Investigation of DIAjet (Direct Injection of Abrasive Jet) Cutting of Granite

The drilling and cutting of rock by a DIAjet system can be an alternative to conventional rock removal methods. In order to assess the practicality of this method, an experimental study has been conducted examining the effect which different cutting parameters have on the process. A total of 128 single pass cuts were made on a sample of Georgia granite. Two different nozzle types were used in the program, and seven different abrasives were evaluated. The depth, width and volume of the resulting slot were measured. Based on these values the specific energy and erosion efficiency of the abrasive was calculated as an indicator of cutting efficiency. The following conclusions could be drawn from the results obtained: Depth of cut increases with an increase in jet pressure, abrasive flow rate, particle size and hardness. Depth of cut decreases with an increase in traverse velocity. The relationships found appeared to be similar to those found with conventional abrasive jet entrainment. Pressure and abrasive hardness were found to be the most influential parameters on the resulting depth of cut. A possible optimum depth of cut occurred when the abrasive feed rate reached a value of 100 g/sec. The rate at which the kerf area was generated appeared to reach a maximum when the traverse velocity lay between 35 and 60 cm/min. Nozzle wear was found to increase as nozzle diameter reduced and as particle size increased