Research on the variability of the burnishing force during processing surfaces with 3D shape by using simultaneous 5-axis ball-burnishing process implemented on CNC milling machine

oai:ojs2.aj-tuv.org:article/20The present research is focused on continuously measuring the variability of the burnishing force during conducting ball-burnishing process for specimens with surfaces with 3D shape, by using CNC milling machine with dual rotary table installed. For measuring the burnishing force and its variability, the specifically developed ball-burnishing tool with miniature force sensor was used. To assess the degree of influence of the main regime parameters on the variability of the burnishing force, the four factors full factorial experiment design with two levels per factor and four replications per run has been carried out. The experimental results are processed statisti-cally and techniques such as Pareto and ANOVA were used after that, for sorting them by degree of significance. Some conclusions about the magnitude and the causes of the obtained variability also are given.The present research is focused on continuously measuring the variability of the burnishing force during conducting ball-burnishing process for specimens with surfaces with 3D shape, by using CNC milling machine with dual rotary table installed. For measuring the burnishing force and its variability, the specifically developed ball-burnishing tool with miniature force sensor was used. To assess the degree of influence of the main regime parameters on the variability of the burnishing force, the four factors full factorial experiment design with two levels per factor and four replications per run has been carried out. The experimental results are processed statisti-cally and techniques such as Pareto and ANOVA were used after that, for sorting them by degree of significance. Some conclusions about the magnitude and the causes of the obtained variability also are given

Experimental research of partial regular microreliefs formed on rotary body face surfaces

The basic regularities in the influence of processing parameters on the geometrical characteristics of the partially regular microreliefs, formed on the rotary body face surface, are established. Combinations of partially regular microreliefs are formed by using a contemporary CNC milling machine, and an advanced programing method, based on previously developed mathematical models. Full factorial experimental design is carried out, which consist of three factors, varied on three levels. Regression stochastic models in coded and natural form, which give the relations between the width of the grooves and the deforming force, feed rate and the pitch of the axial grooves, are derived as a result. Response surfaces and contour plots are built in order to facilitate the results analysis. Based on the dependencies of the derived regression stochastic models, it is found that the greatest impact on the width of the grooves has the magnitude of the deforming force,followed by the feed rate. Also, it is found that the axial pitch between adjacent toolpaths has the least impact on the width of the grooves. As a result of the full-factorial experiment, the average geometric parameters of the microrelief grooves were obtained on their basis. When used, these values will provide for the required value of the relative burnishing area of the surface with regular microreliefs, and, accordingly, the specified operational properties

Application of New Generation Geometrical Product Specifications—Position Tolerancing

The geometrical product specifications (GPSs) from new generation are composed of several standards issued by the ISO/TC 213. They are related to the way of denoting the requirements in the design engineering drawings, such as drawing indication, definition of tolerance and values of specifications, characteristic, parameters and definitions of actual features. They also include requirements relating to compare verification, measure instrument and calibrate size, distance, radius, angle, form and position of geometrical features, roughness profile, waviness profile, primary profile, surface imperfection and edges. A lot of new and mathematical terms, the size system, indications of dimensions other than linear sizes by using geometrical tolerances, uncertainty series, etc. are introduced in this chapter. The aim of this chapter is to explain the new requirements of new generation standards for geometrical product specifications related to positional deviation. The advantages and disadvantages of the possibility to indicate the accurate requirements for location of surfaces and axes are discussed

Applying regular relief onto conical surfaces of continuously variable transmission to enhance its wear resistance

While investigating the variator transmission of vehicles, the relationship between the technological and service parameters of the working surfaces of conical disks treated by technological methods was established. The service properties are proposed to be enhanced by Regular MicroReliefs (RMRs) created on such surfaces. The optimal technological processing conditions were found, which allow retaining the greatest amount of lubricant. The causes of surface defects, formed on the working surfaces of conical disks of the Continuously Variable Transmission (CVT), are systematized and classified. The wear resistance of such surfaces is proposed to be enhanced by technological methods, in particular, by forming partially RMRs on them. Their application facilitates relaxation processes on the material near to the surface, reduces shear stresses and strains, thus preventing the formation of burrs and extending the life of the conical disks of the CVT. A novel approach for obtaining the toolpaths of the deforming element, based on the so-called “Commis–Voyageur problem” algorithms, is employed in order to research the possibilities for involving that methods in toolpath generation. Dependences between the partial RMR’s formation conditions (deforming forces and feedrate) and microgeometric quality parameters are established. The latter include surface roughness, with a partially RMR applied onto the face surfaces of the test specimen (rotary body). It is found that these microreliefs enhance the ability of oil retaining in plastically deformed traces, formed over the operational surfaces, in comparison with those, that are processed by traditional cutting methods, as turning for example

Experimental research on the effect of the ball burnishing process, using new kinematical scheme on hardness and phase composition of surface layer of AISI 304L stainless steel

In this paper, experimental results about hardness and phase composition of surface layer of AISI 304L SS, machined by using ball burnishing process, conducted under a new kinematic scheme, are presented. The effect of different combinations of the process regime parameters on the amount of strain induced martensitic phase, is discussed. The amounts of austenitic and strain induced martensitic phases are identified by x-ray diffractometer. Micro hardness along the depth of the hardened layer is measured. Conclusions about the influence of the ball burnishing process on strain induced martensitic phase are given

Experimental research on the effect of the ball burnishing process, using new kinematical scheme on hardness and phase composition of surface layer of AISI 304L stainless steel

In this paper, experimental results about hardness and phase composition of surface layer of AISI 304L SS, machined by using ball burnishing process, conducted under a new kinematic scheme, are presented. The effect of different combinations of the process regime parameters on the amount of strain induced martensitic phase, is discussed. The amounts of austenitic and strain induced martensitic phases are identified by x-ray diffractometer. Micro hardness along the depth of the hardened layer is measured. Conclusions about the influence of the ball burnishing process on strain induced martensitic phase are given

Application of GeoGebra software into teaching mechanical engineering courses

Mechanics courses traditionally characterize with a rather low percentage of passing students. Dynamic mathematical packages like GeoGebra are widely used nowadays for teaching mathematics, but its interactive capabilities can be used for simulation of different physical phenomena. In this article few interactive applets for Static, Dynamic, Strength of Materials and Theory of Mechanisms and Machines courses, are presented. An experiment with comparison of the test results of two group of students after the exercise beam about internal forces, shows that group trained with GeoGebra applets have significantly higher mean result

A study for determining the most significant parameters of the ball-burnishing process over some roughness parameters of planar surfaces carried out on CNC milling machine

Ball burnishing process often applies for obtaining specifically characteristics in the surface layer of the functional surfaces of the machine parts. Using CNC machines for carrying out this process significantly increases the possibility of control the characteristics of the toolpath of the ball tool and thus to produce regularly distributed roughness with specific size and direction of cells alignment. The current study presents obtained results from L8 Taguchi experimental design for determining the significantly influenced parameters of the ball burnishing process carried out on CNC milling machine on the size and arrangement direction of the cells form regular distributed roughness on planar surfaces

Evaluating Some Functional Properties of Surfaces with Partially Regular Microreliefs Formed by Ball-Burnishing

In the present work, functional properties of three different types of regular microreliefs, formed by ball burnishing process on flat surfaces are evaluated. For their estimation, heights and material ratio curve’s criteria were used, according to the international standard ISO 21920-2:2021. The influence of the regular relief’s type and ball burnishing process parameters on the surface functional properties were investigated using full factors experimental design. Based on the obtained results, statistical models were derived that describe the dependencies between the topography characteristics and the regular reliefs’ types and regime parameters of the ball burnishing process. Based on the obtained results, several conclusions have been formulated about the applicability of these standardized methods and criteria for evaluating the functional characteristics of the different types of regular reliefs at the end of the work