Water Jet Cutting

Water jet cutting machinery can generate jet pressures between 30,000 and 90,000 PSI. Some high-pressure water cutting systems can produce pressures of up to 120,000 PSI; such systems are limited in their use to the cutting and machining of very thick or strong materials. In the case of the toughest material, abrasive water jet cutting systems, which combine fine abrasive particles with a water stream, are used to reduce a material's resistance to cutting. Brittle materials like glass and ceramics are cut with machinery operating at much lower pressures to reduce the risk of breakage. Water jet cutting is an attractive process to many professionals because it can cut materials without creating jagged or burred edges. Abrasive jet and abrasive flow machining in particular can produce very smooth edges without causing the warping that can occur during traditional blade cutting. In order to create the most precise products possible, almost every water jet cutting system is managed by a computer numerical control (CNC) system, which controls the movement and pressure of the water jet according to designs programmed into them by technicians. CNC systems make possible the accurate cutting of all kinds of shapes out of many kinds of materials with different thicknesses and tolerances.

Many industries that make use of intricate, precisely-cut products require access to water jet cutting services. The automotive, aerospace, industrial equipment manufacturing and communications industries as well as artists, food processors and lumberyards all enjoy the benefits of water jet cutting and fabrication. Blade cutting and other more conventional cutting methods often create the need for secondary processing; burrs created at metal edges must be removed, warping must be corrected and discoloration from heat generated by friction must be addressed. Water jet cutting is not subject to any of these deficiencies. There is no heat involved in water jet cutting, so discoloration or damage to surfaces because of friction or other heat sources is not possible. Also, the force of the jet stream is borne only in the area where the cut is being created, so no surface deformation away from the cutting area is created during water jet cutting and machining. Because no heat is involved in the water jet cutting process, heat-sensitive materials like certain thermoplastics can be easily shaped without the risk of melting or accidental ignition. Also, because water jet cutting is a cold-cutting process, several sheets of raw material can be stacked and cut simultaneously, greatly increasing water jet cutting's efficiency compared to other cutting methods. Water jet cutting machinery's many favorable qualities make it an excellent complement to other cutting equipment like laser cutters, routers and plasma cutters; adding water jet cutters to an operation is a great way to increase productivity.

Some materials are not appropriate for water jet cutting processes. Some glass compositions and thicknesses are too vulnerable to becoming shattered when exposed to water jets, and some ceramics are similarly vulnerable to damage when subject to water jets. On the opposite end of the hardness spectrum, diamond and certain metals can be too hard to be cut with water jets. Moisture-sensitive materials and hydrophobic elements are obviously also not suited to water jet cutting, but aside from these limitations, water jet cutting is an extremely effective, efficient and versatile cutting and machining process. Water jet cutters are capable of cutting many different kinds of materials and involve minimal setup time. They can efficiently accommodate product runs of all sizes (including prototype runs) and can be configured with multiple heads working simultaneously to increase output. One of the reasons for water jet cutting processes' high effectiveness and efficiency is that nearly all water jet processing methods are managed by computer numerical control systems. Designers using computer-aided design software can create designs that CNC-managed equipment interpret and execute with extreme precision. For example, a CNC-managed water jet cutting system can cut shapes out of a metal sheet without errors while leaving the smallest possible amount of space between cutouts, saving raw material and maximizing output. Once a project is finished, there is no need for time-consuming tool changes; a new computer design can quickly and easily be programmed into the computer. All of the different shapes that emerge from this process are free of burrs or other imperfections and can be handled immediately; because no heat is involved in the process, no time is required for cooling or setting.

Another reason for the high efficiency of water jet cutting systems is their capacity for materials reclamation. Most of the water and abrasive media expelled from water jet nozzles can be reclaimed and re-circulated, minimizing water and media consumption. The recycling of water and abrasive media reduces the amount of investment in materials costs and increases the sustainability of the process. Professionals interested in reducing the environmental impact of their operations can appreciate the low energy-intensiveness and high efficiency of water jet cutting. Also, because materials costs are low, companies can invest the materials expenses they have saved in equipment maintenance, new equipment and raw materials. Compared to other cutting and machining methods, water jet cutting presents few threats to workplace safety. It produces no noxious gasses or liquids, as can be the case with hot cutting methods like laser and plasma cutting. It also produces no sparks or flying debris, which further reduces the number of hazards compared to other cutting processes. The only substantial threat to workplace safety present in water jet cutting is noise; high-pressure water jet cutting in particular can be quite loud. However, this issue is easily addressed by sound-proofing the cutting workspace and issuing personal ear protection to employees. Minimal safety hazards, the absence of dangerous byproducts and low heat levels allow water jet cutting operations to continue without interruption for as long as 20 hours, further contributing to high output and efficiency.

Water Jet Cutting Types

• Abrasive flow machining (AFM) is a secondary processing operation used to smooth, polish, radius, and remove cracks and burrs from hard to reach or internal surfaces of machinery, parts and products.
  
• Abrasive jet machining is water jet cutting with the addition of an abrasive material to increase the cutting ability, used for cutting hard materials. The abrasive particles are what accomplish the erosion cutting process in addition to the water and high speed.
• Abrasive waterjet cutting is an alternative to using pure water to cut through a wide variety of materials. To add strength and the ability to shape and form metals, brick, marble, stone, ceramics and composite materials, abrasive particles like garnet and diamond are mixed in with the water.
• CNC water jet cutting uses computer software instead of manual operation to cut, drill and engrave many materials.
• High pressure water cutting is able to form, shape and design products out of almost any material, including ceramics, foam, marble, plastic and glass.
• Hydro cutting is a cold working manufacturing process that uses high pressure water jets to cut a wide variety of materials and shape them.
• Pure waterjet cutting is the use of a pressurized jet of water through a tiny aperture at an extreme velocity. This is the original water jet cutting method, and it generally cuts soft materials like rubber, cloth and paper.
• Water jet cutters use a stream of pressurized water to cut through materials.
• Water jet glass cutting severs glass into pieces, adds detail, and makes holes in many kinds of glass.
• Water jet machining is a process by which materials are cut into shapes using pressurized water.
• Water jet metal cutting is strong enough to cut through nearly any material, including metal.
• Waterjet cutting machinery uses water under high pressure and velocity to precisely cut through and grind away small amounts of material.
• Water knives are cutting tools that use pressured water to slice food.
• Waterjet is a pressurized stream of water used to erode and cut materials.
• Waterjet cutting is the process that uses pressured water to cut various products.

Top 10 reasons to choose Waterjet Cutting

Long regarded as a tool for trained experts, water jet cutting has changed dramatically in the last few years. New technologies have made it possible for just about any machine or fabricating shop to purchase and profitably operate a precision water jet cutting system, with little or no prior special experience.

1. Wide range of materials
   Water jet cutting can work with a wide variety of materials, ranging from metals to ceramics, composites, glass-even marble and granite.
2. Quality finish
   The finish provided by the water jet cutting is a smooth, sandblasted finish. No rough edges, burrs or jagged ends. We can control the edge cut finish to meet your needs.
3. No heat in machining process
   Because the water jet uses water and abrasive, the material is not heated up significantly during the cutting process. This makes the water jet cutting ideal for materials that are affected or deformed by heat, such as titanium, foam, wood, heat treated steel and glass.
4. Environmentally friendly
   Water jet cutting uses water and garnet to cut. Garnet is an inert gemstone, which can be disposed of in the municipal waste stream. No toxic fumes are produced during machining.
5. No tool changing
   You don't need to change cutting tools with the water jet cutting. One nozzle is used to machine all the different types of materials and shapes, saving time and the expense of multiple cutting tools.
6. Minimal Burr
   Using water jet cutting, there is little or no burr in most materials.
7. Quick to program
   Water jet cutting is supported by a wide variety of third party software products such as CAD/CAM, Nesting, and scanning.
8. Fast set-up and programming
   Water jet cutting takes the tool path created by software and calculates the exact position and cutting speed of the nozzle at a resolution of over 2,000 points per inch (800 points/cm).
9. Complement existing tools, used for either primary or secondary operations
   Water jet cutting can also work with your other machine tools to take advantage of the unique capabilities of each. An example of this is roughing out nested parts to maximize material usage, and then performing final machining on a mill or machining center.
10. Reduce setup times
    Little or no side force on the material being machined reduces the need for complex fixtures and greatly speeds setup times.

Water Jet Cutting Terms

Abrasive Flow Rate - Rate that an abrasive material streams into the cutting head of the water jet cutting device.
 
Abrasive Substances - What an abrasive water jet cutting machine uses to cut. These are typically garnet or substances similar to sand.
 
Attenuator - This pressurized vessel sustains output pressure for a continuous flow of water out of the water jet cutting device, accommodating irregular pressure produced by some pumps.
 
Bridge/Bridging - When parts are connected together with a narrow piece of metal while cutting to avoid falling into the catch tank. Once the water jet cutting process is done, the connecting pieces are removed.
 
Catch Tank - A tank of water below the water jet cutting head that disperses the water from the cutting beams and prevents holes in the floor. The tank also collects used abrasives that are ejected from the water jet cutting device with the water stream.
 
Common Line Cutting - A method of water jet cutting used when multiple parts are being cut at once. This technique saves time, but it is hard to program, and the cuts are not as precise as they would be if the parts were cut separately.
 
Crankshaft Pump - A pump in which plungers driven by a crankshaft create the pressure needed to run water jet cutters.
 
Cutting Index/Machineability - A quantitative value representing how easy it is for abrasive water jet cutting or water jet cutting of a particular material.
 
Cutting Model - A model of the way a water jet cutting will cut, used to predict when to slow down and how to compensate for using a "floppy tool"
 
Draft Angle - The angle resulting from taper.
 
Dynamic Pierce - A way of piercing the material by permitting the water jet to initiate travel along the part path.
 
Etch - Creating marks on the material without completely water jet cutting through it, done with the reduction of pressure and abrasive flow rate.
 
Feed Rate - The speed of the water jet cutting head movement.
 
Focusing/Mixing Tube - A tube of hardened material that directs the water and abrasive substance into a coherent cutting beam out of the water jet cutting device.
 
Frosting/Hazing - Stray abrasive particles that cause a "frosting" effect on the material being cut. This usually occurs at the edge of a water jet cut, or in a rounded pattern around a pierce point.
 
Garnet - The most common abrasive material in abrasive water jet cutting; it is able to cut many different materials, and soft enough to maintain a long life for the mixing tube.
 
Hard Limit - A limit on the water jet cutting machine that prevents it from moving in a particular direction or beyond its physical limits.
 
Hard Water - Water that has a large number of dissolved minerals, typically calcium and magnesium. Hard water tends to leave behind deposits of the dissolved minerals, which necessitates regular clean-up or replacement of jewels, pipes and filters.
 
Intensifier - A high-pressure pump that uses hydraulics to create extremely high pressure. Used in the water jet cutting process
 
Jet Lag - A term for the lag in the spot where the water jet cutting exits the material to the spot where it entered the material.
 
Jewel - The aptly named aperture that the water exits to create the water jet cutting stream, usually made of ruby, diamond or sapphire.
 
Kerf - The cutting beam width of the water jet cutting stream.
 
Kick Back - A term for what the water jet cutting head does as the water jet cutting machine accelerates away from a corner that has just been cut.
 
Mesh - A measure of the degree of coarseness of the abrasive.
 
Muff - A brush or sponge around the tip of the nozzle on the water jet cutter, that is used to prevent splashing
 
Nozzle - Includes the focusing/mixing tube, jewel, nozzle body and sometimes the plumbing of water jet cutters.
 
Pierce - The process of drilling a hole through the material using water jet cutting.
 
Reverse Osmosis - A method for filtering water, used in water jet cutting.
 
Slat - A prop for the material as it is being water jet cut, typically disposable.
 
Soft Limit - A way of using software to program the boundaries in which a water jet can move. The soft limit is used to define the area the head can move in so it does not collide into anything nearby.
 
Splash Back - A common occurrence during piercing. This is the mess that results from the water jet cutting splashing water off the slat, or when the piercing does not go all the way through the material.
 
Stationary Pierce - A slow method of piercing used for thin materials and very small holes. The water jet cutting stays stationary in one position until the material is cut.
 
Striation Marks - Marks caused by the wiggling movements of the water jet cutting machine. The quicker the cut, the more striation occurs.
 
Super-Water® - A chemical additive that enables water jet cutting machines to increase cutting speed, focus the cutting stream and reduce wear of high-pressure components.  
 
Tab/Tabbing - A procedure for keeping parts in place by leaving a small piece of material attached to the original piece from which the material was cut. This prevents the material from falling into the tank or from tipping and colliding with the nozzle.  
 
Taper - The amount of difference between the top and bottom profiles of the cut made by the water jet machining.
 
Tool Offset - The necessity of slightly offsetting the tool from the cutting line, because of the width of the water jet cutting stream.
 
Traverse - Any movement of the machine's head without water jet cutting anything, such as moving it into a cutting position
 
Velocity - A measure of motion relative to time, generally expressed in feet per second. Velocity expresses the amount of space passed over by a moving body in a certain period of time.
 
Weep Hole - A small hole drilled into the side of the high pressure fittings that allows water to escape safely if there is a leak.
 
Wiggle Pierce - A method of cutting where the water jet wiggles back and forth as it cuts. This method is faster than a typical clean water jet cut.