Cryogenically assisted manufacturing processes are emerging as environmentally-benign, toxic-free, hazardless operations, producing functionally superior products. This paper presents an overview of major cryogenic manufacturing processes, summarizing the state-of-the-art and significant developments during the last few decades. It begins with a summary of historic perspectives, including definitions, scope, and proceeds to analysis of process mechanics and material performance covering tribological and thermo-mechanical interactions, followed by surface integrity, product quality and performance in cryogenic manufacturing. Process analysis and applications includes machining, forming and grinding. Economic, safety and health issues are then discussed. Finally, progress in developing predictive performance models and future outlook are presented.
COBISS.SI-ID: 14829851
A nanoparticle-based cooling-lubricating fluid (nCLF), designed and fabricated by suspending engineered nanoparticles (ENPs) in biodegradable vegetable-based fluids, has been developed for integration into material processing technologies. This new product exhibits tribological properties superior to those of conventional metalworking fluids. The major innovation is the ability to create a stable nCLF through the modification of ENP surfaces. Functionalized MoS2 nanotube ENPs were successful used as low friction additives. The experimental work, required for the proof-of-concept and technology validation, was carried out on three different levels to quantify the improved tribological behavior of nCLF. These experiments include standard tribological tests, mock-up tests to simulate machining, and actual machining tests. It is demonstrated that the specific properties of ENPs, fluid design and composition, as well as specific lubrication mechanisms, exhibit superior performance of nCLF in terms of friction and wear. The objective of this paper is to demonstrate how recent nanotechnology developments support innovation needed for transitioning to sustainable production via new product development and integrated industrial applications.
COBISS.SI-ID: 14444315
The tool-wear of cutting tools has a very strong impact on the product quality as well as efficiency of the machining processes. Therefore, it in-the process characterization is crucial. This paper presents an innovative and reliable direct measuring procedure for measuring spatial cutting tool-wear with usage of laser profile sensor. The technique provides possibility for determination of 3D wear profiles, as advantage to currently used 2D techniques. The influence of the orientation of measurement head on the accuracy and the amount of captured reliable data was examined and the optimal setup of the measuring system was defined. Further, a special clamping system was designed to mount the measurement device on the machine tool turret. To test the measurement system, tool-life experiment was performed. Additionally, a new tool-life criterion was developed, including spatial characteristics of the tool-wear. The results showed that novel tool-wear and tool-life diagnostic represent objective and robust estimator of the machining process. Additionally, such automation of tool-wear diagnostics on machine tool provides higher productivity and quality of the machining process.
COBISS.SI-ID: 14193947
A numerical model based on computational fluid dynamics is developed to analyze fluid flow and thermal aspects in grinding. The model uses multiphase fluid flow with heat transfer based on the volume-of-fluid method, convection, con- duction in solids and a multiple reference frame model of the porous grinding zone. Fluid velocity vectors, useful flow rate, grinding temperatures and energy partition are predicted using the model. In lieu of direct measurements of these quantities, the verification relies on the indirect assessment of surface integrity. The simulation results provide adequate agreement with the measured residual stress, depth of heat-affected zone and full width at half maximum profile with respect to the grinding temperatures.
COBISS.SI-ID: 14459931
In the post-affluence phase of socio-economic development, innovation may be equally crucial, if it can be more usual and holistic, hence socially responsible, including youngsters. Many countries are, like Slovenia, lagging behind most developed economies in innovation and economic results. In order to alleviate this problem, authors developed a model for the sustainable promotion of creativity, innovation and entrepreneurship among primary school students. Deliberately, no complex strategy for the revision of the curriculum is proposed. Such a revision, though necessary, is questionable now. Authors’ approach is almost minimalist and, thus, feasible in the current environment. Here three forms of the proposed educational activities are presented. Each of the three sets of activities has work guidelines founded on authors’ concept. The introduction of these guidelines will help improve the creative, innovative and entrepreneurial competencies of youngsters. Although the proposal envisions no immediate financial effects, it presents an important and socially responsible long-term investment.
COBISS.SI-ID: 21982950