Waterjet Cutting Applications

Understanding Waterjet Cutting Technology

Waterjet cutting has emerged as one of the most versatile and precise manufacturing processes available to modern engineering firms. This technology utilises an extremely high-pressure stream of water, often mixed with abrasive particles, to cut through virtually any material with exceptional accuracy. For manufacturers across Atlantic Canada, waterjet cutting offers distinct advantages that make it an increasingly popular choice for both prototyping and production runs.

The fundamental principle behind waterjet cutting is remarkably straightforward: water is pressurised to levels between 30,000 and 90,000 pounds per square inch (PSI) and forced through a small orifice, typically ranging from 0.076 mm to 0.635 mm in diameter. This creates a coherent stream travelling at speeds up to 900 metres per second—approximately three times the speed of sound. When abrasive particles such as garnet are introduced into this stream, the cutting capability expands to include metals, stone, composites, and virtually any other material.

What distinguishes waterjet cutting from other thermal cutting methods is its cold-cutting nature. Unlike laser or plasma cutting, waterjet technology produces no heat-affected zone (HAZ), meaning the material's molecular structure remains unchanged at the cut edge. This characteristic is particularly valuable for heat-sensitive materials and applications requiring precise metallurgical properties throughout the finished component.

Pure Water vs. Abrasive Waterjet Cutting

Understanding the distinction between pure water and abrasive waterjet cutting is essential for selecting the appropriate method for your manufacturing requirements. Each approach offers specific advantages depending on the material type, thickness, and precision requirements of your project.

Pure Water Cutting Applications

Pure waterjet cutting, which uses only the high-pressure water stream without abrasive additives, excels at processing softer materials. This method is ideally suited for:

• Rubber and foam products up to 25 mm thick

• Gasket materials and sealing compounds

• Food products requiring sanitary cutting processes

• Paper, cardboard, and packaging materials

• Textiles and fabric for industrial applications

• Thin plastics and disposable medical products

Pure water cutting operates at lower pressures, typically around 40,000 PSI, and achieves cutting speeds significantly faster than abrasive methods when processing suitable materials. The orifice diameter ranges from 0.076 mm to 0.25 mm, creating an extremely fine kerf width that minimises material waste.

Abrasive Waterjet Cutting Applications

When cutting harder materials, abrasive waterjet technology becomes necessary. Garnet particles, typically 80-mesh size, are introduced into the water stream through a mixing chamber, creating a powerful cutting tool capable of processing:

• Steel and stainless steel up to 300 mm thick

• Aluminium and aluminium alloys

• Titanium and aerospace-grade materials

• Granite, marble, and natural stone

• Glass and ceramic materials

• Carbon fibre and advanced composites

• Hardened tool steels and armour plate

The abrasive waterjet process typically operates at pressures between 55,000 and 90,000 PSI, with the mixing tube (focusing tube) diameter ranging from 0.5 mm to 1.2 mm. Cutting speeds vary based on material type and thickness, but modern systems can achieve tolerances of ±0.1 mm on most materials.

Industrial Applications Across Maritime Industries

The diverse industrial landscape of Nova Scotia and the broader Atlantic Canadian region presents numerous opportunities for waterjet cutting applications. From the shipbuilding yards of Halifax to the manufacturing centres throughout the Maritimes, this technology addresses specific challenges faced by regional industries.

Marine and Shipbuilding Applications

Atlantic Canada's maritime heritage creates substantial demand for precision-cut components in shipbuilding and marine repair. Waterjet cutting proves invaluable for producing hull plates, deck fittings, and structural components from marine-grade aluminium and steel. The absence of heat distortion is particularly critical when working with thin hull materials where warping could compromise vessel integrity.

Common marine applications include cutting stainless steel propeller components, aluminium superstructure panels, and composite materials used in modern vessel construction. The ability to cut intricate shapes with tight tolerances makes waterjet technology ideal for producing custom brackets, mounting plates, and specialised hardware for the fishing and offshore industries that drive much of our regional economy.

Aerospace and Defence Manufacturing

With Nova Scotia's growing aerospace sector, waterjet cutting plays an essential role in producing components from advanced materials. Titanium brackets, aluminium structural members, and carbon fibre composite panels all benefit from the cold-cutting process that preserves material properties critical to aerospace applications.

Defence contractors in the region utilise waterjet cutting for armour plate processing, where maintaining the material's ballistic properties is paramount. The technology can cut through AR500 armour steel while preserving the heat treatment that provides protective capabilities.

Mining and Resource Sector Components

Nova Scotia's mining industry requires robust components capable of withstanding severe operating conditions. Waterjet cutting produces wear plates, conveyor components, and structural elements from abrasion-resistant materials. The process handles Hardox and similar wear-resistant steels without compromising the surface hardness that extends component service life in demanding environments.

Technical Advantages and Material Considerations

The engineering advantages of waterjet cutting extend beyond the basic capability to process diverse materials. Understanding these technical benefits helps engineers and technical managers make informed decisions about manufacturing processes for their specific applications.

Elimination of Heat-Affected Zones

Perhaps the most significant advantage of waterjet cutting is the complete absence of thermal effects on the workpiece. When laser or plasma cutting processes metals, they create a heat-affected zone where the material's properties change due to rapid heating and cooling cycles. This can result in:

• Hardening or softening of the cut edge

• Micro-cracking in sensitive materials

• Residual stress that causes warping or distortion

• Changes to corrosion resistance in stainless steels

• Degradation of heat treatment in hardened materials

Waterjet cutting eliminates these concerns entirely, producing cut edges that maintain the same properties as the parent material. This characteristic proves essential when cutting pre-hardened tool steels, precipitation-hardened aluminium alloys, and other materials where heat exposure would compromise performance.

Edge Quality and Surface Finish

Modern waterjet systems produce edge quality classifications ranging from Q1 (separation cut) to Q5 (high-precision finish). The Q5 finish typically achieves surface roughness values of Ra 1.6 to Ra 3.2 micrometres, often eliminating the need for secondary finishing operations. By adjusting cutting speed and abrasive flow rate, operators can optimise the balance between edge quality and production efficiency.

For applications requiring exceptional edge quality, taper compensation technology automatically adjusts the cutting head angle to minimise the natural taper that occurs during waterjet cutting. This produces edges with perpendicularity tolerances of ±0.05 mm on materials up to 50 mm thick.

Material Thickness Range

Waterjet cutting accommodates an extraordinary range of material thicknesses within a single setup. The same machine can process 0.5 mm aluminium sheet and 200 mm thick steel plate, providing flexibility unmatched by other cutting technologies. This capability proves particularly valuable for job shops and contract manufacturers serving diverse customer requirements.

Design Considerations for Waterjet-Cut Components

Optimising designs for waterjet cutting requires understanding the process characteristics and limitations. Engineers can significantly improve both part quality and manufacturing efficiency by incorporating waterjet-specific design principles from the project's outset.

Kerf Width and Tolerance Planning

The kerf width in abrasive waterjet cutting typically ranges from 0.8 mm to 1.5 mm, depending on the mixing tube diameter and material thickness. Designers should account for this material removal when dimensioning parts, particularly for features requiring precise fits. Modern CAM software automatically applies kerf compensation, but understanding the underlying mechanics helps engineers communicate effectively with manufacturing partners.

Achievable tolerances depend on material thickness, cutting speed, and edge quality requirements. General guidelines suggest:

• Materials under 25 mm: ±0.1 mm achievable

• Materials 25-75 mm: ±0.15 mm typical

• Materials 75-150 mm: ±0.25 mm expected

• Materials over 150 mm: ±0.5 mm or greater

Corner Geometry and Feature Size

Internal corners in waterjet-cut parts will have a radius equal to half the kerf width—typically 0.4 mm to 0.75 mm minimum. Designs requiring sharp internal corners may need secondary machining operations. However, this limitation rarely presents problems for structural components or assemblies where small corner radii are acceptable or even beneficial for stress distribution.

Minimum feature sizes depend on material thickness and type. As a general rule, features should be at least 1.5 times the material thickness, with an absolute minimum of approximately 1.5 mm for thin materials. Narrow slots and small holes may require reduced cutting speeds to maintain precision and prevent breakthrough issues.

Nesting and Material Utilisation

Efficient nesting of parts on raw material sheets significantly impacts project economics. Waterjet cutting's omnidirectional capability—the ability to cut in any direction without repositioning—enables optimal nesting strategies that minimise material waste. Modern nesting software can achieve material utilisation rates exceeding 85% on complex multi-part layouts.

Cost Factors and Economic Considerations

Understanding the economic aspects of waterjet cutting helps project managers and procurement specialists evaluate this technology against alternative processes. Several factors influence the total cost of waterjet-cut components.

Operating Costs

Abrasive consumption represents the largest variable cost in waterjet cutting, typically accounting for 60-70% of total operating expenses. Garnet abrasive costs approximately $0.30-$0.50 CAD per kilogram, with consumption rates ranging from 0.3 to 0.6 kg per minute depending on cutting parameters. High-pressure pumps require periodic maintenance, with seal rebuilds needed every 500-1,000 operating hours.

Electrical consumption for a typical 50-horsepower waterjet pump ranges from 37-45 kW during cutting operations. Water consumption, while significant in absolute terms (3-15 litres per minute), represents a relatively minor cost factor in most Canadian jurisdictions.

Comparison with Alternative Technologies

When evaluating waterjet cutting against laser, plasma, or mechanical cutting, consider these comparative factors:

• Setup costs: Waterjet typically offers lower setup charges than CNC machining, making it economical for small batch quantities

• Material range: Single waterjet setup handles materials that would require multiple different processes otherwise

• Secondary operations: Superior edge quality often eliminates deburring, grinding, or heat treatment steps required after thermal cutting

• Tooling requirements: No material-specific tooling needed, reducing inventory and changeover costs

Partner with Atlantic Canada's Engineering Experts

Selecting the optimal manufacturing process for your components requires careful analysis of technical requirements, production volumes, and economic factors. Waterjet cutting offers compelling advantages for many applications, but the best choice depends on your specific project parameters.

Sangster Engineering Ltd. brings decades of engineering expertise to manufacturers throughout Nova Scotia and the Maritime provinces. Our team understands the unique challenges facing Atlantic Canadian industries and provides comprehensive engineering support from initial concept through production implementation.

Whether you're developing new products, optimising existing manufacturing processes, or seeking expert guidance on material selection and fabrication methods, we deliver practical solutions grounded in sound engineering principles. Our Amherst location positions us to serve clients throughout the region with responsive, personalised service.

Contact Sangster Engineering Ltd. today to discuss your manufacturing requirements and discover how our engineering expertise can benefit your next project. Let us analyse your applications and recommend the most effective solutions for your specific needs.

Partner with Sangster Engineering

At Sangster Engineering Ltd. in Amherst, Nova Scotia, we bring decades of engineering experience to every project. Serving clients across Atlantic Canada and beyond.

Contact us today to discuss your engineering needs.