This article: 10 years QRM at Bosch Hinges
Source: Business-improvement.eu
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QRM: Cellular organization |
10 years of QRM at Bosch Scharnieren
By Dr Jaap van Ede, editor-in-chief business-improvement.eu. 18-04-2018
Bosch Scharnieren (‘Bosch Hinges’) is a SME company that manufactures stainless steel hinges. Ten years ago, they were the first in the Netherlands that started to apply Quick Response Manufacturing (QRM). Like Lean, this improvement method focuses on throughput-time reduction. However, QRM encompasses specific methods and tools to do this in an environment with high mix, low volume production, see the box below. Which lessons did Bosch Hinges draw in the past decade, and what does this mean for the applicability of QRM in other companies? QRM Quick Response Manufacturing (QRM) is a process improvement method developed from the standpoint of logistics. It aims to improve the flow. QRM increases the throughput, by reducing waiting times. The most important difference with Lean is that QRM was developed specifically for high-mix / low-volume production. Besides this, QRM uses only one performance indicator, the Manufacturing Critical-path Time (MCT). This is the time from the raw materials until product delivery. The underlying idea: Reduction of the MCT reduces the overhead, and consequently the non-value adding activities, the most. Important QRM tools are Quick Response Cells (QRC’s) and POLCA. QRC’s are multidisciplinary teams that autonomously perform a number of sub-processes for Focused Target Market Segments. POLCA is a Kanban variant which regulates the workstreams between the QRC’s, on the basis of pull signals. > more about QRM In companies with mass production, semi-finished products move like "express trains" along the processing stations. This situation is ideal for the formation of (Lean) production lines. The waiting times between the stations are than almost zero. Intermediate stock, if any, can be managed with Kanban cards. These send out a signal when replenishment is needed. Regional trains The work content at each station could be compared with the time passengers need to board and unboard. Often, this time span can be estimated fairly well. This is also true at Bosch Scharnieren. Nevertheless disruptions are inevitable, because "trains" cross each other regularly, and because unexpected delays occur at the stations. So, it cannot be prevented that trains stand still now and then, waiting for a signal that they can continue their journey. What can be done is organizing the work within the stations in such a way, that this passes as smootly as possible. Besides this, you can try to reduce the waiting times between the stations. QRM Bosch Scharnieren manufactures stainless steel hinges in small series, tailered to the needs of their customers
Ten years ago, QRM was still unknown in the Netherlands. ‘At that time, we struggled to get grip on our production planning. Our main problem was to comply to the delivery times. In the railway metaphor: many of our trains arrived too late at their end stations, our customers.’ Lean Shortening waiting times For the purpose of Quick Response Manufacturing, the factory floor was divided into task-oriented clusters of machines with multidisciplinary teams. Each of these Quick Response Cells has its own color.
QRM replaces the departments with Quick Response Cells. ‘A QRC is a cluster of machines, associated with a multidisciplinary group of people, who carry out a predefined group of similar activities. It resembles a kitchen, which can prepare a certain group of dishes. Choosing and designing your QRC’s as smart as possible, might well be the most important aspect of QRM.’ POLCA Kanban uses cards to inform supplying stations, that specific semi-finished products or materials have been processed, and that new ones can be supplied. This does not work in the case of customer-specific production, because then the quantity of different semi-finished products, and therefore also the quantity of required Kanban cards, becomes infinite. POLCA tunes the work in Quick Response Cells to each other by sending out cards to potentially supplying QRC's, at the moment that processing capacity becomes available downstream
POLCA cards are sent with the orders, and are returned later to the supplying QRC. That way, the people in that cell are informed that they can supply again to the cell mentioned on the card.
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Transformed Bosch Scharnieren started with QRM in 2007. After two months of preparation, they transformed their work floor into a network of loosely coupled QRC’s, within three weeks. Subsequently, they started to control the work streams between the QRC’s, with circulating POLCA cards. ‘Within a few months, we already got results. Our throughput time fell to less than four weeks, and, more importantly, our delivery reliability became what we wished for.’ The POLCA system acts as an emergency brake, it prevents excessive workloads at Quick Response Cells
‘We discovered that POLCA is not the most important part of QRM. POLCA acts as an emergency brake that prevents overloading of QRC’s, when regular forms of buffer management fail. However, when you improve the flow, the emergency brake is needed less and less frequently.’ ‘The true strength of QRM is the transformation of your company into a cellular organization, with flexible and scalable QRC’s, passing the batton to each other. This resembles a smart railroad network, over which your semi-finished products can move. When this network of QRC’s is ready, it forms the basis to shorten your throughput times further and further.’ Buffers On paper, POLCA may appear to be the ideal signalling system, but this is not always true. According to Kaanen, this explains why not every job shop factory uses POLCA, where Kanban cards are seen in almost every Lean environment. Sometimes, POLCA turnes out to be unnecessarily complicated. ‘With simple visual management, such as visible buffers in front of the QRC’s in which a limited number of "trains" fit, much progress can also be made. In that case you achieve the same as with POLCA cards, without the iron discipline your employees need to bring those cards back timely to the supplying work cells. QRM makes your employees more and more flexible, after a while they can exchange between QRC’s. This makes the use of POLCA-cards as emergency brake less and less necessary over time.’ Waste of time Software-based QRM planning at Bosch Scharnieren
Priority During the ride, one train will become more delayed than the other. Unexpected events can for example occur on the route to be traveled along the QRC stations. Therefore, it is desirable that delayed trains (production orders) can overtake relatively fast trains. In the ‘paper POLCA’ system, lists with ideal arrival dates at each QRC are calculated regularly, and brought to all QRC’s. This gives the people in those QRC’s the opportunity to prioritize delayed orders. ‘However, sending those lists is laborious and error-prone. In addition, it is better to reschedule continuously. Therefore we use software to track the position of all trains in realtime.’
According to Kaanen, the calculations for the second decision criterion roughly correspond with the Theory of Constraints (TOC) solution for project management. In that case, a time buffer is linked to each order. Next, orders with the lowest remaining percentage of time buffer, get priority. The planning software Bosch Scharnieren uses was developed by Robert Peters. Since 2012, this solution is marketed by Propos Software, a Dutch software company owned by Fried Kaanen and Robert Peters. ‘Propos is a modular factory floor control system’, explains Kaanen. ‘POLCA is one of the modules, which can be activated where this is useful.’ The modulair factory floor control system Propos
According to Kaanen, the priority calculations are based on clear rules, including POLCA. However, for employees in companies that start with QRM, the planning software may resemble a black box. This is not a problem within Bosch Schanieren, since all their operators already understand the underlying idea. However, if you start with QRM, it may be wise to begin only with visible buffers and/or tangible POLCA cards. That way, everyone on the floor can learn why it is important to stick to the production sequence as indicated by POLCA, which makes the throughput as large as possible. Versatile Decathletes ‘For example, it can happen that a certain QRC has no work for a day. In addition, people can move to certain QRC’s, when these have capacity problems. In the railway metaphor you could compare this with temporarily creating an extra platform at a QRC, to recieve "trains" (read: semi-finished products to be processed). This makes the capacity in your QRC’s flexible.’ In the context of QRM, the production workers should become decathletes. They should be able to switch between tasks and Quick Response Cells
At this moment the delivery time of the hinges, tailered to the needs of the customers, is about 2 to 3 weeks. The delivery date is almost always met. Shorter delivery times are possible, but currently have more disadvantages than advantages. ‘Thanks to QRM, our delivery time has become something that we can choose strategically. With even shorter delivery times, our business becomes too nervous. We are no snack bar, quality remains paramount.’ Do you need help with the implementation of QRM and/or POLCA? Referral to this article on internet? Use this link: https://www.business-improvement.eu/qrm/Bosch_Scharnieren_QRM_10year.php |
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