Optimization of Machining Parameters to Minimize Cutting Forces and Surface Roughness in Micro-Milling of Mg13Sn Alloy.

This comprehensive study investigates the micro-milling of a Mg13Sn alloy, a material of considerable interest in various high-precision applications, such as biomedical implants. The main objective of the study was to explore the optimizations of variable feed per tooth (fz), cutting speed (Vc), and depth of cut (ap) parameters on the key outcomes of the micro-milling process. A unique experimental setup was employed, employing a spindle capable of achieving up to 60,000 revolutions per minute. Additionally, the study leveraged linear slides backed by micro-step motors to facilitate precise axis movements, thereby maintaining a resolution accuracy of 0.1 µm. Cutting forces were accurately captured by a mini dynamometer and subsequently evaluated based on the peak to valley values for Fx (tangential force) and Fy (feed force). The study results revealed a clear and complex interplay between the varied cutting parameters and their subsequent impacts on the cutting forces and surface roughness. An increase in feed rate and depth of cut significantly increased the cutting forces. However, the cutting forces were found to decrease noticeably with the elevation of cutting speed. Intriguingly, the tangential force (Fx) was consistently higher than the feed force (Fy). Simultaneously, the study determined that the surface roughness, denoted by Sa values, increased in direct proportion to the feed rate. It was also found that the Sa surface roughness values decreased with the increase in cutting speed. This study recommends a parameter combination of fz = 5 µm/tooth feed rate, Vc = 62.8 m/min cutting speed, and ap = 400 µm depth of cut to maintain a Sa surface roughness value of less than 1 µm while ensuring an optimal material removal rate and machining time. The results derived from this study offer vital insights into the micro-milling of Mg13Sn alloys and contribute to the current body of knowledge on the topic.

Image Processing Approach to Investigate the Correlation between Machining Parameters and Burr Formation in Micro-Milling Processes of Selective-Laser-Melted AISI 316L.

In industrial manufacturing and research laboratories, precise machining of work materials is crucial to meet the demand for fast assembly and sustainable high-quality production. Precise machining procedures play a vital role in manufacturing compatible parts that meet the production requirements. This study investigates the impact of different parameters on burr formations and slot dimensions during the micro-milling of AISI 316 material. A careful examination was conducted using scanning electron microscopy (SEM) images under varying conditions. The variables considered include cutting speed, feed rate, and depth of cut. The main finding revealed that the feed rate and depth of cut significantly influence burr formation, with lower rates and depths resulting in noticeable reductions. A higher feed rate was associated with more pronounced burr formation. Moreover, burr widths on the down-milling sides were typically wider than those on the up-milling sides due to continuous chip formation and compressive forces during down-milling. Utilizing image processing, the study further quantified burr and slot widths with high accuracy, offering a reliable method to characterize burr formation. This research presents potential ways to minimize burr formation during micro-milling processes by effectively managing machining parameters.

Effect of Drilling Parameters and Tool Geometry on the Thrust Force and Surface Roughness of Aerospace Grade Laminate Composites.

Carbon fiber-reinforced plastics (CFRPs) have been specially developed to enhance the performance of commercial and military aircraft because of their strength, high stiffness-to-density ratios, and superior physical properties. On the other hand, fasteners and joints of CFRP materials may be weak due to occurring surface roughness and delamination problems during drilling operations. This study's aim is to investigate the drilling characterization of CFRPs with different drilling parameters and cutting tools. Drilling tests were performed with the Taguchi orthogonal array design (L18: 2^1 3^3). Tests were conducted with three levels of cutting speed (15, 30, 45 m/min), three levels of feed rate (0.05, 0.1, 0.2 mm/rev), two levels of drill diameter (3 and 5 mm), and three different types of drills (two twist drills with a point angle of 138° and 120° and one brad drill). Thrust forces were recorded during drilling tests, and afterwards surface roughness and hole delamination were measured. Obtained results were analyzed with Taguchi and two-way ANOVA. The general tendency was that low cutting speed, high feed rate, and small diameter drill caused an increase in thrust force. Surface roughness decreases with increasing tool diameter, decreasing feed, and cutting speed. Delamination factors of the samples dropped depending on decreasing thrust force levels. Remarkably, it is possible to control the delamination factor values via better surface quality. The brad drill and larger point angle have a negative effect on the drilling quality of CFRPs. According to all results, the cutting speed of 45 m/min and feed rate of 0.05 mm/rev using a type II drill having a 120° point angle and 5 mm diameter (12th trial) and the cutting speed of 30 m/min and feed rate of 0.05 mm/rev using a type II drill having a 120° point angle and 3 mm diameter (2nd trial) were determined as optimum drilling conditions.

Optimization of Micro-Drilling of Laminated Aluminum Composite Panel (Al-PE) Using Taguchi Orthogonal Array Design.

Aluminum Matrix Composite (AMC) represents an innovative class of materials that is extensively utilized in industries such as automotive, defense, aerospace, structural engineering, sports, and electronics. This study investigates the thrust force, exit burr formation, changes in the micro-tool, and drilled hole diameters during the micro-drilling of an aluminum-polyethylene composite panel (Al-PE). The panel consists of 3501 series aluminum skin materials bonded to a polyethylene (PE) core. Micro-drilling test parameters were designed using Taguchi's L16 (42 23) orthogonal array. Tests were conducted with five control parameters: cutting speed with four levels (10 m/min, 20 m/min, 30 m/min, 40 m/min), feed rate with four levels (0.5 µm/rev, 1 µm/rev, 2 µm/rev, 4 µm/rev), the tool diameter with two levels (0.7 mm, 1 mm), and tool point angle with two levels (100°, 140°) using both AlTiN-coated and uncoated drills. The maximum thrust force (Fz), maximum burr height, and changes in both the drill tool and hole diameters were measured for analysis of variance (ANOVA). The results showed that, in terms of impact on Fz, tool point angle had the highest positive influence (64.54%) on the micro-drill at the entrance of composite (upper aluminum plate). The cutting speed had the highest positive influence (45.32%) on the tool in the core layer (PE core layer). The tool point angle also had the highest positive influence (68.95%) on the micro-drill at the lower layer of the composite (the lower aluminum plate). There was noticeable chip adhesion on the major cutting edge and nose area under micro-drilling conditions with higher thrust forces and burr height. The AlTiN coating had a positive effect on tool wear and hole diameter deviations, but it adversely affected the burr height.

Comparative Analysis of Minimum Chip Thickness, Surface Quality and Burr Formation in Micro-Milling of Wrought and Selective Laser Melted Ti64.

Selective laser melting (SLM) is a three-dimensional (3D) printing process that can manufacture functional parts with complex geometries as an alternative to using traditional processes, such as machining wrought metal. If precision and a high surface finish are required, particularly for creating miniature channels or geometries smaller than 1 mm, the fabricated parts can be further machined. Therefore, micro milling plays a significant role in the production of such miniscule geometries. This experimental study compares the micro machinability of Ti-6Al-4V (Ti64) parts produced via SLM compared with wrought Ti64. The aim is to investigate the effect of micro milling parameters on the resulting cutting forces (Fx, Fy, and Fz), surface roughness (Ra and Rz), and burr width. In the study, a wide range of feed rates was considered to determine the minimum chip thickness. Additionally, the effects of the depth of cut and spindle speed were observed by taking into account four different parameters. The manufacturing method for the Ti64 alloy does not affect the minimum chip thickness (MCT) and the MCT for both the SLM and wrought is 1 µm/tooth. SLM parts exhibit acicular α martensitic grains, which result in higher hardness and tensile strength. This phenomenon prolongs the transition zone of micro-milling for the formation of minimum chip thickness. Additionally, the average cutting force values for SLM and wrought Ti64 fluctuated between 0.072 N and 1.96 N, depending on the micro milling parameters used. Finally, it is worth noting that micro-milled SLM workpieces exhibit lower areal surface roughness than wrought ones.

A Multi-Flow Production Line for Sorting of Eggs Using Image Processing.

In egg production facilities, the classification of eggs is carried out either manually or by using sophisticated systems such as load cells. However, there is a need for the classification of eggs to be carried out with faster and cheaper methods. In the agri-food industry, the use of image processing technology is continuously increasing due to the data processing speed and cost-effective solutions. In this study, an image processing approach was used to classify chicken eggs on an industrial roller conveyor line in real-time. A color camera was used to acquire images in an illumination cabinet on a motorized roller conveyor while eggs are moving on the movement halls. The system successfully operated for the grading of eggs in the industrial multi-flow production line in real-time. There were significant correlations among measured weights of the eggs after image processing. The coefficient of linear correlation (R2) between measured and actual weights was 0.95.

Microstructure, Mechanical, and Corrosion Behavior of Al2O3 Reinforced Mg2Zn Matrix Magnesium Composites.

Powder metallurgy (PM) method is one of the most effective methods for the production of composite materials. However, there are obstacles that limit the production of magnesium matrix composites (MgMCs), which are in the category of biodegradable materials, by this method. During the weighing and mixing stages, risky situations can arise, such as the exposure of Mg powders to oxidation. Once this risk is eliminated, new MgMCs can be produced. In this study, a paraffin coating technique was applied to Mg powders and new MgMCs with superior mechanical and corrosion properties were produced using the hot pressing technique. The content of the composites consist of an Mg2Zn matrix alloy and Al2O3 particle reinforcements. After the debinding stage at 300 °C, the sintering process was carried out at 625 °C under 50 MPa pressure for 60 min. Before and after the immersion process in Hank's solution, the surface morphology of the composite specimens was examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. With the hot pressing technique, composite specimens with a very dense and homogeneous microstructure were obtained. While Al2O3 reinforcement improved the mechanical properties, it was effective in changing the corrosion properties up to a certain extent (2 wt.% Al2O3). The highest tensile strength value of approximately 191 MPa from the specimen with 8 wt.% Al2O3. The lowest weight loss and corrosion rate were obtained from the specimen containing 2 wt.% Al2O3 at approximately 9% and 2.5 mm/year, respectively. While the Mg(OH)2 structure in the microstructure formed a temporary film layer, the apatite structures containing Ca, P, and O exhibited a permanent behavior on the surface, and significantly improved the corrosion resistance.

Image Processing of Mg-Al-Sn Alloy Microstructures for Determining Phase Ratios and Grain Size and Correction with Manual Measurement.

The study of microstructures for the accurate control of material properties is of industrial relevance. Identification and characterization of microstructural properties by manual measurement are often slow, labour intensive, and have a lack of repeatability. In the present work, the intermetallic phase ratio and grain size in the microstructure of known Mg-Sn-Al alloys were measured by computer vision (CV) technology. New Mg (Magnesium) alloys with different alloying element contents were selected as the work materials. Mg alloys (Mg-Al-Sn) were produced using the hot-pressing powder metallurgy technique. The alloys were sintered at 620 °C under 50 MPa pressure in an argon gas atmosphere. Scanning electron microscopy (SEM) images were taken for all the fabricated alloys (three alloys: Mg-7Al-5Sn, Mg-8Al-5Sn, Mg-9Al-5Sn). From the SEM images, the grain size was counted manually and automatically with the application of CV technology. The obtained results were evaluated by correcting automated grain counting procedures with manual measurements. The accuracy of the automated counting technique for determining the grain count exceeded 92% compared to the manual counting procedure. In addition, ASTM (American Society for Testing and Materials) grain sizes were accurately calculated (approximately 99% accuracy) according to the determined grain counts in the SEM images. Hence, a successful approach was proposed by calculating the ASTM grain sizes of each alloy with respect to manual and automated counting methods. The intermetallic phases (Mg17Al12 and Mg2Sn) were also detected by theoretical calculations and automated measurements. The accuracy of automated measurements for Mg17Al12 and Mg2Sn intermetallic phases were over 95% and 97%, respectively. The proposed automatic image processing technique can be used as a tool to track and analyse the grain and intermetallic phases of the microstructure of other alloys such as AZ31 and AZ91 magnesium alloys, aluminium, titanium, and Co alloys.

Measurement of Micro Burr and Slot Widths through Image Processing: Comparison of Manual and Automated Measurements in Micro-Milling.

In this study, the burr and slot widths formed after the micro-milling process of Inconel 718 alloy were investigated using a rapid and accurate image processing method. The measurements were obtained using a user-defined subroutine for image processing. To determine the accuracy of the developed imaging process technique, the automated measurement results were compared against results measured using a manual measurement method. For the cutting experiments, Inconel 718 alloy was machined using several cutting tools with different geometry, such as the helix angle, axial rake angle, and number of cutting edges. The images of the burr and slots were captured using a scanning electron microscope (SEM). The captured images were processed with computer vision software, which was written in C++ programming language and open-sourced computer library (Open CV). According to the results, it was determined that there is a good correlation between automated and manual measurements of slot and burr widths. The accuracy of the proposed method is above 91%, 98%, and 99% for up milling, down milling, and slot measurements, respectively. The conducted study offers a user-friendly, fast, and accurate solution using computer vision (CV) technology by requiring only one SEM image as input to characterize slot and burr formation.