Metal cutting is often associated with heat generation from the material compression at the primary shear zone as well as friction surfaces of the tool and workpiece at the secondary cutting zone. Consequent of high temperature or heat generation at these zones significantly influenced the tool wear mechanisms; namely, as abrasion, adhesion, diffusion, and built-up layer. Excessive amount of heat generated is a primary cause for accelerated tool wear that shorten tool useful life. In addition, heat conducted from the tool insert to the tool holder increases its temperature which compromises the dimensional accuracy and machined surface quality and integrity. Conventionally, cutting fluid is utilized as a key approach to metal removal, reduce temperature and facilitate heat transfer at the cutting zone as well as removing the chip from that zone [1, 2]. Presence of cutting fluids during machining process results in substantial improvement on cutting tool and workpiece. This is an excellent practice, as it alleviates the effects of friction on the tool flank face and the machined surface since cooling can be attained through dissipation and conduction of the generated heat. Thermal damage on workpiece material and cutting tools can be prevented through lubrication and cooling effect of the cutting fluid, consequently alleviating the tool wear .
Despite the key functions of cutting fluids for machining process improvement, it also has a few drawbacks as subsequently elucidated. Firstly, the cost associated with the procurement of the cutting fluids is as high as 16–30 % of the total manufacturing costs . Secondly, due to the non-biodegradable nature of the fluids, expensive treatments prior to disposal are mandatory, which lead to high maintenance and disposal costs of up to two-folds of the cutting fluids purchasing costs [4, 5]. Thirdly, it has been reported that 80% of occupational skin diseases, respiratory ailments and cancer diseases among the machine operators were caused by inhalation of the cutting fluid . Hence, the importance of sustainable manufacturing emerges to alleviate the aforementioned burden on the machining processes, environmental and their associated costs. This is where the dry cutting has a great advantage and can be a favorable option.
Dry cutting is an eco-friendly approach that assists in reducing harmful wastes and discharges. Elimination in the use of cutting fluids is possible through dry machining, hence, attributed to low processing cost and ecological hazard . However, commercial and practical applications of dry machining are uncertain because of the absence of cooling and lubrication at tool-workpiece interface . Excessive frictions at the tool- workpiece interfaces also trigger temperature rise that attributed to significant abrasion, diffusion and/or oxidation types of tool wear mechanisms. The reduction of tool sharpness hinders the achievement of close tolerances as there can be metallurgical damage on the workpiece superficial layer .
To compensate for the absence of cutting fluids or express the possibility of avoiding the use of cutting fluids, numerous studies have been undertaken. Encouraging approach would be through internal cooling, which included internal heat sinks, heat exchangers, vortex tubes and heat pipe [9–12]. Previously, researchers had proposed internal cooling tool by creating a cooling channel in the cutting tool to cool down tool temperature from underneath of the cutting insert [13–15]. In these designs, cooling fluids was able to decrease the tool temperature at its back. However, Hong SY et al.  discovered that the tool back cooling was less effective than cooling at tool rake face. This is because of the apparent distance between flank and the tool rake surfaces. Thus, it was suggested that the location of cooling source had close relationship with the cutting zone when determining the effectiveness of cooling strategy [15, 17]. Molinari et al.  reported a high thermal energy generation within the primary and secondary shear zones. Temperature profile has depicted a hot spot at the rake face and the generated heat intensity was subjected to specific workpiece deformation. Therefore, it is important to accurately locate the cooling source near to the cutting edges to revoke the insert’s low thermal conductivity.
Meanwhile, magnesium alloys have received a great interest recently, because of its useful in several applications; namely, automotive, aerospace, microelectronics, and most lately in bio-medical applications. The recent uses of magnesium alloys in bio-medical industries can be attributed to their superior biodegradable properties and corrosion resistant . However, their low melting point contributed to ignition of the chips when machining temperature exceeds 450 oC . As a result, the use of cooling fluids is needed during machining of magnesium alloys for proper cutting temperature controlled. However, problem occurs when water-based coolant is applied during machining of magnesium alloys, because the reaction of water to magnesium alloys produces hydrogen gas that can lead to an explosion. To minimize this risk, dry cutting is favorable in cutting magnesium alloy, but suitable cutting parameter must be properly determined to ensure cutting process is conducted below critical temperature to avoid fire hazard, especially at elevated cutting speed.
Despite of widely established study on indirect cooling, there are limited research focusing on indirect cooling for machining light weight alloys especially on magnesium alloy. Most of previous studies are mainly devoted on cutting titanium alloy and nickel-based alloy [9, 13, 15]. Besides, there is still lack of study in tackling adhesion wear mechanism such as BUE and BUL by using indirect cooling. Therefore, in this study, an innovative and sustainable technique of submerged convective cooling (SCC) was introduced by partially submerged the tool rake face into a cooling medium to reduce tool temperature via internal cooling. Performance of the SCC was evaluated based on the capability of its heat removal, effect on cutting temperature and tool wear mechanism.