Drilling Of Stainless Steel Research Articles

Multi-response optimization and characterization for micro-EDM drilling of stainless steel (AISI 304) using a hybrid DFA-fuzzy logic approach

Multi-response optimization and characterization for micro-EDM drilling of stainless steel (AISI 304) using a hybrid DFA-fuzzy logic approach

Effect of Strain Hardening on Burr Control in Drilling of Austenitic Stainless Steel

Austenitic stainless steel has been widely used in various industries, such as aerospace, medical, and hydrogen energy, due to its high strength over a wide range of temperatures, corrosion resistance, and biocompatibility. However, stainless steel is a difficult-to-cut metal because its ductility and low thermal conductivity induce a strain hardening with significant plastic deformation at high temperatures. Burr formed at the back side of a plate is a critical issue which deteriorates the surface quality, especially in drilling. Burr removal operation, therefore, should be done in the machine shop. This study discusses the effect of strain hardening of austenitic stainless steel, SUS 316L, on burr formation. Hardness and cutting tests were conducted to compare the strain hardening effect for three types of workpieces: as-received, pre-machined, and tensile treated specimens. In the employed specimens, the tensile treated specimen is harder than the as-received specimen. Those specimens have uniform hardness in the depth direction from surfaces. Pre-machined specimen, in which the back side of the plate was finished by face milling, has a distribution of hardness in the depth direction from a surface. The highest hardness appears in the subsurface of the pre-machined specimen. The cutting forces in the steady processes, in which the entire edges remove material, were nearly the same as the tested specimens each other. However, remarkable differences were confirmed in the chip thickness and burr formation. The higher strain hardening of the tensile treated specimen is effective to suppress burr formation. The cutting characteristics are then identified to associate burr control with the shear plane model of orthogonal cutting using an energy-based force model. The shear stresses, shear angles, and friction angles of the tensile treated and as-received specimens are compared to discuss the effect of strain hardening on reduction of burr formation.

Tunable simultaneous Bayesian optimization of hole taper and processing time in QCW laser drilling

Laser drilling (LD) finds extensive applications in the manufacturing industry, and the improvement of LD quality has been actively pursued by researchers and engineers. However, the large number of tunable processing parameters makes the optimization of LD extremely difficult. In this study, we introduce an innovative approach by applying Bayesian optimization (BO) to tackle the long-standing challenge of multi-dimensional optimization in the field of LD. Moreover, the drilling efficiency was integrated into the optimization objective, representing a crucial metric for practical manufacturing that has frequently been overlooked. As a proof-of-principle demonstration, the drilled-hole taper and processing time were simultaneously optimized relative to four processing parameters in quasi-continuous-wave laser spiral drilling of stainless steel. Results reveal that BO can effectively and efficiently optimize the LD process in a four-dimensional parameter space. Furthermore, we show that the balance between drilling quality and efficiency can be tuned by customizing the objective function. By employing a quality-oriented objective function, the hole taper was significantly improved from 4.3° to 0.8° within just 20 iterations. Meanwhile, with an efficiency-oriented objective function, the processing time was reduced from 13.5 s to 1.6 s. The physical mechanisms underlying how different parameters influenced the drilling process were also discussed. The results in this study reveal the power of BO in multi-dimensional optimization of LD, and the methodology can readily be applied to other laser machining applications.

Numerical simulation of nanosecond laser drilling of 316L stainless steel: addition of laser focus and analysis of manufacturing process

A two-dimensional model of nanosecond laser drilling 316L stainless steel was established with the consideration of laser focus, which was indeed different from the original two-phase flow model without laser focus, especially in the temperature field, velocity field, surface morphology and hole depth. Simulation and experiment of drilling holes with different laser repetition frequencies (100 kHz, 50 kHz and 20 kHz) were carried out. The results show that manufacturing process could divide into three stages: high-efficiency phase, stabilization stage and low-efficiency phase. Meanwhile, the limited number of pulses at 100 kHz, 50 kHz and 20 kHz were obtained, and the values were approximately 289, 367 and 492, respectively. More, the values at 10 kHz and 200 kHz obtained by modeling were very close to those calculated by the fitted equation. All the research provides theoretical, simulation and experimental basis for designing and optimizing parameters on laser surface manufacturing.

Soft computing for sustainable drilling of AISI 316L stainless steel under formulated neem oil minimum quantity lubrication condition

Soft computing for sustainable drilling of AISI 316L stainless steel under formulated neem oil minimum quantity lubrication condition

Novel drill geometries for dry drilling of stainless steel

One completely new geometry and two modified chip breaker geometries were designed to increase the stability and reliability of the stainless steel dry drilling process. Experiments were performed and the results of individual tools were compared with a conventional solid carbide twist drill Gühring Ratio with a diameter of 5 mm. A matrix of three feed rates (0,03–0,07 mm/rev) and three cutting speeds (20–30 m/min) was designed for the cutting conditions. Precipitation-hardenable stainless steel 17-4 PH was chosen as a workpiece. During the experiment, the values of thrust force, spindle torque, temperature of the tool, surface roughness, chips morphology and chips division were recorded and compared with the reference tool.The results showed that compared to the reference tool A, the tool C - a multipoint drill with grooves through the cutting edge achieve approximately 4 % lower values of thrust force and 10–15 % lower values of spindle torque. Tool D with a step drill geometry achieve approximately 17 % lower values of thrust force and 10–15 % lower values of spindle torque and there is no chip clogging in the flute with C and D geometries. This effect is confirmed by the fact the spindle torque basically does not increase with the increasing depth of drilling. Tool B – new designed geometry achieve approximately 15 % lower values of thrust force and similar spindle torque values as the reference drill A. Tool temperature is a very important factor when dry drilling. Compared to the reference drill A, it was possible to achieve the tool temperature reduction of 20 % with the new geometry B, as well as with the multipoint drill C reduction by 26 % and with the step drill D reduction approximately by 30 %. All the modified drills also achieved a reduction in the surface roughness of the drilled holes. By 17 %, 35 % and 48 % lower surface roughness Ra was achieved with drills B, C and D. Chip morphology was significantly different for the tested drills. Conventional twist drills A and B generated helical short chips. While C and D twist drills with divided cutting edges generated ribbon snarled chips. Thanks to the reduction of cutting forces and temperature, it is possible to stably operate the drilling process with a higher cutting speed and feed rate, which leads to an increase in the efficiency and reliability of the machining process.

Application of Taguchi coupled with genetic algorithm (GA) for optimizing surface quality in drilling of duplex stainless steel 2205

This paper aims to explore the drilling performance of duplex stainless steel (DSS) 2205 under sustainable machining, that is dry, MQL, and LCO2. Furthermore, for the correct choice of process parameters, the Taguchi statistical method is used to create a relationship between input parameters, that is cooling environment, spindle speed ( N), feed rate ( Vf), and responses, that is Ra, and hole deviation. From the ANOVA analysis, it was discovered that for measured Ra and hole deviation, the most effective parameter was the cooling environment. The model for Ra and hole deviation was obtained with a precision of 99.32% and 99.70%, respectively. In addition, a genetic algorithm (GA) was implemented for an optimum combination of process parameters and an optimized value of responses. From GA, it was obtained that the optimum process parameters were an LCO2 cooling environment with a high spindle speed (1120 RPM) and a low feed rate (0.02, 0.04 mm/rev), respectively. Also, the optimized value for Ra and hole deviation is 0.375271 and 0.0207519, respectively.

Drilling- and withdrawing-related thermal effects of implant site preparation for ceramic and stainless steel twist drills in standardized bovine bone.

Excessive surgical trauma is believed to be among the most important causes for early implant losses. As thermal injury to the bone is not only dependent on the amount of generated heat but also on the tissue exposure time, and the greatest temperature increase was found within the withdrawing period, the entire osteotomy procedure with the parameters contributing to thermal damage is of particular clinical relevance. The aim of this study was to investigate the thermal performance of metal-based and ceramic implant drills regarding the temperature exposure time during the whole osteotomy process. This investigation consisted of 240 individual preparations in total, comprising two different drilling depths (10 and 16 mm), two irrigation methods (external and without irrigation), two implant drill materials (stainless steel and zirconia), and three consecutive drill diameters per material (2.0/2.2, 2.8, and 3.5 mm) with 10 identical repetitions. Real-time multichannel temperature measurement was conducted during automated drilling procedures in standardized bovine bone specimens. The maximum temperature changes were highly associated with the time period of passive drill withdrawing (p≤ 0.05), irrespective of drill material, drilling depth, or drill diameter. Statistically significant differences in temperature generation between stainless steel and ceramic drills were observed in irrigated testing sites at both drilling depths with smaller drill diameters (2.0/2.2 and 2.8 mm, p≤ 0.05). Results of this in vitro study could demonstrate a strong association between the highest temperature increase and the passive withdrawing time period in both investigated drill materials. Considering these findings and the resulting thermal bone damage due to the whole surgical procedure, high overall temperatures in combination with a prolonged heat exposure time may impact the future osseointegration process.

Comparative Study of the Drilling Operation in Duplex Stainless Steels with Drills of Two and Three Cutting Edges

The three cutting edge drills are not the most common drills, nevertheless, are characterized by superior stability, excellent precision and finishing, due to the intersection of three cutting edges at one point. In general, stainless steels are considered as difficult to machine materials due to their tendency to work harden, their toughness and relatively low conductivity, leading to poor surface finish, poor chip breaking and built-up-edge formation. In the case of duplex stainless grades, the high strength, and the very good corrosion resistance, only compared with austenitic steels, make these materials as an alternative to the austenitic stainless steels, with superior mechanical properties. In this study, the performance of the drills with two and three cutting edges were evaluated in the drilling of duplex stainless steels, when low-pressure external cooling or high-pressure internal cooling were applied. Whether used drills of two or three cutting edges, the most important factor to increase the number of holes made, is the use of high-pressure internal cooling, in detriment of external low-pressure external cooling. The drills of three cutting edges have better results in roughness and dimensional tolerance of the holes. However, these drills proved to be more fragile and more sensitive to the cutting parameters. The use of three cutting edges drills is recommended for situations where hole quality is more important, while two cutting edges drills is recommended for situations where productivity is the main objective.

Investigation of the Process of Deep Drilling of Stainless Steel

Purpose of research. Experimental assessment of the effect of deep drilling modes for high-alloy steel on the components of cutting forces. Making holes in a solid material with a hole depth equal to or greater than ten hole diameters refers to deep drilling operations. For drilling, special tools are used – drills for deep drilling - ejector, cannon, gun drills. Universal or special equipment is applied, the tooling includes travelling or fixed rests, guide bushes. To achieve this goal, it is necessary to choose equipment: type of tool for deep drilling, type of setting; create a model of the forces acting on the cutting part of the tool during deep drilling; evaluate the degree of influence of processing modes on cutting forces.Methods. The research is based on the cutting theory provisions, mechanical engineering technology, experiment planning and regression analysis.Results. Based on the provisions of mechanical engineering technology, the setting up for deep drilling with a rotating workpiece and a non-rotating drill, which is imparted only by the axial feed, was developed. A cutting tool for performing a deep drilling operation is defined – a gun drill. A pattern was created for such a processing scheme and experimental cutting forces were calculated. According to the results of the calculations, it is determined that the greatest influence on the components of the cutting force in a given range of cutting modes is exerted by the axial feed rate of the tool.Conclusion. The cutting forces that occur during deep drilling reach significant values. The polynomial equations obtained as a result of the study allow us to assess the degree of influence of processing modes on cutting forces, calculate cutting forces for further calculation for the sag of the stem of a gun drill.

Experimental analysis on drilling of super duplex stainless steel 2507 (SDSS 2507) using cryogenic LCO2 and MQL process

Experimental analysis on drilling of super duplex stainless steel 2507 (SDSS 2507) using cryogenic LCO2 and MQL process

The effects of multiple drilling of a bone with the same drill bit: thermal and force analysis

Repeated use of the same drill bit during drilling wears off the cutting edges, which can lead to a significant increase in heat as a result of friction, which is harmful to a bone above 55 °C. Few previous studies have examined the effects of using the same drill bit several times, on temperature. The objective of this study was to determine the effect of each drilling on temperature and force. 72 trials were performed. A total of 24 stainless steel drill bits of ∅3.2 mm were used to drill bovine bone samples. Each drill bit was used at least 3 times. T thermocouples were used to measure temperatures during each drilling test. Possible correlations of cutting parameters were studied. Tests were performed on a test rig measuring forces and temperatures during drilling. Effects of spindle speed (N), feed rate (Vf), and several trials (E) on temperature and forces were measured. Images of the drill bits were analyzed by digital microscopy before and after the drilling series for signs of wear. Temperatures increased significantly from E1 to E3. They decreased moderately with Vf. The best cutting conditions were at N = 200 rpm for Vf = 60 mm/min and N = 100 rpm for Vf = 30 mm/min drilling. At N > 200 rpm, they were very high. Temperature rise is significantly related to number of drilling (E), spindle speed (N), and inversely to feed rate (Vf). Analysis of images by digital microscopy confirmed drill bits wearing off, following the number of trials.

Temperature Performance of Stainless Steel AISI420B Orthopedic Drill Bits Simulation Study

In orthopedic and trauma surgery, the drilling of bone is the process of preparing, making, and enlarging a hole of circular crosswire in a solid anisotropic material bone structure. The failure of irreversible osteonecrosis occurs when the temperature rises to 47 °C or higher during bone drilling. Osteonecrosis is a disorder that leads to the death of bone tissue cells, resulting in weaker contact between implants and bone, and in some cases, the loss of strong and stable attachment to the bone. Previous studies had concentrated on drill bit material, design, point angle, force, speed, and feed rate. This study outlines the technique for developing a drilling-related finite element model to verify the drilling process’s efficacy using a computer simulation approach. Software LS-DYNA © 2011-2020 LST was used to conduct a drilling model based on the finite element (FE) technique. The temperature behavior of orthopedic chromium type martensitic magnetic stainless steel AISI420B twist drill bit (Ø 4.3 mm) was determined. The findings were quantified, and the outcomes of the simulated and actual evaluations were compared. The surgeon’s typical drilling technique or pattern was used in this study, with a penetration angle of no more than 30°, and performed using a battery-powered surgical hand drill. A forward-looking infrared (FLIR) camera for temperature detection was used to record drill bits thermal data throughout the experiment. The utilization of two factorial analyses in the design of experiment (DOE) and analysis of variance (ANOVA) revealed that the simulation result had higher mean performance confirmation than the actual experimental result, with a difference of 10.9102%. The AISI420B showed good heat conductivity, and minor wear than typical stainless steel drill bits in the market for bone drilling. Therefore, the AISI420B stainless steel twist drill bit tested able to perform well for bone drilling.

Process limits for percussion drilling of stainless steel with ultrashort laser pulses at high average powers

The availability of commercial ultrafast lasers reaching into the kW power level offers promising potential for high-volume manufacturing applications. Exploiting the available average power is challenging due to process limits imposed by particle shielding, ambient atmosphere breakdown, and heat accumulation effects. We experimentally confirm the validity of a simple thermal model, which can be used for the estimation of a critical heat accumulation threshold for percussion drilling of AISI 304 steel. The limits are summarized in a processing map, which provides selection criteria for process parameters and suitable lasers. The results emphasize the need for process parallelization.

Experimental Research on Longitudinal Ultrasonic Assisted Vibration Drilling of 0Cr17Ni4Cu4Nb

In the present study, by adding ultrasonic vibration in the longitudinal direction to assist the drill bit to drill on 0Cr17Ni4Cu4Nb stainless steel, in order to obtain high-quality deep small holes and prolong the service life of the drill bit. By establishing the movement mathematical model of the drill bit under ordinary drilling and longitudinal vibration drilling, the movement trajectory of the main cutting edge of the drill bit in two different drilling methods is compared and analyzed, and the anti-friction mechanism of longitudinal vibration drilling is analyzed. The conventional drilling and longitudinal ultrasonic drilling of 0Cr17Ni4Cu4Nb stainless steel are carried out on a longitudinal ultrasonic vibration drilling device. After drilling test, the wear morphology of the drill bit, the surface roughness of the hole wall and the chip morphology are observed and analyzed by the detection equipment. The result shows: the wear degree of the drill bit after longitudinal ultrasonic vibration drilling is lower than that of conventional drilling, which can prolong the service life of the drill bit. The surface roughness of the hole wall is reduced, and the drilling chips are more finely divided and easier to discharge.

An experimental investigation on the effect of Al2O3/ cutting oil based nano coolant for Minimum Quantity Lubrication drilling of SS 304

Now a day's energy has the most important input for the growth of any system. Today energy demand has rapidly increased across all sectors, including agriculture, transport, residential, commercial and industry. To deal with these issues in many production processes, the effective cutting fluid pays an important role in reducing the friction force between the cutting tool and work piece surface. In this study we explore the experimental investigation to study the potential of Al2O3 Nano particles/Mineral oil-based cutting fluid during drilling of Stainless Steel 304 on tool life and the surface roughness. During investigation two step method is used to synthesis the Nano cutting fluid by using Al2O3 nanoparticles with volume fraction 0.3,0.8 and 1% in metal cutting fluid. Ultrasonic agitation force is used to achieve stability of Nanofluid. The Drilling operation on vertical CNC machine for 1000 rpm and 1500 rpm speed at constant feed rate of 0.050 mm/rev. Result shows that the Nano coolants increases the tool life and reduces the surface roughness. Tool life is observed highest for Nano cutting fluid of 1% volume fraction and achieve the lowest surface roughness 2.01 μm at 1000 rpm. The derived results are witnessing the usability of nano coolant.

Experimental investigation of femtosecond laser through-hole drilling of stainless steel with and without transverse magnetic assistance.

An experimental investigation of femtosecond laser through-hole drilling of stainless-steel 304 with and without transverse magnetic assistance was conducted. The characteristics of the through-hole geometry and sidewall as well as the chemical composition of the through-hole sidewall surface were analyzed. In addition, a theoretical analysis of magnetic-field-assisted femtosecond laser through-hole drilling is proposed. The results showed that transverse magnetic assistance could improve both the femtosecond laser through-hole drilling quality (through-hole geometry and sidewall characteristics) and efficiency. The primary reason is that transverse magnetic assistance changes the distribution of plasma and reduces the plasma density, which weakens the shielding effect of the plasma. However, compared with nanosecond laser drilling, the effect of the magnetic field on the femtosecond laser through-hole drilling was not obvious. A noticeable thermal effect appeared near the through-hole entrance at a pulse repetition rate of 500 kHz, and a heat affected zone and oxidation zone were produced, which is disadvantageous to laser drilling. This research has good prospects for industrial applications.

Multi objective taguchi–grey relational analysis and krill herd algorithm approaches to investigate the parametric optimization in abrasive water jet drilling of stainless steel

This novel study deals with the investigation of abrasive mixtures on abrasive water jet (AWJ) drilling of stainless steel 304 using multi objective soft computing techniques. In this study, the drilling parameters such as abrasive mixture, stand-off distance and feed rate were varied. The abrasive mixture was prepared with the composition of different types of abrasives such as silicon carbide & garnet, and aluminium oxide & garnet, and different mixture ratios. This mixing ratio was done based on the total mass of the abrasive mixture. The effect of abrasive water jet drilling parameters was examined on the hole features such as the hole diameter, circularity, cylindricity, and surface roughness. Multi objective optimization and algorithm techniques were employed in this study, namely Taguchi–Grey Relational Analysis (TGRA) and Krill Herd Algorithm (KHA). In this research work, the performance of KHA method was also compared with another recent metaheuristic technique i.e. grey wolf optimization (GWO) based on the quality measurement tools such as Spacing and Inverted generational distance. For this approach, the main parameters of metaheuristics algorithms were tuned using a robust design approach to acquire the best feasible solution. Besides, different multiple linear regression model equations were established to determine the best model for the KHA method based on the similarity between experimental and calculated attributes. With the assistance of these approaches, it is found that the abrasive mixtures have improved the performance of the AWJ drilling process in SS 304 rather than the use of a single type abrasive such as 100% Garnet. The results of this study proved that the KHA optimization technique is successfully utilized to find the best configuration parameter setting for AWJ drilling process, and that results are found to be efficient than the TGRA. To validate the predicted results of KHA, confirmation test was conducted. The results of the confirmation test showed that the predicted hole features of KHA were acceptable as that the error deviation was found as less than 2% with the experimental results. It is also noticed that the computational time and the selected quality metrics of KHA are found to be lower than the GWO method. Hence, it is confirmed that a new metaheuristic algorithm namely, KHA was found suitable for AWJ drilling process. The outcome of the present work explores a new paradigm to the AWJ machining to improve performance features in various operations.

Statistical analysis of process parameters in drilling of SS410 stainless steel

Performance characteristics of SS410 stainless steel during the drilling process while conducting experimental studies is discussed in this paper. The material was blocked up from the ingot form and has the following dimensions of 100x75x15 mm. Drilling experiments were carried out on BMV 35 T12 Gaurav BFW CNC machine using HSS drill bit. Process parameters such as Speed (S) (30, 40, 50, 60 m/min), Feed (F) (0.05, 0.075, 0.1, 0.125 mm/rev) and Point angle (P) (100, 110, 120, 130 degree) were varied for about four levels, to determine the test cases with the help of Taguchi’s Orthogonal Array. The methods used for analysing the results were; response table, Signal to Noise ratio and Analysis of Variance. It was concluded that better surface finish was obtained at high spindle speed, low feed, and high point angle, better material removal rate was obtained at high spindle speed, high feed, and low point angle and better dimensional accuracy (ovality) was obtained at low speed, low feed, and low point angle. Analysis of Variance (ANOVA) results revealed feed as the most significant parameter that influenced the surface roughness (Ra) of SS410 material, followed by speed and point angle. Similarly, for material removal rate (MRR) and ovality (O), speed was the most influencing parameter followed by feed and point angle. To predict the Ra, MRR and O, regression analysis was also performed and was validated through confirmation test.

Thermal effects of various drill materials during implant site preparation-Ceramic vs. stainless steel drills: A comparative in vitro study in a standardised bovine bone model.

ObjectivesThe aim of this study was to evaluate thermal effects of ceramic and metal implant drills during implant site preparation using a standardised bovine model.Material and MethodsA total of 320 automated intermittent osteotomies of 10‐ and 16‐mm drilling depths were performed using zirconium dioxide‐based and stainless steel drills. Various drill diameters (2.0/ 2.2, 2.8, 3.5, 4.2 mm ∅) and different cooling methods (without/ with external saline irrigation) were investigated at room temperature (21 ± 1°C). Temperature changes were recorded in real time using two custom‐built multichannel thermoprobes in 1‐ and 2‐mm distance to the osteotomy site. For comparisons, a linear mixed model was estimated.ResultsComparing thermal effects, significantly lower temperatures could be detected with steel‐based drills in various drill diameters, regardless of drilling depth or irrigation method. Recorded temperatures for metal drills of all diameters and drilling depths using external irrigation were below the defined critical temperature threshold of 47°C, whereas ceramic drills of smaller diameters reached or exceeded the harmful temperature threshold at 16‐mm drilling depths, regardless of whether irrigation was applied or not. The results of this study suggest that the highest temperature changes were not found at the deepest point of the osteotomy site but were observed at subcortical and deeper layers of bone, depending on drill material, drill diameter, drilling depth and irrigation method.ConclusionsThis standardised investigation revealed drill material and geometry to have a substantial impact on heat generation, as well as external irrigation, drilling depth and drill diameter.