DETROIT – Waterjet cutting simply refers to speeding up the erosion of material. High-pressure water is fired through a diamond or ruby nozzle into mixing chromium, drawing garnet sand into the stream. Sand particles wear away at the material, eroding at high speeds called cutting. A waterjet cutter is a powerful tool that can be used in many industries worldwide.

Waterjet cutting is a manufacturing process using high-pressure Waterjets. These Waterjets are supplied by pressurising pumps and deliver a supersonic stream to cut and shape different materials. Waterjet cutting technology uses water that has been pressurised to 392 MPa. A small precision projector projects the water. The water travels three times faster than sound as it leaves the nozzle.

Pure Waterjet cutting using water as the medium is intended for soft materials like wood, plastics, and rubber. The water stream can be enriched with an abrasive, such as aluminium, titanium, stainless steel, glass, ceramic, and concrete. This makes cutting more aggressive and can cut hard metals.

There are many ways to Waterjet cut. Most of these methods use an abrasive mixed into the water to remove any particles. You can use a versatile CNC waterjet machine in the manufacturing process for cutting, shaping, and designing workpieces to exact specifications.

Waterjet cutting offers several advantages over other cutting methods such as plasma and laser. Waterjet cutting is more precise and can cut intricate designs and thermally sensitive surfaces.

Kerf refers to the material that is removed during a cutting operation. The term initially meant removing material during a saw blade’s cutting process. It refers to the Waterjet cutter’s stream width, usually 0.04 inches or fewer. Waterjet cutting cuts the inside corners with a radius equal to the stream’s width. The material thickness, cutting quality, and nature of the waterjet nozzle all affect the kerf.

When determining the dimensions for the final product, it is essential to consider the size of the kerf. The kerf should be at least 0.042 inches in size. It must adjust the final product dimensions to compensate for the cutting width if it is less than that. Otherwise, the final product will be 0.042 inches off.

The pierce is the first cut made with a Waterjet cutter. It is wider than the standard kerf. The first step of the Waterjet cutting is to start the pierce. You can do it in various ways, the most popular being stationary, circular, low pressure, and linear. The material being cut and the scrap produced will determine which piercing method is used.

Tapering is the difference between the kerf width at its top and the bottom of the Waterjet cutting. Waterjet cuts exhibit a V-shaped taper. The stream loses energy as it cuts deeper into the material. There is more material removed at the top than at the bottom.

Slower cutting speeds result in a reverse taper where the kerf width at the bottom is more expansive. This is due to removing more material from the bottom. This is clear when you are cutting flexible materials.

Barrel tapers can be created when the cut is wider in the middle, such as when cutting very thick materials.

Tapering is not an issue for most types of cutting and can be a valuable tool to help with specific jobs. Tapering can cause problems when precision tooling, where pieces fit together perfectly.

There are many ways to pressurise water. These include linear intensifiers or rotary direct-drive pumps. These pumps have a motor, water filters, and control systems.

Linear intensifier pumps are made from pressurised hydraulic oil at 3000 psi. The piston is pushed against by low-pressure oil. It has a face area 20 times greater than the high-pressure plunger, which goes against the water. The low-pressure pump’s volume is 20 times greater than the high-pressure one. This causes the pressure on the giant plunger to be 20 times. This results in a strain of 60,000 PSI.

Hydraulic oil is not included in a direct drive rotary pump. The electric motor rotates a crank which drives the pistons that create the water pressure. The 30 HP motors of direct drive pumps are equipped with an inlet to supply water to the pump.

The pump’s pressurised water travels through high-pressure tubing to reach the cutting head. High-pressure tubing is exceptionally smooth and has excellent yield, tensile, and tear strength. You can make it from either cold-worked stainless steel or thermoplastic pressure tubing sizes from 0.25 to 0.563 inches. The lengths are flexible to suit the needs of your Waterjet cutter.

The pressure water flows through the orifice in the cutting head. It comprises a diamond, ruby, or sapphire and has a hole smaller than a pin’s point. The water’s velocity increases dramatically as it passes through the cutting head, reaching speeds of over 90,000 PSI or 2500 mph. The power of the cutting head directly affects the cutting process. When used correctly, precision tooling cutting heads can last between 500 and 1000 hours.

Below is an illustration of two types of cutting heads: water only or water with abrasive. You can see the difference in the tube that carries the abrasive into the water stream.

The original Waterjet cutter is the pure Waterjet cutter. Because they leave less water on the surface of the workpiece than can be created by touching it, they are popular. The jet cutters have a fine stream that creates precise geometries and minimises material loss. A pure waterjet cutter is a beautiful piece of engineering. Including rubies makes it unsuitable to work with pure water. The stream travels at Mach 2, 40,000 psi, and Mach 3, 60,000 psi.

The abrasive waterjet cutting system uses abrasive materials to feed into the cutting head. It is then mixed with the water stream. Adding an abrasive sharpens the stream and makes it more efficient at cutting. An abrasive can make a Waterjet cutter capable of cutting any material, regardless of its thickness or hardness.

An abrasive waterjet cutter speeds up the flow of abrasive materials that erodes the cut material. Abrasive Waterjet cutters are 1000 times more potent than pure Waterjet cutters. The stream is more expansive in diameter and can cut materials up to ten inches thick without causing heat or mechanical stress.

As you can see, waterjet cutting is the best and most versatile method in the industry. It is the most popular procedure in many industries because it can cut thicker and more intense materials while creating a safe environment.

AUTHOR: Today’s Techni Waterjet Manufacturing Manager, Jonathan Schlick, has over 20 years experience in the field of industrial machinery.

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