New assembly methods at Toyota

Toyota’s latest plants in Ohira, in Japan’s Miyagi prefecture and in Tupelo, Mississippi, feature new approaches to assembly. According to press reports, the Miyagi plant is small, with 900 employees making 250 cars/day for export to the US, with a plan to double output and employment. It was designed to require a minimal investment and be easy to change. The plant started operations shortly before the Fukushima earthquake and, even though it is the Northern part of Japan that was most affected, it resisted well and was able to resume operations about six weeks later.

This is how Barry Render described it:

“The Miyagi factory is designed for advanced low-volume, hyperefficient production, with 1/2 the workers and 1/2 the square footage of Toyota’s 16 other plants. Inside, half-built Corollas and Yaris sit side-by-side, rather than bumper-to-bumper, shrinking the assembly line by 35% and requiring fewer steps by workers. Instead of car chassis dangling from overhead conveyor belts, they are perched on raised platforms. This is 50% cheaper, and also reduces cooling costs by 40% because of lower ceilings. Finally, the assembly line uses quiet friction rollers to move the cars along. The rollers use fewer moving parts than typical chain-pulled conveyor belts.”

Toyota is not providing details, but I have been able to glean some information about it from the press and Barry Render’s blog, on the following features:

This is followed by a few conclusions.

Side-by-side assembly

Side-by-side assembly at Toyota Miyagi

Side-by-side assembly at Toyota Miyagi

I have seen side-by-side assembly at the Volvo Bus factory in Turku, Finland. In the picture of the building below, bus bodies are assembled in the hall on the left, side-by-side under they are mounted on a chassis and move forward on their wheels, laid out front to back in the hall you see in the background.

Volvo Bus assembly building in Turku, Finland

Volvo Bus assembly building in Turku, Finland

Volvo bus main assembly flows

Volvo bus main assembly flows

The ratio of width to length  is more favorable to this arrangement for buses than for cars. A straight assembly line with a front-to-back arrangement throughout would require a long and narrow building and a snaking line would have problematic turnarounds. With cars, the side-by-side arrangement seems suitable for work done at the front or the back of the car, such as installing headlights or bumpers. but less for work that requires access from the middle, such as installing instrument panels or upholstery. The following press picture (AP), however, shows an assembly operation done inside the car body in what appears to be a side-by-side layout. It implies that space for the part cart must be provided between cars, which forces them apart.

Assembly operation at Miyagi

Assembly operation at Miyagi

None of the available pictures from the Miyagi plant shows the raku-raku seat that was a prominent feature of the early 1990s designs and made it easier for operators to work inside the car bodies. Not only is a raku-raku seat an added investment, but it is also easier to use in a front-to-back than in a side-by-side layout.

Raku-Raku seat

Raku-raku seat in a 1990s plant

Modular paint booths

I could not find pictures or sketches of the Miyagi painting system. Following is how CNN Money described it on 2/18/2011:

“…Toyota developed a modular paint spray line. The modules can be built somewhere else and are assembled at the plant in a much shorter time. Advantage: Cost savings. However, you don’t build a modular paint spray line factory somewhere unless you intend to build a lot of paint spray lines. Usually, cars get three coats of paint, usually water-based, and usually each coat is dried with heat. Not in Ohira. Here, the third coat is applied onto the still wet second coat and both are dried together. Advantage: Huge energy savings, faster paint time. Lower expenses…”

Friction roller conveyors

Toyota assembly line new concepts 2011 Miyagi plant Conveyance

Following is how CNN Money described the Miyagi conveyor systems on 2/18/2011:

“Where the car moves along the floor, factories usually have below ground pits that house the motors, chains and gears that keep the line moving. Not in Ohira. Here, the cars move on maybe a foot high conveyor system that is simply bolted into the concrete flooring. Advantage: Cheaper to build, cheaper to tear down and rebuild somewhere else. The line can be lengthened or shortened at will. The assembly line doesn’t ‘grow roots’ as they say in Toyota-speak.”

Note that the sketch shows car bodies without wheels. In this system, the bar supporting the cars forms

A photographs of final assembly at Ohira shows operations done further downstream, with the wheels on:

toyota--ohira-plant-in-japan-front-to-back assembly line 2011

Assembly operations after wheels are put on

In this picture, the floor the operators stand on is flush with the assembly line,  meaning that it is either a classical line with the drive mechanism in a pit under the floor, or the operators are in a raised platform spanning the length of this assembly line segment.

Elevated platform versus suspension conveyor

Toyota assembly line new concepts 2011 Miyagi plant Suspension

From suspension conveyor to elevated platform

The following photographs contrast the suspension conveyor approach as previously used at Toyota with the elevated platform at Tupelo, Mississippi:

From these pictures, it is clear that the elevated platform is a cheaper system to build, but I can see two issues with it:

  1. Flexibility in vehicle widths. The Yaris and the Corolla differ in width by less than half an inch, and therefore the same elevated platform can accommodate both. A Land Cruiser, on the other hand, is 11 inches wider, which makes you wonder whether it could share an elevated platform with the Yaris. The jaws of the suspension conveyor, on the other hand, look adjustable to a broad range of widths.
  2. Ergonomics. Working standing with your head cocked back and your arms overhead is just as ergonomically inadequate in both cases. By contrast, the VW plant in Dresden, Germany, uses suspended conveyors that can tilt the body, which is both ergonomically better and much more expensive:
VW Dresden suspended adjustable conveyor

VW Dresden suspended tilting conveyor


The journalists take on the Ohira plant is that it is intended to prove a design for low-volume, low-cost, high-labor content plants that can be deployed easily in emerging economies with small markets. The designs of the early 1990s instead used more automation to make the work easier for an aging work force, with tools like the raku-raku seat. This is a different direction, addressing different needs. But why build it in Northern Japan rather than, say, the Philippines? It shows Toyota’s commitment to domestic manufacturing in Japan, and it is easier to test and refine the concept locally than overseas.

29 comments on “New assembly methods at Toyota

  1. Thanks for the your continued sharing ! It is great to see the ‘side-by-side’ assembly concept. I believes most companies get into the ‘standardization & replicating’ the manufacturing system; which eventually leaves little room to explore other best means.

  2. Like the article you shared. And a quick question: do you think the side-by-side assembly would retain disadvantages of straight assembly, e.g. low flexibility?

    • I wish I could give you an answer. This is the first time I hear of side-by-side assembly for cars, and increasing flexibility is not the reported motivation.

      As I indicated, I have seen it in bus assembly. Buses are highly customized, but the customization is mostly in the upholstery and the outside paint, and takes place primarily at end of the process, where buses are laid out front-to-back.

  3. Comment in the Lean Six Sigma Canada discussion group on LinkedIn:

    “Tweaked” would be more accurate than “new”. But I was especially intrigued by the friction roller system that is loosely bolted to the floor. None of the illustrations show a way to power the system. Perhaps Toyota is getting feed-back from HR costs by having workers convert their wages back to motive energy through the Krebs cycle.

  4. Comment in the discussion group on LinkedIn:

    Maybe the future of manufacturing is to move towards one piece flow whereby there are many more but much smaller factories making smaller numbers servicing smaller markets. This way the customer base of each plant is smaller and their specific requirements easier to deliver.
    Why Japan? – Why not trial it first in the place that best understands the reasoning behind its development and those armed with the greatest knowledge of the systems that will support it. You can bet once this is proven it will be quick to grow. Plan meticulously implement swiftly!

  5. The side by side assembly was in place since the end of the 90’s for the assembly line of Mobilvetta motorhomes, and is in place right now for the first 5 stations of the new assembly line (end of 2009) of Elnagh, Mobilvetta and McLouis motorhomes in Poggibonsi (Italy).
    An Elnagh motorhome
    An Elnagh motorhome

  6. Very interesting to see the wheel being reinvented again. Many assembly methods and processes have be tried over the years by many companies and engineers. I have seen many myself but the key element here is to remember this is low volume production. I being a former former LSS champion of low volume production can speak to the advantages and disadvantages of it.

    Most associates chose to work in low volume for several reasons… A few reasons are the ease of less repetitive work, less fatigue and better ergonomics conditions…less stressful (psychologically) work as opposed to high volume… Low volume typically has longer work cycles and more flexibility for creativeness. Low volume typically was where new product launches often take place before they get ramped up…There is often less cross training requirement than high volume where the need for cross training is much greater… Pride, integrity and ownership of associates have a higher requirement and demand for continuous improvements needs in low volume.

    In other words you need to have very smart-sharp, focused and alert worker in these operations to make them work properly as they will be working more as teams rather than as individuals…If one team member cannot keep up the rest of the teams can be effected and a new member or a benchmarking procedure could be changed as with a process change request (PCR) or a new associate that can keep up…

    I did experience this type of assembly operation many years ago at Ford Tractor operations where many teams and assembly methods and processes were used for low volume production but back then there was not a lot of automation or computerization yet.It was usually low volume,low demand. High volume high demand production methods and techniques used…Thanks and thank you Mr. Michel Baudin because I know from many of my past readings that you are one of the sharpest knifes in the drawer…Sincerely, Bill Ryan.

    • Thanks for your kind words.

      I do not understand why you say that low volume work needs less cross-training than high volume. I would have thought the opposite, with high volume supporting more specialization. If the volume is so low that you only need 1 person, that person clearly needs to know how to build the product from start to finish.

      Best regards.

  7. Comment in the Operational Excellence discussion group on LinkedIn:

    The amazing thing is, Toyota Engineers can think outside their borders.
    For many companies and many engineers: Bumber to bumber assembly is industry standard. The expensive suspension conveyor is industry standard. They even can not think to change these “standards” – which actually are the borders in their minds…

  8. Comment in the Operational Excellence discussion group on LinkedIn:

    Great discussion Michel!
    The question that springs to mind is: Is this an product of Kaizen or Problem Solving?
    I suggest that this is more akin to problem solving.

    Building and operating a factory in any country represents a very large investment, a reduction in the capital invested will provide a reduction in LT to profit and also reduce the risk.

    Finding the right skills in an emerging market can be problematic, also labour retention can be an issue. With low maintenance equipment, the skills needed will be lower and easier to train, many more activities can be autonomous. The cost avoidance on these OH might easily fund the additional assembly line workers needed to run a condensed line.

    Plant build and equipment installation and commissioning time will likely be reduced, therefore, product to market LT is also reduced.

    It seems that Toyota are well on the way to flexible plant model that can be operational and profitable significantly faster than their competition.

  9. Comment in the Operational Excellence discussion group on LinkedIn:

    Thanks Michel for sharing …. This model of Side by Side has been firstly drafted and dropped later by bus manufacturers considering amount of Leaps required on either end …… Any how Practicability in 4 meter long car’s seems workable …. For me following benefits are upfront ……

    1. Takt time decreases as throw length changes from length of car to its Width … Production Rises !!

    2. Operator access increased to 2 sides { 1 side each of both adjacent vehicles ) instead one earlier … Considering Interchangeability , Cycle Time , Muda , Mura and Muri will all be decreased and that is Cost Leadership. !!

    3. Kanban can be better implemented considering interchangeability of small parts.

    4. 1+1 operator on new layout reference earlier 1 operator will always be helpful Ergonomics and cutting cycle time or Advent conditions

    5.Washing and Painting with drop down ponders will increase efficiency 100 % ..

    6.Above all PPC and Self inspection will be better for Q.A …..

  10. Comment in the Operational Excellence discussion group on LinkedIn:

    1974-1994 Volvo produced cars in the Kalmar Factory. The experiment became very famous and lot of research has been done on the non-conventional methods and organization of the assembly work.The Ford type of line was abandoned and the car was built by very flexible workers on special platforms.
    Flexibility and employee empowerment were key.The experiment was stopped 1994 since it turned out to be less productive than the conventional approach. So there are previous experiments in line with the Toyota one. I do not know if technology has now developed so that it can be productive and efficient. But I hope so, the Volvo experiment was very interesting but possibly a bit too early. As was the Volvo pioneering into hybrid cars beginning of the 90ies. There are quite a lot of material on the web describing the Volvo experiment.

    • I have heard of this experiment, but I thought the location was Uddevalla rather than Kalmar. And, as I understand it, it was about not using assembly lines at all, which is quite different from what Toyota is doing in its new plants.

      That fixed-station assembly is less productive than line assembly is a discovery that was made at Ford in 1913, and reverting to this old mode or operation sounds more like a rearguard action than pioneering work.

  11. Comment in the Operational Excellence discussion group on LinkedIn:

    Thanks for posting an interesting article. I can see many potential advantages. It is possible to carry out more than one activity within TAKT at any one station on side by side – Front and Rear bumpers for example. Operator walking is reduced considerably – car width + gap and only half of the car length. I suspect the biggest potential gain is the cheap nature of the equipment for the line as suggested in the article for developing countries. However, if a factory is considerably smaller and cheaper, why not put plants closer to the customer and serve a smaller region?

  12. Comment in the Operational Excellence discussion group on LinkedIn:

    In 1992 we at A.O.Smith built the frame for the Suburban Blazer Crew cab on a weld line that transferred the frames in a transverse direction and not longitudinal like we did the pick up trucks in 1987. The cycle time for the pick up truck was 60 seconds with 20 seconds of transfer time. In 1987 the robots were floor mounted and the frame did not lift over them. In 1992 the cycle time for the Suburban Blazer Crew Cab was 60 seconds with a 9 second transverse transfer time. The robots were mounted above the line and the frame did not have to lift over them. In both cases the operators were loading parts into fixtures during the transfer in safe zones as an example of combination work. The benefit to transfer transversely with a benefit of 11 seconds made a difference.

  13. Comment in the Operational Excellence discussion group on LinkedIn:

    Thanks for posting an interesting article. I can see many potential advantages. It is possible to carry out more than one activity within TAKT at any one station on side by side – Front and Rear bumpers for example. Operator walking is reduced considerably – car width + gap and only half of the car length. I suspect the biggest potential gain is the cheap nature of the equipment for the line as suggested in the article for developing countries. However, if a factory is considerably smaller and cheaper, why not put plants closer to the customer and serve a smaller region?

  14. Comment in the Lean Six Sigma Worldwide discussion group on LinkedIn:

    Thanks – amazing company… when you think you have caught up with them, you realize they are already one step ahead – in fact they have been preparing massively on production enginering innovations since 2008 crisis when my sources tell me they set themselves stretch target to produce cars at 30% less operating costs.
    They will remain the model for a long time on how you can still make good margins in the automotive industry you continuously improve and dare to make some ‘out of the box thinking’ moves..

  15. Comment in the Lean Six Sigma Worldwide discussion group on LinkedIn:

    Something like this opens up mass customization possibilities to another level other manufacturers are not prepared to compete against. Interesting!!

  16. Comment in the Lean Six Sigma Worldwide discussion group on LinkedIn:

    Very interesting article. Thanks for the research. I remain impressed by Toyota’s “open to changes” mindset, this capacity to constantly go forward for the efficient “out of the box” solutions in their production process. This is finally how you can get a real competitive advantage & achieve to become a benchmark.

    • Comment in the Lean Six Sigma Worldwide discussion group on LinkedIn:

      Hi Olga, I would like to put it more strongly than “open to changes mindset”.

      In my opinion Toyota shows a proactive approach and infrastructure towards beneficial change, they are not only open to beneficial change but they actively drive it at all levels of the organisation.

      To me one of the big differences between them and the other big automotive manufacturers / assemblers is their clinical and scientific approach towards finding better ways to do things.

      Not only do they “talk the talk” but they also “walk the walk”.

    • Most manufacturers are committed to one way of making things. It has worked for them on some major products, so they consider it to be the “proven method” and apply it everywhere regardless of differences in product technology, mix, or demand pattern.

      When they do try something new, they tend to do it in remote, foreign locations where the local management does not have the clout to resist the will of Production Engineering from the parent company.

      What impresses me in the story of Toyota’s new plants is (1) their willingness to use a radically different design to meet different needs, and (2) their prudence is implementing it first in a domestic plant in Japan before deploying it elsewhere in the world.

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