Production Aspects Affecting the Final Precision Machining of Advanced Materials

2017 ◽  
Vol 756 ◽  
pp. 155-161
Author(s):  
Tomáš Stejskal ◽  
Miroslav Štofa ◽  
Jozef Svetlík ◽  
Martin Pituk ◽  
Adam Žilinský
Keyword(s):  
Machine Tools ◽  
Dynamic Stiffness ◽  
Construction Materials ◽  
Great Influence ◽  
Advanced Materials ◽  
Static Stiffness ◽  
Positioning Accuracy ◽  
Work Area ◽  
Static Rigidity ◽  
Definition Of

When creating products of modern construction materials has a great influence on their endpoints right way and the quality of working on machine tools. The article deals with positioning accuracy of machine tools which is carried out in an unloaded condition, according to international standard ISO 230-2. Overall accuracy of working machining is determined mainly static rigidity, geometrical accuracy of mechanical components, positioning accuracy and dynamic stiffness. Static stiffness is defined in new machine tools in a limited workspace. Therefore, the article deals with the definition of static stiffness in the expanded work area and also defines its impact on the positioning accuracy at individual points in workspace of the machine tool.

scholarly journals Cast Iron And Mineral Cast Applied For Machine Tool Bed - Dynamic Behavior Analysis

2015 ◽  
Vol 60 (2) ◽  
pp. 1023-1029 ◽  
Author(s):  
N. Kępczak ◽  
W. Pawłowski ◽  
Ł. Kaczmarek
Keyword(s):  
Cast Iron ◽  
Machine Tool ◽  
Machine Tools ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Structural Elements ◽  
Static Structure ◽  
Static Rigidity

Abstract Cast iron and mineral cast are the materials most often used in the machine structural elements design (bodies, housings, machine tools beds etc.). The materials significantly differ in physical and mechanical properties. The ability to suppress vibration is one of the most important factors determining the dynamic properties of the machine and has a significant impact on the machining capabilities of a machine tool. Recent research and development trends show that there is a clear tendency to move away from the traditional iron casting to the mineral casting, due to better dynamic properties of the latter. However mineral cast as a structural material for the whole machine tools bed turns out to be insufficient due to its poor mechanical strength properties. The best solution should benefit from the advantages of the cast iron and mineral cast materials while minimizing their drawbacks. The paper presents numerical modal analysis of two lathe beds: the first one made of gray cast iron and the second one made of hybrid connection of cast iron and mineral cast. The analysis was conducted in order to determine the dynamic properties of two bodies of similar shapes made in the traditional (cast iron) and innovative hybrid (cast iron and mineral cast) technology. In addition, an analysis of the static structure rigidity of the two beds was performed. During the simulation studies it was found a significant increase in dynamic stiffness and static rigidity of the machine tool body made of hybrid connection of cast iron and mineral cast. The results of numerical simulations have confirmed the desirability of using hybrid construction because the dynamic properties of such a body are more advantageous in comparison with the conventional body made of cast iron.

scholarly journals Investigation of the fluctuation of the static axial rigidity for double-nut preloaded ball screws

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882218
Author(s):  
Kai Wang ◽  
Chang-guang Zhou ◽  
Yi Ou
Keyword(s):  
Machine Tools ◽  
Test Bench ◽  
Torsional Rigidity ◽  
Accurate Method ◽  
Friction Torque ◽  
Numerical Control ◽  
Static Stiffness ◽  
Feed System ◽  
Static Rigidity ◽  
Bearing Rigidity

This article aims to investigate the fluctuation of the static rigidity for preloaded ball screws. Based on the correlation between preload and friction torque, a new model to calculate the contact rigidity by friction torque is proposed. Meanwhile, a novel test bench is constructed to measure the static stiffness at different positions. The experimental results agree well with the theoretical values, which proves the validity of the model. Furthermore, it is found that the screw shaft rigidity has the greatest influence on the system stiffness fluctuation, compared to the bearing rigidity, and the torsional rigidity. For the feed system, increasing the bearing rigidity, which is the lowest stiffness of the whole system, is an effective method to increase the system stiffness. The study provides an accurate method to obtain the stiffness fluctuation in the effective travel of ball screws, which is significant for improving the positioning accuracy of ball screws and computer numerical control machine tools.

Analysis of Static and Dynamic Stiffness for Coupled Double-Rotor Spindle System of High Speed Grinder

2012 ◽  
Vol 522 ◽  
pp. 278-282
Author(s):  
Ya Li Hou ◽  
Wei Ping Mao
Keyword(s):  
Transition Matrix ◽  
High Speed ◽  
Dynamic Stiffness ◽  
Theoretical Models ◽  
Static Stiffness ◽  
Spindle System ◽  
Overhang Length ◽  
Static Rigidity ◽  
Dynamic Rigidity ◽  
The Moment

This study was focused on the theoretical modeling and numerical investigation about the dynamic and static stiffness of coupled double-rotor spindle system of high speed grinder. The moment balance and the transition matrix, the state vector, field matrix of spindle system of high speed grinder were analyzed and deduced. The theoretical models about dynamic and static stiffness were established using the transfer matrix method. The numerical results showed that increased rigidity of front bearing significantly increased static and dynamic rigidity of spindle end and the rigidity of front bearing increased, dynamic rigidity increased more significantly than static rigidity. Furthermore, it can be conclued that increased overhang length reduced dynamic and static rigidity of spindle end at an increasingly slower rate and the span of bearing increased, static and dynamic rigidities of spindle end were reduced

scholarly journals A Reliable Turning Process by the Early Use of a Deep Simulation Model at Several Manufacturing Stages

2017 ◽  
Author(s):  
Gorka Urbikain ◽  
Luis Norberto López De Lacalle ◽  
Mikel Arsuaga ◽  
Alvaro Alvarez ◽  
Miguel A. Alonso
Keyword(s):  
Machine Tools ◽  
Manufacturing Companies ◽  
Machining Processes ◽  
Knowledge Based ◽  
Direct Benefits ◽  
Definition Of ◽  
The Right ◽  
Machining Operations ◽  
Physical Laws ◽  
Manufacturing Problems

The future of machine tools will be dominated by highly flexible and interconnected systems, in order to achieve the required productivity, accuracy and reliability. Nowadays, distortion and vibration problems are easily solved in labs for the most common machining operations by using models based on equations describing the physical laws of the machining processes; however additional efforts are needed to overcome the gap between scientific research and the real manufacturing problems. In fact, there is an increasing interest in developing simulation packages based on “deep-knowledge and models” that aid machine designers, production engineers or machinists to get the best of the machine-tools. This article proposes a methodology to reduce problems in machining by means of a simulation utility, which uses the main variables of the system&process as input data, and generates results that help in the proper decision-making and machining planification. Direct benefits can be found in a) the fixture/clamping optimal design, b) the machine tool configuration, c) the definition of chatter-free optimum cutting conditions and d) the right programming of cutting toolpaths at the Computer Aided Manufacturing (CAM) stage. The information and knowledge-based approach showed successful results in several local manufacturing companies and are explained in the paper.

scholarly journals PECULIARITIES OF MATERIAL RESOURCE MANAGEMENT OF ENTERPRISES OF BUILDING MATERIALS

2021 ◽  
Author(s):  
Iryna Hobyr ◽  
Lidiia Hobyr
Keyword(s):  
Inventory Management ◽  
Building Materials ◽  
Construction Materials ◽  
Design And Technology ◽  
Resource Saving ◽  
New Production ◽  
Utilization Factor ◽  
Resources Management ◽  
Material Resources ◽  
Definition Of

In a market economy, it becomes important to improve the organization of enterprise management and, above all, the production process, efficient use of financial, material resources and inventories. Effective management of material resources increases profits and provides the necessary investment. To maintain high profitability and liquidity, the management of current activities of enterprises, in particular inventory management plays a significant role. The categorical apparatus of material resources management at the enterprise is considered, the definition of “material resources” is generalized, the definition of "material resources management" is offered, and also the system of material resources management at the enterprise is considered. In the management of material resources at the enterprise there are 2 approaches – logistics and reengineering. The main tasks of the mechanism of management of material resources of the enterprise of building materials are defined. These are: increasing the efficiency of material resources and choosing cheap sources of funding; introduction of new production, resource-saving technologies; minimization of costs for procurement, production and marketing activities; increasing the interest of employees of all services in the effective performance of their duties; product quality management. The analysis of efficiency of use of material resources at the enterprises of building materials which has shown, that manufacture of production is rather material-intensive is carried out. This is evidenced by the share of material costs in the cost of work, and the value of the utilization factor of materials indicates the economical use of material resources in production. Reserves for improving the efficiency of material resources at construction materials enterprises have been identified. The ways of the most rational use of material resources of construction materials enterprises are offered, in particular it is improvement of a design and technology of manufacturing of products, introduction of more progressive norms of expenses of resources, use of substitute materials, and reduction of losses at stages of transportation, storage and industrial use.

Störgrößenkompensation für Vorschubantriebe/Disturbance compensation for feed drives

2021 ◽  
Vol 111 (01-02) ◽  
pp. 82-87
Author(s):  
Felix Brenner ◽  
Armin Lechler ◽  
Alexander Verl
Keyword(s):  
Machine Tools ◽  
Position Control ◽  
Dynamic Compliance ◽  
High Accuracy ◽  
Considerable Improvement ◽  
Disturbance Compensation ◽  
Positioning Accuracy ◽  
Feed Drives ◽  
Modern Machine ◽  
Large Machine

Zahnstange-Ritzel-Antriebe werden überwiegend bei großen Werkzeugmaschinen eingesetzt und häufig mit indirekter Lageregelung betrieben. Hieraus resultiert eine geringe Positioniergenauigkeit und ein unzureichendes dynamisches Nachgiebigkeitsverhalten. Um den hohen Genauigkeitsanforderungen moderner Werkzeugmaschinen gerecht zu werden, wird in diesem Beitrag eine beschleunigungsbasierte Störgrößenkompensation vorgestellt. Experimentelle Ergebnisse belegen eine Verbesserung des Störverhaltens.   Rack-and-pinion drives are mainly used in large machine tools and controlled by indirect position control. This leads to low positioning accuracy as well as an insufficient dynamic compliance. To meet the high accuracy requirements of modern machine tools, this paper presents an acceleration-based disturbance compensation. Experimental results prove a considerable improvement of the disturbance behavior.

Intelligent Three-dimensional Node Localization Algorithm Using Dynamic Path Planning

2021 ◽  
Vol 14 ◽  
Author(s):  
Songhao Jia ◽  
Cai Yang ◽  
Xing Chen ◽  
Yan Liu ◽  
Fangfang Li
Keyword(s):  
Path Planning ◽  
Dynamic Stiffness ◽  
Three Dimensional ◽  
Localization Algorithm ◽  
Node Localization ◽  
Positioning Accuracy ◽  
Dynamic Path Planning ◽  
Anchor Nodes ◽  
Simulation Results ◽  
Dynamic Path

Background: In the applications of wireless sensor network technology, three-dimensional node location technology is crucial. The process of node localization has some disadvantages, such as the uneven distribution of anchor nodes and the high cost of the network. Therefore, the mobile anchor nodes are introduced to effectively solve accurate positioning. Objective: Considering the estimated distance error, the received signal strength indication technology is used to optimize the measurement of the distance. At the same time, dynamic stiffness planning is introduced to increase virtual anchor nodes. Moreover, the bird swarm algorithm is also used to solve the optimal location problem of nodes. Method: Firstly, the dynamic path is introduced to increase the number of virtual anchor nodes. At the same time, the improved RSSI distance measurement technology is introduced to the node localization. Then, an intelligent three-dimensional node localization algorithm based on dynamic path planning is proposed. Finally, the proposed algorithm is compared with similar algorithms through simulation experiments. Results: Simulation results show that the node coordinates obtained by the proposed algorithm are more accurate, and the node positioning accuracy is improved. The execution time and network coverage of the algorithm are better than similar algorithms. Conclusion: The proposed algorithm significantly improves the accuracy of node positioning. However, the traffic of the algorithm is increased. A little increase in traffic in exchange for positioning accuracy is worthy of recognition. The simulation results show that the proposed algorithm is robust and can be implemented and promoted in the future.

scholarly journals A Full-Scale Experimental Study of the Vertical Dynamic and Static Behavior of the Pier-Cap-Pile System

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianlei Liu ◽  
Meng Ma ◽  
Flavio Stochino
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Dynamic Stiffness ◽  
Soil Layer ◽  
Low Frequency ◽  
Full Scale ◽  
Single Pile ◽  
Static Stiffness ◽  
Loading Test ◽  
Test Technique

The bearing capacity evaluation of bridge substructures is difficult as the static loading test (SLT) cannot be employed for the bridges in services. As a type of dynamic nondestructive test technique, the dynamic transient response method (TRM) could be employed to estimate the vertical bearing capacity when the relationship between static stiffness and dynamic stiffness is known. The TRM is usually employed to evaluate single piles. For the pier-cap-pile system, its applicability should be investigated. In the present study, a novel full-scale experimental study, including both TRM test and SLT, was performed on an abandoned bridge pier with grouped pile foundation. The test included three steps: firstly, testing the intact pier-cap-pile system; then, cutting off the pier and testing the cap-pile system; finally, cutting off the cap and testing the single pile. The TRM test was repeatedly performed in the above three steps, whereas the SLT was only performed on the cap-pile system. Based on the experimental results, the ratio of dynamic and static stiffness of the cap-pile system was obtained. The results show that (1) in the low-frequency range (between 10 and 30 Hz in this study), the dynamic stiffness of the whole system is approximately four times of that of a single pile; (2) the ratio of dynamic and static stiffness of the cap-pile system tested in the study is approximately 1.74, which was similar to other tested values of a single pile; (3) to evaluate the capacity of similar cap-pile system and with similar soil layer conditions by TRM, the value of Kd/Ks tested in the study can be used as a reference.

scholarly journals Nonlinear Static and Dynamic Stiffness Characteristics of Support Hydraulic System of TBM

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Jianfeng Tao ◽  
Junbo Lei ◽  
Chengliang Liu ◽  
Wei Yuan
Keyword(s):  
Hydraulic System ◽  
Vibrational Energy ◽  
Dynamic Stiffness ◽  
Operating Conditions ◽  
Static Stiffness ◽  
Railway Tunnel ◽  
Relief Valve ◽  
Component Structure ◽  
Stiffness Characteristics ◽  
Stable Stage

AbstractFull-face hard rock tunnel boring machines (TBM) are essential equipment in highway and railway tunnel engineering construction. During the tunneling process, TBM have serious vibrations, which can damage some of its key components. The support system,an important part of TBM, is one path through which vibrational energy from the cutter head is transmitted. To reduce the vibration of support systems of TBM during the excavation process, based on the structural features of the support hydraulic system, a nonlinear dynamical model of support hydraulic systems of TBM is established. The influences of the component structure parameters and operating conditions parameters on the stiffness characteristics of the support hydraulic system are analyzed. The analysis results indicate that the static stiffness of the support hydraulic system consists of an increase stage, stable stage and decrease stage. The static stiffness value increases with an increase in the clearances. The pre-compression length of the spring in the relief valve affects the range of the stable stage of the static stiffness, and it does not affect the static stiffness value. The dynamic stiffness of the support hydraulic system consists of a U-shape and reverse U-shape. The bottom value of the U-shape increases with the amplitude and frequency of the external force acting on the cylinder body, however, the top value of the reverse U-shape remains constant. This study instructs how to design the support hydraulic system of TBM.

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