Green Machining Characteristics Study of Al-6063 in CNC Milling Using Taguchi Method and Grey Relational Analysis

Green machining strategies in the manufacturing sector help to maintain the product value by considering the environmental impacts. Also, improvisation in the quality contribution of the parts can minimize the environmental consequences by improving resource efficiency, specifically in terms of coolants used in machining. Certain hazardous impacts have been witnessed because of longer exposure to such a machining environment. To address it, many researchers have concentrated on providing a healthy machining environment either by introducing dry machining or by minimum quantity lubrication (MQL). The proposed study addresses this context. The influence of these tactics on the attained surface quality of Al-6063 is quantified in this paper in terms of surface integrity (Ra) and removal rate of material (MRR). The study involves single-response optimization using the Taguchi design and multiresponse optimization using grey relational analysis (GRA). The results reveal that the depth of cut (Dc) and spindle speed (Ss) have the greatest impact on Ra and MRR. The machinability of Al-6063 is examined by considering the key machinability parameters, such as the spindle speed (Ss), feed rate (Fr), and the depth of cut (Dc), to arrive at the best possible surface roughness and removal rate of the material. As a typical Taguchi approach cannot perform multiresponse optimization, grey relational analysis is used. The grey relational analysis combined with Taguchi gives a novel methodology for multioptimization. The entire study is performed in dry condition and under minimum quantity lubrication. The results suggest that the responses are highly influenced by the depth of cut and spindle speed.

Impact of Cutting Environments on Sustainable Machining of H13 Tool Steel Alloy

The use of electrical energy and coolants/lubricants has been widely reported in mechanical machining. However, increased research and process innovation in high speed machining has brought about optimised manufacturing cycle times. This has promoted dry machining and the use of minimum quantity lubrication (MQL). This work understudies the impact of different cutting environments in machining H13 tool steel alloys at transition speed regime with emphasis on sustainable machining of the alloy. To achieve this, end milling tests were performed on AISI H13 steel alloy (192 BHN) on a MIKRON HSM 400 high speed machining centre using milling inserts. After each cutting pass, the milling insert was removed for tool wear measurement on the digital microscope. The electrical power consumed was measured with the Fluke 435 power clamp meter mounted on the three phase cable at the back of the machine. It was discovered that MQL has a promising advantage in terms of tool life with 25 minutes of machining, net power requirement of 10% when compared to dry cutting, and environmental benefits when machining H13 tool steel alloy. This work is fundamentally important in assessing the environmental credentials and resource efficiency regime for green machining of H13 tool steel alloysKeywords— H13 tool steel, green machining, process optimization, tool life, cutting environments, energy consumption

Material Removal Mechanism of Green Machining on Powder Metallurgy Parts during Orthogonal Cutting

Due to its energy-saving and cost-reducing characteristics, a novel green machining technique for powder metallurgy (PM) parts is attracting increasing concern. Unlike in the traditional PM machining technique, in the PM green-machining method arranges, the processing operation is performed before sintering. Since the pristine PM compacts are relatively soft because it just bonds the particles together, direct cutting on pristine PM compacts is a tool-saving and cost-effective manufacturing technique and its cutting mechanism is different from that of both solid plastic metals and conventional brittle materials because of the special characteristics of a discontinuous material. The influences of cutting parameters on machined surface roughness are investigated by orthogonal cutting experiments. The results show that the machined surface roughness decreases with increasing cutting thickness and rounded cutting edge radius and slightly increases with increasing rake angle. It is suggested that these results are contrary to the long-held notions of machined surface roughness. Moreover, a geometric model illustrating the PM green-machining process was established to reveal the mechanism of material removal and machined surface formation. This model shows that the material removal of PM is composed of particle shearing deformation, peeling, and ploughing/extruding. Finally, this machining model was validated through observations of machined surface morphology and chip morphology.