《Statistical Quality Control》课程教学课件（PPT讲稿）06 Control Chart

Control ChartThe tools of monitoring and controlling processQuality control begins with control chartand ends up with control chart武汉理工大学机电工程学院工业工程系李存荣（cunrong_li@163.com2007.4Control Chart

2007.4 Control Chart —The tools of monitoring and controlling process Quality control begins with control chart and ends up with control chart Control Chart 武汉理工大学 机电工程学院 工业工程系 李存荣（cunrong_li@163.com ） 1

Control chart: main content1, Understanding the meaning and function of thecontrol chart2,Establishing the basic theory and establishmentmethod of the control chart and observing andanalyzing the criterion of controlapplicableconditions andusage process3, X-barand Rcontrol chart4, Singlevalue-moving range control chart5, Control chart for fraction defective6, Control chart for defects per unit2007.4The main requirements of the chapter2

2007.4 1、Understanding the meaning and function of the control chart 2、Establishing the basic theory and establishment method of the control chart and observing and analyzing the criterion of control,applicable conditions and usage process 3、X-bar and Rcontrol chart 4、Single value-moving range control chart 5、Control chart for fraction defective 6、Control chart for defects per unit The main requirements of the chapter Control chart：main content 2

In 1924, contro chart was proAosed for proress control in thefirst place by Shewhart from America,wich achieved the purposeof contolking the production brocess directly, stabilizing thequality of production process and putting prevention first.It's a graphic technique that is painted insequence by sample data which is collectedregularly from a process.Control chart can showprocess variation and find variation, and thenbecome the important means of taking preventivemeasures2007.4The origin of Control Chart3

2007.4 The origin of Control Chart In 1924, control chart was proposed for process control in the first place by Shewhart from America,which achieved the purpose of controlling the production process directly, stabilizing the quality of production process and putting prevention first. It's a graphic technique that is painted in sequence by sample data which is collected regularly from a process.Control chart can show process variation and find variation, and then become the important means of taking preventive measures 3

It'sa dynamic method that directly studies statisticalregularity of quality data changing over time on thespot;Controlchart is a means that judges whether theproduction process is in the state of control,and it canbe usedto distinguish thatthe quality fluctuation iscaused by accidentalreasons or the systematic reasons2007.4Controlchart4

Control 2007.4 chart It's a dynamic method that directly studies statistical regularity of quality data changing over time on the spot; Control chart is a means that judges whether the production process is in the state of control,and it can be used to distinguish that the quality fluctuation is caused by accidental reasons or the systematic reasons. 4

1、 Paying attention to customers;2、Adoptingeffective means;3.Thegoal ofprocesscontrolisprevention;4、 Skill training and continuingeducation;5,Development strategies, implementation measures,policies andregulations, methods and steps and practical process of ensuring quality;6、 Greater progress can be made by incremental improvements step by step,thereconston of the enterprise operating procedure and inventionandinnva7、Sixprhoplebcoordinatecomprehensivelyandplayarole;customer?6management2007.4Quality control principles (Australia )5

2007.4 1、Paying attention to customers； 2、Adopting effective means； 3、The goal of process control is prevention； 4、Skill training and continuing education； 5、 Development strategies, implementation measures,policies and regulations, methods and steps and practical process of ensuring quality； 6、Greater progress can be made by incremental improvements step by step, the reconstruction of the enterprise operating procedure and invention and innovation； 7、Six principles need to coordinate comprehensively and play a role； Quality control principles（Australia） customer management 1 4 3 6 2 7 ⑤ 5

Usingthe correct process control technology,which canmakequalityimprove and cost reduce.25~40%10~25%the gap of 25%preventpreventtesttestcheckcheckbreakdownbreakdownBeforeusingsevenqualityAfter using seven qualitycontrolprinciplescontrolprincipleseliminatewasteQuality cost(calculating as a percentage of the2007.4production costs)6

Q 2007.4 uality cost(calculating as a percentage of the production costs) Before using seven quality control principles After using seven quality control principles breakdown test check prevent breakdown test check prevent 25~40% 10~25% the gap of 25% eliminate waste Using the correct process control technology, which can make quality improve and cost reduce. 6

Process control should befor the purpose of preventionratherthan simplyreworkafter finding outtheproblemThe control conditions are defined by InternationalQualityStandards:4,It amrrsinkraoueta de mrpsteha hstionrfiomfherinet focshefsuritd bttipnoiestapatimehedssa ndi product properties;, Phectse la ntHaspeaiadsegshiopud btempprbprai pterfoed ;production,,installation and seryice and we also shouldheimplementationwavsoftheprocessstandardSrala esapuatedaeanyconditions;ropriateworki.Strictlyfollowin'sstandardneal'segualiyplans-2?Eguipments.shouldtbensureandexpresslystipulatedprocedure:thatproductioncanrunsmoothly;2007.4Re-recognized process7

Re-recognized process 2007.4 Process control should be for the purpose of prevention rather than simply rework after finding out the problem. The control conditions are defined by International Quality Standards: 1、It must have a clear stipulation for the methods of production,installation and service; 2、The tools that we use should be appropriate for production, installation and service and we also should create appropriate working conditions; 3、Strictly following the standards,rules,quality plans and expressly stipulated procedure; 7 4、Carrying out a comprehensive monitoring for the suitable process parameters and product properties; 5、Process and special equipment must be approved; 6、The implementation ways of the process standard should be stipulated clearly; 7、Equipments should be maintained regularly to ensure that production can run smoothly;

On March 27,1977,two Boeing 747 aircraft collided on therunway at Canary Islands's airport, killing 583 people莎32Thesystem oflackingprevention2007.4andexaminationability8

The 2007.4 system of lacking prevention and examination ability 3 2 On March 27,1977,two Boeing 747 aircraft collided on the runway at Canary Islands's airport, killing 583 people. 8

leaded petrolunleaded petrolThree core power plugsPreventing the use ofhave only one positionleadedpetrolinato insert only three corevehicle designed forsocketunleaded petrol2007.4Based on the system of prevention9

2007.4 Based on the system of prevention Three core power plugs have only one position to insert only three core socket leaded petrol unleaded petrol Preventing the use of leaded petrol in a vehicle designed for unleaded petrol 9

Quality characteristic value can be described as ageneral form:x, =μ+r +dr ~ N(0,α)Type: x, stands for product quality characteristic valueat time t, ustands for the mean values of the distributionof quality characteristic value, r, stands for the noisecaused by random factors, d stands for the interferencecausedbyabnormal factorsx, ~ N(μu,α?)x ~ N(u+d,α)2007.4Control chart10

Control chart 2007.4 t t x r d = + +  t x  t r d Quality characteristic value can be described as a general form: 2 ~ (0, ) t r N  2 ~ ( , ) t x N   2 ~ ( , ) t x N d   + Type: stands for product quality characteristic value at time t, stands for the mean values of the distribution of quality characteristic value, stands for the noise caused by random factors， stands for the interference caused by abnormal factors. 10