Browse

You are looking at 1 - 10 of 2,220 items for :

  • Materials Processing x
Clear All
Open access

Majda Paweł and Joanna Jastrzębska

Abstract

After many years of intensive work the international experts from ISO TC 39 published the technical report called ISO TR 16907 “Machine tools – numerical compensation of geometric errors”. This document defines the terminology, presents benefits and limitations of numerical compensation of machine tools’ and measuring machines’ errors. It gives machines manufacturers and users vital information about how to use numerical compensation. In the context of those types of compensation defined in ISO TR 16907, this article shows rules of selecting models of Volumetric Error for three-axis machine tools. What is more, this paper presents some principles of reduction of these proposed models because of the functional tasks for machine tools. One of the obtained results is an array of reduced models for three-axis machine tools. This array determines the degree of detail of the model and the experimental research program that needs to be carried out in order to determine the Volumetric Error distribution.

Open access

Kinga Mencel and Łukasz Kemnitz

Abstract

The nanocomposites of polyamide 6 (PA6) with halloysite nanotubes (HNT) were prepared by extrusion using co-rotating twin-screw extruder and then the standard test specimens were injected using a screw injection moulding machine. The content of HNT in the nanocomposites was 5 or 10 weight percent. The heat treatment of unmodified PA6 and nanocomposites was carried out in silicone oil in temp. 150±2°C. The samples were annealed for 3 hours and then cooled at a rate of 4 K/min. Differential scanning calorimetry (DSC) causes annealing to increase the crystallinity of the polyamide matrix. After an annealing treatment a nanocomposite with better mechanical properties was obtained. Halloysite nanotubes in polyamide matrix play the role of a nucleating agent.

Open access

Bartosz Powałka and Michał Dolata

Abstract

This article presents a process of developing a computational model of a light construction vertical lathe. The model is made using the finite elements method. Due to the complexity of the machine tool and the optimization of the computation time superelements have been used in the model. The application of this method has reduced the computation time allowing the analysis of many variants of the mutual position of the machine components. The results of the analyzes led to the indication of weak links of the machine tool. After the improvement of the machine tool construction the movement of the tool tip and the workpiece was much smaller.

Open access

Tamás Ruppert and János Abonyi

Abstract

Human resources are still utilized in many manufacturing systems, so the development of these processes should also focus on the performance of the operators. The optimization of production systems requires accurate and reliable models. Due to the complexity and uncertainty of the human behavior, the modeling of the operators is a challenging task. Our goal is to develop a worker movement diagram based model that considers the stochastic nature of paced open conveyors. The problem is challenging as the simulator has to handle the open nature of the workstations, which means that the operators can work ahead or try to work off their backlog, and due to the increased flexibility of the moving patterns the possible crossings which could lead to the stopping of the conveyor should also be modeled. The risk of such micro-stoppings is calculated by Monte-Carlo simulation. The applicability of the simulator is demonstrated by a well-documented benchmark problem of a wire-harness production process.

Open access

Hayder Al-Maliki and Gábor Kalácska

Abstract

A review to enrich the literature concerning the effect of various plasmas on the tribological behaviour of polymers and monitor the developments of plasma for the modification of polymer surfaces over recent decades using up-to-date data. A comparative study of plasmas was conducted to identify the most useful and efficient ones which facilitate optimal improvements with regard to the characterizations of polymer surfaces and tribological properties. The studies included in this review strongly suggest that (besides Plasma-Immersion Ion Implantation, PIII) atmospheric plasmas (dielectric barrier discharges, DBD) are an effective technique in terms of modifying the characterizations of polymer surfaces thereby enhancing the tribological behaviour of polymers under different operating conditions that extends the operating life of elements within the machine.

Open access

Eszter Virágh and Bálint Kiss

Abstract

The controllability of reactions is an important issue in the chemical industry. The control of reactions is of great practical interest in order to ensure the energy- and time-efficient production of compounds. This paper studies the dynamical models of some chemical reactions in order to verify their controllability with regard to a candidate input signal, namely the change in the ambient temperature of a reaction.

Open access

Otto During, Silu Bhochhibhoya, Ramesh Kumar Maskey and Rajendra Joshi

Abstract

Rice Husk Ash (RHA) is a well-known supplementary cementitious materials (SCMs) that can be used for concrete with reduced CO2 contributions. In 2016, only Nepal produced 5.2 million tonnes rice that gave about 1.14 million tonnes rice husk. The rice husk can also be used directly in a cement kiln as a fuel. This study analysis the potential CO2 reductions from three scenarios and emphasis strengths, weaknesses, opportunities and treats in the production systems for initiate a decision process with possibilities to get an industry project financed from the green climate found. The highest CO2 benefits were from rice husk used in a cement kiln were half of the yearly rice husk production in Nepal could reduce the climate impact with 808000 tonnes CO2.

Open access

Robert Koteras, Michał Wieczorowski, Piotr Znaniecki and Natalia Swojak

Abstract

The purpose of the article is to show the practical side of reverse engineering.Many times during the process of optimizing parts, before we intervene in the tool that produces them, we want to makesure that the optimization will work in practice.For this purpose, currently, we often use 3D printers. Unfortunately, they introduce distortions of geometry to the printed prototyperesultingfrom the technology of its production.

Open access

Veronika Varga, Katalin Bélafi-Bakó, Dávid Vozik and Nándor Nemestóthy

Abstract

Itaconic acid is an organic acid produced mainly for non-food purposes. It can be manufactured by biotechnological synthesis using various strains which results in the salt form of the acid. In this work, the separation of sodium itaconate by electrodialysis was studied. Homopolar cation- and anion-selective membranes were applied and the module was operated under a constant voltage. The transport of the acid was followed by on-line ultraviolet and visible absorption spectroscopy, where the detector was installed in the system. The experiments with models of aqueous solutions confirmed that the technique is suitable for the effective recovery of itaconic acid.