lean system & six sigma lecture 6.. value that customer is willing to pay that changes products...
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Value
That customer is willing to pay
That changes products color, function, shape, other attributes so that the product is getting closer to the customers requirements
That we do right at first time
Wastes
Those processes which directly do not create value for customers (muda, mura, muri) : that are not necessary, and must be eliminated That are necessary, because these are
supporting value-add processes, cannot be eliminated (like transporting)
Muda – 7 wastes of lean Mura – not leveled workflow Muri – overloading of workers and assets
Lean thinking
Operation
Traditional improvement
Lean improvement
Non value-add process
Value-add process
Supporting goals
A balanced system, smooth, rapid flow of materials and/or work
Supporting goals: Eliminate disruption Make the system flexible eliminate waste,
especially exess inventory
There are 7 wastes in LEAN (TIMWOOD): Inventory Overproduction Waiting Unnecessary
transportation Processing waste Inefficient work methods Defects
Quality improvement - Jidoka
Autonomation – automatic detection of defects during production.
It consist two activities: One for detecting defects when they occure Another for stopping production to correct the cuase of defects.
Fail- Safe methods – Poka Yoke Methods:
The contact method identifies product defects by testing the product's shape, size, color, or other physical attributes.
The fixed-value (or constant number) method alerts the operator if a certain number of movements are not made.
The motion-step (or sequence) method determines whether the prescribed steps of the process have been followed.
Kanban Production Control System Kanban is the Japanese
word meaning “signal” or “visible record” Sign to produce
Sign to transport
Paperless production control system
Preventive maintenance and housekeeping 5S
Sort –decide which item is needed
Straighten – needed items can be assessed quickly
Sweep – clean workplace Standardize – use
standard intructions Self discipline – make
sure that employees understand the need for uncluttered workplace
mean
3σ3σ
LSL USL
3 sigma process 1 sigma process
LSL USL
6σ6σ
mean
5% is out of limits!
1 σ – 691 462 ppm
2 σ – 308 538 ppm
3 σ – 66 807 ppm
4 σ – 6 210 ppm
5 σ – 233 ppm
6 σ – 3,4 ppm
Project Risk and Return matrix
0 10 20 30 40 50 60 70 80 90 100 Risk factor
100
90
80
70
60
50
40
30
20
10
0
STARS
LOW-HANGING FRIUTS DOGS
?
Rw
turn factor
TAGUCHI DESIGN EXPERIMENT (DOE) Robust Design – select technology Parameter Design – set parameters which
affect quality Tolerance Design – improve the quality if
parameter design doesn’t work
Definition of quality – loss to society
QLF (Qualtiy Loss Function)
L=K*V2
K – constant, and V2- mean squared dviation from target value
K=C/T2
C - unit repair cost T – tolerance interval
Target valueLSL USL
Exercise - QLF
Suppose the cost to repair a radiator on an automobile is $200. Compute the QLF for losses incurred as a result of a deviation from target setting where a tolerance of 6±0,5 mm is required and the mean squared deviation from target is (1/6)2.
Solution: K=200/0,52=800 L=K*V2=800*(1/6)2=$22,22/unit
TAGUCHI PROCESS 1. Problem identification 2. Brainstorming session
identify factors, its settings, interactions, Control factor Noise factor
Identify objectives The less is better Nominal is best The more is the better
Experimental design Offline experimentation (number of replications)
Experimentation Orthogonal array (determined by the number of factors and levels) Record the result Compute average performance for each factor Showing the best outcomes
Analysis (which level of each factor is the proper one) Confirming experiment (validate results)
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