carbon fiber and composite panels
  • Stone and ceramic inlay shapes
  • Rubber and soft-material gaskets
  • Architectural and decorative metal panels

When to Choose Waterjet Cutting

Choose waterjet cutting for flat parts in thick, hard, or sensitive materials where you must avoid a heat‑affected zone and preserve material properties. It fits prototypes and low to medium volumes with complex 2D geometry, tight nesting, or mixed materials that thermal cutting struggles with. It also works well when you want near-net shapes from plate before final machining.

vs Laser Cutting (CO2)

Pick waterjet cutting when you need to process reflective materials (copper, brass, aluminum) in thicker gauges or when any heat‑affected zone is unacceptable. Waterjet also handles non‑metals and composites that CO2 lasers may cut poorly or burn, at the expense of slower speed and higher cost on thin sheet.

vs Laser Cutting (Fiber)

Choose waterjet over fiber laser when cutting very thick plate, composites, glass, stone, or materials prone to laser reflection or thermal damage. Waterjet gives no HAZ and better edge integrity on thick or heat‑sensitive parts, though fiber laser is usually faster and cheaper on thin metal sheet.

vs Plasma Cutting

Use waterjet instead of plasma when you need tighter tolerances, cleaner edges, and no HAZ, especially in stainless and aluminum plate. Plasma is faster and cheaper for rough, heavy‑fab parts, but waterjet wins for precision profiles, fine details, and parts that go straight to assembly or light finish machining.

vs Shearing

Select waterjet cutting when your part requires internal profiles, contours, small features, or anything beyond straight-line cuts. Shearing is economical for simple rectangles at high volume, while waterjet supports complex nesting, tight corner radii, and varied geometries from the same sheet or plate.

Design Considerations

  • Assume a typical kerf width of 0.030–0.045" and avoid internal features narrower than 1.5× kerf for consistent quality
  • Keep smallest hole diameters at least equal to material thickness; for very small or precise holes, plan for secondary drilling or machining
  • Call out only truly critical dimensions and edges; allow standard waterjet tolerance elsewhere to keep cost down
  • Avoid extremely sharp internal corners; use small fillets (≥0.030–0.050") to match jet diameter and reduce dwell marks
  • Flag thin webs, small tabs, and delicate features so the shop can adjust cut order and support to prevent part movement
  • Provide clean 2D CAD (DXF/DWG) with a clear layer convention for cut vs. etch/mark to speed quoting and reduce errors