Increase Of Spindle Speed Research Articles

Investigation of the effect of electrophoresis-assisted milling on machinability

In this study, the electrophoresis-assisted milling (EAM) method, an alternative method to the conventional milling (CM) method, was proposed to increase the machinability of Ti6Al4V alloy, which is difficult to machine. The nanoparticles in the electrophoresis solution generated an electric field. This electric field collected abrasive particles around the cutting tool, and the machining quality was improved. The impacts of different cutting parameters on the performance characteristics were examined using both EAM and CM methods. The experimental results demonstrate that the proposed EAM method significantly improves these performance characteristics. In addition, increasing spindle speed increased tool wear and cutting temperature for both machining methods; It was observed that it reduced cutting force and surface roughness. It was concluded that as the feed rate increased, tool wear, cutting temperature, cutting force, and surface roughness increased. The experimental results showed that feed rate, machining method, and spindle speed affect machining quality. In conclusion, the experimental results significantly impact improving the machining performance of the EAM method.

Longitudinal torsional ultrasonic vibratory assistant milling of borosilicate glass material removal mechanism based on the thickness of undeformed chips

Borosilicate glass is an ideal material for microfluidic chip substrates due to its excellent light transmittance and stable chemical properties. However, it is also prone to brittle fracture during processing, making it a typical difficult-to-machine material. As an emerging processing technology, longitudinal torsional ultrasonic assistant milling (LTUVAM) can effectively reduce the surface damage of glass materials and improve the proportion of plastic removal of materials. The mechanism of LTUVAM of borosilicate glass was studied in this paper. Critical undeformed chip thickness (hc) is a key factor in achieving plastic material removal. At present, the influence of LTUVAM on the hc is not clear. Therefore, in this paper, the material-specific cutting energy model in the LTUVAM process was established to predict the hc. Firstly, the motion path of LTUVAM was analyzed, and the undeformed chip thickness model and the tool-workpiece separation rate model were established. Then, based on the above model, the material-specific cutting energy model was established according to the material removal principle. Finally, an LTUVAM orthogonal experiment was carried out to study the surface quality of the material. The experimental results showed that with the increase of ultrasonic power, the roughness and side damage area increased first and then decreased. With the increase of spindle speed, it showed that the roughness and side damage area decreased first and then increased. With the increase of feed per tooth, it showed that the roughness increased first and then decreased, and then increased, and the side damage area increased first and then decreased. Through the analysis of the experimental and model results, the increase of the separation rate between the tool and the workpiece contributes to the increase of the hc and the improvement of the processing quality.

Investigation on two-dimensional ultrasonic vibration plane turning method based on elliptical plane swinging strategy along short axis

In the ultrasonic elliptical vibration cutting (UEVC) process, the surface morphology suffers from the large fluctuation of ridge height and residual height, which has restricted the development of UEVC technology. Therefore, on the basis of the elliptical plane swinging strategy along a short axis, a surface topography improvement method (i.e., swing ultrasonic elliptical vibration turning (SUEVT)) for two-dimensional ultrasonic vibration plane turning is proposed in this study. The core idea of the method is to swing the ultrasonic elliptical vibration plane along the short axis to form a machining inclination angle, which reduces the ridge height of the machined morphology to a certain extent, thereby optimizing the surface microstructure and reducing the surface roughness. First, this study establishes a mathematical model of the tool tip trajectory of ultrasonic elliptical vibration under different swing angles, theoretically analyzes the influence of swing angles on the tool tip trajectory and surface topography, and provides a theoretical basis for revealing the surface topography formation mechanism of SUEVT. Second, an engineering practice scheme of SUEVT is proposed, and a processing experiment platform is built. Finally, cutting experiments of SUEVT for TC4 titanium alloy were conducted, studying the influence of swing angles on surface topography and roughness and assessing the feasibility of the method. Results showed that compared with ultrasonic elliptical vibration turning (UEVT), SUEVT has certain advantages in improving surface morphology. When the swing angle of SUEVT is 15°, the surface roughness decreases the most, reaching 19.00 %. Under the condition of SUEVT θ = 15°, the surface roughness decreases first and then increases with the increase in spindle speed, while it is proportional to the feed speed and ultrasonic power. The method proposed in this study can provide new methods and new ideas for ultrasonic elliptical vibration high surface quality machining.

Investigation on high-precision drilling of Cf/SiC composites with brazed diamond core-drill

Carbon fiber reinforced silicon carbide ceramic matrix (Cf/SiC) composites have promising applications as lightweight and hot end components due to their unique mechanical and high-temperature properties. However, high-precision drilling of Cf/SiC composites is still a difficult task, which is attributed to material's high hardness, anisotropy, and heterogeneity. In this work, a kind of core-drill with cemented carbide as shank and polycrystalline diamond (PCD) as grits, was prepared with vacuum brazing method. Experiments on drilling of 2D-Cf/SiC composite with the brazed core-drill were carried out. The effects of drilling parameters on the hole dimensional accuracy, surface roughness and defects were investigated. The results showed that with the increase of spindle speed and the decrease of feed rate, the dimensional accuracy was improved and surface roughness was reduced. Delamination, burr, and hole edge collapse were the main defects. The feed rate had a significant influence on the formation of defects. When the feed per revolution was equivalent to the diameter of a single carbon fiber, the defects were reduced effectively and the hole quality was improved substantially. In the investigated range of parameters, the optimal spindle speed and feed rate for high-precision drilling of Cf/SiC composites were 5000 r/min and 30 mm/min, respectively. Under this condition, the hole dimension accuracy was IT 10, and barely defects were observed on the machined surface. The surface roughness of hole sidewall reached a minimum value of 1.9 μm. This work provides a vital process for high-precision drilling on fiber reinforced ceramic matrix composites.

Experimental and numerical study on micro ball-end milling of pin fin-interconnected reentrant microchannels

Pin fin-interconnected reentrant microchannels (PFIRM) of microchannel heat sink cooling systems provide a promising solution for efficient heat dissipation of high heat flux devices. They feature interconnected Ω-shaped reentrant configurations in cross-section, with large circular cavities at the bottom and diamond pin fins at the top. In this paper, a micro ball-end milling process was proposed to fabricate PFIRM. The burr formation process and deformation mechanisms during the micromilling process of PFIRM were investigated with experiments and finite element (FE) simulations. Results revealed that the burrs were mainly formed under the vertex of diamond pin fins on both up-milling and down-milling sides. The burrs on the up-milling side were pushed by the tool neck to the left side of feed direction, whereas the burrs on the down-milling side were thrusted by the flank face to the right side of feed direction. Besides, two unique types of chips, i.e., swallowtail-shaped chips and half swallowtail-shaped chips, were found to be formed during the micro ball-end milling process. Moreover, the effects of spindle speed and feed rate on the machining accuracy and surface roughness of PFIRM were also explored. The machining accuracy and surface roughness firstly increased and then decreased with increasing spindle speed. As the feed rate increased, the machining accuracy decreased in general, and the surface roughness firstly decreased and then increased. The present study suggested that the spindle speed of 15000 r/min and feed rate of 20 mm/min was optimal to improve the surface quality and machining accuracy.

Materials removal mechanism for ultra-precise cutting of single-crystal silicon with natural single-crystal diamond tools by experiment and atomic simulation

The influence of tool rake angle and cutting speed on the ultra-precision cutting of single crystal silicon with natural single crystal diamond tools is studied by experiment and molecular dynamics (MD) simulations. The findings demonstrate that the 0° rake angle tool attains superior surface quality, reduced cutting force and friction coefficient in comparison to the −10° and − 20° rake angle tools. Moreover, the MD results reveal that a smaller negative rake angle tool can decrease the formation of high pressure phase atoms and other defects. In addition, the PV, RMS and Ra surface roughness parameters decrease as the machine spindle speed increases. Additionally, higher cutting speeds improve the surface morphology of the machined workpiece and produce fewer defective atoms.

Surface morphology, burr formation, and spindle axial drift in high-speed robotic milling of complex features

Industrial robots are garnering increased attention in the manufacturing sector, their application in high-precision tasks such as milling is however hindered by inherent limitations, notably low stiffness and instability. This study aims to investigate the influence of cutting parameters within segmented curve trajectories on surface quality during high-speed robotic milling process. The investigation covers surface morphology, the mechanism of burr formation, and the underlying causes of tool axial runout. The findings reveal that as spindle speed increases and feed speed decreases, the surface topography of the machined workpiece gradually improves and the quantity and dimensions of burrs on both sides of the slot have been decreased. Axial runout occurs during robotic milling due to insufficient robot stiffness, leading to vibrations that cannot effectively resist the reaction forces of cutting forces.

Multi-objective optimization of turning process parameters and wood sawdust contents using response surface methodology for the minimized surface roughness of recycled plastic/wood sawdust composites

The objective of this work was to investigate the effect and optimization of turning parameters such as spindle speed, feed rate, and depth of cut as well as wood sawdust content on the roughness quality of wood-plastic composites (WPCs). The Box–Behnken design and response surface methodology were used in experiments. Three roughness parameters, namely average roughness (Ra), root mean square average of roughness (Rq), and average maximum height (Rz) were employed to evaluate the surface quality of WPC samples. Based on the findings of the experiments, the Ra, Rq, and Rz values reduced with increasing spindle speed in a range of 430 to 1030 rpm, whereas the values increased when increasing the feed rate in a range of 0.05 to 0.15 mm/min. Also, an increase in depth of cut ranging from 1 to 3 mm and WPCs with a higher amount of wood sawdust in a range of 30 to 50 wt% raised their surface roughness. Finally, optimal conditions for the turning of the WPCs were determined to comprise a spindle speed of 781 rpm, a feed rate of 0.05 mm/min, a depth of cut of 2.8 mm, and wood sawdust content of 30 wt% with the highest desirability score of 1.000. Under such conditions, the sample had Ra, Rq, and Rz values of 1.8, 2.2, and 11.3 µm, respectively. The optimal conditions for turning can be used to effectively process different WPC products into various shapes.

Corrosion Behaviour of Stainless Steel 316L in Chloride Environment After Dry Machining by Face Milling at Various Spindle Speed

This study attempts to investigate the impact of spindle speed on the corrosion characteristics of 316L stainless steel during the face milling process in dry condition. The machining parameters, such as spindle speed, have an impact on the surface properties of the material after the processes. It is essential to devote significant attention that these parameters can still affect the surface condition of 316L stainless steel, which may then affect its corrosion properties. This research aimed to examine the corrosion characteristics of 316L stainless steel subsequent to the face milling process using the potentiodynamic polarization technique in a chloride-containing environment. The face milling technique use a 6 mm carbide cutter tool, with spindle speed variations of 1800 rpm, 1600 rpm, and 1400 rpm. The feed rate is maintained in constant rate, which is 0.002 mm/rev. The findings of the corrosion rate test indicate that variations in spindle speed lead to fluctuations in the corrosion rate value. There finding shows an inverse relationship between the value of spindle speed and the corrosion rate, wherein an increase in spindle speed corresponds to a decrease in the corrosion rate.

Study on the removal mechanism and milling quality of helical milling hole of SiCp/Al composites

SiCp/Al composites have been widely used in the aviation field due to their excellent properties such as high strength and good wear resistance, but there are still some problems in their hole-making, such as unclear helical milling removal mechanism and poor hole quality. In this paper, the removal mechanism of SiCp/Al composites in helical milling was analyzed by finite element simulation and a three-factor four-level single-factor test. Then, the effect of process parameters on the surface quality of the hole wall is analyzed by a single-factor test. Finally, the formation mechanism of orifice damage and the influence of process parameters on the quality of the orifice edge are analyzed. The results show that in the helical milling process of SiCp/Al composites, the SiC particles are mainly broken and some fall off. Partial tearing of the aluminum matrix occurs. The quality of the hole wall and orifice becomes better with the increase of spindle speed, and worse with the increase of pitch. The revolution speed has a negative effect on the surface quality of the hole wall and a positive effect on the outlet quality. After the spindle speed increased from 500 r/min to 2000 r/min, the surface roughness decreased by 17.13 %. The surface roughness increased by 68.86 % when the pitch increased from 0.1 mm to 0.4 mm. The surface roughness increased by 9.1 % when the spindle speed increased from 30 r/min to 60 r/min. This paper can provide an important reference for SiCp/Al composites with high efficiency and low damage.

Investigation on roller-type ultrasonic assisted magnetorheological finishing for biomedical small and complex surface of titanium alloy

Biomedical small workpieces made of titanium alloys are widely used in orthopedic implants. However, the poor abrasive resistance and the complex shape of the parts with small size could seriously reduce its finishing quality and efficiency. In this study, a roller-type ultrasonic assisted magnetorheological finishing (R-UMRF) for biomedical small and complex surface of titanium alloy was proposed. The R-UMRF principle was illustrated in detail. Then, the magnetic circuits of R-UMRF with three-pole electromagnet excitation device was designed and mathematical expressions of magnetic flux density in the MR fluid polishing region was further established. Moreover, simulation analysis of the designed magnetic circuit was performed as well. An experimental prototype was fabricated and tested to the feasibility of the developed MR polishing fluid and R-UMRF device. The results showed that the surface roughness decreases with the increase in spindle speed and roller speed, however, it first decreases and then increases with the increase in ultrasonic amplitude and the applied current. In addition, the surface roughness change rate increases with the increase in spindle speed and roller speed, however, it first increases and then decreases with the increase in ultrasonic amplitude and the applied current. The optimized process parameters for the titanium alloy screws are the MR polishing fluid of MRPF-2, the spindle speed of 240 r/min, the roller speed of 110 r/min, ultrasonic amplitude of 10 µm, and applied current of 4 A. The surface roughness Ra of 0.089 µm can be obtained after 140 min finishing under the optimized parameters. R-UMRF is an adaptable and efficient method for finishing small and complex surface of titanium alloy.

Effect of D-Allulose Use as a Sugar Substitute on Some Physicochemical, Textural and Sensory Properties of Cakes

D-allulose is a monosaccharide that belongs to the class of sugars known as rare derivatives of monosaccharides in nature. The aim of this study was to investigate how the sugar substitute D-allulose influenced the physicochemical, textural, and sensory characteristics of cakes. Solvent water retention capacity analysis of flour used in cake production and ash, dry matter, texture, color and reducing sugar analyses of cake dough were carried out in a day while water activity, pH, titratable acidity, antioxidant activity analysis and sensory analyses of cakes were performed in three different days. The average heights of control, AL50 and AL100 cakes were 2.60±0.14, 1.75±0.1 and 1.50±0.0 cm while they had the cake yields of 87.2±1.9, 86.2±4.1 and 87.6±3.2%, respectively. Viscosity analysis results showed that viscosity of dough samples decreased with an increase in spindle speed for all groups. The total dry matter content of control cakes was 76.1±3.0% while AL50 and AL100 cakes had a dry matter content of 76.4±4.6 and 75.0±2.6%, respectively. Total ash contents were 1.2±0.0, 1.3±0.0 and 1.4±0.0% for control, AL50 and AL100 cakes, respectively. The mean radical scavenging activity (RSA) of control cakes on the first day of production was 26.1±5.8, 51.6±1.3 in the AL50 group and 53.9±1.2 in the AL100 group. When evaluating the panelists' overall acceptability scores for the sensory qualities of cakes, the first day yielded the highest AL50 (7.9±1.2), while the 8th day of storage yielded the lowest AL50 (8.5±0.8) for the control group. The 8th day analysis yielded the lowest result (6.7±1.4) for the AL100 group. Results indicated that D-allulose preserved the physicochemical, textural, and sensory characteristics of cakes while increasing their antioxidant capacity, and it could be utilized to create novel products in the food industry because of these qualities.

Research on the machining mechanism of AISI 304 ultrasonic vibration assisted grinding

Compared with conventional grinding (CG), ultrasonic vibration assisted grinding (UVAG) has more prospects and competitiveness in processing AISI 304. Due to the change of strength of materials, when the vibration is superimposed on the workpiece, the mechanism of ultrasonic assisted machining is different from that of tool ultrasonic assisted machining. Therefore, this article proposes a workpiece vibration grinding device suitable for UVAG to study the corresponding grinding mechanism. The vibration characteristics of workpiece ultrasonic generator were discussed based on finite element simulation and the vibration situation of the device was tested with instruments to verify the accuracy of the simulation. Meanwhile, the machining mechanism of workpiece ultrasonic vibration was studied through grinding comparative experiments. The experiment showed that the displacement curve of the output end of the ultrasonic vibration of AISI 304 with time could be approximated to a sine wave and there was no other clutter. As the amplitude percentage of the ultrasonic generator increased, the output amplitude of the transducer showed an increasing trend. The ultrasonic amplitude and the amplitude percentage of ultrasonic generator approximately follow a linear relationship. The grinding force decreased with the increase of spindle speed and amplitude, and increased with the increase of feed rate and grinding depth. Compared with conventional grinding force, the grinding force of tangential ultrasonic vibration assisted grinding (TUVAG) decreased by about 29 %, while the grinding force of radial ultrasonic vibration assisted grinding (RUVAG) decreased by about 28 %. Under the action of ultrasound, the workpiece obtained better surface morphology. Under processing conditions of vw = 25 mm/min, ap = 0.01 mm, n = 2000r/min, A = 8 μm, f = 20000 Hz, the minimum surface roughness Ra of TUVAG is 0.51, followed by RUVAG with Ra = 1.02, while the surface roughness Ra of CG is the worst at 1.56 due to grinding burns.

Experimental study on ultrasonic vibration assisted grinding of GCr15SiMn bearing steel

Many problems of GCr15SiMn high-carbon chromium bearing steel have been found in the ordinary grinding (OG) process. Aiming at the problems of high grinding force, low residual compressive stress and low surface quality, ultrasonic machining technology is combined with OG. The test of ultrasonic vibration assisted grinding (UVAG) GCr15SiMn high carbon chromium bearing steel is carried out. The residual stress, surface roughness, grinding force, and surface morphology are analyzed by changing machining parameters. The research showed that as the grinding depth and feed speed become larger, the grinding force increased, when the spindle speed rises, the grinding force becomes smaller. In the test range, with the ultrasonic amplitude from small to large, the grinding force from large to small. The ultrasonic grinding force is 27.8% lower than that of OG. The surface roughness increases with increasing grinding depth and feed speed and decreases with increasing spindle speed and ultrasonic amplitude, and at an amplitude of 6 μm, the surface roughness is reduced by 27% compared to OG. When the feed speed and grinding depth are lowered or the ultrasonic amplitude is increased, the surface residual compressive stress is increased. Compared to OG, it is increased by more than 13.5% under the same parameters. At the same time, the phenomenon of burrs and surface tears can be reduced, and the surface quality of the workpiece becomes better.

Experimental study of rotary ultrasonic high-quality hole processing of Glass Fiber Reinforced Plastic with a new diamond trepanning bit

Glass Fiber Reinforced Plastic is widely used in manufacturing and other fields because of its high specific strength and high specific modulus. Since the workpiece requires secondary hole processing during assembly, machining defects are prone to occur during hole making, which seriously affects the service life of the workpiece. A novel type of thin-walled diamond trepanning bit was fabricated and combined with ultrasonic processing technology to conduct a pilot study on hole processing. Compared with conventional twist drill hole processing, the novel diamond trepanning bit grinding hole-making method can significantly reduce the axial force when drilling, and effectively reduce the delamination and tearing damage at the exit of the hole, so that the delamination ratio at the exit is reduced by 9.6%. Combined with ultrasonic machining technology, hole machining experiments were carried out, and the results showed that: spindle speed increase or feed rate reduction can make axial force, hole wall surface roughness, and exit delamination damage all show a decreasing trend. Compared with conventional machining, the rotary ultrasonic hole machining technology can effectively reduce the axial force by 20.1% and effectively reduce the exit delamination problem by 7.3% in the delamination ratio. At the same time, considering the hole-making quality and efficiency, rotary ultrasonic processing can better reflect the advantages of the process and obtain better hole-making quality at the speed of 3000–4000 r/min and the feed rate of 14–20 mm/min. The above research can provide theoretical and technical support for the hole processing problems of Fiber Reinforced Plastic, which has important engineering application value.

Additively Manufactured Parts from AA2011-T6 Large-Diameter Feedstocks Using Friction Stir Deposition.

The current work investigates the possibility of fabricating additive manufacturing products in solid-state form, from AA2011-T6 of 40 mm diameter rods as a feedstock, using an additive friction stir deposition (A-FSD) technique. The use of large diameter feedstocks, especially high-strength aluminum alloys (2XXX series), is a challenge, as it necessitates high power and the critical selection of the optimal A-FSD parameters, such as feed rate and spindle rotation speed. The study included applying a wide range of spindle rotation speeds, ranging from 400 to 1200 rpm, at three levels of feeding rates of 1, 3, and 5 mm/min. The AA2011-T6 friction stir deposited parts (FSDPs) were visually evaluated. This was followed by an examination of macrostructures through the thickness of the fabricated specimens. The characterization of microstructures was also carried out using optical microscopy and a scanning electron microscope equipped with advanced EDS analysis. Furthermore, the mechanical properties in terms of hardness and compressive strength of the AA2011-T6 base material (BM) and deposited materials were evaluated. Sound, additively manufactured products were successfully fabricated from 40 mm diameter AA2011-T6 feedstocks using the suggested deposition variables of 600 and 800 rpm spindle speeds and feeding rates of 1, 3, and 5 mm/min. The results indicated that the spindle speed and feeding rate govern the quality of the FSDPs. Furthermore, the axial load during the A-FSD process increased with increasing these parameters. In comparison to the AA2011-T6 BM, the additively deposited materials showed a refined grain structure and uniform dispersion of the fragment precipitates in their continuous multi-layers. The reduction ratio in grain size attains 71.56%, 76%, and 81.31% for the FSDPs processed at 800 rpm spindle speed and feeding rates of 1, 3 and 5 mm/min, respectively, compared to the grain size of BM. The Al2Cu and Al7Cu2Fe intermetallics are detected in the AA2011-T6 BM, and their deposited parts are in different shapes of spherical, almost spherical, irregular, and rod-like shapes. The compressive strength and hardness of the deposited parts increased with increasing spindle speed and feeding speeds. At a spindle speed of 800 rpm and a 5 mm/min feeding rate, the higher hardness and compressive strength gained were 85% and 93%, respectively, from that of the AA2011-T6 feedstock.

Experimental Assessment of Hole Quality and Tool Condition in the Machining of an Aerospace Alloy

This paper deals with an experimental investigation of hole quality in Al2024-T3, which is one of the aerospace alloys used in aircraft fuselage skin due to its high level of resistance to fatigue crack propagation. The experiments are conducted with 6 mm uncoated carbide and HSS drill bits using a CNC machine under dry conditions and different drilling parameters. The characteristics of the hole quality are investigated in terms of its perpendicularity, cylindricity, circularity and hole size. An ANOVA (analysis of variance) and Pareto charts are used to analyze the effects of the drilling parameters on the hole quality. The hole quality is also assessed using a digital microscope to observe the formation of hole burrs. Moreover, scanning electron microscopy is also used to investigate the inside-hole surface defects. Further investigations are carried out using optical microscopy to inspect the post-drilling tool condition at high drilling parameters. The results show that hole quality reduces as the feed rate and spindle speed increase. However, from the ANOVA results and Pareto charts, the influence of the feed rate on the hole quality is found to be insignificant. At the same time, the type of drill bit material shows the highest percentage of contribution affecting the hole quality, following the spindle speed. The HSS drill bit shows more adhesion and built-up edges than the uncoated carbide drill bit. There were more burrs formed at the hole edges when the holes were drilled with uncoated HSS drill bits. In the same way, the SEM analysis reveals more surface deformation and damage defects inside the hole walls of holes drilled using the uncoated HSS drill bit.

Influence of Cutting Parameter on Scarface Quality in Dry Turning of Different Materials

In machining operations, surface roughness (Ra) is an essential measure of product quality. It is determined by the cutting settings. The parameters that have been worked on are the Feed (F) (0.72, 0.88, 0.96, 1.12 mm/min), depth of cut (DOC) (0.5mm), and spindle speed (N) (545, 710, 1000, 1400 r.p.m). Three types of ferrous metals were employed in this study low-carbon steel St 3, medium-carbon steel St 45, and high-carbon steel Y8. According to the data, the optimal operating condition for obtaining the best surface roughness is 1.119 µm for low-carbon steel. St 3 from the product is by employing the following cutting settings for the cutter (feed 0.72 = mm/rev), (DOC= 0.5mm), and (machine speed =1400 rpm). But when using the cutting variables (feed 1.12 = mm/rev), (DOC = 0.5mm), and (machine speed = 545 rpm) for high-carbon steel Y8, gives the highest surface roughness is 4.999 µm . The experimental findings indicate that the surface roughness of turned components is considerably affected by cutting settings and machine equipment. According to the results of this study, increasing spindle speed lowered the Ra of the turned components, but rising feed increased the surface roughness. The value acquired by this approach will benefit other researchers for future work on tool vibrations, cutting forces, and so on.

Performances of cryo-treated and untreated cutting tools in machining of AA7075 aerospace aluminium alloy

The quality of drilled holes in aluminium alloys used in the aerospace industry is vital to ensure high-precision structural integrity. For this reason, optimum selection of cost-effective cutting tools and cutting parameters is of great importance. Nowadays, due to their high cost and supply difficulties, there is a great interest in improving the performance of traditional HSS cutting tools as an alternative to ceramic, carbide and coated cutting tools. HSS cutting tools are widely used in different industries due to their cost-effectiveness and suitability to improve tool performance. In this research, the performances of cryo-treated (DC&T) and untreated (UT) HSS cutting tools used in dry machining of AA7075 aluminium alloys were investigated. Thanks to DC&T processes applied to HSS cutting tool, improvements have occurred in its microstructure. The hardness value of HSS cutting tool increased by 6.89% with the effect of DC&T processes applied. When the highest and lowest Ra values obtained using DC&T and UT HSS cutting tools were compared, it was seen that DC&T HSS cutting tool performed better by 11.05% and 25.91%, respectively. It has been determined that the hole surface quality of the aluminium workpiece machined with DC&T and UT HSS drills is negatively affected by the increase in spindle speed and feed rate. The highest S/N ratios calculated according to Ra values of holes drilled on aluminium workpieces using DC&T and UT HSS cutting tools were found to be -7.12 dB (2.27 μm) and -9.62 dB (3.03 μm), respectively. In the ANOVA analysis, it was determined that the most effective parameters on Ra values were spindle speed (70.62%), tools (18.19%) and feed rate (9.98%), respectively. In the regression analysis, R2 value for Ra values was calculated as 98.30%. High R2 value result shows that the model developed is quite successful in estimating Ra values.

Mathematical Modeling and Experimental Study of Cutting Force for Cutting Hard and Brittle Materials in Fixed Abrasive Trepanning Drill.

Hard and brittle materials have excellent physical and mechanical performance, which are widely applied in the fields of microelectronics and optoelectronics. However, deep-hole machining of hard and brittle materials is very difficult and inefficient due to the high hardness and brittleness of these materials. To improve the quality and efficiency of deep-hole machining of hard and brittle materials, according to the brittle crack fracture removal mechanism of hard and brittle materials and the cutting model of the trepanning cutter, an analytical cutting force prediction model of hard and brittle materials processed using a trepanning cutter is established. This experimental study of K9 optical glass machining shows that as the feeding rate increase, the cutting force increase, and as the spindle speed increase, the cutting force decrease. By comparing and verifying the theoretical and experimental values, the average errors of axial force and torque are 5.0% and 6.7%, respectively, and the maximum error is 14.9%. This paper analyzes the reasons for the errors. The results indicate that the cutting force theoretical model can be used to predict the axial force and torque of machining hard and brittle materials under the same conditions, which provides a theory for optimizing machining process parameters.