Login  |  Newsletter  |   News   |   Agenda   |   Search   |   Jobs   |   Forum   |   Advertize
Source: Business-improvement.eu
QRM: Cellular organization
10 years QRM at Bosch Scharnieren10 years of QRM at Bosch Scharnieren
By Dr Jaap van Ede, editor-in-chief business-improvement.eu. 18-04-2018

Bosch Scharnieren (‘Bosch Hinges’) was the first company in the Netherlands that implemented Quick Response Manufacturing (QRM), to shorten the throughput times for customer-specific production. What did they learn in the past ten years?

‘The power of QRM lies in the transformation to a cellular organization with Quick Response Cells or QRC’s’, says CEO Fried Kaanen. ‘Next, customer-specific orders can move freely along a selected number of these QRC stations. You could compare this with "regional trains" choosing their own route. After this, you can focus on reducing the waiting times between the QRC stations.’

Reducing waiting times can be done in different ways, ranging from buffers to the application of the Kanban variant POLCA. ‘The latter is an important tool, but is not sufficient', warns Kaanen. ‘POLCA ensures that on average production orders move as quickly as possible. However, sometimes it is needed that orders can overtake each other. 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. Therefore we use software to track the position of all production orders in realtime.’

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?

POLCA planning loopQRM

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

Express trains

The logistic challenges that companies can face, can be described with a railway metaphor.

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
In companies with customer-specific production, semi-finished products move like "regional trains" along a number of processing stations, selected beforehand. So, each train follows its own route.

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.

Quick Response Manufacturing (QRM) pursues both objectives: optimally organized workstations, and smart workflow management between those stations.

Bosch Scharnieren manufactures stainless steel hinges in small series, tailered to the needs of their customers Bosch Scharnieren manufactures stainless steel hinges in small series, tailered to the needs of their customers

Small series
Fried Kaanen, the CEO of Bosch Scharnieren, likes the railway metaphor. ‘We have the situation with regional trains. We manufacture stainless steel hinges in small series, tailered to the needs of our customers. The amounts vary per order, and every hinge is different. As a result, the work steps needed to produce them also vary, and hinges under construction follow diverse routings across our factory floor.’

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.’

At that moment, Bosch Scharnieren did already apply Lean. ‘We could not form production lines, and certainly could’t produce in a One Piece Flow. However, Lean tools like value stream mapping and 5S, to create organized workplaces, did turn out to be useful. With those tools, we could reduce our delivery time from 6 to 8 weeks, to 4 to 5 weeks.’

Still, the main problem wasn’t solved. Orders were finished between zero and three days after the scheduled time. Bosch Scharnieren asked a team of consultants to help. One of them was the recently graduated Jacob Pieffers. ‘He talked about his research about a kind of traffic light system, with which you could regulate work flows. It was a system he had seen, when he visited Rajan Suri in the US. This turned out to be the POLCA system, one of the QRM tools.’

Shortening waiting times
‘After reading Suri’s book, Quick Response Manufacturing - A Companywide Approach to Reducing Lead Times, I was immediately enthusiastic’, Kaanen continues. ‘It exactly described the problems we had. In particular, I found the idea appealing to focus on shortening the waiting times. In the railway metaphor, these are the times that trains stand still between stations. If you can shorten those waiting periods, you can increase the flow in your whole network a lot.’

For the purpose of Quick Response Manufacturing, the shop floor was divided into task-oriented clusters of machines and associated multidisciplinary teams
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.

Quick Response Cells
In many job shop environments, there is not much thought about the design of the factory floor. Often you see, for example, "functional departments". In the railway metaphor, these are comparible with stations at which only one type of person can enter or exit, for example only someone older than 75 with a walking stick. This results into a lot of unnecessary "train movements" and associated waiting times.

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.’

However, in the early days of QRM much more attention was given to a tool that regulates the workstreams between the QRC’s, a tool to prevent traffic congestion. This tool is the Kanban variant 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 otherPOLCA 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

Therefore, POLCA uses cards with a capacity message. By sending such a card, a QRC informs a (potentially) supplying cell, that they have the capacity to receive - and process further - semi-finished products. If there is not such a card, the signal for the route to that station is red. This means that the supplying QRC should first work on an order that has to go to another station.

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.

The mission of this website: Inspire to create flow in business processes!
Three advantages of free registration:
  1. You will to be able to read all our articles, with many process improvement hints
  2. You will receive our newsletter every 6 months, with summaries of all new articles and case studies
    (and we promise to send you no other e-mail)
  3. You will be able to post on our forum

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 brakeThe POLCA system acts as an emergency brake, it prevents excessive workloads at Quick Response Cells

Emergency brake
Bosch Hinges learned a lot during the past ten years, both about the layout of the QRC’s, and about optimally dividing the workstreams between those.

‘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.’

To this end a job shop control system is needed, which regulates the "train traffic" between the QRC stations. This is done via signals, which indicate which trains should ride, and which trains should better stop and wait a little while.

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
Unnecessary circulating POLCA-cards can become a waste of time. ‘We had more than 2000 production orders last year. In our case that would have corresponded with more than 10,000 card movements! During the years, we had to add more and more cards, because the sizes of the orders continuously decreased. Later, in 2010, our factory was expanded with a new hall after a business takeover. As a result, employees regularly had to go outside, to bring POLCA-cards back to the other hall. You can imagine that this provokes saving of cards. If you do that, the POLCA-system will not work.’

Software-based QRM planning at Bosch ScharnierenSoftware-based QRM planning at Bosch Scharnieren

The hassle with the POLCA-cards disappeared, after those cards could be sended and returned digitally. ‘However, even then POLCA doesn’t solve everything without adjustments. When our production is for example half-way, some semi-finished products go to an external party, to have them powder coated there. This is comparable with part of your railway network runned by others. Fortunately, the available powder coating capacity turned out to be virtually infinite. We made this visible with a lot of POLCA cards circulating between us and the external party. ’

QRM releases production orders on the basis of the desired delivery date. Starting with that date, it is calculated back when a certain "train" should start, including a time buffer for an estimated standstill period. To prevent clogging of the rail network, a maximum of X trains is allowed to run simultaneously.

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.’

When there is more than one train standing still in the buffer in front of a QRC-station, an order gets priority if:

  1. It can proceed immediately to the next station after processing it, as signalled with POLCA.
  2. The delivery date of that particular order is threatened the most. The software calculates this.

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 shop floor control system ProposThe modulair factory floor control system Propos

Adjusted continuously
It is intriguing to see how Bosch Schanieren at first switched radically to autonomous production in QRC’s, with the production planning only regulated with POLCA-cards. Later, scheduling software was added again, be it that the software now tracks the orders in realtime, on basis of which the planning is adjusted continuously.

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.

As emphasized earlier, the core of QRM is the transformation of your company into QRC’s. In fact, these are self-managing teams with dedicated production resources. Bosch Schanieren learned a lot in the past 10 years, about the best way to organize these teams.

‘An important principle is that your employees must become as versatile as possible. Often, one particular task suits a person best, but he or she should acquire other skills as well. That way this person can help or replace others, for example in case of illness. We have three skill levels. Juniors and mediors can perform a certain task, respectively under supervision and with follow-up quality control. So, these people can assist at a certain position in a particular QRC, when necessary. A senior in a QRC is the person with the most experience in a specific area, he or she can carry out the corresponding tasks completely independently.’

So this person may never be ill? ‘In that case one of our production leaders steps in. They can perform multiple tasks in multiple QRC’s.’

It is encouraged that employees acquire skills outside the scope of their own QRC. ‘We want them to become decathletes. Such an athlete not only performs very well at some disciplines, but masters the other disciplines also reasonably well. Ideally, this makes it possible to continuously redistribute our production workers over the QRC’s, so that on average we score the most points.’ 

‘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 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