# Recent Progress Trend on Abrasive Waterjet Cutting of Metallic Materials: A Review
## 3 Abrasive Waterjet Cutting Process Parameters and Influences
### Abrasive Waterjet Cutting Input Process Parameters Functions and Influences
#### 3.1.4 Cutting System  
These are the traverse speed, stand-off distance and jet impact angle. The traverse speed corresponds to the turning of a tank during machining, measured in mm/min. The standoff distance is the height from the endpoint of the nozzle up to the top surface of the target material, where it is indicated in mm. The jet impact angle is the angle of the jet towards a cutting level surface [6]. Recently, a relevant increase in productivity was obtained by utilizing AWJM with multiple cutting heads. There are two traverse systems that can be utilized simultaneously and independently to machine larger and multiple parts [5]. Impacts of traverse speed: Traverse speed variation has a significant effect on AWJM output parameters. [PERSON] et al. [98] reported that minimizing the kerf angle and surface roughness in AWJ cutting of hybrid aluminum 7075 metal matrix composites can be obtained by applying a low level of traverse speed and a high level of pressure. Their results are consistent with [PERSON] et al. [77], who explored minimizing the kerf taper angle in cutting AA6061 using a low level of traverse speed. [PERSON] et al. [99] have distinguished that traverse speed was the most significant and impacting parameter for the material removal rate in AWJ cutting of stainless-clad steel workpieces. Additionally, the feed rate was revealed to be the most influential parameter in controlling the responses on surface roughness and kerf-angle in abrasive waterjet cutting of AISI 1018 with 5 mm thickness [94]. Moreover, [PERSON] et al. [100] explored AWJM multiple passes and achieved a higher depth of cut by utilizing a higher number of passes and higher-level traverse speed; hence, under particular conditions, the application of multiple passes can provide better results as compared with single pass machining. On the basis of these studies, the traverse speed is directly proportional to the material removal rate but inversely relative to the depth of cut, surface roughness, and kerf taper. Impacts of stand-off distance: A higher distance from the nozzle exit and workpiece top surface results in decreasing velocity of the particles, which denotes a lower material removal rate, roughness, and kerf taper angle [92]. [PERSON] et al. [81] have examined that decreased kerf width and roughness of cut parts can be obtained by applying a near standoff distance, a lower rate of traverse speed, and a smaller nozzle diameter at a higher material thickness when cutting steel sheets using an abrasive waterjet machine (TRIP 800 HR-FH and TRIP 700 CR-FH). In summary, it has been found that a combination of a high-level standoff distance and high-rate traverse speed lowers the contact time of abrasive particles within the cutting process. Impacts of jet impact angle: Varying the jet impingement angle leads to different impacts in AWJM output parameters depending on the hardness scale of a a workpiece [101]. For instance, [PERSON] et al. [35] have proposed the importance of managing the jet impact angle to intensify AWJ cutting output responses. They reported that varying the impingement of the jet angle, along with using a different abrasive mesh size can affect the kerf width, taper ratio, and cut surface roughness when cutting AA5083-H32. An oblique jet angle of 70\({}^{\circ}\) was shown to lead to lesser kerf taper ratio, roughness and striations. Furthermore, [PERSON] et al. [80] have conducted an experiment using a different metal, D2 Steel, and concluded that a jet impact angle of 70\({}^{\circ}\) sustained better cut surface integrity. A larger degree of jet impingement angle results in a higher material removal rate, particularly in hard-to-cut materials; thus, an acute jet impact angle provides a precise cutting performance predominantly in soft materials [91].