ENDÜSTRİ 4.0 ÜRETİM SÜRECİNDE SÜREÇ DEĞİŞKENLİĞİNİN OPTİMİZASYONUNDA HEIJUNKA YÖNTEMİ

Geleneksel firmalar müşteri talebini karşılamak ve üretim verimini arttırmak için genellikle yüksek adetli partiler halinde üretim yapmaktadırlar. Aynı üründen büyük miktarlarda üretmek belki daha az kalıp değişimine neden olmaktadır. Ancak; bu durum genellikle stokların şişmesine, büyük miktarlı hata olasılıklarının oluşmasına, değişkenliğin artmasına ve aşırı boş zamana ya da fazla mesaiye neden olabilmektedir. Rekabetin bu denli yoğun yaşandığı Endüstri 4.0 çağında firmanın bu üretim tarzı sadece para kaybetmek anlamına gelmeyip aynı zamanda ciddi pazar kaybı yaşamasına neden olmaktadır. Bunun için firmalar, operasyonlarında esnekliği sağlamak ve müşteriye özgü üretim gerçekleştirebilmek için yönetim bilişim sistemlerinin de desteğiyle yeni yaklaşımlar kullanmaktadırlar. Bu yaklaşımlardan biri de Yalın Yönetim tekniklerinden biri olan ve ilk olarak Toyota’da kullanılmaya başlayan Heijunka’dır. Toyota üretim sisteminin köşe taşlarından biri olan Heijunka, aynı zamanda farklı müşteri taleplerini karşılamak ve değişkenliği azaltmak için kullanılır. Heijunka, değişkenliği azaltmak için sadece israfları (muda) değil aynı zamanda makine ve insanlar üzerindeki aşırı yükü (muri) ve düzensizliği de (mura) ortadan kaldırır. Böylece müşteri taleplerinden ve/veya planlama eksikliklerinden meydana gelebilecek talep dalgalanmalarının üretime daha dengeli bir şekilde yansımasını sağlayarak, müşterinin istemiş olduğu ürünün istemiş olduğu zamanda üretilmesini sağlar. Bu çalışmayla; Heijunka tekniğinin tüm yönleriyle ele alınarak endüstride ve akademide tanınması ve kullanımının yaygınlaştırılması hedeflenmiştir. 

HEIJUNKA METHOD FOR THE OPTIMIZATION OF PROCESS VARIANCE WITHIN THE FRAME OF INDUSTRY 4.0

Traditional companies usually manufacture high-quantity batches in order to meet the customer demand and increase production efficiency. Manufacturing with high-quantity batches may lead to fewer die change operations, but this causes on the other hand the inflation of stocks, the probability of defects in high quantities, increasing the variance and excessive idle time or overtime. In the age of Industry 4.0 where the competition is so fierce, this kind of a production approach does not only cause financial loss but also leads to a significant amount of market share. Therefore, companies today deploy new approaches with the support of management information technologies in order to achieve operational flexibility and perform custom-made production for customers. One of these approaches is Heijunka, which is among the lean management techniques and initially used at Toyota. Being one of the cornerstones of Toyota manufacturing system, Heijunka is utilized to meet varying customer demands in the same period of time and decrease the variance. In order to decrease the variance, Heijunka eliminates not only the waste (muda) but also the overload on machines and workforce (muri) and the irregularity (mura). This ensures that the product demanded by the customer is manufactured at the requested point of time, by assuring a more equal reflection of demand variations and/or deficiencies of planning to the production process. The aim of this study is to familiarize both the industry and the academy with Heijunka by examining the technique with all of its traits and contribute to the dissemination of its use.

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