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Problems related to ultra-high pressure water jet and numerical control water jet


*What is CNC waterjet?

*What are the characteristics and advantages of CNC waterjet?

*What accuracy can CNC waterjet achieve?

*What is the maximum thickness that the CNC waterjet can cut?

*What is the working principle of the high-pressure pump (high-pressure generator)?and many more...

The following will explain to you one by one.

 *What is CNC waterjet?

  The CNC waterjet is a plane cutting machine tool that combines an ultra-high pressure water jet generator and a two-dimensional CNC machining platform. It raises the pressure of the water flow to a high enough level (above 200MPa), so that the water flow has great kinetic energy, which can penetrate chemical fiber, wood, leather, rubber, etc., mixing a certain proportion of abrasive in the high-speed water flow can penetrate almost all Hard materials such as ceramics, stone, glass, metals, alloys, etc. Under the guidance of the two-dimensional numerical control processing platform, start or end processing at any position of the material, and move at an appropriate speed according to the set track to realize the plane cutting of any graphics.

 *What are the characteristics and advantages of CNC waterjet?

Compared with the traditional "hot" cutting process, the ultra-high pressure water jet cutting machine uses water as the cutting medium, which is a "cold" cutting process. It has the following functions and advantages:

1. No thermal deformation during cutting, avoiding physical and chemical changes of materials;

2. It is widely adapted to the cutting process of various materials and has the reputation of "universal cutting machine";

3. The cut is smooth and flat without burrs, and generally does not need to be processed again;

4. Operated by the numerical control system, with high cutting precision;

5. The cutting seam is less than 1.2mm, which is convenient for nesting cutting and saving materials;

6. The processing process will not produce waste that pollutes the environment.

 CNC waterjet is ideal or the only processing method for materials that are difficult to cut by other methods, such as Kevler, titanium alloy and various composite materials.

 *What accuracy can CNC waterjet achieve?

Strictly speaking, although CNC waterjet can cut more accurately than flame and plasma cutting machine tools, it is not a precision processing machine tool and should not be marked with accuracy. When cutting a sheet of less than 10mm, the cutting speed and compensation should be properly controlled, and the error can be +-0.1mm. *What is the maximum thickness that the CNC waterjet can cut?

Since the target distance of the water jet is uncertain or variable, the maximum cutting thickness of the CNC water jet is not well defined. It is reasonable for the bold to call 400 or 500mm, and conservatives to call it within 100mm. The current numerical control waterjet generally has a flow rate of 2 to 3 liters, and the working pressure

With a force of 200-380MPa, the jet passes through the air resistance, and the energy decays extremely fast. When it reaches 400mm or 500mm, it basically drifts away with the wind, and there is no impact. For general applications, the thickness of the cut metal sheet is recommended to not exceed 100mm, and the thickness of foamed materials such as sponge is recommended to not exceed 300mm.

*What is the working principle of the high-pressure pump (high-pressure generator)?

   Working principle of oil circuit part

 The electric motor drives the oil pump to pump the hydraulic oil from the oil tank and send it to the oil pressure pipeline through the one-way valve. At this time, the oil circuit is divided into three ways, one is connected to the accumulator and the pressure gauge, the pressure gauge shows the oil pressure, the accumulator can play the role of stabilizing the oil pressure, the second way is connected to the reversing valve, and the other way is connected to the overflow valve. When the water jet button is not pressed, the hydraulic oil sent from the oil pump flows directly back to the oil tank through the overflow valve, water-cooled cooler and oil return filter, and a small amount of hydraulic oil enters the oil chamber of the booster through the reversing valve , It is not enough to push the oil piston to reverse or change slowly; and when the water jet button is pressed, the overflow valve is closed, and the hydraulic oil enters the oil chamber of the booster through the reversing valve, pushing the oil piston to move, and the oil piston is another The hydraulic oil on one side is pushed out of the cylinder and flows back to the oil tank through the water-cooled cooler and the oil return filter. When the oil piston is pushed to the end of the oil cylinder and collides with the reversing mandrel, the mandrel triggers the reversing valve to generate a reversing signal, so that the hydraulic oil circuit enters from the other end of the oil cylinder and the oil piston returns. To the end of the oil cylinder, the reversing ejector rod is triggered again, and the oil piston returns. In this way, the commutator is continuously triggered to switch the oil circuit, thereby forming the reciprocating motion of the supercharger.

Working Principle of Waterway

 After the tap water is filtered by the filter, it is pressurized by the water pump and enters the high pressure cylinders at both ends of the booster. When the oil piston reciprocates, the high pressure cylinder at one end enters the water through the water inlet check valve, and the water in the high pressure cylinder at the other end is pushed out and enters the high pressure pipeline through the water outlet check valve. This action is performed alternately in the high-pressure cylinders at both ends to form a continuous flow of high-pressure water. Due to the reversing cycle of the supercharger, the pressure of the output water flow forms periodic fluctuations. Therefore, the high-pressure water flow needs to be stabilized by a high-pressure accumulator and delivered to the spray head through the high-pressure pipe. A jewel nozzle with an aperture of 0.25~0.33mm is installed on the jet head. The high-pressure water flow forms a high-speed "water arrow" with great kinetic energy under the restriction of the jewel nozzle, which can penetrate soft materials such as fibers, leather, and rubber. Mixing a certain proportion of abrasive in the "Water Arrow" will form an abrasive water jet that can penetrate any hard material.

Supercharger principle

 When hydraulic oil acts on the piston, the high-pressure plunger rod connected to the piston pushes out the water in the high-pressure cylinder. According to the law of conservation of energy, assuming no friction loss, the work of the two is equal. At this time, oil pressure multiplied by the cross-sectional area of the piston is equal to water pressure multiplied by the cross-sectional area of the plunger rod, that is, the ratio of water pressure to oil pressure is equal to the ratio of the cross-sectional area of the oil piston to the cross-sectional area of the high-pressure plunger rod. The ratio of the cross-sectional area of the oil piston to the cross-sectional area of the high-pressure plunger rod is called the "pressurization ratio". Since the ratio is fixed, the water pressure can be adjusted by controlling the oil pressure.



label: water jet
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