Fragrance finishing of textiles is receiving substantial interest, with aromatherapy being one of the most popular aspects of personal health care. However, the longevity of aroma on textiles and ...presence after subsequent launderings are major concerns for aromatic textiles directly loaded with essential oils. These drawbacks can be weakened by incorporating essential oil-complexed β-cyclodextrins (β-CDs) onto various textiles. This article reviews various preparation methods of aromatic β-cyclodextrin nano/microcapsules, as well as a wide variety of methods for the preparation of aromatic textiles based on them before and after forming, proposing future trends in preparation processes. The review also covers the complexation of β-CDs with essential oils, and the application of aromatic textiles based on β-CD nano/microcapsules. Systematic research on the preparation of aromatic textiles facilitates the realization of green and simple industrialized large-scale production, providing needed application potential in the fields of various functional materials.
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Gyro finishing —a type of mass finishing—is one of the potential processes for finishing complicated shapes. This study proposes a cover plate located above a workpiece to improve finishing ...efficiency in gyro finishing. First, the effect of the cover plate on the force acting on the workpiece, which is related to the finishing efficiency, was investigated, and we confirmed that the force increased by using the cover plate. This was considered to be caused by the restriction of upward motion of the abrasive media. Subsequently, the effect of the cover plate on the finishing efficiency was evaluated by comparing the surface roughness variation with and without the cover plate. The finishing efficiency of the workpiece surface increased by approximately a factor of 2.0 with the cover plate due to the large force acting on the workpiece. Additionally, the bad effect caused by using the cover plate via larger force acting on the workpiece―worsening of the surface roughness―was not revealed. Therefore, the cover plate was confirmed a highly effective method to improve its performance. Furthermore, the effect of the cover plate was investigated under the workpiece-stopped condition for an improved understanding. We confirmed that the surface roughness obtained using the cover plate improved over the entire front surface of the workpiece due to the increase of the contact pressure.
•A cover plate for restricting abrasive media motion was proposed.•The force acting on the workpiece increased 2.6 times with the cover plate.•The finishing efficiency increased approximately 2.0 times with the cover plate.•The bad effect caused by using the cover plate was not revealed.•The effect of the cover plate was revealed over the entire front surface.
Gyro finishing is a mass-finishing process in which fixed workpieces are finished by contact with the flow of abrasive media owing to the rotation of the barrel. The process is used to finish large ...complex-shaped workpieces, such as large gears and parts constructed using additive manufacturing. In our previous study, we proposed a cover plate positioned above a workpiece to restrict the upward motion of abrasive media after contact with the workpiece, thereby improving the finishing speed. In this study, plates were added at the side of the workpiece to restrict the flow of the abrasive media toward the side of the workpiece and further improve the finishing speed. First, we evaluated the effect of the side plates using a simple-shaped workpiece. The difference in the surface roughness during a 5 min process was evaluated under certain conditions of the side cover plates. We confirmed that the finishing speed can be increased by using a side cover plate whose front was positioned behind the workpiece center because of the restriction of motion of the abrasive media. In contrast, the finishing speed decreased when a side cover plate whose front was positioned in front of the workpiece center was used because of the interruption in the transmission of force from the barrel wall to the abrasive media near the workpiece, owing to the side cover plates. Subsequently, the effect of the side cover plates placed at a suitable position was evaluated based on variations in the surface roughness during the process. We confirmed that the finishing speed increased by approximately a factor of 1.5 when the side cover plates were used owing to restrictions in the motion of the abrasive media. Finally, a spur gear was finished with cover plates, as a sample of practical workpieces. The finishing speed was determined based on the difference in the surface roughness of the gear teeth during the process. The finishing speed increased when a side cover plate whose front was positioned behind the workpiece center was used. Therefore, it can be concluded that the use of side cover plates is an effective technique to improve the finishing speed in gyro finishing.
Fast progress in near-net-shape production of parts has attracted vast interest in internal surface finishing. Interest in designing a modern finishing machine to cover the different shapes of ...workpieces with different materials has risen recently, and the current state of technology cannot satisfy the high requirements for finishing internal channels in metal-additive-manufactured parts. Therefore, in this work, an effort has been made to close the current gaps. This literature review aims to trace the development of different non-traditional internal surface finishing methods. For this reason, attention is focused on the working principles, capabilities, and limitations of the most applicable processes, such as internal magnetic abrasive finishing, abrasive flow machining, fluidized bed machining, cavitation abrasive finishing, and electrochemical machining. Thereafter, a comparison is presented based on which models were surveyed in detail, with particular attention to their specifications and methods. The assessment is measured by seven key features, with two selected methods deciding their value for a proper hybrid machine.
High-performance devices usually have curved surfaces, requiring high accuracy of shape and low surface roughness. It is a challenge to achieve high accuracies for form and position on a device with ...low surface roughness. However, due to the unique nonlinear rheology, magnetorheological fluids with hard abrasives are widely applied in ultra-precision surface finishing. Compared with conventional mechanical finishing, magnetorheological finishing displays obviously advantages, such as high precision shape of machined surface, low surface roughness and subsurface damage, and easy control for finishing processes. However, finishing performance depends on various factors, e.g. volume fraction and distribution of magnetic particles, types of hard abrasives and additives, strength of magnetic field, finishing forms. Therefore, a comprehensive review on related works is essential to understand the state-of-the-art of magnetorheological finishing and beneficial to inspire researchers to develop lower cost, higher machining accuracy and efficient approaches and setups, which demonstrates a significant guidance for development of high-performance parts in fields of aerospace, navigation and clinical medicine etc. This review starts from the rheological property of magnetorheological fluids, summarizing dynamically nonlinear rheological properties and stable finishing approaches. Then, the effect of components in magnetorheological fluids is discussed on finishing performance, consisting of magnetic particles, carrier fluid, additives and abrasives. Reasonable configuration of magnetorheological fluids, and different magnetorheological finishing methods are presented for variously curved surfaces. In addition, the current finishing forms and future directions are also addressed in this review.
Precision complex surfaces components are in high demand for optical imaging, high-power lasers, and medical implants. Magnetorheological finishing (MRF) is widely used in ultra-precision machining ...of complex surfaces components due to its advantages of low processing cost, high precision, stable removal function, no surface damage, and the ability to achieve nano-scale surface roughness and micro-scale surface shape accuracy. However, the removal efficiency of MRF is still low, the material removal mechanism is not completely clear, and the properties of magnetorheological fluid (MR fluid) need to be improved, so its application in industrial production is limited. In order to further promote the development of MRF and break through the difficulties of current MRF, it is necessary to review and summarize the MRF technology. Recent studies progress on MRF need to be more comprehensive. It is not comprehensive to introduce only several different removal theories and the appearance of compound MRF. Research progress like MR fluid, MRF tools or other also should be mentioned in a short sentence. This paper gives a detailed literature review on MRF for complex surfaces. Firstly, the principle of MRF is introduced. The finishing tools are classified based on shape and the workpieces suitable for each tool are analyzed. Some new compound MRF techniques with high machining efficiency are introduced. Then, the researches on MRF influence function and force were reviewed, and the researches on three factors affecting MRF machining performance, including process parameters, MR fluid, and magnetic pole arrangement, were reviewed. Finally, the key works of MRF technology in the future are prospected: material removal theory, preparation of high performance MR fluid, and development of novel composite MRF based on interdisciplinary and universal optimization of MRF machine tools. This paper has important reference value for researchers in MRF-related fields.
High efficiency, high quality and green machining of single crystal silicon carbide (SiC) is an important issue in the third-generation semiconductor industry. In this paper, a novel machining method ...for single crystal SiC based on tribo-oxidation is proposed. The formula and preparation process of polysaccharide bonded soft abrasive tool were designed. Dry machining of C-face of 4H–SiC substrate was carried out with the prepared environmentally friendly abrasive tool sample. The material removal mechanism of the proposed machining method was preliminarily analyzed, and the material removal rate, surface roughness and subsurface residual stress were studied. The experimental results show that the maximum material removal rate of 4H–SiC can reach 1.03 μm/min with a corresponding average surface roughness of Sa 0.816 nm. The machined surface has no brittle flaw, and subsurface residual compressive stress exists with a maximum value of 58.9 MPa. The material removal mainly attributed to the active oxidation of SiC surface induced by the friction between alumina abrasives and SiC substrate. The proposed machining method has potential application value in thinning of SiC wafers.
Micro-/nano-machining (abbreviated as MNM) processes are classified mainly in two classes: traditional and advanced. Majority of the traditional MNM processes are embedded abrasive or fixed geometry ...cutting tool type processes. Conversely, majority of the advanced MNM processes are loose flowing abrasive based processes in which abrasive orientation and its geometry at the time of interaction with the workpiece is not fixed. There are some MNM processes which do not come under the abrasive based MNM category, for example, laser beam machining, electron beam machining, ion beam machining, and proton beam machining. This paper gives a comprehensive overview of various flowing abrasive based MNM processes only. It also proposes a generalized mechanism of material removal for these processes. The MNM processes discussed in this paper include: Abrasive Flow Finishing (AFF), Magnetic Abrasive Finishing (MAF), Magnetorheological Finishing, Magnetorheological Abrasive Flow Finishing, Elastic Emission Machining (EEM) and Magnetic Float Polishing. EEM results in surface finish of the order of sub-nanometer level by using the nanometer size abrasive particles with the precisely controlled forces. Except two (AFF and EEM), all other processes mentioned above use a medium whose properties can be controlled externally with the help of magnetic field. This permits to control the forces acting on an abrasive particle hence the amount of material removed is also controlled. This class of processes is capable to produce surface roughness value of 8
nm or lower. Using better force control and still finer abrasive particles, some of these processes may result in the sub-nanometer surface roughness value on the finished part. Understanding the mechanism of material removal and rotation of the abrasives in these processes will help in rationalization of some of the experimental observations which otherwise seem to be contradicting with the established theories. It also explains why a magnet used in MAF should have a slot in it even though the area under the slot has “non-machining” zone. It elaborates based on the experimental observations why to use pulse D.C. power supply in MAF in place of smooth D.C. power supply.
Ball end magnetorheological finishing is a recently developed nanofinishing process suitable for finishing of complex three-dimensional surfaces. This process makes use of magnetically stiffened ...ball-shaped tool of abrasive-mixed magnetorheological fluid that is known as magnetorheological polishing (MRP) fluid. The stiffness of the ball-shaped MRP fluid can be precisely controlled for the gentle finishing action, which is the prime requirement for the finishing of soft materials such as copper. Due to the nonmagnetic nature of the copper, the magnetic field is not enough to provide sufficient finishing forces in ball end magnetorheological finishing (BEMRF) process. In the present study, finishing forces have been analyzed for carbonyl iron particles (CIPs) and electrolytic iron powder (EIP)-based fluids. It is observed that electrolytic iron powder-based fluid exerts higher normal force during the finishing. A permanent magnet with the opposite pole facing the tool tip can enhance the finishing forces up to an appreciable extent to finish the copper workpiece significantly. The composition of MRP fluid depends on the material to be polished. The effects of fluid composition parameters on surface finish have been studied, and it is observed that abrasive mesh size is the most important fluid parameter in BEMRF of copper followed by iron powder and abrasive concentrations. Optimum fluid composition is suggested for ball end MR finishing of copper, and sample finished using optimum fluid composition is analyzed using surface analyzer and scanning electron microscopy.
Magnetic abrasive finishing (MAF) is one of the most important final machining processes, and the performances of finishing media play an important role in the finishing effects and efficiency. In ...this study, a new magnetic finishing media with semi-solid state was presented and prepared, and finishing setup for the inner or outer rotary surface was developed. In order to determine the optimum angle between N pole and S pole, simulation was performed using ANSYS Maxwell 14.0. Mathematical modelling of the material removal ratio (MRR) was built as a function of magnetic pressure and velocity based on Archard wear model, and the developed model predicted the MRR as a function of magnetic flux density, mass ratio, rotational speed of magnetic poles, rotational speed of cam, and diameter of abrasive particles and ferromagnetic particles. The material removal coefficient of the predicted model was determined. The model was validated by experiment, and the relative error between the experiment value and the theoretical value was 4.51%. Finishing experiments of main parameters on surface roughness Ra and MRR were examined. Experimental results indicate that the percentage change % ΔRa in surface roughness Ra and the material removal amount increase with the increase of the rotational speed, the mesh number of the abrasive particles, and the mass ratio of base polymer, ferromagnetic phase and abrasive phase. For the 6061 aluminum alloy tube, the maximum improvement in surface roughness Ra is 96.67%, and the maximum MRR is 1.916 mg/s.
