Lean manufacturing is the flavour of the season. Almost everyone has heard about the same and probably most of them are attempting to implement Lean through consultants. It’s a philosophy that outlines multi-dimensional approaches to reduction of waste. It can be applied in day-to-day operations, strategy, customer satisfaction, manpower training and many other places. As someone from Lean group puts it, “For Lean to be successful, it should be a part of their life”. However, there are several myths regarding the philosophy, which needs to be redressed. In the last article of the ‘Myth Buster’ series, Professor Prabir Jana, from National Institute of Fashion Technology, New Delhi unmasks some of the fat truths about Lean.
Going by the wikipedia definition “Lean”, is a production practice that targets elimination of waste that does not create value for the end-customer. Lean is the set of “tools” like Value Stream Mapping, 5S, Kanban (pull systems), and Poka-Yoke that assist in the identification and steady elimination of waste (muda). The second approach to Lean Manufacturing (which although lacks popularity), is promoted by Toyota, in which the focus is upon improving the “flow” or smoothness of work, thereby steadily eliminating mura (“unevenness”) through the system and not upon ‘waste reduction’ per se. Typical practice in garment industry is to follow one or more of the above tools to implement Lean. Techniques to smoothen flow include production levelling, “pull” production (by means of kanban) and the Heijunka box. There are loads of books and websites defining each tool and technique in detail, in this article I will try to demystify the perceptions about applications.
Value stream mapping, Five S, Seven W are popular Lean approach: True
Consultants always resort to those practices that are easier to implement, requires negligible cost, and most importantly where existing standard is comparatively low so that showing improvement is easier and quicker. Garment manufacturing factories are generally very disorganized and people tend to cover their backside by keeping buffer. Therefore, it is relatively easy for consultants to plan, organize (by following 5S process) and/or eliminate/reduce buffer (both material and time) by following seven W approach. Value stream mapping maps the VA, NVA, NNVA activities and due to a very low percentage of VA (generally less than 3%) prevailing in the industry, it makes the favourite choice of Lean implementation.
Kanban and Poka-Yoke are less popular Lean approach: True
Kanban is one of the most promising yet less popular (under-utilized) approach to Lean due to poor understanding of logic amongst both manufacturers and consultants. Although some manufacturers unknowingly use kanban (or some improvised version) system in managing accessories inventory without realizing that they already are practicing Lean. Kanban can be potentially helpful in maintaining inventory between cutting & sewing, between different operators in sewing line, and sewing and finishing department; however, rarely anyone attempts the same. Wherever there is a problem of transparency and non-accountability of pieces, one should try to implement kanban approach to limit the stock. Poka-Yoke requires innovative ‘out of box’ thinking and therefore lacking effort from both manufacturers and consultants.
Inventory reduction in one echelon implies Lean implementation in supply chain: Wrong
Reduction of inventory in supply chain is like an enigma. The supply chain encompasses all departments in an organization and also that of the suppliers and customers of the organization. Lean supply chain means reduction of total inventory in the chain, and not merely shifting inventory from one organization to another. As the common Lean implementation approach is reducing inventory department wise or organization wise, there lays risk of pushing inventory from one department to another or from one organization to another, instead of actually reducing inventory. For example while attempting to reduce inventory (WIP) in sewing line, very often the cut parts inventory in cutting room increases. Similarly while a retailer attempts to reduce inventory, invariably the finished goods inventory increases at manufacturers’ or wholesalers’ end. One should be cautious as the apparel supply chain is downstream dominated; (i.e. a downstream player like retailer is always the dominating partner in relation to manufacturer) very often the inventory is pushed upstream.
Lean implementation compliments quick response retailing: False
One needs to understand that scale and scope generally does not go together. Quick response works on reduced time to react. Inventory is replacement to information, if we have the correct information what will sell, then we need not maintain inventory. At any given level of information clarity, quick response will require more inventory to be maintained as there is lesser time to react. Technically any company dealing in commodity merchandise can attempt to make the supply chain Lean. In contrary, any company following quick response business model ideally should not wish to be Lean at least in inventory stocking, as the business model requires the company to maintain inventory. That does not mean a quick response company can’t become Lean; the company can implement and practice tools of Lean other than inventory reduction.
Lean implementation compliments fast fashion: False
Fast fashion is changing of style faster in the store. To change old style faster with new style (and that too with uncertainty), one needs to maintain considerable amount of stock in the supply chain, whereas a commodity product is replenished at slower pace (and with better certainty), meaning information is available, thereby the supply network upstream can be planned in advance. As the certainty of information is better, inventory requirement is lower. Lower inventory means Lean organization.
Kanban implementation in sewing line means Lean approach: True
There are several ways that Lean can be implemented in the sewing line. An organization which is working in PBU system in sewing line may decide to follow pull system by implementing kanban, where upper limit of WIP that can be created between any two sewing operations be set and adhered to. In this system the last operator controls the flow of material, thus called ‘pull’ system. If any succeeding operator slows down then WIP consumed at slower pace, will reach kanban limit and will slow down the preceding operator eventually. Any organization implementing kanban from PBU system can be attributed to Lean implementation.
Lean implementation in sewing mandates single piece flow: Partially True
Single piece flow in sewing means Lean implementation, but the reverse is not true, as Lean implementation does not necessarily require single piece flow. There are other ways of implementing Lean in sewing line. Single piece flow means there is zero work in process (WIP) between any two operators in sewing line. This is an extreme form of teamwork, popularly known as Toyota Sewing System (TSS) when pieces moves from hand to hand in a stand up work format and are never kept in bin/trolley. In PBU system WIP is maximum to ensure continuity, but in TSS number of operators are less than number of sewing machines and multi-skill operators work as self-balanced team in hands-off or bump-back system where succeeding members take the WIP from preceding operators. The objective of Lean is reduction of WIP, therefore Lean implementation may lead to ‘single piece flow’ but not necessarily mandatory.
Conclusion
Lean production not only successfully challenged the accepted mass production practices in the automotive industry, significantly shifting the trade-off between productivity and quality, but it also led to a rethinking of a wide range of manufacturing and service operations beyond the high-volume repetitive manufacturing environment. Most importantly we need to understand why we need Lean… To reduce inventory? To better organize things? To checkmate mistakes? What is our priority? Instead of starting to think about Lean, we should start thinking about the objective first which will help us identify the correct Lean tool. As waste is eliminated gradually, quality improves while production time and cost are reduced.
