Lean product development Flashcards
what is set-based design process?
Three strategies:
- Gradually narrow the initial requirements
- Aggressively test the concepts to eliminate inferior alternatives
- Reduce the extensions/space of each concept through development work, testing
A common design problem?
we cannot simultaneously optimize everything
What is a trade-off curve?
- Relating different variables
- often counteracting variabels - find the form of the curve through tests or mathematical relationships
(the curve changes with time)
Michael Kennedy LPD process?
Knowledge buildup in time
—> run projects to build things with the knowledge
—> each project will become Better and better with knowledge and time
LAMDA?
Learning cycle of knowledge creation - look —> go and see - ask —> why? and who knows? - model —> visualize knowledge and models - discuss —> get input and decide - act —> implement your decision
LPD according to Jeffrey Liker
The triangle:
1. skilled people
2. process
3. Tools and technology
are the main focus to be able to have a lean product development system
(with more on skilled people/ management applications than other methods)
How can we shorten the time to market at the same time as we get premium product quality?
- Lean production
2. Lean product development (LPD)
name some good reasons to shorten the “time to market”!
- First on the market opportunity
—> become top seller
—> possibility to charge a comparatively high price
—> set technology standard - The product development process aims at a moving target
—> need for continuous change and improvement
—> the quicker PD process, more accurately launching - Keep up with competitors
- Cost,
—> Engineering time is expensive
What is the Toyota philosophy?
Product development is not about developing cars, it is about developing KNOWLEDGE about cars
How is the work done according to the Toyota philosophy?
- keeping everything simple
- Making it visible
- Trusting everybody to do the right thing
Problems with listening to customers?
- Customers are bad at innovations
—> extending knowledge a step further is not developing science (faster horses ideas did not result in the locomotive) - The customer often mix up true quality and substitute quality
—> thinks they want a bigger engine because they want higher speed but maybe they rather need optimized streamline design eg.
What is the difference between True quality (TQ) and substitute quality (SQ)?
True quality is what the customer really wants but instead they often ask for substitute quality believing that SQ is a prior condition of true quality (TQ)
Name some often observed PROBLEMS in western PD projects?
- schedules, detailed requirements and system concept are set early
- Decisions on the product are made
—> before customer needs are well understood
— >without understanding why past product failed
—> before feasibility is proven
How do western companies spend their PD time?
- 20% value adding
- 20% not value adding but neccessary
- 60% waste
give some examples of waste?
- poor tools and methods
—> e.g. not using experimental methodology
—> making too many experiments instead of putting time on designing the experiments - Wishful thinking
- making decisions without data
- discarding knowledge
—> “unsuccessful” experiments ( but there is no such thing)
—> not properly documenting
—> “dead ends”
- testing to specifications
—> missing relevant circumstances and perspective that we have missed in the specification
What does discarding of knowledge usually depend on?
Lack of understating and useful systems and routines for capture proper storage, generalization, dissemination and reuse of knowledge
How should we make PD tests?
Always test to failure!
- Always susccessively increasingly the variable until something “breaks” reach a sure limit
- always try to find limits
why are design limits important to know?
because if we stay within the limits when we design our product won’t break
Name some differences between experimenting with traditional product development and lean product development!
1. Number of concept Traditional: —>one/few concepts: Lean: —> many concepts
2. experiment method Traditional: —> non-destructive methods Lean: —> test to failure
3. Experimental stage in the PD process Traditional: —> late Lean: —> early
4. economical perspective Traditional: —> complicated and expensive Lean: —> simple and inexpensive 5. Why we experiment Traditional: —> to VERIFY something we think we already know Lean: —> to learn things we don't know
what did the Wright Brothers want to do?
To build a manned, heavier-than-air flying device
What knowledge gaps did the wright brothers identify?
- How can we create lift?
- How can we create propulsion?
- How can we control the device in flight?
What did the wright brothers use for their experiments?
- kite
- manned gliders
- airfoil models on bicycles
- windtunnels
What did the wright brothers have to design?
- an engine
- propellers (good even by todays standards)
- wing warping to control the airplane
In what sense did the wright brothers use a lean knowledge-based approach?
- they acquired knowledge before they designed
- They experimented at an early stage to gain knowledge
- they used simple and inexpensive experimenting
Describe the Write Brothers PD process!
TDB (Test- Design- Build)
-Test to learn
- Decide on what to accomplish but not the solution
—> solution-independent problem formulation - Study the existing knowledge
—> which might turn out to be incorrect - identify the key problems to solve
- identify the knowledge gaps
- Close the knowledge gaps
—> learn through inexpensive and safe experimentation and testing of components to understand performance and limitations - Base design choices on what you have learned
—> knowledge-based design - Design and build the full product
what is set-based concurrent engineering?
- try to come up with as many alternative solutions as you can
- Successively eliminate inferior alternatives
- Make all necessary decisions as late as possible
What does set in set-based concurrent engineering mean?
- The set of technically different concepts
2. The set of different alternatives without within each concept, represented by different parameter combinations
what can we say about meticulously recorded data?
Non-glamorous lab work is absolutely crucial to the success of a project
Name an advantage of set-based data?
Set-based data from LPD experiments can in many cases also be generalized to represent many other cases!
—> which adds further value
name some various ways of describing the concepts?
- collection of data from experiments
- diagrams
- sketches
How can a trade-off curve be pushed into the “not possible right now” area,
- through further development of the existing design
2. Through development of new concepts, with or without new technology
What does it mean when a trade-off curve is pushed into the “not possible right now” area?
It means that a concept has better performance
What are trade-off curves primary a tool for within Toyota?
- Understand
- Communication
—> between developers and managers - Communication and negotiation
—> between specialists and functions (?)
—> between customers and suppliers - Train new engineers
- Record knowledge
- Conduct design reviews
- Design quality into the product
- tool to compare data
what can we see from the stress analysis diagram regarding the stress in the cylindrical tank? (PPT- t/D=sqrt(3/4)*p/sigma_b))
- Safe area above the line (it won’t break)
—> design space - The wall thickness increases directly proportional to the diameter for constant pressure and fracture stress
- If the ratio t/D is kept constant, the pressure can be increased directly proportional to the fracture stress
- If the ratio (t/D)/(p/sigma_b) is constant, any of the four variables can be expressed in the other three
- We have a tool for comparing data from different tank ruptures in the hope of finding a pattern
How does a constant safety factor impact the trade-off(?) curve?
The curve gets steeper
In what way can we use the diagram (trade-off curve?) to illustrate the operating conditions?
The location of the point of operation gives us a visual impression of the safety margin
Name some possibilities to increase the safety margin for the stress in cylindrical tank problem?
(make the curve steeper)
- t/D=(sqrt(s)/4)*(p/sigma_b)
- Increasing the fracture stress (sigma_b) at the same pressure
- Lower pressure
(decrease the pressure/stress ratio)
- Make the wall thicker
- Decrease the diameter
(increase the thickness/diameter ratio)
What is within the R&D scope and engineering scope within a lean product development process?
R&D:
Continuous development of existing knowledge and development of new
—> test to failure
—> gain a knowledge base
Engineering:
Application of knowledge within a project
—> Generate concepts, combine, find more limits, evaluate and eliminate
—> further develop
—> documentation and feedback of new knowledge from the project
