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Dr. Genichi Taguchi (Loss Function), 1924- 1989 65 years, Japan, Textile Engineer
Q in Descon Chemicals
Leaders in Quality Leaders in Quality RevolutionRevolution
Dr. Genichi TaguchiDr. Genichi Taguchi
Mechanical Engineer – Won Deming award -4 timesMechanical Engineer – Won Deming award -4 times Taguchi methods emphasize Taguchi methods emphasize consistency of consistency of
performance and reduced variationperformance and reduced variation, (Cost, , (Cost, target & Variation)target & Variation)
Quality Loss function (deviation from target is a Quality Loss function (deviation from target is a loss )loss )
Parameter design which is an application of Design Parameter design which is an application of Design of Experiments (DOE).of Experiments (DOE).
Taguchi Definition of Quality:Taguchi Definition of Quality:– Stresses on Stresses on engineering approachengineering approach to Quality to Quality– Produce with Produce with minimum variationminimum variation to target goals to target goals– Focus on DesignFocus on Design for Quality for Quality– Quality is Quality is Loss function. Loss function.
The application of scientific and mathematical principles to practical ends such as the design, manufacture, and operation of efficient and economical structures, machines, processes, and systems
It is a structured and organized method used to determine the relationship between the different factors (XS) effecting a process and the output of process (Y).
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTION
Upper Specificatio
n Limit
Lower Specificatio
n Limit
Goal Post View
No Loss Incurred
Loss Incurred
Loss Incurred
Traditional Loss Function
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTION
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTION Loss function; provides a process Loss function; provides a process
for computing the for computing the cost of cost of deviationdeviation from the target value. from the target value.
Taguchi’s view was that Taguchi’s view was that any any variation from the expected variation from the expected value was a loss. This places value was a loss. This places emphasis or emphasis or reducing process reducing process variationvariation, not merely accepting , not merely accepting it. it.
If If process variation can be process variation can be reducedreduced, then design tolerances , then design tolerances can be reduced. This increases can be reduced. This increases quality of manufacturing and quality of manufacturing and quality of the product. The quality of the product. The ultimate aim of Taguchi would be ultimate aim of Taguchi would be zero tolerance.zero tolerance.
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTION
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTION
– Quality is Loss functionQuality is Loss function. . Loss function Loss function measures qualitymeasures quality Loss function establishes a Loss function establishes a financial measurefinancial measure of of
the user the user dissatisfaction with product dissatisfaction with product performanceperformance as it deviate from a target value. as it deviate from a target value.
Product quality is influenced by uncontrolled Product quality is influenced by uncontrolled sources of variance i.e. sources of variance i.e. the noise factorsthe noise factors..
Concept of societal loss (failure to meet Concept of societal loss (failure to meet customer requirements and ideal performance, customer requirements and ideal performance, harmful side effects, toxic by product)harmful side effects, toxic by product)
Example of vinyl sheet thicknessExample of vinyl sheet thickness
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTIONSony Corporation- An
Example
• Sony uses the Taguchi model in managing the television sets it produces.
• Quality characteristic=Color density of the televisions.
• Color density measured between Upper and lower tolerance level.
• The Taguchi model provides a good way to analyze the costs associated with variability, even within the limits.
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTION
ActivityActivity Plant 1Plant 1 Plant 2Plant 2
Color density measured between UTL & LTL.
uniformly distributed televisions that fell between the specification limits.
normal distribution with an average near the set target.
Quality ControlQuality Control focusing on a defect rate rather than a variation from the target.
focusing variation from target rather than the defect rate
ShipmentShipment shipped at a zero defect rate, the specification limits allowed for too much variation
shipped at a zero defect rate, the limits were smaller and the quality was more consistent
Customer Customer ResponseResponse
Lower level of satisfactionwarranty expenses were high.
higher level of satisfactionwarranty expenses were lower.
Sony Corporation- An Example
TAGUCHI LOSS FUNCTIONTAGUCHI LOSS FUNCTIONSony Corporation- An
Example
LTL LTLUTL UTLTarget Target
ConclusionIf companies want to remain competitive, they have to
provide quality productsprovide quality products. To accomplish this, a
company must focus on the reduction of variability of a product’s characteristics around a specific target value. The traditional approach is not enough. To remain a world competitor, a
company must consider the Taguchi QLF approach.
Dr. Joseph M. JuranDr. Joseph M. Juran
““Fitness for Use”Fitness for Use” Seven Basic ways to improve Seven Basic ways to improve Renowned for his quality trilogy.Renowned for his quality trilogy.
Reduce Errors. Reduce Errors. (Better Control Reduce and eliminate (Better Control Reduce and eliminate rework and wastes).rework and wastes).
Meet or exceed expectations of customerMeet or exceed expectations of customer Register abnormalities (Register abnormalities (find root cause , do find root cause , do
corrective action, document for future)corrective action, document for future) Use technical tools Use technical tools (like statistical process (like statistical process
Control, benchmarking etc)Control, benchmarking etc) Education and training.Education and training. Make the Process safer.Make the Process safer.
Approaches towards Approaches towards Continuous ImprovementsContinuous Improvements
Juran’s TrilogyJuran’s Trilogy Shewhart’s Plan-Do-Study-Act CycleShewhart’s Plan-Do-Study-Act Cycle Kaizen (Change +Good)Kaizen (Change +Good) Reengineering Reengineering (Rethinking , Redesign of business processes to (Rethinking , Redesign of business processes to
Quality Improvement. Allocate Resources, People to Pursue Quality
Training
Improvement Improvement StrategiesStrategies
Rep
air
Refi
nem
en
t
Ren
ovati
on
Rein
ven
tion
Improvement Improvement StrategiesStrategies
Repair:
“Anything broken must be fixed so that it functions as designed.”
Strategies divided into two levels:
1. Temporary or Short- term measure (Correction)
2. Permanent measure (Corrective action)
Refinement: “Activities that continually improve a process that is
not broken.” Gradual change – face little resistance from
employees Refinement improves efficiency and effectiveness.
Improvement Improvement StrategiesStrategies
Renovation:
“This Strategy results in major or breakthrough Improvement.”
It look different from original but same. (Hole drilling by hands and by drill machine)
Innovation & technological advancement are key factors in this approach. (Rechargeable drill machine same as hand drill)
Reinvention (Re-Engineering): “Reinvention begins by imagining that the current
approach can never satisfy customer requirements. ( Reinvention is done by understanding customer requirement, such as process of drilling hole by laser.)