- Hidden Costs: Work-in-Process

1998 ◽  
pp. 52-61
Keyword(s):  
Work In Process

scholarly journals Short-Term Scheduling Model of Cluster Tool in Wafer Fabrication

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1029
Author(s):  
Ying-Mei Tu
Keyword(s):  
Arrival Time ◽  
Time Estimation ◽  
Advanced Technology ◽  
Shop Floor ◽  
Process Time ◽  
Short Term ◽  
Work In Process ◽  
Scheduling Model ◽  
Cluster Tools ◽  
Cluster Tool

Since last decade, the cluster tool has been mainstream in modern semiconductor manufacturing factories. In general, the cluster tool occupies 60% to 70% of production machines for advanced technology factories. The most characteristic feature of this kind of equipment is to integrate the relevant processes into one single machine to reduce wafer transportation time and prevent wafer contaminations as well. Nevertheless, cluster tools also increase the difficulty of production planning significantly, particularly for shop floor control due to complicated machine configurations. The main objective of this study is to propose a short-term scheduling model. The noteworthy goal of scheduling is to maximize the throughput within time constraints. There are two modules included in this scheduling model—arrival time estimation and short-term scheduling. The concept of the dynamic cycle time of the product’s step is applied to estimate the arrival time of the work in process (WIP) in front of machine. Furthermore, in order to avoid violating the time constraint of the WIP, an algorithm to calculate the latest time of the WIP to process on the machine is developed. Based on the latest process time of the WIP and the combination efficiency table, the production schedule of the cluster tools can be re-arranged to fulfill the production goal. The scheduling process will be renewed every three hours to make sure of the effectiveness and good performance of the schedule.

Instandhalter sind Mitgestalter ihres Assistenzsystems/Maintenance engineers are co-designers of their assistance system

2019 ◽  
Vol 109 (03) ◽  
pp. 189-193
Author(s):  
A. Keller ◽  
S. Adler ◽  
N. Zobel
Keyword(s):  
Technological Development ◽  
Assistance System ◽  
User Requirements ◽  
Shift Workers ◽  
System A ◽  
Work In Process ◽  
Kleine Und Mittlere Unternehmen ◽  
System P ◽  
Process Manufacturing ◽  
Maintenance Work

Im Forschungsprojekt „CPPSProcessAssist“ wurde für vier kleine und mittlere Unternehmen (KMU) der Prozessindustrie ein modulares und mobiles Assistenzsystem zur Instandhaltungsunterstützung entwickelt. Neben der technologischen Entwicklung des Systems wurde im Projekt eine Vorgehensweise zur Gestaltung und Einführung des Systems in den Unternehmen erarbeitet. Mitarbeiter der Schicht und Schichtleitung, Projektingenieure, Instandhalter sowie Technologieentwickler wurden als Mitgestalter des Systems und der daraus folgenden Veränderungen im Unternehmen eingebunden. Das resultierende System bildet die unternehmensübergreifenden Anforderungen von Instandhaltungsaufgaben in der Prozessindustrie technisch ab und ist an vorhandene IT-Infrastrukturen anpassbar. Die gewählte Vorgehensweise zur Einbindung der Mitarbeiter in der Gestaltung des Systems trug dazu bei, die unternehmens- und nutzerspezifischen Anforderungen in das System zu integrieren sowie die Mitarbeiter zu Eingabe bedarfsgerechter Assistenzinhalten zu befähigen.   A modular and portable maintenance assistance system was developed for four small and medium-sized process manufacturers in the research project CPPSProcessAssist. Along with the technological development of the system, a procedure for designing and implementing the system in the companies was developed. Shift workers and managers, project engineers, maintenance engineers and technology developers were involved in designing the system and implementing the ensuing changes in their companies. The resulting system technically maps cross-company requirements for maintenance work in process manufacturing and can be modified for existing IT infrastructures. The selected procedure for involving employees in the system design helped integrating specific company and user requirements in the system and enabling employees to enter content in the assistance system based on their needs.

Research on DBR Production Scheduling System Application Based on Simulation

2014 ◽  
Vol 889-890 ◽  
pp. 1207-1212
Author(s):  
Guo En Sun ◽  
Zai Lin Guan ◽  
Lei Yue ◽  
Zhi Ming Zheng ◽  
Han Lin
Keyword(s):  
Production Scheduling ◽  
Simulation Optimization ◽  
Production Capacity ◽  
Production Plan ◽  
Process Scheduling ◽  
Scheduling System ◽  
Work In Process ◽  
Planning Methods ◽  
On Time Delivery ◽  
High Output

Traditional planning methods ignore the enterprise production capacity,the paper depend on the specific case in enterprise production to build a Production Scheduling System which applies Drum-Buffer-Rope theory. This system proposes the high output, low work in process and on time delivery as the goals, considering the bottleneck resource as well as providing the master production plan with the bottleneck resource, in addition employing the simulation optimization software-Simio to optimize the bottleneck process scheduling and raise the utilization ratio of bottleneck resource.

Multi-Period Virtual Cell Formation: A New Methodology Based on Non-Linear Mixed-Integer Programming Model

2013 ◽  
Vol 278-280 ◽  
pp. 2210-2217
Author(s):  
Jie Lv ◽  
Jing Yuan ◽  
Wen Min Han
Keyword(s):  
Cell Size ◽  
Production Cost ◽  
Dynamic Condition ◽  
Cell Formation ◽  
Real Life ◽  
Mixed Integer ◽  
Virtual Cell ◽  
Work In Process ◽  
Non Linear ◽  
Internal Production

This paper researched on multi-period dynamic virtual cell formation problem, and filled the gap on objectives of previous literatures. A developed 0-1 non-linear mixed-integer mathematical model was proposed, it incorporates real-life parameters like alternative routings, operation sequence, duplicate machine, processing time and machine capacity. The advantage of the model is to embed the function relationship between cell size and internal production cost in the model, thus the effects of set-up cost, work-in-process inventory cost, coordination cost and inventory handling cost on VCMS are acted on the model. Finally a numerical example solved by Lingo11.0 software package was presented to verify the model and related discussion was made. The results show that the cell size changes as time in dynamic condition and different scenarios of internal production cost can obtain different cell configurations.

Social Work in Process of Change: 1930-33

1934 ◽  
Vol 8 (1) ◽  
pp. 58-78
Author(s):  
Pierce Atwater
Keyword(s):  
Social Work ◽  
Process Of Change ◽  
Work In Process

scholarly journals Improving the Performance of Modular Production in the Apparel Assembly: A Mathematical Programming Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoqing Wang ◽  
Chun-Hung Chiu ◽  
Wei Guo
Keyword(s):  
Optimal Allocation ◽  
Programming Approach ◽  
Time Interval ◽  
Work In Process ◽  
Target Values ◽  
Modular Production ◽  
Mathematical Programming Approach ◽  
Holding Cost ◽  
Assembly Operations ◽  
Assembly Tasks

We construct the mathematical models to find the optimal allocation of the module’s capacity (module members) to different assembly operations in a module for given garment assembly tasks in a modular production system. The objectives of the models are minimizing the holding cost for work in process (WIP) inventories in the module and the total deviation of the WIP inventories from their corresponding target values in the module during a specific time interval. The solutions of the models can be used as reference to achieve better allocation of the module members to different operations in a module to fulfill the given garment assembly tasks.

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