Waterjet cutting is a popular alternative to conventional cutting methods. It is the most versatile cutting process that is able to provide the highest precision cutting on almost any type of material. It uses a high-pressure water jet to cut the material without thermal stress and only generates a small amount of heat during the process. Its cold cutting feature has allowed the material to be cut would not be melted, burned, or cracked, and is very suitable for heat-sensitive materials. It can perform the cutting by water jet alone or by the addition of abrasive particles to speed up the process. Water jet cutting is very efficient, able to provide precise and fine cut edges with its minimal kerfs without the need for secondary finishing processes. It also can cut the material into complex shapes easily. However, the process may be slower and the cost is more expensive when compared to plasma cutting. More cutting time results in a lesser output.
The working principle of the waterjet cutter is relatively simple. A fine jet of water hits the material surface at a very high speed to remove and separate the material. In order to generate a high-pressure water jet, the machine consists of several components and at the heart of the system is the high-pressure system with the intensifier pump that will bring up the water to a certain level of pressure and then direct it to the nozzle opening at the cutting head. Depending on the types and sizes of the material to be cut, we can set different cutting speeds and depths for the application. There are many factors that can influence the quality and performance of the cutting, such as the pump pressure, the diameter of the nozzle opening, speed of the cutting head, cutting pressure of the water jet, and the distance between nozzle and the material surface. The level of pressure exerted on the material surface determines the depth of the cut. In general, a pressure of 1000 to 4000 bar is used for industrial purposes. For achieving a precise and efficient cutting, it requires a pressure from 1000 to 6000 bar generated by the high-pressure pump to perform the cutting. We can increase the pressure by up to 6480 bar depending on the application and material type. The nozzle opening has a diameter ranging from 0.1 to 0.5 millimeters which define the speed and diameter of the water jet.
Other main components of the waterjet cutting system including the jet destroyer, control system, electric motor, pressure intensifier, high-pressure piping, oil tank/oil pump, water treatment, and a device for moving or positioning of the cutting head. The waterjet cutting is fully operated under CNC control. It has a CAD interface and also a CAM connection for the water jet cutting in some quality models. Some may also be equipped with a PC control that allows the user to easily perform the cutting process.
Types of Waterjet Cutting
1. Pure Waterjet Cutting
Pure water jet cutting can perform both soft and hard cutting processes. It is more suitable for soft materials such as plastic, rubber, leather, textiles, foam, paper, food, etc. The separation is completed by pure and filtered water that won't generate additional dust, chips, or toxic gases during the process. The pure water jet cutting process is considered a very environmentally friendly method as the water can be recycled or reuse for the next cutting and the water does not pollute the food during the cutting process. In order to prevent the formation of drops, the diameter of the water jet is relatively small which can be less than 0.1mm. So that it can provide precisely fitting cutting results.
2. Abrasive Waterjet Cutting
With the addition of an abrasive into the water jet, it can probably cut all the hard materials such as metal, marble, glass, ceramics, wood, stone, etc. During the process, powdery materials such as garnet or corundum are used as abrasive agents and added to the water jet. It is important to take note that, the abrasive powder is required to be harder than the material to be cut in order to make sure that the desired cutting result can be achieved. The abrasive agent is added which requires other parameters such as focus length, focus diameter, grain size, hardness, and mass flow in the process. The separability is increased and the join is wider as a result of the abrasive water jet cutting. There are three additional components in the abrasive water jet cutter, which are the pure water focusing nozzle, abrasive focusing nozzle, and abrasive mixing chamber. As the water is mixed with various substances during the abrasive process, scratch conveyors are used for removing residues from the jet shredder. After the water has been filtered, it can be re-used again for the next water cutting which helps to save costs and resources.
Each cutting technique has its own pros and cons, we choose the right method according to the application and specific parameters. At MecHero, we provide the waterjet cutting service to turn your ideas into real products according to your designs. We cover a wide range of materials such as aluminum, metal, steel, plastic, wood, etc.
Photo credit: ant-ag, performancewaterjet, isotoptech, thefabricator