Drilling Of Stainless Steel Research Articles

Experimental investigation on friction drilling of stainless steel AISI 304

Friction drilling is an unexplored manufacturing process to produce holes in thin-walled sheet metals. In this study, the effects of process parameters in friction drilling of austenite stainless steel investigated experimentally and statistically. It was confirmed, sufficient heat generation, which cause to better bushing shape and height, acceptable drilled-hole diameter and lowest roundness error result from low spindle speed and high feed rate. It was obtained, although effect of feed rate on hole-wall thickness was negligible; spindle speed has significant effect on that which is inverse from spindle speed effect on bushing height. Moreover, micro-hardness reduced gradually away from the drilled-hole edge. Observing on tool shape and wear damage using optical microscope and scanning electron microscope quantifies effects of spindle speed and feed rate on tool performance and tool wear characteristics. Results indicate that better performance of drilling tool obtained from lower spindle speed and high feed rate.

A novel, new generation drill coating for osteotomy site preparation.

Implant success and survival rate ranges from 93% to 97%; however, failures are not very uncommon. These failures can be caused due to a variety of reasons out of which increased heat during drilling of osteotomies is a major contributor. The aim of this study was to develop a new generation diamond-coated drill and compare the thermal changes between commercially available drills and the experimental diamond coated drill during implant site preparation in artificial bone. Three types of drills were selected for the study; Group A (Carbide), Group B (Stainless Steel), and Group C (Experimental). A total of 60 implant site preparations were performed with all the drills in artificial bone using a surgical unit linked to a testing device, in order to standardize implant drilling procedures. Bone temperature variations were recorded when drilling at a depth of 10 mm. A constant irrigation of 50 ml/minute and drilling speed of 800 r.p.m. was maintained. The mean temperature of Group A, Group B, and Group C was 35.57°C, 36.83°C and 34.23°C, respectively. The results were assessed and statistically analyzed using ANOVA test and post hoc Bonferroni test. Statistically significant higher temperatures were obtained with stainless steel drill and carbide drill when compared with the experimental diamond coated drill. (P = 0.000). Diamond coated osteotomy drills have shown promising results in reducing heat generation at the osteotomy. Further studies need to be conducted to maximize the potential use of diamond as components of drills in implant dentistry.

Intraosseous Heat Generation During Osteotomy Performed Freehand and Through Template With an Integrated Metal Guide Sleeve: An In Vitro Study.

To investigate drill wear and consequent intraosseous temperature elevation during freehand and guided bone drilling, with attention to the effect of metal-on-metal contact during guided drilling. Osteotomies were performed on bovine ribs, with 2.0 mm diameter stainless steel drill bits of the SMART Guide System, under 3 sterilization protocols, at 800, 1200, 1500, and 2000 rpm. Sterilization was performed after every 3 drilling. Temperature was measured after every 30 drilling. The studied contributing factors had a cumulative effect, and each contributed significantly to temperature elevation. Whether guide use led to a near-necrotic (47°C) temperature increment depended largely on the applied sterilization protocol. The metal sleeve is a significant contributing factor to heat generation during guided osteotomy, but its effect can be offset by keeping the other studied factors under control.

Improved Dental Implant Drill Durability and Performance Using Heat and Wear Resistant Protective Coatings.

The dental implant drilling procedure is an essential step for implant surgery, and frictional heat in bone during drilling is a key factor affecting the success of an implant. The aim of this study was to increase the dental implant drill lifetime and performance by using heat- and wear-resistant protective coatings to decrease the alveolar bone temperature caused by the dental implant drilling procedure. Commercially obtained stainless steel drills were coated with titanium aluminum nitride, diamond-like carbon, titanium boron nitride, and boron nitride coatings via magnetron-sputter deposition. Drilling was performed on bovine femoral cortical bone under the conditions mimicking clinical practice. Tests were performed under water-assisted cooling and under the conditions when no cooling was applied. Coated drill performances and durabilities were compared with those of three commonly used commercial drills with surfaces made from zirconia, black diamond. and stainless steel. Protective coatings with boron nitride, titanium boron nitride, and diamond-like carbon have significantly improved drill performance and durability. In particular, boron nitride-coated drills have performed within safe bone temperature limits for 50 drillings even when no cooling is applied. Titanium aluminium nitride coated drills did not show any improvement over commercially obtained stainless steel drills. Surface modification using heat- and wear-resistant coatings is an easy and highly effective way to improve implant drill performance and durability, which can improve the surgical procedure and the postsurgical healing period. The noteworthy success of different types of coatings is novel and likely to be applicable to various other medical systems.

Mechanical study in drilling of heat resistant austenitic stainless steel

Machining of difficult-to-cut-materials like heat resistant stainless steels leads to the rapid tool wear and tool failure. The analysis of drilling process of these steels is even more difficult as it is not easy to investigate the cutting process at the drill tip. Therefore for this critical operation, modelling of cutting forces is very important. The study of the mechanical loading is based on the cutting tool geometry variation along the cutting edge. This study aims to investigate the drilling of heat resistant stainless steels with two geometries of twist drills, by analyzing specific cutting energy and forces at a global and a local scale.

Experimental studies and FEM simulation of helical-shaped deep hole twist drills

This study investigates the chip formation in drilling of AISl 316L stainless steel using TiAIN coated helical-shaped deep hole twist drills. The aim of this research is to determine suitable cutting parameters with a focus on favourable chip formation, to achieve a better process stability. The experimental investigations were conducted with varying cutting speed, feed rate and cooling lubricant pressure, in stages that were based on the recommendations of the tool manufacturer. In addition to the experimental tests, the mechanical loads and chip formation were simulated with the aim of providing a basis for the simulative development of the tool shape and the cutting parameters. With mathematical methods, a geometrical kinematic imprint, in accordance to the axial feed force of the helical-shaped deep hole twist drill, was implemented into the three-dimensional workpiece model. Based on the experimental results, which show that the chip shape has a great dependence on the feed rate, which in turn strongly affects the feed force and the drilling torque suitable cutting parameters were chosen for the simulation. The simulation results were validated with the experimental data and show a good agreement.

Initial adhesion of methicillin-sensitive and methicillin-resistant Staphylococcus aureus strains to untreated and electropolished surgical steel drill bits

Electropolishing of stainless steel has been thoroughly investigated as a prophylactic measure to prevent bacterial colonization of orthopaedic implants and infection. Initial bacterial adhesion onto surgical drill bits as a possible factor for orthopaedic surgical site infections has not yet been documented. The present study investigated the influence of electropolishing on initial staphylococcal adhesion onto AISI 440A stainless steel drill bits. Specifically, one methicillin-susceptible standard laboratory Staphylococcus aureus type strain (DSM 20231T), one methicillin-resistant S. aureus reference strain (DSM 46320) and one methicillin-resistant clinical isolate from an infected orthopaedic implant were used. After standard sterilization, drill bits were immersed in the respective bacterial suspension; bacteria adherent to surface were harvested by vortexing the drill bits in phosphate-buffered saline and viable counts of bacteria transferred from the suspension were made (transferred to log10 for further analysis). Electropolishing significantly reduced adhesion of the clinical S. aureus strain and the S. aureus DSM 20231T. However, electropolishing significantly increased adhesion of the S. aureus DSM 46320. These results show that electropolishing significantly influences initial adhesion of S. aureus strains to surgical drill bits and that the nature of this influence depends on the S. aureus strain examined. For a general recommendation of electropolishing drill bits and guidelines for their handling during surgery, further studies with more strains isolated from infected wounds are suggested.

Roundness in Drilling of Low-Rigidity Workpiece

This study described the effect of mechanical properties on the roundness of a drilled hole in the drilling of low-rigidity workpieces. A thin-thickness part workpiece model involving a beam plate structure fixed on both ends was used in the study. The effects of feed, workpiece length, distance from the fixed end to the drilling point, and mechanical properties of the workpiece on the roundness of the hole were investigated. The thrust force increased with feed and the roundness became worse with feed. The hole was enlarged in the longitudinal direction of the workpiece at the upper section of the hole. An increase in the workpiece length decreased the rigidity of the workpiece and deteriorated the roundness of the hole. The roundness error was extremely small when the drilling point was near the fixed end. Carbon steel, aluminum alloy, stainless steel, and titanium alloy were used as workpiece materials. The thrust force in the drilling of titanium alloy and stainless steel was considerably larger than that of the carbon steel and aluminum alloy. The roundness of the hole was worse in the drilling of titanium alloy and stainless steel than that in the drilling of carbon steel and aluminum alloy. Plastic deformation occurred in the workpieces made of titanium alloy and stainless steel, which is probably because the workpiece was yielded by the large thrust force. The value of the ratio of the thrust force in drilling to the Young’s modulus of the workpiece was used in evaluating the deflection of the workpiece and the roundness error of the hole in drilling.

Minimally invasive, multi-port approach to the lateral skull base: a first in vitro evaluation.

The aim of the study was to validate a minimally invasive, multi-port approach to the internal auditory canal at the lateral skull base on a cadaver specimen. Fiducials and a custom baseplate were fixed on a cadaver skull, and a computed tomography image was acquired. Three trajectories from the mastoid surface to the internal auditory canal were computed with a custom planning tool. A self-developed positioning system with a drill guide was attached to the baseplate. After referencing on a high precision coordinate measuring machine, the drill guide was aligned according to the planned trajectories. Drilling of three trajectories was performed with a medical stainless steel drill bit. The process of planning and drilling three trajectories to the internal auditory canal with the presented workflow and tools was successful. The mean drilling error of the system (Euclidian distance between the planned trajectory and centerline of the actual drilled canal) was [Formula: see text]mm at the entry point and [Formula: see text]mm at the target. The inaccuracy of the drill process itself and its physical limitations were identified as the main contributing factors. The presented system allows the planning and drilling of multiple minimally invasive canals at the lateral skull base. Further studies are required to reduce the drilling error and evaluate the clinical application of the system.

Tool speed and polarity effects in micro-EDM drilling of 316L stainless steel

This paper focuses on the issues of Resistor-Capacitor-based Electrical Discharge Micro-Machining process and investigates the effects of tool speed and polarity on the performance measures such as Tool Wear Rate, Material Removal Rate, Overcut and Taper Angle by drilling on 316L Stainless Steel. Taguchi’s L54 mixed orthogonal array design is employed to conduct experiments by varying tool polarity at two levels and voltage, capacitance, spindle speed at three levels. The cause and effect relationship between the experimental factors and responses are analysed and discussed using Factorial Analysis of Variance technique. Optimum combinations of machining parameters are also evaluated using Taguchi-based Grey Relational Analysis, by considering grey relational grade matrix and influence of process parameters on the responses. Further, microscopic analysis is done to identify the micro-voids, globular formation, and cracks present on the surface of the hole produced under various machining conditions.

Improvement of hole quality and process characteristics by adopting reduced quantity lubrication in drilling of stainless steel 304

The objective of this study is to improve the performance of drilling process using reduced quantity lubrication (RQL), which is based on minimum quantity lubrication (MQL) and compare its performance with that under dry condition and flooded lubrication. The MQL technique is usually too expensive for small-scale industries to afford. RQL, which is based on MQL technique employs slightly higher flow rate compared to MQL and is relatively cheaper to afford than MQL. This work is performed to check the effectiveness of the RQL process for drilling stainless steel 304. A readymade sprayer setup which generates flow rate in the range of reduced quantity lubrication is employed and soluble oil is sprayed as a mist in combination with compressed air. Performance characteristics such as cutting force, tool wear, surface roughness, diameter, and roundness are analysed. The results produced by RQL drilling are comparable with wet lubrication and proved to be quite satisfactory than dry drilling. Employing RQL, the tooling cost is reduced three to four times compared to dry drilling whereas the lubricant cost is reduced to 0.125% of wet lubrication.

Improvement of hole quality and process characteristics by adopting reduced quantity lubrication in drilling of stainless steel 304

Improvement of hole quality and process characteristics by adopting reduced quantity lubrication in drilling of stainless steel 304

Micro-electro discharge machining drilling of stainless steel with copper electrode: The influence of process parameters and electrode size

This article is about the implementation of an acquisition system for the measurement of micro-electro discharge machining process parameters and the statistical analysis of their influence on the process performance. The micro-electro discharge machining drilling of 316L stainless steel with copper tubular electrodes was studied and the exchanged power was taken into account as a comprehensive variable able to represent the effect of the peak current and voltage on the final result. The direct proportionality between the exchanged power and the nominal process parameters was verified. A linear and non-linear regression approach was used in order to obtain predictive equations for the most important aspects of micro-electro discharge machining process, such as the machining time and the electrode wear.

Experimental investigation on performance of additive mixed dielectric during micro-electric discharge drilling on 316L stainless steel

ABSTRACTThis study investigates the impact of machining factors on the performance of additive mixed micro-electric discharge drilling of 316L stainless steel. The effects of three kinds of powder, powder concentration, voltage, capacitance, feed rate, and speed on tool wear rate, material removal rate, taper angle, and overcut (OC) were also investigated. The experimental results show that adding additives to the dielectric enhanced rate of material removal and reduced rate of tool wear significantly. Mixing powder with dielectric increased the length of the sparking, resulting in significant OC, and process performance also improved with the increase in amount of powder added. Further, scanning electron microscopy analysis was carried out to examine the surface characteristics and material migration properties, which confirmed that the properties of the machined surface are indeed significantly improved.

The effects of electrode size and discharged power on micro-electro-discharge machining drilling of stainless steel

This article is about the measurement of actual micro-electro-discharge machining parameters and the statistical analysis of their influence on the process performances. In particular, the discharged power was taken into account as a comprehensive variable able to represent the effect of peak current and voltage on the final result. Thanks to the dedicated signal acquisition system, a correlation among the discharged power and the indexes representing the process parameters was shown. Finally, linear and non-linear regression approaches were implemented in order to obtain predictive equations for the most important aspects of micro-electro-discharge machining, such as the machining time and the electrode wear.

Pinealectomia em ratas Wistar (Rattus norvegicus albinus): descrição de um novo método cirúrgico

A necessidade de manejo adequado antes, durante e após a implementação de procedimentos em animais de laboratório é essencial para proporcionar bem-estar. Portanto, no presente trabalho, objetivou-se padronizar uma nova técnica de pinealectomia em ratas Wistar. Trinta fêmeas nulíparas aos 90 dias de idade foram submetidas à anestesia dissociativa. Após a tricotomia e a assepsia, realizou-se uma incisão na linha média dorsal da cabeça. Com um micromotor e uma broca de aço PM 03, realizou-se a craniotomia; a glândula pineal foi removida por intermédio de um fórceps cápsula arruga. Em seguida, o fragmento ósseo foi recolocado em seu lugar de origem, e a pele aproximada por pontos simples. Finalizado o procedimento cirúrgico, foi realizada antibioticoterapia e soroterapia parenteral. O acompanhamento diário dos animais não evidenciou nenhum comprometimento da ferida operatória com padrão de cicatrização por primeira intenção. Os animais apresentaram normalidade de atos fisiológicos, como alimentação, defecação e micção, assim como socialização com o grupo. Técnicas cirúrgicas vêm sendo realizadas com o desenvolvimento das pesquisas envolvendo a glândula pineal. A técnica ideal para pinealectomia consiste no pouco sangramento, na curta duração da cirurgia e na nitidez da glândula pineal, diminuindo a probabilidade de acidentes neurológicos. Considerando-se os resultados obtidos ao longo do desenvolvimento experimental e clínico, o aprimoramento da técnica cirúrgica utilizando a broca PM03 associada ao fórceps cápsula arruga foi exímio na pesquisa científica da pinealectomia de ratas Wistar em virtude da rapidez e praticidade alcançadas. Tem-se a perspectiva de que este artigo sirva de subsídio para o aprimoramento e a otimização do modelo experimental para posteriores estudos acerca de pesquisas com a glândula pineal e, assim, maior compreensão de sua complexidade sobre todos os sistemas do organismo.

Model for Optimization of the Tool Life and the Cutting Speed for Maximum Productivity at Drilling of the Steel X5CrNiMo17-12-2

The research in the last decade regarding their cutting machinability have highlighted the insufficiency of the data for establishing of the optimum cutting processing conditions and the optimum cutting regime. The purpose of this article is the optimization of the tool life and the cutting speed at the drilling of the stainless steels in terms of the maximum productivity. A nonlinear programming mathematical model to maximize the productivity at the drilling of a stainless steel is developed in this paper. The optimum cutting tool life and the associated cutting tool speed are obtained by solving the proposed mathematical model. The use of this productivity model allows greater accuracy in the prediction of the productivity for the drilling of a certain stainless steel and getting the optimum tool life and the optimum cutting speed for the maximum productivity. The obtained results can be used in production activity, in order to increase the productivity of the stainless steels machining. Finally the paper suggests new research directions for the specialists interested in this field.

Machining Accuracy and Cutting Temperature Property in Deep Hole Drilling of Stainless Steel

In this study, it is discussed how the cutting conditions for drilling deep holes in austenite stainless steel affect the machining accuracy of the hole straightness and the cutting temperature rise. As a result, it is possible to reduce the thrust force and make the machining time short by the combination of the step-feed amount and the feed rate. By changing the drill in incremental step from short drill length to long drill length, the straightness was improved. It was also found that the temperature rise of the drill was around 10 K regardless of the cutting speed when the small step-feed amount of 10 μm was given.

Investigation of Chip Formation and Tool Wear in Drilling Process Using Various Types of Vegetable-Oil Based Lubricants

Cutting fluid is a well-known as one of an important element in machining process. However, the consumption of mineral oils as cutting fluid has been raising concern due to worldwide interest in environmental and health matters. The application of vegetable-oil based lubricant is seen can overcome the problem but requires a research study about the machinability. This research paper represents the machinability of using several possible vegetable oils as cutting fluid in term of chip formation and tool wear during drilling operation on stainless steel, AISI 316. In particular, the performance of the vegetable oils; palm, sesame, olive and coconut oils were compared under minimum quantity lubrication (MQL) technique. The result reported that the coconut oil indicates the best machinability in term of highest and uniform chip thickness and least wear on the drill bit under same condition with others. These performances are followed by palm, olive and sesame oil. In additional, the viscosity measurement indicates that coconut oil has the lowest value which can possesses better fluidity and faster cooling capacity than other oils. Overall, coconut oil is recommended as viable alternative lubricants during drilling of stainless steel.

Tool life and cutting speed for the maximum productivity at the drilling of the stainless steel X22CrMoV12-1

Two addressed issues in the research regarding the cutting machinability, establishing of the optimum cutting processing conditions and the optimum cutting regime, do not yet have sufficient data for solving. For this reason, in the paper it is proposed the optimization of the tool life and the cutting speed at the drilling of a certain stainless steel in terms of the maximum productivity. For this purpose, a nonlinear programming mathematical model to maximize the productivity at the drilling of the steel is developed in the paper. The optimum cutting tool life and the associated cutting tool speed are obtained by solving the numerical mathematical model. Using this proposed model allows increasing the accuracy in the prediction of the productivity for the drilling of a certain stainless steel and getting the optimum tool life and the optimum cutting speed for the maximum productivity. The results presented in this paper can be used in the production activity, in order to increase the productivity of the stainless steels machining. Also new research directions for the specialists in this interested field may come off from this paper.