LCA of machine tools with regard to their secondary effects on quality of machined parts

2003 ◽  
Author(s):  
J. Akbari ◽  
K. Oyamada ◽  
Y. Saito
Keyword(s):  
Machine Tools ◽  
Secondary Effects ◽  
Machined Parts

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

Dynamisches Verhalten von Gestellwerkstoffen in Werkzeugmaschinen*/Dynamic behavior of different machine frame materials

2015 ◽  
Vol 105 (05) ◽  
pp. 263-268
Author(s):  
P. H. Nebeling
Keyword(s):  
Dynamic Behavior ◽  
Machine Tools ◽  
Dynamic Behaviour ◽  
Influencing Factor ◽  
Complex Structures ◽  
Geometric Properties ◽  
Long Time

Das dynamische Verhalten von Werkzeugmaschinen ist für die Stabilität während der Bearbeitung sowie die Qualität der erzeugten Werkstücke von besonderer Bedeutung. Ein Einflussfaktor darauf ist die Dämpfung. Im Bereich der Maschinengestelle kommen seit langer Zeit unterschiedliche Materialien zum Einsatz. In diesem Fachbeitrag werden die Dämpfungskennwerte unterschiedlicher Gestellwerkstoffe an geometrisch gleichen Proben vergleichend gegenübergestellt. Als weitere Kenngröße wurde die Lage der (1. Biege-) Eigenfrequenz als Maß für die massebezogene dynamische Steifigkeit verwendet. Die Effekte beim Übergang von einfachen Bauteilen zu komplexen Strukturen runden den Fachartikel ab.   The dynamic behaviour of machine tools is of great importance for stability and quality of the machined work pieces. One influencing factor in this area is damping. In the field of machine bases different materials have been use since long time. In this article the damping values of different materials with equal geometric properties are compared. As further parameter the first bending Eigenfrequency as dimension for mass related stiffness is use. The transition from simple components to complex structures is touched at the end of the paper.

scholarly journals Features and Characteristics of Motorized and Non-Motorized Milling Spindles

2020 ◽  
Vol 9 (4) ◽  
pp. 1095-1100
Keyword(s):  
Machine Tools ◽  
Cutting Tools ◽  
Control Device ◽  
Common Type ◽  
Machining Process ◽  
Industrial Practice ◽  
Quality Of Products ◽  
Efficiency And Reliability ◽  
Reliability And Availability

The Cutting process used in milling is one of the most common type of industrial machining methods. Similar to traditional milling spindles, the motor driven spindles are fitted with an integrated motor, thereby eliminating belts and gears for the transmission of power from the motor to the cutting tools. The innovative machine tools should be highly characterized systems in order to retain the necessary precision, efficiency and reliability. To satisfy their end user's reliability and availability requirements, both the spindle system (Tool/Tool-Holder/ Spindle) and motor tool system need to be configured for their usability and output results. However, the quality of a control device in industrial practice is greatly affected by the spindle cutting output and its reliability. The motor spindles are nothing but the rotating drive shafts which acts as axes for cutting force tools or in machining process for holding cutting instrument. Hence the spindles are one of the important factor in machining tool process and productivity, as these are used to produce parts as well as machines that produce components, which in turn have a significant impact on production levels and quality of products.

scholarly journals Virtual Optimization of Machine Tools and Production Processes

2007 ◽  
Vol 1 (2) ◽  
pp. 136-140 ◽  
Author(s):  
Jochen Bretschneider ◽  
◽  
Thomas Menzel
Keyword(s):  
Life Cycle ◽  
Machine Tools ◽  
Cost Effective ◽  
Processing Times ◽  
Virtual Production ◽  
Machine Productivity ◽  
Increase Productivity ◽  
Market Leadership ◽  
Faster Development

Faster development of innovative machine tools, shorter processing times, improved surface quality of workpieces, higher machine productivity – these are just a few of the wishes and demands of machine manufacturers and end-users. Time-to-market is decisive; in some industries, six months too late on the market can already be decisive in losing the race for market leadership. The key to success lies in virtual techniques. These are an extremely cost-effective way to increase productivity in all phases of the machine tools life cycle. Siemens AG, the leading provider for control and drive technology, sees itself as a partner for the whole machine tool industry and offers four phases of simulation support which cover the entire life cycle of a machine: Mechatronic Support for simulation for machine development, Machine Simulator for supporting commissioning, Virtual Production for the optimization of production and, finally, Virtual NC Kernel (VNCK) for the testing of NC part programs at the end-user.

scholarly journals Quality of life after treatment for cervical cancer

2018 ◽  
Vol 22 (4) ◽  
Author(s):  
Rafaella Araújo Correia ◽  
Cristine Vieira do Bonfim ◽  
Daniela Karina da Silva Ferreira ◽  
Betise Mery Alencar Sousa Macau Furtado ◽  
Heitor Victor Veiga da Costa ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Cervical Cancer ◽  
Cancer Screening ◽  
Analytical Study ◽  
Leisure Activities ◽  
Socioeconomic Conditions ◽  
Secondary Effects ◽  
Socioeconomic Characteristics ◽  
Alternative Measures

Abstract Objective: Identify the quality of life of women treated for cervical cancer according to their clinical and socioeconomic characteristics. Methods: This was a analytical study on women who were treated for cervical cancer by means of surgery, radiotherapy and chemotherapy. To evaluate their quality of life, the WHOQOL-bref questionnaire was applied. The Mann-Whitney test was used to investigate associations between domains and variables. Results: There were associations (p < 0.05) between the WHOQOL-bref domains and the variables of income, conjugal situation, leisure activities and treatment undergone. The physical and psychological domains were associated with overall quality of life (R = 0.54 and R = 0.63, respectively). Conclusions: Socioeconomic conditions and the type of treatment undergone influenced the quality of life of these women after their treatment. There is a need to increase the reach of cervical cancer screening among women who are less economically favored; and, after treatment, to offer alternative measures that soften the secondary effects.

DESIGN AND ANALYSIS OF SUPER TWISTING SLIDING MODE CONTROL FOR MACHINE TOOLS

2016 ◽  
Vol 78 (10-3) ◽  
Author(s):  
Chiew Tsung Heng ◽  
Zamberi Jamaludin ◽  
Ahmad Yusairi Bani Hashim ◽  
Nur Aidawaty Rafan ◽  
Lokman Abdullah ◽  
...  
Keyword(s):  
Machine Tools ◽  
Sliding Mode ◽  
Tracking Error ◽  
Control Algorithms ◽  
Sliding Mode Controller ◽  
Control Input ◽  
Positioning System ◽  
Direct Drive ◽  
Chattering Effect

High demands of precision on machine tools are hardly cope by using existing classic control algorithms. This paper focuses on the design, analysis and validation of a super twisting sliding mode controller on a single axis direct drive positioning system for improved tracking performances. The second order positioning system parameters were determined using input and output of measured data. Effects of two gain parameters in control algorithm on the quality of the control input and tracking error were analysed experimentally. The gain parameters were selected based on magnitude reduction in chattering during practical application. The performance of tuned super twisting sliding mode controller was compared with a traditional sliding mode controller using sigmoid-like function. Results showed that super twisting sliding mode controller reduced the chattering effect and improved the performance of system in terms of tracking error by 16.5%.  

scholarly journals Analysis of the Machining Process of Titanium Ti6Al-4V Parts Manufactured by Wire Arc Additive Manufacturing (WAAM)

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 766 ◽  
Author(s):  
Fernando Veiga ◽  
Alain Gil Del Val ◽  
Alfredo Suárez ◽  
Unai Alonso
Keyword(s):  
Additive Manufacturing ◽  
Arc Welding ◽  
Machine Tools ◽  
Optimal Strategies ◽  
Machining Process ◽  
Manufacturing Processes ◽  
Plasma Arc Welding ◽  
Traditional Manufacturing ◽  
Wire Arc Additive Manufacturing

In the current days, the new range of machine tools allows the production of titanium alloy parts for the aeronautical sector through additive technologies. The quality of the materials produced is being studied extensively by the research community. This new manufacturing paradigm also opens important challenges such as the definition and analysis of the optimal strategies for finishing-oriented machining in this type of part. Researchers in both materials and manufacturing processes are making numerous advances in this field. This article discusses the analysis of the production and subsequent machining in the quality of TI6Al4V produced by Wire Arc Additive Manufacturing (WAAM), more specifically Plasma Arc Welding (PAW). The promising results observed make it a viable alternative to traditional manufacturing methods.

Analyzing processing quality of machine tools via processed product: Example of ball valve processing machine

2020 ◽  
Vol 234 (4) ◽  
pp. 331-341 ◽  
Author(s):  
Kuen-Suan Chen ◽  
Der-Fa Chen ◽  
Ming-Chieh Huang ◽  
Tsang-Chuan Chang
Keyword(s):  
Machine Tools ◽  
Process Capability ◽  
Quality Characteristics ◽  
Process Quality ◽  
Quality Analysis ◽  
Process Capability Indices ◽  
Processing Quality ◽  
Accuracy And Precision ◽  
Capability Indices

Machine tools are fundamental equipment in industrial production, and their processing quality exerts a direct impact on the quality of the component product that they process. Thus, machine tool manufacturers develop various machine tools depending on market needs and processing functions, and the processed component products generally possess multiple smaller-the-better, larger-the-better, and nominal-the-best quality characteristics at the same time. For this reason, this study employed the widely used process capability indices, [Formula: see text], [Formula: see text], and [Formula: see text] to develop a model that can evaluate the process quality of component products and analyze the processing quality of various machine tools. We first converted the process capability indices into functions of the accuracy and precision indices and constructed a multi-characteristic quality analysis chart that can identify the reason for poor process quality in a quality characteristic. Furthermore, considering the fact that the process capability indices can only be estimated, which may lead to misjudgment in the evaluation of process quality, we derived the [Formula: see text] upper confidence limits of indices and the coordinates formed by the corresponding accuracy and precision indices. Manufacturers can then evaluate the process quality levels of the quality characteristics based on where the coordinates falls in the multi-characteristic quality analysis chart. This can more reliably assist manufacturers in monitoring the processing quality of their machine tools and providing feedback to the machine tool manufacturers for machine improvement.

scholarly journals Mechanismen genetischer Epilepsien

e-Neuroforum ◽  
2013 ◽  
Vol 19 (2) ◽  
Author(s):  
Ulrike Hedrich ◽  
Snezana Maljevic ◽  
Holger Lerche
Keyword(s):  
Ion Channels ◽  
Secondary Effects ◽  
Therapeutic Approaches ◽  
Neuronal Populations ◽  
The Everyday ◽  
The Common ◽  
Genetic Epilepsies ◽  
Idiopathic Epilepsies ◽  
The Brain

AbstractMechanisms of genetic epilepsies. Epilepsy is one of the most common neurological disorders. Already at the time of Hippocrates (460 - 370 BC) it was reported on as the “holy disease” (Fröscher 2004). Today it is known that an epileptic seizure is a consequence of synchronous discharges of neuronal populations in the brain, which abruptly and usually without an observ­able cause evoke involuntary behavioural dysfunction or impaired consciousness. Epilepsies can have various causes and lead to extensive implications for the everyday life of affected patients. Up to 50 % of all epilepsies are caused by genetic defects, in particular the so-called idiopathic epilepsies which occur without easily observable structural alterations of the brain. Genetically caused dysfunctions of neuronal ion channels play a central role in the formation of such epilepsies. The ion channels control the ion flux over the cell membrane of neurons and thus present the basis for the excitability of these neurons. Therefore, medications used for epilepsy treatment affect predominantly ion channels. However, the common anticonvulsants have limited success, not only because one third of epilepsy patients exhibits pharmacoresistance, but also because of the secondary effects which can dramatically affect their quality of life. Furthermore, current therapeutic approaches are mainly symptomatic and do not act on the epileptogenic mechanisms which are still largely unknown. In this review article we will highlight the current main topics of our research on genetically caused epilepsies, their pathomechanisms and therapeutic options.

Machining a Micro-Scale Structure Using an in-House Developed Miniature Machine Tool

2011 ◽  
Vol 418-420 ◽  
pp. 1502-1506
Author(s):  
Abdul Shukor Syaimak
Keyword(s):  
Surface Quality ◽  
Machine Tools ◽  
Milling Process ◽  
Micro Milling ◽  
Batch Size ◽  
End Mill ◽  
Geometrical Accuracy ◽  
Custom Made ◽  
Solid Carbide

Custom-built Miniature Machine Tools (MMTs) are now becoming more popular with the demand for reduced energy consumption and workshop floor when machining small/medium batch size micro-components. This paper investigates the capability of a custom-built 4-axis MMT through machining a micro-component demonstrator. The experiments have been carried out in Titanium Alloyed (TiAL6V4) using 0.6mm solid carbide flat end mill cutters. From here, the surface quality and geometrical accuracy of the machined testpiece are evaluated and analysed. The investigation has shown that acceptable geometrical accuracies and surface quality of the machined micro-demonstrator can be achieved using the in-house developed MMT. These results show that the use of the custom-made MMT does not hinder the micro-milling process to produce a good and satisfactory surface quality and acceptable geometrical accuracy.

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