This paper investigates the application of the high-pressure jet assistance (HPJA) in rough turning of Inconel 718 with coated carbide tools. The region of operability, which sets the boundaries of the process parameters, has been experimentally determined using the tool-material pair (TMP) methodology. The assessment of HPJA machining performance is based on response surface methodology (RSM), which integrates a design of experiment (DOE) and a regression modelling technique for fitting a model to experimental. This leads to a new insight into the influence of the cutting process on chip breakability, cutting forces, contact length, surface finish and tool temperature, which are the key machining performance measures.
COBISS.SI-ID: 11119387
This two part paper presents general issues, methods and a case study for achieving production sustainability on a machining technology level. In order to tackle these issues, the paper promotes sustainable production via the alternative machining technologies, namely cryogenic and high pressure jet assisted machining that have a high potential to cut costs and improve competitiveness by reducing resource consumption and thus creating less waste. The general issues of sustainable technologies pointed out with a comparative case study life cycle assessment performed for alternative machining processes are covered in part I of the work, concluding that future of sustainable production is going to entail the use of alternative machining technologies to reduce consumption rates, environmental burdens, and health risks simultaneously, while increasing performances and profitability. As an upgrade to this part, overall cost evaluation is covered by a case study in part II of this work.
COBISS.SI-ID: 11150619
This paper presents results of the influence of cryogenic machining on the process stability. The stability diagrams are obtained experimentally using the coarse-grained entropy rate estimator for chatter detection from measured cutting forces. In comparison with conventional machining, enlarged stability windows are observed for the case of cryogenic machining. Based on the defined specific force models in turning operations, it is shown that a higher machining stability is achievable in cryogenic machining due to the reduction of specific cutting force components, in comparison with dry machining.
COBISS.SI-ID: 11827739
This experimental study focuses on high performance cryogenic machining of porous tungsten, which is classified as a difficult-to-machine material, where the quality of the machined surface porosity is one of the most important objectives. For achieving the required postmachining porosity and surface roughness, the optimum machining parameters and tool grade, as well as cryogenic machining method, an alternative to conventional machining, were chosen. For smearing evaluation, pores on the machined surface are individually analyzed from SEM pictures. Different tool grades (uncoated carbide, ceramic, polycrystalline diamond and cubic boron nitride) are analyzed in this study. A precise correlation between the performance measures and the machining parameters, including tool grade, is developed to achieve the required performance measures. Surface roughness, porosity, tool-wear and cutting forces are measured and analyzed. A performance-based multi-objective optimization model is developed based on genetic algorithms (GA) and is used to predict the optimal cutting parameters for achieving improved machining performance.
COBISS.SI-ID: 12316187
The development of cutting simulation still requires an improvement in the understanding of the frictional phenomena at the tool-work material interface. This paper introduces a method for a fast identification of friction and heat partition models, based on a special tribometer able to simulate wide ranges of contact pressures and sliding velocities, similar to those occurring along the tool-work material interface in cutting. The method is applied for a wide spectrum of work materials and lubrication conditions. Combined with an analytical post-treatment, this set-up provides a modelling of the frictional behaviour that may improve significantly thermal aspects in cutting simulations.
COBISS.SI-ID: 12859163