What is Waterjet Cutting?
Waterjet cutting is a non-traditional machining process that uses a high-pressure jet of water to cut through materials. It is an extremely versatile process that can accurately cut a wide variety of materials while producing no heat or contaminating the workpiece.
How Waterjet Cutting Works
A waterjet cutter directs a thin, high-pressure stream of water through a tiny hole in a cutting head. The water pressure can reach up to 94,000 psi, allowing it to cut through materials as hard as metal, stone, glass, and composites.
To cut harder materials, a waterjet cutter mixes the water with abrasive materials like garnet or aluminum oxide. The abrasives help erode the material during cutting. This abrasive waterjet cutting produces precise, clean cuts through practically any material up to 8 inches thick.Also, read:
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Benefits of Waterjet Cutting
Compared to other cutting methods, waterjet offers numerous advantages:
- Cuts virtually any material, including metals, composites, stone, glass, foams, foods, rubbers, etc.
- No heat affected zone (HAZ) - does not alter material properties or leave burn marks
- Minimal force applied to workpiece - no warping or deforming
- Very precise cutting with tight tolerances
- No masking or finishing required for most materials
- Cooling and flushing action reduces dust and fumes
- Environmentally clean process with no hazardous chemicals
Waterjet Cutting Applications
Waterjet cutting is used across many industries to cut parts with accuracy and precision:
- Aerospace - titanium and aluminum aircraft components
- Automotive - headliners, carpets, insulation, prototypes
- Electronics - circuit boards, electronics enclosures
- Machine Shops - gaskets, seals, shims, washers, prototypes
- Metal Fabrication - thin metals, tubes, pipes, extrusions
- Stone Cutting - granite, marble, slate, sandstone cutting
Other common applications include cutting fabrics, foams, food, paper, cardboard, artwork, 3D part prototyping and more. Industrial water jets can cut thicknesses over 12 inches for metals and even thicker materials like stone.
Waterjet Cutting Process
The waterjet cutting process involves several main components and steps:
- High pressure pump - generates water pressure up to 94,000 psi
- Abrasive hopper and mixing tube - mixes abrasive into waterjet
- Cutting head with orifice - directs waterjet stream
- X-Y cutting table - controls jet motion
- Catcher tank - catches abrasive runoff
- Waste removal system - removes spent material
- Water is pressurized by an intensifier pump up to 94,000 psi.
- Pressurized water is forced through a tiny orifice in the cutting head.
- The resulting thin, high-speed waterjet stream exits the orifice.
- Abrasive material is introduced into the jet stream in the mixing tube.
- The abrasive waterjet is directed by the cutting head along the cut path.
- The high velocity jet quickly erodes through the material, splitting it apart.
- The jet follows the programmed path while the cutting table moves the workpiece.
- Waterjet produces a narrow kerf cut through the material.
- Water and abrasive drain into a catcher tank to be filtered and recycled.
Waterjet Cutting Equipment
Waterjet cutting systems consist of several main components:
- High pressure pump - Typically an intensifier pump rated from 30,000 to 94,000 psi. Higher pressure improves cutting capability.
- Abrasive hopper - Holds and delivers abrasive like garnet into the jet stream via venturi suction.
- Mixing tube - Mixes abrasive into jet stream for abrasive cutting. Made of sapphire or carbide.
- Cutting head - Houses waterjets orifices sized from 0.007” to 0.04” diameter. Focusing tubes accelerate jet.
- X-Y cutting table - CNC controlled table moves workpiece in X and Y axes during cutting.
- Controller - Computerized controller operates pump and axes motors. Can be manual or CNC.
- Catcher tank - Collects used water and abrasive material during cutting.
- Waste removal - Filtration system filters and recycles abrasive material.
- Chiller - Chiller unit cools pump and maintains water temperature.
Waterjet Cutting Costs
The operating costs for waterjet cutting include:
- Abrasive material - Garnet or aluminum oxide abrasive costs $0.10 to $0.50 per pound.
- Water usage - Water is not consumed but is pressurized and recycled. Usage is 1-2 gallons per minute.
- Electricity - Pump motor uses up to 50 horsepower. Power costs vary by region.
- Consumable parts - Orifices, focusing tubes, and mixing tubes wear over time.
- Maintenance - Routine maintenance is required on pump, lines, valves, etc.
- Labor - Operating labor depends on complexity of cuts and level of automation.
For most shops, abrasive costs are around 20% of total operating costs. Consumables, maintenance and labor make up the majority. Overall operating costs are lower than most other cutting methods.
Waterjet Cutting FAQ
What materials can waterjet cut?
Waterjet can cut any material up to 8" thick including metals, stone, composites, glass, plastics, rubber, foam, food, and more.
How thick of material can waterjet cut?
Waterjets can cut thicknesses over 12 inches in softer materials like foam or food. For metals, waterjet typically cuts up to 8 inches thick.
Is waterjet cutting affordable?
Waterjet is very affordable compared to other cutting processes. Operating costs are around $3 to $8 per hour.
What tolerances does waterjet produce?
Waterjet cutting can hold tolerances as tight as 0.005", depending on material and part geometry. Typical tolerance is ±0.005" to ±0.015”.
What cut quality does waterjet produce?
Waterjet produces very good edge quality with a smooth, narrow kerf width. Most materials require no secondary finishing.
How fast does waterjet cut?
Cutting speeds vary based on material, thickness, pump pressure, etc. But waterjet typically cuts between 10-25 inches per minute for 1" metal.
What machine maintenance is required?
The main maintenance involves changing consumable orifices, mixing tubes, and focusing tubes as they wear over time.
What safety precautions are needed?
Waterjets require standard machine safeguarding, proper ventilation, and personal protection equipment for noise and slipping hazards.