《Statistical Quality Control》课程教学课件（PPT讲稿）08 Quality Cost

Principle of quality costWuhan univenityofteehnologyMechanicalandelectricalengineering collegeIndustrial Engineering机电工程学院工业工程系Cuntengnltjaa162ofom

Principle of quality cost 机电工程学院 工业工程系 Wuhan university of technology Mechanical and electrical engineering college Industrial Engineering Cunrong_li@163.com zhengnl@21cn.com

Themeaningof qualitycost1) The incrested cost for the quality of productwhen the the product quality of the productionless than 100% qualified.2) The quality cost is the difference between theactual cost of production and the cost of theperfect quality level

The meaning of quality cost 1）The incrested cost for the quality of product when the the product quality of the production less than 100% qualified. 2) The quality cost is the difference between the actual cost of production and the cost of the perfect quality level

“Gold mineIf we control the loss caused by quality faulteffectively, and reduce it to a minimum, thebenefit is "a mountain of gold mining

“Gold mine” If we control the loss caused by quality fault effectively, and reduce it to a minimum, the benefit is "a mountain of gold mining

ProductCost and valuehighleadincrementProductdifferentiationOrdinarycostlowleadershipgoodslowhighcost advantageDifferenttypes of competition

Product increment Cost and value lead Ordinary goods cost leadership cost advantage low high low high Product differentiation Different types of competition

3."Iceberg in Glacier”水面以上水面以下SieDiagramoficebergsintheiceriverITip of theiceberg (The obvious part of the loss offault quality)IThe iceberg is hidden in the bottom of the water.(Theobscurepart of thelossoffaultquality)

3.“Iceberg in Glacier” ◼ Diagram of icebergs in the ice river ◼ Ⅰ—Tip of the iceberg（The obvious part of the loss of fault quality） ◼ Ⅱ—The iceberg is hidden in the bottom of the water. （The obscure part of the loss of fault quality）

Average statistical resultsThe obvious quality failure costs just like the tipof the iceberg in the ice river, while the iceberghidden in the bottom of the water is the obscurepart of the loss of fault quality, about 90% of thetotal loss If we can control the obvious part of quality loss.especially the obscure part, and reduce it , theenterprise's total cost can be reduced greatly, theobtained enterprise benefits and social benefitswill be very considerable

Average statistical results ◼ The obvious quality failure costs just like the tip of the iceberg in the ice river, while the iceberg hidden in the bottom of the water is the obscure part of the loss of fault quality, about 90% of the total loss。 ◼ If we can control the obvious part of quality loss, especially the obscure part, and reduce it , the enterprise's total cost can be reduced greatly, the obtained enterprise benefits and social benefits will be very considerable

Quality fluctuation and quality costThe quality fluctuation comes from two aspectsthe system factor, the accidental factor. Japanese quality experts put forward therelationship between quality fluctuation andquality loss:L(y) = k(y-m)2

Quality fluctuation and quality cost ◼ The quality fluctuation comes from two aspects: the system factor, the accidental factor. ◼ Japanese quality experts put forward the relationship between quality fluctuation and quality loss： L(y) = k(y-m)2

Quality fluctuation and costquality lossfunctionL(y)L(y) = k(y-m)2MM-△M+△L(y)-ThefluctuationlossofqualitycharacteristicsforyThe quality characteristic value of the actual measurementy-Standardvalueofqualitycharacteristic.m△Thedeviation betweentheactualvalueandthestandard valuek-Ratio constant

Quality fluctuation and cost L(y) y M-Δ M M+Δ L(y)——The fluctuation loss of quality characteristics for y. y——The quality characteristic value of the actual measurement. m——Standard value of quality characteristic. Δ——The deviation between the actual value and the standard value. k——Ratio constant. quality loss function L(y) = k(y-m)2

The basic task of quality cost managementProper standard quality lossHow to take effective measures to control andreduce the loss of qualityExpressing the work in the form of moneyAbove constitute the basic task of qualitycostmanagement

The basic task of quality cost management ◼ Proper standard quality loss ◼ How to take effective measures to control and reduce the loss of quality ◼ Expressing the work in the form of money  Above constitute the basic task of quality cost management

Definition of quality costQuality cost refers to the cost incurred in order toensure and guarantee the satisfactory quality, andthe loss caused by no reaching the satisfactoryquality

Definition of quality cost ◼ Quality cost refers to the cost incurred in order to ensure and guarantee the satisfactory quality, and the loss caused by no reaching the satisfactory quality