Machining and grinding of ultrahigh-strength steels and stainless steel alloys

Machining and grinding of ultrahigh-strength steels and stainless steel alloy

A Study of Influence of Electrolyte Composition on ECH of Bevel Gears using Mixture D-Optimal Design

This paper discusses the experimental investigation to find out the optimal electrolyte composition in improving the surface quality of the gear teeth profile during surfacing finishing of bevel gears by the electrochemical honing process. In this study, AISI 1040 was used as the workpiece material, mixtures of sodium chloride and sodium nitrate in different ratios were used as the input parameter, and the percentage improvement in the surface roughness and material removal rate of the process were used as measures of process performance. The experimental runs were designed according to the Mixture DOptimal design. The analysis of the experimental outcome was carried out and 80% NaCl + 20% NaNO3 was found to be theoptimal electrolyte composition to conduct the confirmation experiments. The finding of the study establishes the process for precision finishing of bevel gears

Rapid Prototyping Of Microfluidic Packages

In the area of MEMS there exists a tremendous need for communication between the micro-device and the macro world. A standard protocol or at least multiple standards would be of great use. Electrical connections have been standardized for many uses and configurations by the integrated circuit industry. Standardization in the IC industry has created a marketplace for digital devices unprecedented. In addition to the number of off the shelf products available, there exists the possibility for consumers to mix and match many devices from many different manufacturers. This research proposes some similar solutions as those for integrated circuits for fluid connections and mechanical configurations that could be used on many different devices. In conjunction with offering the capability to facilitate communication between the micro and macro worlds, the packaging solutions should be easy to fabricate. Many devices are by nature non-standard, unique, designs that make a general solution difficult. At the same time, the micro-devices themselves will inevitably need to evolve some standardization. In BioMEMS devices the packaging issue is concerned with delivering a sample to the device, conducting the sample to the sensor or sensors, and removing the sample. Conducting the sample to the sensor or sensors is usually done with microchannels created by standard MEMS fabrication techniques. Many current designs then utilize conventional machining techniques to create the inlet and outlet for the sample. This work proposes a rapid prototyping method for creating the microchannel and inlet / outlet in simplified steps. The packages developed from this process proved to be an effective solution for many applications

Micro/Nano Manufacturing

Micro- and nano-scale manufacturing has been the subject of ever more research and industrial focus over the past 10 years. Traditional lithography-based technology forms the basis of micro-electro-mechanical systems (MEMS) manufacturing, but also precision manufacturing technologies have been developed to cover micro-scale dimensions and accuracies. Furthermore, these fundamentally different technology platforms are currently combined in order to exploit the strengths of both platforms. One example is the use of lithography-based technologies to establish nanostructures that are subsequently transferred to 3D geometries via injection molding. Manufacturing processes at the micro-scale are the key-enabling technologies to bridge the gap between the nano- and the macro-worlds to increase the accuracy of micro/nano-precision production technologies, and to integrate different dimensional scales in mass-manufacturing processes. Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on novel methodological developments in micro- and nano-scale manufacturing, i.e., on novel process chains including process optimization, quality assurance approaches and metrology

Plasma texturing for enhanced tribological performance of cast iron

Cathodic plasma electrolysis (CPE) was used to create surface texturing on gray iron samples, which could reduce the friction and increase the wear resistance. During the treating process, cast iron sample served as a cathode where the plasma discharging occurred, increasing the surface hardness and leaving an irregular array of micro craters on the surface. Modified surface morphology was determined from scanning electron microscope (SEM) and surface profiler. Recessed and protruded surface textures were observed when the CPE was applied at low and high voltages, respectively. Pin-on-disk tribotests were conducted on CPE-treated samples and untextured sample. The friction of as-treated samples could be reduced in boundary lubrication regime at low sliding speed due to the ability to store lubricant. Besides that, the surface texture generated extra hydrodynamic pressure that separated two sliding surfaces, increased the oil film thickness and accelerated the transition from boundary to mixed lubrication at high sliding speeds

Synopsis of lectures on the subject «Special technologies in mechanical engineering» for students of all forms of study Direction of preparation 131 " Applied mechanics"

1. METHODS OF PROCESSING STRUCTURAL MATERIALS 5 2. BASIC INFORMATION ABOUT METAL CUTTING AND METAL CUTTING MACHINES 15 3. METHODS OF RESTORATION OF PARTS 24 4. MAIN PARTS AND ELEMENTS OF THE CUTTER, ITS GEOMETRIC PARAMETERS 29 5. GEOMETRY OF CUTTERS 35 6. ELEMENTS OF CUTTING AND CUT LAYER 39 7. TECHNOLOGY OF PROCESSING BODY PARTS ON AUTOMATED MACHINES 44 8. TECHNOLOGY OF SHAFT PROCESSING 53 9. METHODS FOR FORMATION OF BASIC SURFACES OF CORRESPONDING PARTS 75 10. LITERATURE 9

Cumulative Index to NASA Tech Briefs, 1963 - 1966

Cumulative index of NASA Tech Briefs dealing with electrical and electronic, physical science and energy sources, materials and chemistry, life science, and mechanical innovation

Replication of metal-based microscale structures by compression molding: a combined experimental and finite element analysis study

Fabrication of microscale Ta mold inserts by micro-electrical-discharge-machining (ìEDM) is reported. Morphology, chemistry, and structure of the near-surface region of as-machined Ta blanks have been characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. A TaC surface layer forms on as-machined Ta surfaces. This altered surface layer was removed by electro-chemical-polishing. Further modification of Ta insert surfaces was accomplished by deposition of a conformal Ti-containing hydrogenated carbon coating. We demonstrate successful replication of high-aspect-ratio microscale structures (HARMS) in Al and Cu by compression molding with such surface-engineered Ta mold inserts. In addition, a hybrid microfabrication technique, combining micropattern definition with LIGA (Lithographie, Galvanoformung, Abformung) fabricated Ni microstructures with parallel micropattern generation with µEDM, was used to fabricate micropattern with some geometrical complexity on elemental Ta and 304 stainless steel. Also, the results of instrumented micromolding of Al are studied. Measured molding response was rationalized with companion high-temperature tensile testing of Al using a simple mechanics model of the micromolding process. The present results suggest that stresses on the mold insert during micromolding are determined primarily by the flow stress of the molded metal at the molding temperature and the frictional traction on the sides of the insert. The influence of strain rate was also considered. In addition, the elasto-plastic response of an Al block indented by a periodic array of long smooth strip punches made of a relatively rigid material is studied through finite element analysis (FEA). First, elastic test problems, for which analytical solution exist, are carried out to calibrate the FEA mesh. Results demonstrate that satisfactory accuracy is achieved for key, peak, contact stresses near the edge-of-contact region and interior stresses. Second, indentation response is tracked with FEA into the elasto-plastic regime. Results show that the yield region within the indented material approaches a self-similar state as indentation progresses. Finally, Al molded by Si inserts at room temperature is studied through experiment and FEA

Improving the performance, reliability and service life of aviation technology products based on the innovative vacuum-plasma nanotechnologies for application of avinit functional coatings

The methods of creating the advanced nanomaterials and nanotechnolo-gies of functional multicomponent coatings Avinit (mono- and multilayer, nano-structured, gradient) to improve the performance of materials, components and parts of aerotechnical purposes are considered. The vacuum-plasma nanotechnologies Avinit were developed based on the use of gas-phase and plasma-chemical processes of atomic-ionic surface modifi-cation and the formation of nanolayer coatings in the environment of nonsteady low-temperature plasma. Considerable attention is paid to the equipment for application of functio-nal multilayer composite coatings: an experimental-technological vacuum-plas-ma automated cluster Avinit, which allows to implement complex methods of coating (plasma-chemical CVD, vacuum-plasma PVD (vacuum-arched, magne-tron), processes of ionic saturation and ionic surface treatment, combined in one technological cycle. The information about the structure and service characteristics of Avinit coatings has a large place. The results of metallographic, metallophysical, tribological investigations of properties of the created coatings and linking of their characteristics with pa-rameters of sedimentation process are described. The possibilities of parameters processes regulation for the purpose of reception of functional materials with the set of physicochemical, mechanical complex and other properties are considered. The issues of development of experimental-industrial technologies Avinit and industrial implementation of the developed technological processes to increase of operational characteristics of aerotechnical products are addressed in detail. Attention is paid to the development prospects of vacuum-plasma nano-technologies Avinit and expansion of these methods applications in mechanical engineering, aviation, power-plant industry, space industry and other fields of science and technology. The book is aimed at specialists working in the field of ion-plasma surface modification of materials and functional coatings application