• A basic understanding of how waterjet cutting works
• Principles behind waterjet cutting and what it takes to produce a good part
• Practical issues such as clamping, jigging and fixturing
• How CAD and CAM will determine the final part quality
• Maintenance of the equipment and pumps

• Cutting Characteristics of waterjet – stream width, kerf, abrasive flow, stream reaction, cornering, drilling holes, small and large radii, overspray, taper, and frosting
• Relationship between orfice/nozzle, horsepower of pump, pressure, edge quality, tolerances, edge finish and speed of cut
• M-Series tank operation – clamping, fixturing of parts, dissipation of energy, and flushing of waste material from tank

• CAD / CAM operation and the advantages of using CAM to control ramping and the waterjet stream
• Understanding what it takes to get the same quality finish in corners, radii and circles as in a straight line cut

Tolerances Tolerances tighter than +/- 0.005" are achievable, especially in thinner materials such as 1" stainless steel. However, high tolerances come with a price, sometimes up to 500% higher than if the same part had been specified with a tolerance of +/- 0.015". By being more flexible with tolerances, prices will plummet as cutting speeds increase. Waterjet cutting has the ability to vary tolerances in different locations on a part, ensuring the best pricing and quality.

Thickness And Kerf Materials ranging from 10" stainless steel to 0.010" acrylics can be cut by waterjet, making it a very versatile tool. Stacking of very thin materials to increase productivity is possible. Kerf ranges from 0.020" to 0.050".
Taper And Edge Finish Taper and edge finish are directly related to cut speed. The greater the speed, the more taper and the coarser the edge finish. As the waterjet slows down, taper can be eliminated and the finish of about 120 achieved. Again, slower means an increase in time...and price. For a finer edge finish, use a finer abrasive.

No Heat Affected Zone (HAZ)

Waterjet cutting is a natural erosion process involving no chemicals or heat. Because of this, warping and distortion typically associated with laser, plasma and oxy-fuel cutting is eliminated, therefore minimizing the need for secondary processing.

Nesting And Common Line Cutting

Unlike laser, plasma and oxy-fuel cutting, waterjet lends itself to common line cutting. WARDJet offers optional state-of-the-art nesting software, allowing you to nest multiple shapes together and cut them with multiple heads. Tracking of remnants and nesting into these odd shapes later, helps save precious material and can contribute toward reducing your operating costs.

FAQ’s

What kind of tolerances can I expect?
Depending on the system operated by the contract cutting company, tolerances approaching +/- 0.005" should be achievable.

How thick can we cut?
Waterjet can cut 10" thick stainless steel without too much difficulty. (Not all systems can cut this thick.) At the other end of the scale, heart valves for transplants are also cut with water.

Can I etch with a waterjet?
Yes, but as the jet slows down, so the stream cuts deeper into the material. It is not easy to get a smooth etched finish using a normal waterjet. Waterjet can certainly be used to mark numbers etc. onto parts, but is not really a good alternative to sandblast etching.

What happens if the nozzle is too far from the material?
The further the nozzle is from the material, the less power the stream has and the wider the cut in the part. There is also an associated overspray that tends to ‘blast’ the edges of the entry point of the water into the materials.

What are the consumables associated with a waterjet?
Like any other piece of machinery your waterjet will have parts that wear and have to be replaced occasionally. The chart below is a general guide of the consumables involved with waterjet cutting as well as the average lifespan of those parts. This will vary by machine and application.

What maintenance does the waterjet require?
Maintenance of a waterjet primarily revolves around servicing and changing consumable items in the cutting head and the pump. In the cutting head, orifices, nozzles, wear inserts, needle and seats, and abrasive delivery tubes will wear out. The pumps will need high-pressure seals, check valves and low-pressure seals serviced and changed as they wear.

Waterjet in Any Industry

The versatility of the waterjet allows it to be used in nearly every industry. There are many different materials that the waterjet can cut. Some of them have unique characteristics that require special attention when cutting. As you can see in the chart below each material you cut will have some unique characteristics that have to be taken into account.

The information below explains some of the cutting techniques we’ve used when cutting these materials. We recognize that there are many materials not listed so if you have a specific question about your material feel free to contact us at (330) 677-9100.

Alloys
Inconel, Hastalloy, Waspalloy, Titanium, Aluminum, Stainless etc. No heat effected zone or change in the molecular structure occurs in the alloy material. There is no distortion as seen with typical heat cutting methods. Generally, cutting with waterjet costs less than traditional machining or cutting methods. In many cases, no secondary removal of slag or damaged material is necessary, and minimal to no burring is seen.

Steels
Waterjet is not always the most cost effective method to cut steels. As a rule, if the finished product is presently being cut using laser, plasma or oxyfuel, and no secondary work is needed to the part after being cut, it is unlikely waterjet will be an economical solution. However, as soon as any secondary work, closer tolerances or removal of the Heat Affected Zone (HAZ) is needed, waterjet is probably the solution. With the use of the WARD (Waterjet Abrasive Recycling Dispenser) companies are able to reduce their operating cost substantially, reducing the gap between laser and waterjet cutting. In many cases, waterjet now costs less than laser!

Laminates
Waterjet, in most cases, does not see any difference between laminated materials - e.g. acrylic, aluminum, stainless and honeycomb section all laminated as one. Many aircraft parts consist of laminated materials where waterjet is the only solution.

Composites
Many composites are very difficult to machine as the cutting tool tips 'gum' up and quickly becomes inefficient. Waterjet has no gumming at all and can leave a good clean surface requiring no additional work.

Rubber
Depending on the durometer value, rubber can be cut with water only or with abrasive. Tests will quickly reveal what the best option is for your application.

Gaskets
By using waterjet for cutting gaskets, it is possible to automatically nest various sized and shaped gaskets on one sheet effortlessly. There is no longer any need for stacks of dies. Software will keep track of all remnant sheets allowing off cuts to be put back into inventory and used for smaller parts. Specialized software is available to track materials through the entire process.

Glass
Intricate cutting and shaping of glass is easy with waterjet. The waterjet can generally drill all its own start holes, making it a highly versatile tool. Glass from 1/32" to 10" thick can be cut, even when laminated in multiple layers.