scholarly journals Evaluation of Pull Production Control Mechanisms by Simulation

Processes ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 5
Author(s):  
Nataša Tošanović ◽  
Nedeljko Štefanić

Today, companies need to continuously improve their production processes, which is a complex task. Lean manufacturing is one of the methodologies for production improvement, and one of the basic goals of any lean implementation is to reduce work-in-process (WIP) and shorten the production lead time. One of the basic lean principles for achieving these goals is pull principle. The adoption of this principle is quite challenging, as it requires a long-term commitment in the application and adoption of various lean techniques and tools that are prerequisites for the successful introduction of the pull principle. Kanban is the most well-known pull production control mechanism, and the first one developed within Toyota production system, but later, other pull control mechanisms were developed. Some of them include Conwip, Hybrid Kanban/Conwip, and Drum Buffer Rope (DBR), and those three, together with Kanban, were the research topic of this study. These four mechanisms were not explored and compared all together not for these specific production configurations considered in this research but also with regard to optimal parameters of control mechanisms. The goal was to analyze and compare how these pull control mechanisms affect lead time in different production conditions. For this purpose, simulation experiments were performed. The results showed that for different production conditions, different pull control mechanisms are optimal in terms of shortening lead time. This finding could help companies as a guideline for making a decision in terms of which pull control mechanism to choose.

2021 ◽  
Vol 11 (3) ◽  
pp. 7069-7074
Author(s):  
M. Masmali

The lean manufacturing concept is a systematic minimization of waste and non-value activities in production processes introduced by the Toyota production system. In this research, lean manufacturing is implemented in a cement production line. Value Stream Mapping (VSM) is applied to give a clear picture of the value chain in cement production processes and to highlight the non-value-added in the shop floor. To begin, the existing VSM is constructed based on the information and data gathered during visiting and observing the manufacturing process in the firm. As a result, the excess inventory between workstations was identified as a major waste generation, hence, the proposed VSM conducts further improvement and makes action plans to alleviate the unwanted activities. Then, the takt time to ensure smooth material flow and to avoid any occurring delay or bottleneck in the production line was figured out. The supermarket pull-based production control is suggested to be adopted in the future map. Two pull production strategies are selected in this case. The first is applying the Kanban system to control the level of inventory between workstations. The other is the CONWIP approach to control the amount of work in process to the entire production line. The outcome of the proposed models indicates a decrease of the none-value time from 23 days in the current state to about 4 and 2 days in Kanban and CONWIP systems respectively, so the CONWIP was suggested as most efficient. Some suggestions for further research are also mentioned.


2015 ◽  
Vol 115 (5) ◽  
pp. 951-970 ◽  
Author(s):  
Lluís Cuatrecasas-Arbós ◽  
Jordi Fortuny-Santos ◽  
Patxi Ruiz-de-Arbulo-López ◽  
Carla Vintró-Sanchez

Purpose – Since lean manufacturing considers that “Inventory is evil”, the purpose of this paper is to find and quantify the relations between work-in-process inventory (WIP), manufacturing lead time (LT) and the operational variables they depend upon. Such relations provide guidelines and performance indicators in process management. Design/methodology/approach – The authors develop equations to analyse how, in discrete deterministic serial batch processes, WIP and LT depend on parameters like performance time (of each workstation) and batch size. The authors extend those relations to processes with different lots and the authors create a multiple-lot box score. Findings – In this paper, the relations among WIP, LT and the parameters they depend on are derived. Such relations show that when WIP increases, LT increases too, and vice versa, and the parameters they depend on. Finally, these relations provide a framework for WIP reduction and manufacturing LT reduction and agree with the empirical principles of lean manufacturing. Research limitations/implications – Quantitative results are only exact for discrete deterministic batch processes without any delays. Expected results might not be achieved in real manufacturing environments. However, qualitative results show the underlying relations amongst variables. Different expressions might be derived for other situations. Practical implications – Understanding the relations between manufacturing variables allows operations managers better design, implement and control manufacturing processes. The box score, implemented on a spreadsheet, allows testing the effect of changes in different operational parameters on the manufacturing LT, total machine wait time and total lot queue time. Originality/value – The paper presents a discussion about process performance based on the mutual influence between WIP and LT and other variables. The relation is quantified for the discrete deterministic case, complementing the models that exist in the literature. The box score allows mapping more complex processes.


2019 ◽  
Vol 5 (1) ◽  
pp. 1-7
Author(s):  
Catur Kusbiantoro ◽  
Ellysa Nursanti

CV. Tanara Textile merupakan salah satu perusahaan tekstil yang termasuk dalam kelompok industri penyempurnaan kain berupa kain kaos. Pada proses produksi di perusahaan masih ditemukan beberapa waste. Penelitian ini bertujuan untuk mengidentifikasi dan menurunkan waste yang terjadi pada proses produksi maka digunakan pendekatan lean manufacturing. Metode Value Stream Mapping (VSM) digunakan untuk pemetaan aliran produksi dan aliran informasi terhadap suatu produk pada tingkat produksi total, melakukan wawancara untuk pembobotan penyebab 7 waste yang sering terjadi pada proses produksi, VALSAT untuk menganalisa pemborosan dari hasil pembobotan yang selanjutnya melakukan detailed mapping tools, serta analisis FMEA untuk mengetahui penyebab kegagalan prosesyang terjadi di lini produksi lalu menghitung nilai RPN tertinggi. Selanjutnya melakukan usulan perbaikan untuk menurunkan waste unnecessary inventory serta menganalisis perbaikan secara berkelanjutan dengan PDCA. Waste terbesar ada pada Unncessary Inventory sebesar 28,571% faktor penyebabnya adalah penumpukan bahan baku, work in process (WIP), sparepart yang tidak terpakai dan penimbunan pada finished goods Sebelum perbaikan proses produksi 16 hari 9 jam dimana Value Added 6 hari 4 jam dan Lead Time 10 hari 4 jam, setelah perbaikan proses produksi menjadi 14 hari 5 jam dimana Value Added 6 hari 4 jam dan Lead Time 8 hari 1 jam, dengan demikian dapat meningkatkan process cycle efficiency sebesar 17,19% dan menghemat lead time sebesar 2,546% dengan penurunan waste sebesar 8,31%


2011 ◽  
Vol 110-116 ◽  
pp. 2062-2066 ◽  
Author(s):  
Paramdeep Singh ◽  
Harpuneet Singh

Lean manufacturing has been proved to be an effective management philosophy for improving businesses in a competitive market by eliminating non-value added waste and improving in process operations. Value stream mapping is an important tool used to identify the opportunities for various lean techniques. The present research mainly focuses on the description of a model that is developed to contrast the “before” and “after” scenarios in detail in order to obtain the various benefits such as reduced production lead time, lower work in process inventory [1] and proper utilisation of the workforce. The current manufacturing system has been compared with the proposed pull (Kanban) system which shows the benefits of the proposed lean manufacturing system over the existing traditional manufacturing system. The present research work has been carried out at typical tractor industry which shows 50.5% reduction in total lead time in the future state value mapping of the crank case and the number of operators involved in processing of crank case has also been reduced from 22 to 18.


2014 ◽  
Vol 5 (4) ◽  
pp. 342-360 ◽  
Author(s):  
Venkatesh Arasanipalai Raghavan ◽  
Sangwon Yoon ◽  
Krishnaswami Srihari

Purpose – This paper aims to focus on integrating a lean framework in a high-mix-low-volume (HMLV) printed circuit board assembly (PCBA) environment to enhance current assembly processes and facility layouts. An HMLV PCBA environment is characterized by stochastic demands, a variety of products in terms of shapes and sizes and different sequences of assembly and test operations, in addition to long cycle times and high fall-out rates. Design/methodology/approach – Preliminary analysis indicates that the push inventory control system led to the longer cycle times, such that various lean methodologies have been applied to enhance the assembly operations. In this research, Kanban sizes for different assembly lines are also estimated to integrate and implement a “pull-system” into the lean framework. In addition, material movement and facility layout have been studied to minimize work-in-process travel time. An “iterative-MAIC” approach has been applied to implement lean principles. Findings – As a result, a lean manufacturing pilot line has been implemented to evaluate the effectiveness of the lean principles before rolling them out across the manufacturing floor. It has been shown that the cycle times of the pilot line products are decreased by 40 per cent and the number of defects decreased by 10-30 per cent, depending on different assembly processes, after the lean implementation. Originality/value – There is limited literature that addresses lean transformation in an HMLV electronics manufacturing service provider handling several product types with different testing methodologies, frequent product revision changes and higher fall-out rates. Hence, in this research, lean manufacturing has been implemented in an HMLV PCBA environment, which has the challenges of varying demand with a mix of assembly and test operations for different product families.


2018 ◽  
Vol 11 (1) ◽  
pp. 161 ◽  
Author(s):  
Aydin Torkabadi ◽  
Rene Mayorga

Purpose: Just-In-Time (JIT) production has continuously been considered by industrial practitioners and researchers as a leading strategy for the yet popular Lean production. Pull Production Control Policies (PPCPs) are the major enablers of JIT that locally control the level of inventory by authorizing the production in each station. Aiming to improve the PPCPs, three authorization mechanisms: Kanban, constant-work-in-process (ConWIP), and a hybrid system, are evaluated by considering uncertainty.Design/methodology/approach: Multi-Criteria Decision Making (MCDM) methods are successful in evaluating alternatives with respect to several objectives. The proposed approach of this study applies the fuzzy set theory together with an integrated Analytical Hierarchy Process (AHP) and a Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) method.Findings: The study finds that hybrid Kanban-ConWIP pull production control policies have a better performance in controlling the studied multi-layer multi-stage manufacturing and assembly system.Practical implications: To examine the approach a real case from automobile electro mechanical part production industry is studied. The production system consists of multiple levels of manufacturing, feeding a multi-stage assembly line with stochastic processing times to satisfy the changing demand.Originality/value: This study proposes the integrated Kanban-ConWIP hybrid pull control policies and implements several alternatives on a multi-stage and multi-layer manufacturing and assembly production system. An integrated Fuzzy AHP TOPSIS method is developed to evaluate the alternatives with respect to several JIT criteria.


2019 ◽  
Vol 31 (3) ◽  
pp. 620-647
Author(s):  
Ozgur Kabadurmus ◽  
Mehmet Bulent Durmusoglu

Purpose The purpose of this paper is to contribute to the lean manufacturing literature by providing a roadmap for pull production control system (PCS) implementation. Design/methodology/approach Axiomatic Design (AD) methodology is used to develop the proposed pull PCS transformation roadmap. Findings The proposed design methodology is validated in a real-life manufacturing system. The results show that the proposed methodology significantly reduces the design efforts. The methodology effectively helps to choose the most appropriate pull PCS and determine its operational settings with respect to the manufacturing system characteristics. Research limitations/implications This study presents only one case study to test the proposed methodology. In future studies, the validity of the proposed method can be further generalized in different manufacturing sectors by real-life implementations. Practical implications In many real-life lean production projects, companies do not know where to start or how to proceed, which leads to repetitive design efforts and inefficient designs. The developed roadmap of this study minimizes incorrect or imperfect design trials and increases the success of pull production transformation projects. Originality/value The implementation of pull PCS requires extensive design knowledge and expertise. Therefore, many real-life applications fail due to costly and time-consuming trial-and-error-based design efforts. In the literature, there is no comprehensive guideline or roadmap for pull PCS implementation. To address this issue, this study provides a novel holistic roadmap to transform an existing push PCS to pull. The proposed methodology uses AD principles and combines fragmentary studies of the pull production literature.


2018 ◽  
Vol 154 ◽  
pp. 01095 ◽  
Author(s):  
W. A. Santosa ◽  
M. Sugarindra

PT. XY produces musical instruments such as Upright Pianos and Grand Pianos. Due to a competitive competition, a good quality product is highly required as well as increasing the production scale. To achieve these objectives, company needs to reduce wastes occurred in its production lines, particularly in the division of sanding panel upright piano (UP) which produces type of PE B1 pianos. High cycle time and lead-time are caused by wastes in UP panel sanding division. Therefore, it is needed improvements to be applied here so that the production lines will be run more effectively and efficiently. This study aims to identify wastes using Value Stream Mapping (VSM) as a tool of lean manufacturing and to implement the improvements using Kaizen. It is found that the wastes are motion and waiting. Furthermore, the improvements (kaizen) are focused on reducing motion and waiting wastes. It is shown that cycle time decreased from 51.16 minutes to 41.90 minutes, work in process or inventory can be reduced to 24 pcs over 32 pcs, and the lead-time is 0.167 days of 0.222 days.


1997 ◽  
Vol 11 (4) ◽  
pp. 241-245 ◽  
Author(s):  
L. E. Holloway ◽  
A. Hall

Lean manufacturing is a philosophy for continually eliminating waste. The practice of this philosophy requires both a management structure and a manufacturing technical structure that facilitate identifying wastes in the firm's operations, focuses management efforts on improving processes to reduce or eliminate any waste elements, and maintains the improvements through a focus on standards for all elements of manufacturing. This paper identifies the types of wastes in manufacturing. It then shows how lean manufacturing focuses on these wastes through employee involvement in continuous improvement of standards, visual management techniques to help identify wastes (deviations from standard), quality at the source techniques that focus on eliminating wastes of defects, and ‘pull’ production control methods that can be used to reduce wastes of inventory and to expose wastes hidden by high inventories.


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