## 1 Introduction  
Austenitic stainless steel 304L (AISI 304L) possesses excellent forming and welding characteristics, which has led to its broad application in industries such as automotive, shipbuilding and marine, material handling equipment, automotive parts, as well as construction materials [1]. AISI 304L is widely used in various thickness in the fabrication industry and in many cases requires contour machining to achieve complex and complicated profiles. However, AISI 304L is a difficult-to-cut material due to its high alloying content (i.e., chromium and nickel), low thermal conductivity, high ductility, and low machinability level [1]. Therefore, when cutting AISI 304L, it can be challenging to choose an alternative to achieve precise cutting without compromising metallurgical properties. Although various non-conventional technologies have been applied to cut stainless steel, such as a laser beam machines; this technology often has a high thermal distortion that alters metallurgical properties of the workpiece [2]. Abrasive waterjet machining (AWJM) is one of these advanced technologies that has been a popular method for cutting metallic and heat-sensitive materials due to several advantages, such as the absence of heat-affected zone (HAZ) and no changes in material properties [3]. AWJM can cut both hard and delicate materials with a wide range of thicknesses with a very low machining force, preventing the destruction of the properties of the target workpiece [4]. Moreover, whilst AWJM is also considered environmentally friendly and sustainable as it does not omit any hazardous vapours; hence, AWJM produces waste abrasives that affect the environment. Accordingly, recycling or reusing of these abrasives has the potential to resolve ecological issues and concerns relating to AWJ application [5; 6; 7]. Abrasive waterjet machining is comprised of several input process parameters that ultimately determine the efficiency and quality of the machining processes. These parameters are generally categorised as hydraulic, abrasives, cutting and mixing, and acceleration [8]. Whilst AWJM demonstrates capability in cutting difficult-to-machine materials, they still experience some challenges. There have been reported issues in material response to AWJM concerning its behaviour, such as kerf tapering and low material removal, since the beginning of its applications. Kerf taper is the tapering angle generated during the AWJM process associated with the variation of kerf widths, which involves cut width of the material at the top and bottom [9; 10]. Further, materials like AISI 304L have a relatively low material removal rate due to their relative machinability. The material removal rate in an AWJM for ductile materials like stainless steel is facilitated by a combination of cutting wear and deformation wear mechanism [9]. This involves determining the quantity of removed material from the workpiece per unit time, where the literature reveals that varied studies have been conducted on the effects of different parameters on the quality and efficiency of abrasive waterjet cutting performance. Therefore, an appropriate combination of AWJM input parameters, such as waterjet pressure, traverse speed, and mass rate of abrasive particles is important to achieve the required machining efficiency and material surface qualities [3]. For instance, [PERSON], et al. [11] studied quality defects such as kerf taper, cutting residue, and striation in AWJ cutting of AISI 304. Their study postulated that decreasing the jet energy is the cause of quality defects. [PERSON] et al. [12] investigated the kerf taper angle generated in AWJ cutting of AISI 1090 mild steel with results indicating that the ratio of kerf taper increases at a higher level of standoff distance. They established that abrasive particles have higher kinetic energy at higher standoff distance leading to wider kerf taper angles; moreover, these particles gradually lose their kinetic energy as it moves towards from jet entry up to the exit. [PERSON] et al.