Back to News 6 of the most commonly asked questions about waterjet cutting systems.

6 Frequently Asked Questions About Waterjets

Waterjet FAQ


What Materials can a Waterjet Cut?

Waterjets are capable of two different cutting methods: Water-only cutting and abrasive cutting. Water-only cutting is preferred when working with soft materials such as foam, rubber, plastic, and foodstuffs. The general rule of thumb is that if the material can be cut with a pair of scissors, a water-only system can be used.

Denser materials will usually require the use of abrasive cutting. This method involves the introduction of an abrasive to the cutting stream. Garnet, which is a hard gemstone that produces sharp edges when fractured, is the most commonly used abrasive. When added to the cutting stream it helps to speed up the erosion process, making this the perfect method for cutting through steel, titanium, and even composites such as carbon fiber.

Waterjets have already proven to be the perfect cutting solution for many different materials, but test cuts are available to manufacturers who want to know the speed and quality at which a waterjet will cut a particular product.

What can a Waterjet be Used For?

From mass producing parts out of sheet metal to carving intricate 3D designs in marble, the waterjet has endless applications, making it the most versatile cutting system in the manufacturing industry today.

The introduction of 5-axis cutting heads triggered massive growth in waterjet cutting. No longer confined to cutting out flat objects, waterjets are now able to produce continuous bevels, revolve around the work piece, and cut at angles from 0-90 degrees.

The functions of a waterjet all depend on customer needs. New waterjets are able to be custom-built to desired specs, creating a tailored experience for the buyer. Existing waterjets can be outfitted with a variety of different accessories that enable them to perform a wide variety of tasks. Whatever the manufacturing job at hand, a waterjet can be developed to cater to that specific demand.

What Are the Advantages of Using a Waterjet?

One of the major benefits of using a waterjet cutting system over a laser or plasma cutter is that there is no heat generated during use. This completely eliminates the creation of any heat-affected zones (HAZ) that could possibly burn or warp the material being cut. The use of water as a cutting tool also prevents the formation of potentially toxic fumes, and any dust or kerf that is created is safely deposited into the tank of the waterjet instead of the atmosphere or the lungs of the operator.

Waterjets operate using an accelerated erosion process that quickly wears away the work piece. This process leaves behind a naturally smooth edge, with little to no burr or chipping of the material. Thus, the need for finishing, which can be both costly and time-consuming, is eliminated.

Laser cutters struggle to cut reflective materials and plasma cutters can only cut through conductive metals. Both have issues cutting through materials thicker than 6”, which severely limits their applications. Waterjets have no problem cutting through reflective or non-conductive materials, and given enough time can cut through massive sheets of metal up to 12” thick.

The accuracy of a cut plays a huge part in the final quality of any fabricated part. Waterjets can reach tolerances as tight as +/- 0.003” and a repeatability of +/- 0.001” per axis. This level of accuracy ensures precise cuts while maintaining consistency over the course of a job.

How Much Does it Cost to Operate a Waterjet?

The hourly cost to run a waterjet will vary depending on factors such as pump size, abrasive flow rate,number of cutting heads etc., but normally the use of consumable parts is the largest contributor to operational cost.

Abrasive is the biggest cost associated with waterjet cutting. Abrasive usage will fluctuate depending on the size and type of material that is being cut. A feed-rate calculator can be used to determine how much abrasive will be needed for a particular job. Garnet, the most popular waterjet abrasive, is a non-renewable resource that can be costly to remove from the machine and replace. Abrasive removal systems save hours of downtime by continuously removing the spent garnet while the waterjet is in operation. Recycling systems can then be used to recover up to 60% of the used abrasive which can then be put right back into the waterjet’s abrasive hopper. The recycling of garnet eliminates a large portion of the costs associated with the removal, disposal, and replacement of used abrasive.

Other consumables such as nozzles and orifices must be replaced regularly. The use of diamond orifices, which have a lifetime 30-fold that of ruby or sapphire, can dramatically decrease hourly operational cost.

Performing preventative maintenance on a waterjet can help to avoid part failure which can lead to costly downtime and repair bills. Just the simple greasing of the ball screws or flipping of the grates can ensure the longevity of a waterjet system. Along with this, having a team of qualified service technicians is imperative to getting your machine back up and running as quickly as possible in the event of breakdown. Ask your waterjet manufacturer if they offer remote services that allows for immediate assistance instead of waiting for a technician to arrive.

Last but not least, investing in CAM software that offers a nesting feature will use as much of the material as possible, eliminating waste and promoting lean manufacturing.

An hourly cost calculator can be used in order to get a general idea of normal waterjet operating costs.

How Fast can a Waterjet Cut?

The composition of the work piece will determine how fast a waterjet will cut. Materials that can be cut with a water-only system can usually be cut quicker than thick materials that require an abrasive. Depending on type of cut desired, the waterjet can be sped up or slowed down. A slower cut will result in a cleaner edge and more consistent kerf (see figure 1), whereas a faster cut can be used if edge quality is not a concern, like that of a separation cut.

Jog speed of the cutting head can have an effect on total cut time. Quick positioning between cuts equates to increased production and a lower cost-per-part.

Several cutting heads can be used in unison to increase production. These heads can be controlled independently of one another which can allow them to cut multiple and unique work pieces at once.

Using strategies like common line cutting and stacking material can be used in order to reduce cut time and increase efficiency of the machine.

Lastly, you can automate many aspects of waterjet cutting by using loading systems like shuttle tables that allow for the loading and unloading of cutting material while the waterjet is still in operation. Automating loading effectively increases production while decreasing lead times and labor rates.

Where Can I Learn More?

Interested in learning more about the capabilities of waterjets? Enroll in WARDJet University, the most comprehensive waterjet training offered online for free! Still want more information? Give us a call at 1-844-WARDJET, and we’ll be happy to answer any questions you have.

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