I don't have experience, I'm an interested reader on lean/TPS too. I'm
currently reading 'the toyota way' by Jeffrey Liker. I've gone flat on my
face with using factories as a metaphor before, so I'm cautious. I do see a
lot of similarity between the Toyota Production System (values, principles as
a basis and practices derived and evolved by focusing on the values).
On Tuesday 09 November 2004 04:22, Kent Beck wrote:
> I am an interested reader about lean manufacturing, so I hope if I say
> something wrong here that someone with experience will correct me. My
> understanding is that lean production lines deliberately mix their
> output, unlike mass production lines which try to maximize the number of
> identical outputs to reduce setup costs. Originally this was because the
> market for cars in Japan was small and fragmented and no more than a few
> of each model could be sold.
This is about as it is stated in 'the toyota way'. Mixing production lines
enables toyota to do 'mass customization'. Mixing production also enables
them (if I understood correctly) to combine just-in-time delivery with
prediction. They'll sometimes rebuild cars that are already on the production
line if the configuration forecasts are off.
> In practice, this reduces the risk that any
> one failure will totally shut down the line (that's my understanding, I
> don't think I've ever seen this explicitly stated).
What do you mean by failure in this case?
I believe it is the intention that at any failure, a worker stops the line, or
at least a work-cell within the line. It is expected workers stop the line
regularly to improve the process. Toyota managers view a plant that never
stops the line as suspicious: it is likely workers are too afraid to stop the
line and bring problems into the open.
The example above, of failing to predict demand, is a way in which mixing
production lines helps: the process is able to deal with a variety of cars,
so fluctuations in demand do not lead to fluctuations in production
('levelling out the load' is one of the TPS principles). Of course this only
works for variations within the same type of car-body.
For those of you interested in lean/TPS in combination with XP, I wrote down
some more impressions on 'the toyota way' and XP last week:
http://ruminations.willemvandenende.com/rublog/rublog.cgi/BeingAgile/LeanAndNotMean.html
kind regards,
Willem van den Ende
Living Software B.V.
>
> Kent Beck
> Three Rivers Institute
>
> > -----Original Message-----
> > From: Luiz Esmiralha [mailto:[EMAIL PROTECTED]
> > Sent: Thursday, November 04, 2004 10:58 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Software Factories Considered Harmful (was RE:
> > [XP] Why NOT XP?)
> >
> >
> >
> > Kent,
> >
> > Could you ellaborate a bit further? Do you mean the same
> > production line could be used to produce products that share
> > common "parts" thus enhancing overall productivity (beat ya
> > on the product-related word count)?
> >
> > Seriously, I see lots of incoherences between software
> > creation and mass production:
> >
> > 1) In a mass production line, work is handed over from
> > machine to machine (even if the machine is called Joe and
> > likes to drink a Bud in his lunch). In software production,
> > handovers are made between thinking entities with very fuzzy
> > interfaces (humans). Communication overload/overhead is more
> > of a problem here.
> >
> > 2) Stupid, drone work consumes very little of a software
> > project's schedule. Someone measured that 90% of a
> > programmer's time is spent thinking (or faking it).
> >
> > 3) The level of customization demanded by software customers
> > is higher than in any other industry. This adds to the cost
> > of adapting your factory to new technologies, new
> > requirements, new knowledge domains.
> >
> > I can see some resemblance between software development and
> > mass production from a 10,000 feet perspective, but looking
> > closer I find these two to be different beasts.
> >
> > Of course I'm not Kent Beck (grovel) so my oppinion is worth
> > about a dented dime. But it's mine and I cherish it. :)
>
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