Witold Habrat

Modelling and Optimization of Machining with the Use of Statistical Methods and Soft Computing

This book chapter pertains to the use of statistical methods and soft computing techniques that can be used in the modelling and optimization of machining processes. More specifically, the factorial design method, Taguchi method, response surface methodology (RSM), analysis of variance, grey relational analysis (GRA), statistical regression methods, artificial neural networks (ANN), fuzzy logic and genetic algorithms are thoroughly examined. As part of the design of experiments (DOE) the aforementioned methods and techniques have proven to be very powerful and reliable tools. Especially in machining, a plethora of works have already been published indicating the importance of these methods.

Morphology of Near- and Semispherical Melted Chips after the Grinding Processes Using Sol-Gel Abrasives Based on SEM-Imaging and Analysis

Selected issues related to SEM-imaging and image analysis of spherical melted chips formed during the grinding process are presented and discussed. The general characteristics of this specific group of machining products are given. Chip formation phenomena, as well as their overall morphology, are presented using selected examples of near- and semispherical melted chips occurring singly or concentrated in clusters on the grinding wheel surface after the machining process. Observation of the spherical melted chips and acquisition of their images were carried out for grinding wheel active surfaces with microcrystalline sintered corundum abrasive grains SG™ after the internal cylindrical grinding process of a 100Cr6 steel and Titanium Grade 2® alloy by use of a scanning electron microscope, JEOL JSM-5500LV. Analysis of the obtained SEM micrographs was carried out by Image-Pro® Plus 5.0 software to determine the selected geometrical parameters describing the morphological features of the assessed chips.

Experimental Investigation of Effect of the Laser-Assisted Finish Turning of Ti-6Al-4V Alloy on Machinability Indicators

In this paper, the experimental studies of the finish turning of Ti-6Al-4V titanium alloy with the laser-assisted machining were described. For the tests, a cemented carbide tool was used. The influence of the laser heating on the microstructure of Ti-6Al-4V titanium alloy for kinematics corresponding with the turning process was determined. For a laser scanning rate of 80 m/min and laser power 1200W, the maximum depth of the melted zone was about 50 μm. The beneficial effect of laser assisted machining on components of the cutting force was established. For a cutting speed of 80 m/min, feed rate 0.1 mm/rev, depth of cut 0.25 mm and laser power 1200 W, over 60% reduction of the tangential components of cutting force was observed. The chip-breaking effect for the conventional and the laser-assisted processes was determined. Roughness parameters of the surface after the conventional and laser-assisted turning are compared.

Potential for improving efficiency of the internal cylindrical grinding process by modification of the grinding wheel structure. Part I: Grinding wheels made of conventional abrasive grains

This article offers an overview of 14 grinding wheel construction modifications used in the peripheral grinding of flat-shaped internal and external cylindrical surfaces, when grinding wheels made of conventional abrasive grains are used (Al2O3, sol-gel alumina, SiC, etc.). The text contains characteristics of grinding wheels with mixed grains, glass-crystalline bond, a centrifugal provision of the coolant into the grinding zone, aggregate grains, zones of different diameters, radial rough grinding zone, extended finish grinding segments, active surface macro- and micro-discontinuities, as well as multiporous, impregnated (self-lubricating), sandwich, sectional and segment grinding wheels. Each of the presented structural modifications was described by giving construction scheme, used abrasive grains, range of applications, advantages as well as disadvantages. Modifications of the grinding wheel construction allow for effective improvement of both the conditions and the results of the grinding process. A wide range of the known modifications allows for their proper selection depending on the required criteria of effective evaluation and taking into account the specific characteristics of conventional abrasive grains. As a result, it is possible to obtain positive influence on a number of technological factors of the grinding process. The described modifications of the grinding wheel structure can be also an inspiration and the basis for creating new solutions in this field.

Experimental Analysis of the Cutting Force Components in Laser-Assisted Turning of Ti6Al4V

In this paper, the experimental analysis of the turning of Ti-6Al-4V titanium alloy with the laser-assisted machining was described. For the tests, a cemented carbide tool was used. The influence of the laser heating and cutting parameters on the tangential and thrust forces was determined. The beneficial effect of laser-assisted machining on components of the cutting force was established. Cutting force models were developed. The significant influence of interaction of cutting speed and laser power on tangential force components was observed. The microstructure of laser-scanned surface and the roughness parameters after turning as the process indicators connected with cutting force were analyzed.

Analysis of the Legal Risk in the Scientific Experiment of the Machining of Magnesium Alloys

In the article, the legal risk of the researcher in the case of a scientific experiment in the machining of magnesium alloys was determined. The use of magnesium alloys in industry and identification of the problems associated with machining were presented. The issues concerning legal liability in the experiment and provisions ensuring a greater scope of legal protection for the researcher were indicated and challenges in the machining of magnesium alloys were analyzed. Moreover, the method to assess legal risk in experiments was proposed and its application in the experiments was presented. The analysis confirmed the applicability of the proposed method to the analysis of the legal risk.

Accelerated Method of Cutting Tool Quality Estimation During Milling Process of Inconel 718 Alloy

Cutting tool wear is a natural consequence of the engagement of cutting tool and workpiece. This phenomenon can progress in a slower or quicker rate and can be attributed to various reasons, such as abrasion, adhesion, chemical reaction, thermal or mechanical phenomena, depending on machining conditions and material properties of cutting tool and workpiece. As the replacement of worn tools is directly related to the cost of machining processes, it is important to select favorable process parameters in order to avoid high wear rates, especially when machining hard-to-cut materials. The experimental determination of tool wear during machining of various materials is a costly and time-consuming process, as it requires carrying out experiments at several cutting speeds until a tool failure criterion is reached each time. In the present work, a novel method for conducting tool wear experiments at various cutting speeds at a single experiment is proposed and applied to a case of milling an Inconel 718 workpiece. Experiments were performed for three different cutting tools and for cutting speeds in the range of 90–170 m/min, at constant feed rate, axial and radial depth of cut values. The results indicate that the proposed methodology can successfully provide an indication of the performance of various cutting tool types during machining of hard-to-cut materials.

Comparison of Geometrical Accuracy of a Component Manufactured Using Additive and Conventional Methods

This chapter describes three different methods of manufacturing a vacuum cleaner connector made of ABS and NECURON plastic material. Basically, the part is produced on an injection molding machine; however, with the help of manual laser scanner analysis, it is possible to compare two other methods: part manufactured by milling is 0.04 mm and part manufactured by injection molding machine is −0.15 mm and 3D-printed part is −0.20 mm. All the above-mentioned methods of producing the connector have their advantages and disadvantages. The fabrication time of all elements (under 1 min for injection molding machine, 1.5 h for milling machine and ca. 7 h for 3D printing) and costs of machines and tooling are decisive factors for manufacturing technique selection.

Forces modeling in a surface peripheral grinding process with the use of various design of experiment (DoE)

The paper presents forces modeling with the use of DoE models, such as (Box-Wilson) central composite design in face centered variant (CCF) and Box-Behnken design in a surface peripheral grinding process of 100Cr6 steel with M3X60K5VE01-35 grinding wheel. Experiment design and result analysis were done with the use of Design-Expert software. Force models, obtained with application of selected designs of experiment, were compared on the basis of the coefficient of determination, and values of residual standard deviation.