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 Analysis of Minimum Cost of Supply Chain Emergencies Based on Diffusion Path Processing

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yan Cao ◽  
Tian Tian ◽  
Wanyu Wei ◽  
Liang Huang ◽  
Yujia Wu
Keyword(s):  
Supply Chain ◽  
Clustering Algorithm ◽  
Minimum Cost ◽  
Diffusion Path ◽  
Critical Event ◽  
Design Structure ◽  
Perform Cluster Analysis ◽  
The Impact ◽  
The Relationship ◽  
Case Data

In view of the complexity and severity of the impact of supply chain emergencies on enterprise economy, this paper proposes modular processing to improve the design structure matrix (DMS), and the designed clustering algorithm is used to perform cluster analysis of the improved DMS, to predict the possible diffusion path of emergencies, and to establish the critical event diffusion path planning model by designing the critical event diffusion path storage method. As in the case data of a certain type of servo motor of the H Company, after data screening, the diffusion path is classified and stored by analyzing the relationship between each member of the supply chain network. Secondly, the same group of data is put into the method of this paper and other scholars’ to calculate the minimum cost of emergency response in time.

Experiment Study on Cutter Disrepair Principle and Optimization for Machining Heat-Resistant Steel

2012 ◽  
Vol 500 ◽  
pp. 58-64
Author(s):  
Yao Nan Cheng ◽  
Xian Li Liu ◽  
Fu Gang Yan ◽  
Zhen Jia Li ◽  
Xian Zhou Wang
Keyword(s):  
Mathematic Model ◽  
Resistant Steel ◽  
Experiment Study ◽  
Premature Failure ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Design Production ◽  
Milling Temperature ◽  
The Difference ◽  
The Impact

In order to find out the cutter disrepair principle and provide a valuable reference for the design, production and use of the heavy-duty hard alloy cutter, have experiment study on machining the heat-resistant steel-the 3Cr-1Mo-1/4Vsteel. First, have impact disrepair experiments with several types of different grooves milling inserts, and find out the difference of the impact disrepair invalidation types among them, and build the impact disrepair life cumulating distribution function mathematic model. Second, based on the adhering disrepair experiments, find out the difference of the adhering disrepair invalidation types, build the quantitative mathematic relation between milling temperature and maximal adhering disrepair depth on rake face of the cutter, and analyze the rule that the milling temperature affects the adhering disrepair. And then, on the basis of the scene machining, have analysis on cutter disrepair phenomenon and mechanism under the joint action of force and heat, so to provide a theoretical basis on how to avoid premature failure of the tool for the actual production process.

An Experimental Examination of the Effect of Interface Cooling on Thermal Wear Mechanisms in Carbon Graphite

2005 ◽  
Author(s):  
Daryl S. Schneider ◽  
Lyndon S. Stephens
Keyword(s):  
Heat Sink ◽  
Elevated Temperatures ◽  
Frictional Heating ◽  
Operating Conditions ◽  
Stable Operation ◽  
Mechanical Seal ◽  
Premature Failure ◽  
Thermally Induced ◽  
Wear Rates ◽  
The Impact

Premature failure of mechanical seal components is often a result of the elevated temperatures at the sealing interface that arise due to frictional heating. The Heat Sink Mechanical Seal (HSS) is a new approach to interface cooling in which a micro heat sink is constructed within millimeters of the sealing interface. Coolant circulated through the highly structured pin fin region carries away the generated heat. This work investigates the impact of interface cooling on carbon wear rates for a tungsten carbide (WC) and carbon graphite material pair. Experiments are performed using a thrust washer rotary tribometer to simulate a mechanical seal operating in dry running conditions within and in excess of the PV limit for the material pair (17.5 MPa*m/s or 500,000 psi*ft/min). Results show stable operation of sealing components in harsh operating conditions as well as the potential to reduce the occurrence of thermally induced wear and failure.

Dial-a-Ride Problem with Users’ Accept/Reject Decisions Based on Service Utilities

2020 ◽  
Vol 2674 (10) ◽  
pp. 55-67
Author(s):  
Xiaotong Dong ◽  
David Rey ◽  
S. Travis Waller
Keyword(s):  
Minimum Cost ◽  
Collective Choice ◽  
Profit Margin ◽  
User Preference ◽  
Computational Time ◽  
Optimal Solutions ◽  
Mobility Service ◽  
Shared Mobility ◽  
Computationally Expensive ◽  
The Impact

The classic dial-a-ride problem (DARP) aims at designing the minimum-cost routing that accommodates all requests under a set of constraints. However, several modeling and computational challenges have hindered the successful deployment of dial-a-ride solutions. This work proposes incorporating user preference decisions within a rich DARP formulation. Specifically, it is considered that two travel modes are available: a shared mobility (DARP) service and a private travel option. Utility functions for each travel mode are integrated and it is assumed that the utility of the shared mobility service depends on the collective choice of travelers whereas the utility of private travel is fixed. Assuming that travelers are rational and seek to maximize their trip utility, extra variables and constraints are added to ensure that all requests are served by the mode with the higher utility. The behavior of the proposed integrated DARP with formulation of user preference constraints is examined by comparing the optimal solutions and computational time of this model with its classic DARP counterpart. Furthermore, the impact of various formulations of fare and the tolerance of the integrated DARP model is explored. Results show that user-personalized fare formulation improves model tolerance and profit margin, albeit it is rather computationally expensive.

Superpave Models: Predicting Performance during Design and Construction

1996 ◽  
Vol 1545 (1) ◽  
pp. 105-112
Author(s):  
Gerald A. Huber ◽  
Xishun Zhang ◽  
Robin Fontaine
Keyword(s):  
Prediction Models ◽  
Permanent Deformation ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Engineering Properties ◽  
Design System ◽  
Widespread Application ◽  
Premature Failure ◽  
The Impact

The Strategic Highway Research Program (SHRP) spent $50 million researching asphalt binders and asphalt mixtures and provided three main products: an asphalt binder specification, an asphalt mixture specification, and Superpave, an asphalt mixture design system that encompasses both the binder and mixture specification. SHRP researchers have provided tools that promise more robust asphalt mixtures with reduced risk of premature failure. Implementation of the specifications and mix design system will require overcoming several obstacles. Superpave must be demonstrated to be practical and easy to use. The impact of Superpave aggregate requirements on aggregate availability must be determined. The Superpave gyratory compaction procedure has been uniquely defined and then calibrated to traffic volume. The reasonableness of this approach must be tested in widespread application. Perhaps the largest implementation hurdle exists in the performance models. Expensive test equipment is necessary to do the performance-based tests. The performance predictions must be established as reasonable to justify the cost. A highway reconstruction project containing three Superpave Level 1 mix designs is documented including quality control done with the Superpave gyratory compactor. Superpave Level 2 performance-based tests were carried out to predict permanent deformation of the design and the mixture as constructed. The performance-based engineering properties obtained from the tests are evaluated, and the reasonableness of the performance prediction models is discussed.

Bus Optimization for Low Power in High-Level Synthesis

2003 ◽  
Vol 12 (01) ◽  
pp. 1-17
Author(s):  
Sungpack Hong ◽  
Taewhan Kim
Keyword(s):  
Optimal Solution ◽  
Minimum Cost ◽  
Maximum Flow ◽  
High Level Synthesis ◽  
Benchmark Problems ◽  
Timing Constraints ◽  
Power Efficient ◽  
High Level ◽  
The Impact ◽  
Operation Scheduling

Sub-micron feature sizes have resulted in a considerable portion of power to be dissipated on the buses, causing an increased attention on savings for power at the behavioral level and the RT level of design. This paper addresses the problem of minimizing power dissipated in the switching of the buses in the high-level synthesis of data-dominated behavioral descriptions. Unlike the previous approaches in which the minimization of the power consumed in buses has not been considered until operation scheduling is completed, our approach integrates the bus binding problem into scheduling to exploit the impact of scheduling on the reduction of power dissipated on the buses more fully and effectively. We accomplish this by formulating the problem into a flow problem in a network, and devising an efficient algorithm which iteratively finds the maximum flow of minimum cost solutions in the network. Experimental results on a number of benchmark problems show that given resource and global timing constraints our designs are 19.8% power-efficient over the designs produced by a random-move based solution, and 15.5% power-efficient over the designs by a clock-step based optimal solution.

Limited static and dynamic delivering capacity allocations in scale-free networks

2017 ◽  
Vol 28 (11) ◽  
pp. 1750140 ◽  
Author(s):  
N. Ben Haddou ◽  
H. Ez-Zahraouy ◽  
A. Rachadi
Keyword(s):  
Dynamic Properties ◽  
Minimum Cost ◽  
Network Capacity ◽  
Capacity Allocation ◽  
Traffic Information ◽  
Node Degree ◽  
Scale Free ◽  
Routing Strategy ◽  
The Impact ◽  
Allocation Strategies

In traffic networks, it is quite important to assign proper packet delivering capacities to the routers with minimum cost. In this respect, many allocation models based on static and dynamic properties have been proposed. In this paper, we are interested in the impact of limiting the packet delivering capacities already allocated to the routers; each node is assigned a packet delivering capacity limited by the maximal capacity [Formula: see text] of the routers. To study the limitation effect, we use two basic delivering capacity allocation models; static delivering capacity allocation (SDCA) and dynamic delivering capacity allocation (DDCA). In the SDCA, the capacity allocated is proportional to the node degree, and for DDCA, it is proportional to its queue length. We have studied and compared the limitation of both allocation models under the shortest path (SP) routing strategy as well as the efficient path (EP) routing protocol. In the SP case, we noted a similarity in the results; the network capacity increases with increasing [Formula: see text]. For the EP scheme, the network capacity stops increasing for relatively small packet delivering capability limit [Formula: see text] for both allocation strategies. However, it reaches high values under the limited DDCA before the saturation. We also find that in the DDCA case, the network capacity remains constant when the traffic information available to each router was updated after long period times [Formula: see text].

Combinatorial design of a minimum cost transfer line

Omega ◽  
2012 ◽  
Vol 40 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Xavier Delorme ◽  
Alexandre Dolgui ◽  
Mikhail Y. Kovalyov
Keyword(s):  
Minimum Cost ◽  
Combinatorial Design ◽  
Transfer Line
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