A General Optimization Model for Multi-Tool Manufacturing Systems

1991 ◽  
Vol 113 (1) ◽  
pp. 10-16 ◽  
Author(s):  
S. B. Billatos ◽  
L. A. Kendall
Keyword(s):  
Optimization Model ◽  
Manufacturing Systems ◽  
Cutting Tools ◽  
Approximate Expression ◽  
Probabilistic Methods ◽  
Time Saving ◽  
Premature Failure ◽  
Machining Center ◽  
Failure Cost ◽  
Tool Replacement

A machining center is a single numerically-controlled machine that incorporates several time-saving features and performs a multiplicity of operations. The life of cutting tools used in machining centers is modeled using probabilistic methods because of the stochastic nature and variability of tool-wear data. An approximate expression for the renewal function is used to establish an optimum scheduled tool replacement interval and an optimum set of cutting conditions to obtain a minimum production cost. A general optimization model for the multi-tool machining center is formulated considering practical machine constraints. Premature failure cost is not considered constant in this study. It is estimated using the tool cost, the expected cost of unplanned downtime, and the expended cost of product damage by premature tool failure. A user friendly computer program was developed to solicit information from a production engineer regarding cutting operations for the various tools used at the machining center. A sensitivity analysis on the results of the optimization process is presented.

Reliability Analysis of Parallel Manufacturing Systems with Two Machines

1979 ◽  
Vol 101 (3) ◽  
pp. 250-254 ◽  
Author(s):  
K. Hitomi ◽  
M. Nakajima ◽  
N. Takahashi
Keyword(s):  
Manufacturing Systems ◽  
Manufacturing System ◽  
Cutting Tools ◽  
Reliability Theory ◽  
Continuous Operation ◽  
Time Interval ◽  
Time To Failure ◽  
Constant Rate ◽  
Tool Replacement ◽  
Two Machines

A stochastic mathematical model was built and analyzed by using the reliability theory for a manufacturing system in which two machines are arranged in parallel. Under the condition that the system is required to be operated at a constant rate of production, the variation of reliability and failure rate of cutting tools with the lapse of time were investigated, using the stress-strength model in failure physics. A time interval of tool replacement in the continuous operation and a time to failure for a manufacturing system which is composed of two lathes were also investigated.

An Optimization of Automated Process Planning for Manufacturing Prismatic Parts on a Machining Center

2015 ◽  
Vol 789-790 ◽  
pp. 1270-1274
Author(s):  
Janjira Kongchuenjai ◽  
Suksan Prombanpong
Keyword(s):  
Mathematical Model ◽  
Process Planning ◽  
Cutting Tools ◽  
Cnc Machining ◽  
Total Production ◽  
Machining Time ◽  
Optimal Sequence ◽  
Machining Center ◽  
Prismatic Parts ◽  
The Mathematical Model

One of the objectives of process planning optimization is to diminish machining time. Nowadays a lot of research papers presented different algorithms to solve this classic problem. Thus, the optimal sequence of parts in the machining operations by considering fixture faces, part faces, number of operations and number of tools is presented in this paper. The mathematical model based on the integer linear programming is developed to minimize the total production time of the prismatic parts manufactured on a CNC machining center equipped with the tombstone-type fixture. The time required for machining, tool traveling and tool changing is taken into consideration under relevant constraints such as precedence, fixture and available cutting tools. The optimal process plan can be obtained from the mathematical model and it is considered practical and acceptable.

Design and Optimization of a Tidal Turbine and Farm

2018 ◽  
Author(s):  
Mohammed S. Mayeed
Keyword(s):  
Flow Simulation ◽  
Vertical Axis ◽  
Fatigue Analysis ◽  
Optimized Design ◽  
Florida Current ◽  
Lower Efficiency ◽  
Premature Failure ◽  
Design And Optimization ◽  
Failure Cost ◽  
Tidal Turbine

Tidal ocean power is a dependable and dense form of renewable energy which is a relatively underdeveloped field. This study optimizes a tidal turbine with respect to performance and economics, and then optimizes a farm to be economically feasible. It was determined that the southeastern portion of the Gulf Stream, Florida current, would be used for the tidal turbine system as it has some of the world’s fastest velocities and is relatively close to shore. The vertical axis designs were ruled out from extended research on turbine design for their lower efficiency in general. Only horizontal axis designs were tested in simulated environments. Using SolidWorks Flow Simulation and SolidWorks Simulation, turbine models were optimized and selected as having the potential for the greatest energy extraction. Static and fatigue analyses were conducted on the optimized models in order to prevent premature failure. Cost analysis was also performed on the turbine models and the model that had the lowest initial cost as well as the highest power generation was chosen for farm development. The optimized design produced reasonable amount of power considering varying velocities throughout the day having a diameter of about 30 m. Through fatigue analysis the optimized design also showed long enough lifetime so that a good return on investment can be acquired. The single optimized turbine was then placed in a farm, and the farm’s shape and arrangement were tested and optimized so that the best arrangement and distances between units could be found. It was found that a farm 1.25 kilometers by 20 kilometers consisting of 800 turbines would be optimal. The farm would produce an average of 249.33 megawatts for a profit of $294.88 million dollars annually. The farm would pay for itself in 7.12 years and have an expected life span of 26.1 years which was obtained through fatigue analysis.

Strategy Study on Comfort Optimization of Metro Train Traction

2011 ◽  
Vol 86 ◽  
pp. 801-804
Author(s):  
Chao Ming He ◽  
Huan Li ◽  
Guo Sheng Fei ◽  
Sheng Jun Pang
Keyword(s):  
Energy Consumption ◽  
Optimization Model ◽  
Operation Mode ◽  
Time Saving ◽  
Speed Reduction ◽  
Strategy Study ◽  
The Road ◽  
The Way

The metro train traction strategy primarily involves the optimization model of the energy consumption and the time. In this paper, how to meet the comfort requirements of the passengers through changing the operation mode of the train is studied. After analysis on the inter-station road conditions, the possible passengers’ uncomfortable points are calculated based on UIC513. The road sections which may bring un-comfort are compromised by the way of speed reduction, so as to meet the metro train traction calculation, and expectation on the energy and time saving.

Machinability of Pearlitic Cast Iron With Cubic Boron Nitride (CBN) Cutting Tools

2002 ◽  
Vol 124 (4) ◽  
pp. 820-832 ◽  
Author(s):  
Jiancheng Liu ◽  
Kazuo Yamazaki ◽  
Hiroyuki Ueda ◽  
Norihiko Narutaki ◽  
Yasuo Yamane
Keyword(s):  
Cast Iron ◽  
Boron Nitride ◽  
Tool Wear ◽  
High Speed ◽  
Cubic Boron Nitride ◽  
Cutting Tools ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Machining Conditions ◽  
Machining Center

In order to increase the accurate finishing productivity of pearlitic cast iron, face milling by CBN (Cubic Boron Nitride) cutting tools was studied. The main focus of the study is the machinability investigation of pearlitic cast iron with CBN cutting tools by studying the relationships among machining conditions such as feed rate, cutting speed as well as CBN cutting tool type, tool wear, workpiece surface quality, cutting forces, and cutting temperature. In addition, an emphasis is put on the effect of Al additive in pearlitic cast iron on its machinability and tool wear characteristics. High-speed milling experiments with CBN cutting tools were conducted on a vertical machining center under different machining conditions. The results obtained provide a useful understanding of milling performance by CBN cutting tools.

A Replacement Model for Multi-Tool Transfer Lines

1990 ◽  
Vol 112 (3) ◽  
pp. 253-259 ◽  
Author(s):  
S. B. Billatos ◽  
L. A. Kendall
Keyword(s):  
Minimum Cost ◽  
Renewal Function ◽  
Production Time ◽  
Tool Failure ◽  
Transfer Lines ◽  
Premature Failure ◽  
Reliability Level ◽  
Transfer Line ◽  
Tool Replacement ◽  
The Impact

Transfer lines have long been used for machining a single product at high production rates. This study deals with the transfer line, in particular, estimating the production time per part and the effect of using probability models in describing tool and machine lives. The production time is estimated using three major causes of line stoppage. An aspiration level criterion is used to establish a scheduled tool replacement interval. The aspiration decision parameter is system reliability. It is shown how a scheduled tool replacement interval could be established to obtain this reliability level. A methodology for selecting the replacement interval for a group of tools is developed and the impact of changing this interval on tool changing costs and tool failure costs is discussed. In this study, only a single premature tool failure is assumed to occur; however, the results are compared with multiple tool failures using the renewal function. It is shown that this single premature failure analysis is equivalent to the renewal function approach for machining systems having a reliability greater than 50 percent and tool failure variabilities having a coefficient of variation less than 1.0. Using the model developed in this paper, an example problem is presented. For this problem, electromechanical equipment failure and tool wear failures are modeled using the exponential and the Weibull probability distributions, respectively. Scheduled tool replacement intervals are developed for a range of target reliabilities. The part cycle time and operating cost for the transfer line based on these reliabilities are computed. These results are compared to the minimum cost reliability level. The minimum cost operating condition is dependent on the ratio of the scheduled replacement costs over the failure replacement costs. For the example presented, the reliability level at minimum cost is much lower than the desired target value of .9. This result illustrates the importance of conducting a careful analysis and using the results to help guide operating practices toward more efficient tool change practices and maintenance policies.

scholarly journals Simulation-based analysis of shared manufacturing systems

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Gustavo Furtado da Silva ◽  
Nelson Casarotto Filho ◽  
Enzo Morosini Frazzon
Keyword(s):  
Information And Communication Technologies ◽  
Optimization Model ◽  
Manufacturing Systems ◽  
Ad Hoc ◽  
Simulation Based ◽  
Simulation Based Optimization ◽  
Information And Communication ◽  
Traditional Manufacturing ◽  
The One ◽  
Resources Sharing

Abstract Advancements in information and communication technologies are encouraging researches in shared manufacturing systems, especially on current high-competitiveness and low-resources scenarios. This paper aims to compare productive resources sharing with traditional manufacturing systems by using a simulation-based optimization model. The model is based on the One Product Integrated Manufacturing paradigm in which the efficiency optimization is pursued by designing ad-hoc virtual factories allocating the best resources available on an existing network. The proposed simulation-based optimization model is capable of identifying the best production path and plan for different distances between network members. Along with a better overall efficiency, it is also possible to argue that dedicated virtual factories ease the identification of problems and allow for improvements without negatively affecting other resources.

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