Waterjet Cutting Tech Tips

JetTalk: Optimal combination of orifice, waterjet nozzle and GMA Garnet (PART I)

Investing in high quality nozzle, orifice and effective garnet abrasives such as GMA Garnet™ for your waterjet cutting machine will enhance the performance and precision of your cutting applications. 

However, you can take this further by setting up the ideal combination of the size of garnet abrasives along with nozzle and orifice to get the best precision cutting.

As you know, when garnet abrasives are added to the waterjet stream. The abrasive particles travel at three times the speed of sound!  

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The cutting speed can be increased by adding more abrasives to the waterjet stream. However, adding too much abrasives will rob speed and energy from the waterjet stream and the cutting speed will start to decrease. 

That’s why waterjet manufacturers conduct extensive testing with various orifice and nozzle combinations to find the optimum abrasive amount with consideration of cost and cutting speed. 

Orifice Selection 

When it comes to orifice selection, we can just refer to an “Orifice Selection Chart” supplied by the pump manufacturer as their design engineers have done most of the calculations for us. From this chart, you can easily pick a 0.014” orifice or two 0.010” orifices for the 50 HP pump. 


In the next edition, we will touch on waterjet nozzle selection and the possible combinations.\


TGEHDawda By Hemanshu Dawda, GMA Middle East