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New woodturning techniques and projects : advanced level
For woodturners at an advanced level, this book offers skills, projects, and inspiration. The techniques allow experts to expand their skills and also learn tips that make for better projects. Step-by-step instructions and photographs give guidance for mastering each technique; then 18 projects are presented with complete photo instructions.
Book
Investigations of Machining Characteristics in the Upgraded MQL-Assisted Turning of Pure Titanium Alloys Using Evolutionary Algorithms
Environmental protection is the major concern of any form of manufacturing industry today. As focus has shifted towards sustainable cooling strategies, minimum quantity lubrication (MQL) has proven its usefulness. The current survey intends to make the MQL strategy more effective while improving its performance. A Ranque–Hilsch vortex tube (RHVT) was implemented into the MQL process in order to enhance the performance of the manufacturing process. The RHVT is a device that allows for separating the hot and cold air within the compressed air flows that come tangentially into the vortex chamber through the inlet nozzles. Turning tests with a unique combination of cooling technique were performed on titanium (Grade 2), where the effectiveness of the RHVT was evaluated. The surface quality measurements, forces values, and tool wear were carefully investigated. A combination of analysis of variance (ANOVA) and evolutionary techniques (particle swarm optimization (PSO), bacteria foraging optimization (BFO), and teaching learning-based optimization (TLBO)) was brought into use in order to analyze the influence of the process parameters. In the end, an appropriate correlation between PSO, BFO, and TLBO was investigated. It was shown that RHVT improved the results by nearly 15% for all of the responses, while the TLBO technique was found to be the best optimization technique, with an average time of 1.09 s and a success rate of 90%.
Journal Article
Obtaining one-sheeted revolution hyperboloid surface by cutting
There are situations when obtaining surfaces that correspond to one-sheeted revolution hyperboloid surface is formulated in industrial practice. Solving such a problem may require the use of expensive procedures and equipment. The analysis of some solutions from the specialized literature led to the acceptance of some possibilities to obtain certain surfaces specific to the one- sheeted revolution hyperboloids by turning and milling. A technological solution that involves using a milling device adaptable to a universal lathe has been proposed.
Journal Article
Nanofluids application in machining: a comprehensive review
Nanofluids are efficient heat transfer media that have been developed over the past 27 years and have been widely used in the electronic microchannel, engine, spacecraft, nuclear, and solar energy fields. With the high demand for efficient lubricants in manufacturing, the application of nanofluids in machining has become a hot topic in academia and industry. However, in the context of the huge amount of literature in the past decade, existing review cannot be used as a technical manual for industrial applications. There are many technical difficulties in establishing a mature production system, which hinder the large-scale application of nanofluids in industrial production. The physicochemical mechanism underlying the application of nanofluids in machining remains unclear. This paper is a complete review of the process, device, and mechanism, especially the unique mechanism of nanofluid minimum quantity lubrication under different processing modes. In this paper, the preparation, fluid, thermal, and tribological properties of nanofluids are reviewed. The performance of nanofluids in machining is clarified. Typically, in friction and wear tests, the coefficient of friction of jatropha oil-based alumina nanofluids is reduced by 85% compared with dry conditions. The cutting fluid based on alumina nanoparticles improves the tool life by 177–230% in hard milling. The addition of carbon nanotube nanoparticles increases the convective heat transfer coefficient of normal saline by 145.06%. Furthermore, the innovative equipment used in the supply of nanofluids is reviewed, and the atomization mechanisms under different boundary conditions are analyzed. The technical problem of parameterized controllable supply system is solved. In addition, the performance of nanofluids in turning, milling, and grinding is discussed. The mapping relationship between the nanofluid parameters and the machining performance is clarified. The flow field distribution and lubricant wetting behavior under different tool-workpiece boundaries are investigated. Finally, the application prospects of nanofluids in machining are discussed. This review includes a report on recent progress in academia and industry as well as a roadmap for future development.
Journal Article
Influence of texture shape and arrangement on nanofluid minimum quantity lubrication turning
Due to the stringent requirements of carbon emissions, traditional cutting using a large amount of mineral-based metal cutting fluid for lubrication no longer fulfilled the rigorous requirements of policies and standards. Nanofluid minimum quantity lubrication has been proven to be a new process to achieve clean manufacturing. However, due to adhesive contact friction, lubricant droplets cannot effectively penetrate the tool and workpiece interface during continuous turning. Changing the microstructure of the rake face of the tool, such as the micro-texture, may provide a geometric channel for the diffusion of the lubricant. However, the effects of micro-texture geometry and arrangement on the film formation and tribological properties of droplets have not been revealed yet. The spreading behavior of minimum quantity lubrication atomized microdroplet on the textured surface was calculated by hydrodynamic modeling. It was proven that the microchannel can effectively store the lubricating medium atomized by compressed air pneumatics. Furthermore, a comparative experiment was conducted on the influence of the texture arrangement on the cutting performance through the turning experiment. Results show that the microgrooves in the direction perpendicular to the main cutting edge obtained the lowest cutting force. The feed force, radial force, and tangential force were reduced by 13.46%, 16.23%, and 6.34%, respectively. Meanwhile, the texture arranged parallel to the cutting edge and crosswise increased the cutting force. The arrangement of the texture perpendicular to the main cutting edge direction obtained the optimal workpiece surface, the smallest chip curling radius, and the smoothest chip surface. Under the optimized texture arrangement, the anti-wear and anti-friction properties of nanofluids in the cutting area are enhanced.
Journal Article
A new mathematical method of modeling parts in virtual CNC lathing and its application on accurate tool path generation
In industry, many taper shafts are designed with tolerances of a few microns. To cut them in finish turning, paths of the tool in virtual machining should be accurately generated beforehand. For this purpose, the dimension errors and surface roughness of the virtually cut workpiece should be predicted. Unfortunately, the current tool path generation methods cannot accurately calculate the errors and the roughness, resulting in the taper errors larger than the part tolerance. Our research formulates equations of the effective turning edge to accurately calculate the dimension errors and the surface roughness, and then proposes a new approach to CNC programming for high-precision CNC turning. It lays a theoretical foundation of modeling parts in virtual turning and can generate tool paths to machine taper parts with high accuracy.
Journal Article
Machinability investigations of hardened steel with biodegradable oil-based MQL spray system
Excessive use of coolant is undesirable in machining due to environmental consciousness; thereby, small but efficacious (improved thermal and tribological properties) amount of coolant has been implemented using minimum quantity lubrication (MQL). In this study, attention was focused on the experimental investigations on tool flank wear, chip morphology, surface roughness (
R
a
and
R
q
) and chip-tool interface temperature in the machining of hardened steel (~ 40 HRC) under olive oil-assisted MQL spray system. As investigating factors, the cutting speed, feed rate, and depth of cut were oriented by following the Taguchi orthogonal array. Then, the cooling and lubrication mechanism of the olive oil-assisted MQL system has been discussed. Outcomes of this study showed that MQL is capable of generating favorable machining outcomes, i.e., lower tool flank wear, reduced temperature, and surface roughness in comparison with dry cutting. The reductions in
R
a
,
R
q
, and cutting temperature were about 23.4%, 23.8%, and 24% respectively in terms of mean values. The two types of dominant chip shapes, i.e., (1) continuous tubular and (2) discontinuous small diameter chips, were produced under the dry and MQL-assisted cooling method. In the nutshell, it is appropriate to claim that the overall thermal and tribological properties of olive oil-assisted MQL system are responsible for fruitful results during turning of hardened steel.
Journal Article
Modeling of Cutting Parameters and Tool Geometry for Multi-Criteria Optimization of Surface Roughness and Vibration via Response Surface Methodology in Turning of AISI 5140 Steel
AISI 5140 is a steel alloy used for manufacturing parts of medium speed and medium load such as gears and shafts mainly used in automotive applications. Parts made from AISI 5140 steel require machining processes such as turning and milling to achieve the final part shape. Limited research has been reported on the machining vibration and surface roughness during turning of AISI 5140 in the open literature. Therefore, the main aim of this paper is to conduct a systematic study to determine the optimum cutting conditions, analysis of vibration and surface roughness under different cutting speeds, feed rates and cutting edge angles using response surface methodology (RSM). Prediction models were developed and optimum turning parameters were obtained for averaged surface roughness (Ra) and three components of vibration (axial, radial and tangential) using RSM. The results demonstrated that the feed rate was the most affecting parameter in increasing the surface roughness (69.4%) and axial vibration (65.8%) while cutting edge angle and cutting speed were dominant on radial vibration (75.5%) and tangential vibration (64.7%), respectively. In order to obtain minimum vibration for all components and surface roughness, the optimum parameters were determined as Vc = 190 m/min, f = 0.06 mm/rev, κ = 60° with high reliability (composite desirability = 90.5%). A good agreement between predicted and measured values was obtained with the developed model to predict surface roughness and vibration during turning of AISI 5140 within a 10% error range.
Journal Article
Effect of cutting parameters on the dimensional accuracy and surface finish in the hard turning of MDN250 steel with cubic boron nitride tool, for developing a knowledged base expert system
In the machining operations, final surface finish and dimensional accuracy are the most specified customer requirements. Hard turning machining operation using cubic boron nitride tool as an alternative of grinding process is a type of turning operation in which hardened steel are machined with the hardness greater than 45 HRc. During the hard turning operation because of the hard condition, the variations of surface finish and dimensional accuracy are completely different from that of the traditional turning operation. Thus, the variation of surface finish and dimensional accuracy under various cutting parameters has been investigated in the hard turning with cubic boron nitride tools. The extracted knolwdge can be used for developing a knowledged base expert system. In order to have a comprehensive study, the variation of vibration, cutting forces, and tool wear has also been considered. The obtained results showed that depth of cut and spindle speed have the greatest effect on the dimensional accuracy, while feed rate is the most important factor affecting the surface roughness. The analysis of the vibration and tool wear proved that the flank wear has insignificant influence on the dimensional accuracy, whereas the vibration effect is considerable. The experimental results showed that when the feed rate is gradually increased from 0.08 to 0.32, the dimensional deviation first decreases unexpectedly until the lowest value is achieved at 0.16 mm/rev, then by further increasing the feed from 0.16 to 0.32 mm/rev, the dimensional deviation increases significantly. It was also seen that the best dimensional accuracy is achieved at the lowest level of the cutting depth, the medium level of the feed rate, and the spindle speed lower than its moderate level. The best surface roughness of 0.312 μm was obtained at 0.08 mm/rev feed rate, 0.5 mm depth of cut, 2000-rpm speed, and 1.2 mm insert nose radius, which is comparable with the surface finish obtained by the grinding operation.
Journal Article