The Influences of the Water Jet Focusing Tubes

In abrasive water jet cutting, the tungsten carbide water jet focusing tube is an important part. After all, it is in this tube where high-pressure water and abrasives are focused on an efficient cutting jet. During this procedure, the physical processes in the tube crucially affect the final speed and precision of the cutting jet as well as the kerf width at the workpieces.      

However, how do the shape and size of a water jet focusing tube influence?

An important feature of a water jet focusing tube is its length and inlet area.

In combination with the inlet area, the length of the wear-resistant water jet tube significantly determines the speed and focus of the exiting jet. The pure water jet created by an orifice is enhanced with abrasive sand in the mixing chamber, which is in front of the focusing tube. In this process, both the correct inlet angle and the minimum tube length are necessary to adjust the abrasive particles to the velocity and direction of the water jet. Thus, it can create a precisely focused and efficient cutting jet. However, the cemented carbide focusing tube should not be too long because friction at the inner surface can slow down the jet.

The interior diameter of the water jet nozzle tube is also important for the precise focus of the cutting jet.

Generally, the focusing tube hole and orifice have to be precisely aligned. The concentric, slightly wavelike wear can be observed, especially at the tube inlet. If the alignment is imprecise, the wear increases and affects the jet’s quality after a shorter period of use. This can lead to diversion of the cutting jet at the outlet of the tube and deterioration of the cutting quality at the workpiece. Other factors that particularly affect product life are the inlet velocity of the water jet and the amount and quality of the abrasive and, of course, the material quality of the focusing tube.

The common sizes of the tungsten carbide water jet focus nozzles: