A method for the design of a technology for the abrasive waterjet cutting of materials is based on the determination of the constant of cuttability of materials using an abrasive waterjet Kawj according to four different versions. Version A, where three deformation parameters are measured on the test cut/sample, namely selected depth hx [mm], local roughness Rax [μm] at depth hx and local deviation of the cut trace from the normal plane Yretx at depth hx. Version B, where merely two deformation parameters are measured, namely the reference depth het [mm] and deviation of the cut trace from the normal plane Yretx [mm] or, according to version C, where one parameter is mearured, namely either the ultrasonic wave speed vLUZ [m · s–1] or Young's modulus Emat [MPa]; Kawj being calculated from relevant deformation parameters. The last option is version D, where the design of the whole technology is carried out by calculation of Kawj according to the Young's modulus Emat or according to the ultrasonic wave speed vLUZ of the cut material.

The development and application of new materials brings, in connection with their technological machining, a number of new questions. Classical methods of machining are supplemented by new technologies. An abrasive water jet represents a universal flexible tool enabling the machining of all natural and artificial materials that are not damaged by direct contact with water. Great attention is paid to the study of the cut surface topography after abrasive water jet machining. The study of surface topography is important from the point of view of modelling and prediction of the topographic function of the abrasive water jet. On the basis of knowledge of the topographic function, we are able to optimise the technological parameters of the abrasive water jet machining process, which has an impact on the output, quality and price of the final product. The mechanism to remove material is an area which has not received much attention. In material disintegration, the mechanisms of cutting, plastic deformation, fatigue and fracture participate physically. By studying the surface topography we can better understand the process of abrasive water jet machining, specify the theory and correctly quantify the mechanism of material removal, which is the subject of this paper.

An important trend today is the continual improvement of product quality with the objective of increased customer satisfaction, but also leading to more effective cost reduction management. Effective quality management in a company also enables increasing production productivity thanks to the increasing amount of top-quality products made and the consequent minimalization of repairs of non-conforming workpieces. This contribution deals with one of the important tools for ensuring quality in the production process using the FMEA (Failure Mode and Effect Analysis) method used in the production of roller bearings for the automobile industry.

Professional paperThe core idea of the paper is a value stream mapping with identification of waste sources, and drawbacks which help to uncover hidden reserves of production. The analysis covers the current state of individual processes within the production line. After determination of the present drawbacks the plan of rationalization was created in which the combination of elements of lean production was used. The proposed solutions could be used when establishing the principles of lean production at particular sections of the assembly line within the whole plant. In case that proposed solution cannot be put into practice it can be used as a blueprint for other types of improvement respectively decreasing of waste and drawbacks. Keywords: increasing of value; semitrailer frame; value stream mapping; waste management; welding Racionalizacija toka materijala u proizvodnji polu-okvira za automobilsku industrijuStručni članak Osnovna ideja rada je prikaz toka vrijednosti uz identifikaciju izvora troškova i nedostataka, koji će pomoći da se razotkriju skrivene pričuve u proizvodnji. Analiza obuhvaća postojeće stanje u pojedinačnim postupcima na proizvodnoj traci. Nakon prepoznavanja postojećih nedostataka napravljen je plan racionalizacije u kojemu je rabljena kombinacija elemenata lean proizvodnje. Predložena bi se rješenja mogla primijeniti kad se primijene principi lean proizvodnje na pojedinim dijelovima montažne trake u cijelom pogonu. U slučaju da se predloženo rješenje ne može primijeniti u praksi može se koristiti kao model za druge vrste poboljšanja kao što su smanjenje otpada i nedostataka.

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The present article is focused on the non-destructive testing (NDT) inspection of pipelines during operation namely Magnetic Flux Leakage (MFL) method and Phased Array ultrasonic (PA) method. MFL inspection technique is electromagnetic test method primarily used to detect flaws or defects in high-permeability of ferromagnetic metals such as carbon steel tubing, plate, wire rope and tubular parts. PA ultrasonic method is an advanced NDT method that is used to detect component failures i.e. cracks or flaws and thereby determine component quality. Due to the possibility to control parameters such as beam angle and focal distance, this method is very efficient regarding to the defect detection and speed of testing. In this article real pipeline defect was identified by MFL method in the internal pipe inspection. This defect was fully mapped by Phased Array ultrasonic method in the terrain. 3D model of defect in the tested material was created from measured data and obtained by PA method. The real dimensions of the defect determined from measurements by the method of MFL and PA are compared.

One of the most important activities in the management of companies is the continuous improvement of products quality concerning their sustainability and better market position. The submitted paper aims to optimise the production process in the production of weldments. The study revealed a significant number of dimensional and threaded defects on the welded chassis of the loader. One possibility of continuously increasing the required performance of a company is to eliminate the number of non-conforming products using the tools of the Six Sigma methodology. This policy must be introduced by a company into the business processes management if a company wants to successfully meet the customers´ needs and improve the processes while cutting the costs of production. The resulting analysis focused on the selected type of defects to reduce their occurrence using the Six Sigma tools, specifically the DMAIC improvement cycle. The presented approach and the results obtained highlight the importance of applying quality tools in practice and their undeniable contribution in improving performance and quality, reducing the number of defects occurring and reducing the cost of poor quality in production, both now and in the future.

The work deals with solderabilty of high-purity aluminium with the lead-free tin solders. Soldering was performed in the air with and without application of flux and with mechanical removal of surface oxides. Wettability measurements have shown that all lead-free solders wetted aluminium surface with wetting angle below 42°. The shear strength of experimental joints attained the values from 25 to 48 MPa. The study of boundary zones of fabricated joints was performed by use of EDX analysis.