An Analysis and Modelling of Spinning Process without Wall-Thickness Reduction

Through the spinning process it is made the different axial-symmetrical parts by acting spinning roller on blank of sheet metal, which is shaped through a chuck. In the paper is shown an analyse of stressed and strained state, as well as forming force components of spinning process. On the ground of experimental results it is made mathematical modelling of spinning forming force. The obtained mathematical model describes enough accurate and reliable (P = 0,98) the spinning forming force

The influence of mechanical properties of workpiece material on the main cutting force in face milling

The paper presents the research into cutting forces in face milling of three different materials: steel Č 4732 (EN42CrMo4), nodular cast iron NL500 (EN-GJS-500-7) and silumine AlSi10Mg (EN AC-AlSi10Mg). Obtained results show that hardness and tensile strength values of workpiece material have a significant influence on the main cutting force, and thereby on the cutting energy in machining

Utjecaj mehaničkih karakteristika materijala obratka na glavnu silu rezanja pri čeonom glodanju

The paper presents the research into cutting forces in face milling of three different materials: steel Č 4732 (EN42CrMo4), nodular cast iron NL500 (EN-GJS-500-7) and silumine AlSi10Mg (EN AC-AlSi10Mg). Obtained results show that hardness and tensile strength values of workpiece material have a significant influence on the main cutting force, and thereby on the cutting energy in machining.U radu su prikazana istraživanja sila rezanja pri čeonom glodanju za tri različita materijala: čelik Č 4732 (EN42CrMo4), nodularni lijev NL500 (EN-GJS-500-7) i silumin AlSi10Mg (EN AC-AlSi10Mg). Dobiveni rezultati pokazuju da vrijednosti tvrdoće i vlačne čvrstoće materijala obratka imaju veliki utjecaj na glavnu silu rezanja, a time i na ukupno utrošenu energiju rezanja pri obradi

Influece of the austempering temperature on the tensile strength of the austempered ductile iron (ADI) samples

Austempered Ductile Iron (ADI) is a class of ductile iron subjected to a two-step heat treatment process – austenitization and austempering. The heat treatment gives to ADI a high value of tensile strength and an especially good strength-to-weight ratio. However, designers in most cases are unfamiliar with this material that can compete favorably with steel and aluminum castings, weldments and forgings. The high tensile strength of ADI is the result of its unique ausferrite microstructure. In this paper, an investigation of the influence of the austempering temperature on the tensile strength of the ADI samples is presented

The machinability of nickel-based alloys in high-pressure jet assisted (HPJA) turning

Due to their mechanical, thermal and chemical properties, nickel-based alloys are generally included among materials that are hard to machine. An experimental study has been performed to investigate the capabilities of conventional and high-pressure jet assisted (HPJA) turning of hard-to-machine materials, namely Inconel 718. The capabilities of different hard turning procedures are compared by means of chip breakability. The obtained results show that HPJA method offers a significant increase in chip breakability, under the same cutting conditions (cutting speed, feed rate, depth of cut)

Physical modelling and numerical finite element method (FEM) simulation of forging in open die of alloy AIMgSi0,5

This paper researches the process of forging in open die of gradual axial-symmetric workpiece made of alloy AIMg-Si0,5. The physical modelling was carried out, for which an original method for physical discretisation and numerical FEM analysis was developed. The components of tensor were determined: strain, strain rate, stress and the corresponding effective parameters. The results obtained experimentally and through a numerical FEM simulation were compared and analysed

Primjena neuronske mreže kod procjene površinske hrapavosti nakon završne obrade valjanjem

In order to increase productivity, machining times and market competitiveness of machining production systems, it is important to continuously develop existing technological solutions. This article describes the usage of the neural network for the prediction of surface roughness after the roller burnishing. Since the observed problem is multidimensional with several input parameters and one output parameter and since nonlinearity and complexity of parameter correlation, there was used the backpropagation neural network algorithm. Empirical and experimental values of input and output parameters were used as initial values for the learning of the neural network. Developed neural network model with its results can be used for easier implementation of further roller burnishing process plans.Ovaj rad opisuje primjenu umjetne neuronske mreže za predviđanje hrapavosti površine obratka nakon završne obrade valjanjem. S obzirom da se radi o višedimenzionalnom problemu sa nekoliko ulaznih te jednim izlaznim parametrom te da je njihova međusobna funkcijska povezanost vrlo kompleksna, nelinearna i na kraju i nepoznata, korištena je višeslojna neuronska mreža sa primjenom algoritma “širenja unatrag”. Naime, iskustvene i eksperimentalne vrijednosti, korištene kao ulazni i izlazni parametar u svrhu učenja neuronske mreže, poslužile su kao dobra polazišna točka sustavu umjetne inteligencije za razradu općenitog modela koji se kasnije može koristiti u svrhu izgradnje nekih viših ekspertnih sustava lako upotrebljivih prilikom izrade tehnologije za završnu obradu površine valjanjem