Waterjet machining has been around for decades. In fact, it is one of the fastest growing machining processes today, mainly due to its high versatility and ease of use. But when it comes to waterjet machining, there are actually two distinct types, pure waterjet and abrasivejet, and understanding the difference is important, if not critical.
Pure waterjet is the original form of the technology and works exactly as its name implies, using a stream of pressurized water to cut. Unlike conventional chip-making operations, pure waterjet is a cold-cutting process that eliminates heat-affected zones on the material, which keeps it from hardening during the machining process.
With pure waterjet, however, its benefits are limited to cutting soft and/or thin materials such as foam, fabric, cardboard, foil, rubber and wood. Abrasivejet technology, on the other hand, extends the advantages of pure waterjet to cutting harder materials.
Abrasivejet follows the same principles as pure waterjet, but introduces abrasive particles, which can range from garnet to aluminum oxide, to the high-pressure water stream. The abrasive and water come together in a mixing tube and then exit the nozzle (pure waterjet does not involve a mixing tube).
With an abrasive, waterjet machines can virtually cut any material of any thickness with speed and precision, from rubber to hardened tool steel to composites to titanium. Such versatility and performance makes abrasivejet machining an ideal choice for fabricators and parts manufacturers across all industry segments. Home developers also rely on abrasivejet machining to cut granite countertops, inlaid marble flooring and stone sculptural pieces.
Overall, pure waterjet and abrasivejet share many of the same advantages, including high cutting speeds; narrow, precise cuts; no heat-effected zones; low cutting forces; and minimal fixturing. But it is important to take a close look at your operations and future business plans to determine which one makes the most sense for you.
In terms of cost, pure waterjet nozzle assemblies are more affordable than abrasivejet equipment. The cost to operate an abrasivejet machine is also higher due to mixing tube wear and abrasive consumption. Keep in mind, these additional costs are well worth the investment if you run a diversified shop and need to cut a wide range of materials and thicknesses. But, if your focus is strictly on soft and/or thin materials, then pure waterjet makes the most economical sense.
And, of course, if you use waterjet machines to cut food, then you must absolutely stick to the technology in its purest form. It is, after all, critical to meet USDA approval for creating a hygienic cutting process in this industry.