TRIZ approach for machining process innovation in cryogenic environment

This paper presents the utilisation of TRIZ approach in machining process of AISI 4340 in cryogenic environment which lead to product improvement in turning process. The machining study is carried out in two stages; FEM simulation for finding the optimum condition and machining experiment to visualise the product improvement that involved plastic deformation. The simulation result revealed that at moderate to high cutting speed, high feed rate and high depth of cut will result in high temperature that enable for the change in phase of AISI 4340 from retained austenite to fully martensite. A sample from machining experiment at optimum cutting condition found that the microstructure changes beneath the machined until at the depth of ∼7 μm with high hardness to 8,500 N/mm2 Martens hardness at the machined surface. This hardness is equivalent to the hardness obtained in conventional case hardening process that is required after the machining of AISI 4340 in their application as automotive engine parts in order to enhance these parts in their service lives. This study reveals that the TRIZ approach helps to systematically analyse the various outcomes in this study started with process limitation, problem identification, axiomatic and Su-field analysis

Chip formation in turning S45C medium carbon steel in cryogenic conditions

This paper presents the tribology issue regarding the chip formation in machining medium carbon steel (S45C) using a coated and uncoated carbide tools. The machining parameters under investigation were cutting speed, feed rate, and depth of cut under dry and cryogenic cutting condition using coated and uncoated carbide tools. The chip shape was largely depended on the combination of machining parameters, especially at high depth of cut and feed rate; the favorable chip was produced. Larger value of shear angle results in smaller shear plane area that provides benefits of lower cutting force needed to shear off the chips and lower cutting temperature being generated during the machining process

Optimization of machining parameters during milling of carbon fibre reinforced plastics

This paper investigates the optimization of cutting parameters on tool life of carbide cutting tools during milling Carbon Fibre Reinforced Plastic (CFRP) of unidirectional fiber orientation of 90°. CFRP is one form of composite material which is highly demand by manufacturing sectors due to its light weight ratio and stronger than aluminium properties. Despite of having high demand in industry, researchers face a lot of problems during machining CFRP during assemble phase. High tool wear and short tool life of cutting tool used during machining, lead to high production cost are among the factors which concern the machinist the most. This research is carried out by using spindle speed of 1000 rpm to 8700 rpm, feed rate of 500 mm/min to 1000 mm/min and depth of cut of 1 mm to 1.5 mm which will be acted as the input variable. The output response is in form of tool wear and tool life of carbide cutting tool. In this study, CNC Mazak Milling Machine with maximum spindle speed of 12000 rpm is used to mill CFRP. Box Behnken Design under Response Surface Methodology is used as Design of Experiment to generate 15 runs. The optimization of cutting parameters for 90° is analyzed using Analysis of Variance (ANOVA). It was found that, higher spindle speed, lower feed rate and lower depth of cut lead to lowest tool wear and highest tool life. ANOVA analysis recorded that feed rate is the most significant factor that influence tool life

Analysis of defects on machined surfaces of aluminum alloy (Al 7075) using imaging and topographical techniques

Aluminum alloys 7075 (Al 7075) are widely used for various industrial components in which machining operations are often conducted during their manufacturing process. However, the machining operations could introduce defects on the machined surfaces of the components which will be carried over and may lead to either issues in the subsequent fabrication process or failure during the products' service life. This study investigates the machined surface's defects of Al 7075 underwent drilling operations using imaging and topographical techniques which include optical microscope, scanning electron microscope and 3D surface profiler. Surface roughness was analysed with respect to the surface defects to investigate the correlation between the roughness parameters and topographical features of the machined surfaces. The defects found on the machined surfaces of Al 7075 are microcrack, adhesion, feed mark and burr. Surface roughness was found to be highly influenced by topographical features particularly feed mark. Thus, in addition to measuring the roughness, inspection through imaging and 3D topographic techniques is important for analyzing the surface characteristic in order to determine the defects, hence deducing the detailed surface features and deformation caused by the drilling operations

Effects of drilled area temperatures on drilling of NFRP composites: a review

The growth of high-performance semi-structural and structural applications made from natural resources is growing universal, due to renewable and ecological matters. Machining natural fibers reinforced polymer (NFRP) has become a challenger in the machining processes for incorporating them into the NFRP industrial production chains. The thermo-physical properties of fiber-reinforced plastics (FRPs) causes high temperatures at the tool tip when machined. The generated heat affects the process behavior as well as the machining surface quality. It causes accuracy errors when machining composites. This papers reviews the research published during drilling of natural fiber reinforced polymer composites with special reference to the effect of different cutting parameters

Machining-induced grain refinement of AISI 4340 alloy steel under dry and cryogenic conditions

Machining significantly influences surface integrity, metallurgical structure, grain size and thereby the mechanical, chemical and physical properties of the component. The presented investigation concentrates on grain refinement in turning of AISI 4340 alloy steel in dry and cryogenic turning. With cutting temperatures below 950 ◦C, the resulted surface layer consists of a microstructure with ultrafine white globular particles in all samples. A higher percentage of these particles was observed when using cryogenic flushing. It resulted in improved surface and subsurface properties in terms of ultrafine microstructure concentration, higher micro hardness, influence on the thickness and composition of the surface, and subsurface layers and thermal stabilit

The investigation of PVD coating, cryogenic lubrication and ultrasonic vibration on tool wear and surface integrity in manufacturing processes

Lubricants are harmful to human health and the environment. However, it is the only effective method to reduce friction and to prevent tool wear, leading to a highquality surface. This paper presents the development and testing of environmental-friendly tribology systems in manufacturing processes – metal forming and machining. PVD coatings, cryogenic lubrication and ultrasonic vibration were introduced to replace the use of oil lubrication in manufacturing processes, and investigated on experimental works of reciprocating rig, sheet-metal forming, turning and drilling with different process parameters, ie. lubrication conditions and speeds. Combating friction and tool wear with potential tribology systems like the PVD coatings, cryogenic lubrication and ultrasonic-assisted technique have led to positive results to improve lubrication, thereby delay tool wear progression

Environmental-friendly tribological and lubrication in manufacturing processes

Lubricants are harmful to human health and environment. However, it is the only effective method to reduce friction and to prevent tool wear, leading to high quality surface. The present work dealt with development and testing of environmental-friendly tribology systems in manufacturing processes – metal forming and machining. The present study involved experimental studies on pin-on-disk, sheet-metal forming, turning and drilling with different process parameters, ie. lubrication conditions and speeds. Combating friction and tool wear with potential tribology systems like hard coatings, cryogenic lubrication and ultrasonic assisted technique have led to positive results to improve lubrication

The effect of cryogenic application on surface integrity in manufacturing process: A review

The quality of work material’s surfaces after undergone various manufacturing processes is very important in determining the functional performance of a component throughout the services. Application of coolant and lubricant in manufacturing operations such as turning, milling, grinding, rolling, etc. has been proven to improve the surface integrity of the work materials. In this review, application of cryogenic coolant in manufacturing operations was investigated in terms of its effects on surface integrity of the work materials which includes surface finish, microstructural changes, refinement of grain size, formation of white layer, residual stresses of internal subsurface layer, and surface hardness. Cryogenic application is able to reduce the value of surface roughness, allow for more comprehensive martensitic transformation, reduce the grain size, prevent the formation of white layer at the subsurface, reduce the tensile residual stresses and increase compressive stresses area, and finally increase the hardness of the work material. In conclusion, cryogenic application in a lot of manufacturing processes has been determined to be able to enhance and improve the quality of the workpiece surface, consequently, boost the functional performance of the components

The influence of machining condition and cutting tool wear on surface roughness of AISI 4340 steel

Sustainable machining by using cryogenic coolant as the cutting fluid has been proven to enhance some machining outputs. The main objective of the current work was to investigate the influence of machining conditions; dry and cryogenic, as well as the cutting tool wear on the machined surface roughness of AISI 4340 steel. The experimental tests were performed using chemical vapor deposition (CVD) coated carbide inserts. The value of machined surface roughness were measured at 3 cutting intervals; beginning, middle, and end of the cutting based on the readings of the tool flank wear. The results revealed that cryogenic turning had the greatest influence on surface roughness when machined at lower cutting speed and higher feed rate. Meanwhile, the cutting tool wear was also found to influence the surface roughness, either improving it or deteriorating it, based on the severity and the mechanism of the flank wea