A waterjet cutter is known as a ‘water jet’ due to the use of a high-pressure jet of water-focused through a nozzle to create a beam of water strong enough to cut through a verity of materials. Waterjet cutting machines are truly versatile in their application on different materials and compliments to other cutting machines and methods. The water cutting process was used as early as 1933 by a Wisconsin Papermill to cut their paper reel but the early application of the waterjet was on soft materials and with low pressure. The commercial viability of waterjet cutting was still a question due to the non-availability of reliable high-pressure pumps. With the development of high-pressure fluid intensifier in 1973 by John Olsen, the foundation was laid for future success and development of waterjet cutting in the industrial scale. The abrasive addition idea to the waterjet cutting was formed in 1935, but the technology got patented in 1985 to Dr. Mohammed Hashish after this works and his first publication on the matter in 1982. He was also the person who coined the term Abrasive Waterjet (AWJ). The nozzle and the waterjet transferring pipes were a challenge in the initial times due to short life because of the high-pressure and use of abrasives. Now the use of ceramic tungsten carbide composite tubes has significantly increased the operation life.
The operation process of the waterjet has the same principle in both pure waterjet and abrasive waterjet. Forcing high-pressure water focused into a beam by a nozzle which is ejected through the nozzle to cut the material placed under it. The beam travels at the speed of Mach 3 forcing the cut in the materials. The difference in the abrasive cut happens at the end of the nozzle where the abrasive is added via an abrasive inlet and mixed and released together with the water at high speed and pressure.
High-pressure pumps are the heart pf the operation in the waterjet cutting systems delivering the water at the required high pressure for the system to function at its optimum. Two types of pumps do this duty. The intensifier-based pumps and direct drive-based pumps.
Intensifier Based Pumps – After the water gone through the filtration units it is boosted by the booster pumps to maintain the feed pressure and availability to the intensifier pump. The intensifier pumps then pressurize it to 60,000 PSI which goes through a shock attenuator which dampens the pressure fluctuations to provide steady and consistent water for the waterjet cutting nozzles.
Direct Drive Based Pumps – The filtered water is pumped to the system via a plunger which pushed by the crankshaft to achieve the pressure. The crankshaft of the direct-drive pumps acts the same as a motor vehicle engine providing the required power. The same power requirement here is applied to the plunger to pressurize the water in the tube.
Waterjet is of two types namely the pure waterjet and the abrasive water jet. As we have mentioned above the abrasive waterjet uses an additional material of abrasive along with the water to get better results in cutting hard and thick materials. The abrasive waterjets are more powerful than the pure waterjets as they have additional materials to tube pushed through and this additional power results in higher cutting capacities. It makes it possible for stack cutting, little material loss due to the thin kerf in cutting, use of the same nozzle of multiple purpose abrasive cuttings, etc.
Pure waterjet cutting is the original waterjet cutting method is used in the industries where the materials to be cut are soft or sensitive. It’s used in cutting materials in the paper industry, interior materials in the automobile industry, for cutting diapers, also extensively used in the food industry.
Advantage waterjet Cutting
Waterjet cutting has brought a load of advantage to the industries that are using it. They are very versatile and offer a cutting range on a wide verity of materials with varied thicknesses. It’s one of the machines which can cut virtually any material.
- It is a cold process that eliminates heat and whatever heat is created will be dissipated by the water in the process. Being a cold process enables a lot of advantages that are not available on a hot cutting process. It is also a easy and fast setup system with minimal programming difficulties through the CNC. The cold process also makes it a safe operating atmosphere.
- The waterjet creates no heat and thus has little stress damage on the materials which are cut. The integrity of the materials will be intact after the cutting process. The lack of stress on the material allows the cutting machine and personnel to ignore or give less important to that factor when considering for the safe cutting unlike other hot cutting processes where the stress has to be factored in the process.
- Unless the material is hazardous the waterjet cutting process does not create any hazardous wastages. The wastage created by the waterjet cutting machines is very less due to the narrow kerf possible by the waterjet machines and the created wastages are the residue of the materials, the abrasive, and the water which can all be suitable for landfills.
- The lack of fumes and hazardous wastages makes the waterjet cutting an environmentally friendly process. The wastage becomes landfills and the water can be dumbed to drains but incases the water has any other substances that make it not acceptable for dumping then filtration or recycling can solve those issues.
The use of a natural element in high pressure for the cutting process has provided a better alternative to other waste generating, high powered, and heat-generating processes. The advancement in the waterjet cutting process is expected to bring down the usages of other processes and help in creating a sustainable process in cutting.