工序过程能力分析

单击此处编辑母版标题样式,*,*,*,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,第六章 工序(过程)能力分析,6.1,基本概念,6.2,工序能力指数的计算,6.3,工序能力的评价与处置,6.4,工序能力调查,1,6.1,基本概念,在产品制造过程,中,中，工序是保证,产,产品质量的最基,本,本环,节。所谓工序,能,能力分析，就是,考,考虑 工序的设,备,备、工艺、,人的操作、材料,、,、测量工具与方,法,法以及环境对工,序,序质量,指标要求的适合,程,程度。工序能,力,力分析是质量管,理,理的一项,重要的技术基础,工,工作。它有助于,掌,掌握各道工序的,质,质量保,证 能力，为产,品,品设计、工艺、,工,工装设计、设备,的,的维修、,调整、更新、改,造,造提供必要的资,料,料和依据。,一工序能力,二工序能力指数,2,一,工,工,序,序能,力,力,1,概,概念,：,：,所谓,工,工序,能,能力,，,，是,指,指处,于,于稳,定,定、,标,标准,状,状态,下,下，,工,工序,的,的实,际,际加,工,工能,力,力。,工序处于稳,定,定状态，是,指,指工序的分,布,布状态不随,时,时间的变化,而,而变化，或,称,称工序处于,受控状态,；,；,工序处于标,准,准状态，是,指,指设备、材,料,料、工艺、,环,环境、测量,均,均处于标准,作,作业条件，,人员的操作,也,也是正确,的,的。,工序的实际,加,加工能力是,指,指工序质量,特,特性的分散(或波动),有,有多大。加,工,工能力强或,弱,弱,的区分,关,关键是,质,质量特,性,性的分,布,布范围,大,大小，,或,或集中,程,程度。,由,由于均,方,方差,是描述,随,随机,变量分,散,散的数,字,字特征,，,，而,且,且，当,产,产品质,量,量特性,服,服从正,态,态分布N(,，,2,)时，,以,以,3,原则确,定,定其分,布,布范围(,3,)，处,于,于该范,围,围外的,产,产品仅,占,占产品,总,总数的0.27%，,因此，,人,人们常,以,以6,描述工,序,序的实,际,际加工,能,能力。,实,实践证,明,明：用,这,这样的,分,分散范,围,围表,示工序,能,能力既,能,能保证,产,产品的,质,质量要,求,求，又,能,能具有,较,较好的,经,经济性,。,。,2 表,达,达式：B=6,或 B,6,S,3 影,响,响因素,：,：,(1),人,人,与,与工序,直,直接有,关,关的操,作,作人员,、,、辅助,人,人员的,质,质量意,识,识和操,作,作技术,水,水平；,(2),设,设备,包括,设,设备的,精,精度、,工,工装的,精,精度及,其,其合理,性,性、刀,具,具参数,的,的合理,性,性等；,(3),材,材料,包括,原,原材料,、,、半成,品,品、外,协,协件的,质,质量及,其,其适用,性,性；,(4),工,工艺,包括,工,工艺方,法,法及规,范,范、操,作,作规程,的,的合理,性,性；,(5),测,测具,测量,方,方法及,测,测量精,度,度的适,应,应性；,(6),环,环境,生产,环,环境及,劳,劳动条,件,件的适,应,应性。,3,二,工,工序能,力,力指数,1,概念,：,工序能,力,力指数,是,是衡量,工,工序能,力,力对产,品,品规格,要,要求满,足,足程,度的数,量,量值，,记,记为,C,p,。通常,以,以规格,范,范围T,与,与工序,能,能力B,的,的比,值来表,示,示。即,：,：,T,=规格,上,上限,T,U,-规,格,格下限,T,L,。,2,工序能,力,力与工,序,序能力,指,指数的,区,区别,：,工序能,力,力是工,序,序具有,的,的实,际加工,能,能力，,而,而工序,能,能力指,数,数是指,工,工序能,力,力对规,格,格要求,满,满足,的程,度,度，这,是,是两个,完,完全不,同,同的概,念,念。工,序,序能力,强,强并不,等,等于,对规格,要,要求的,满,满足程,度,度高，,相,相反，,工,工序,能,能力弱,并,并不等,于,于对,规格要,求,求的满,足,足程度,低,低。当,质,质量特,性,性服从,正,正态分,布,布，而,且,且其,分布中,心,心,与,与,规,规格中,心,心,T,m,重合时,，,，一定,的,的工序,能,能力指,数,数,将与一,定,定的不,合,合格品,率,率相对,应,应。因,此,此，工,序,序能,力,力指数,越,越大，,说明工,序,序能力,的,的贮备,越,越充足,，,，质量,保,保证能,力,力越强,，,，潜力,越,越大，,不合格品率,越,越低。但这并,不,不意味着加工,精,精度和技术水,平,平越高。,4,6.2 工,序,序能力指数的,计,计算,一 计量值,1 双侧规格,界,界限,（1）无偏,（2）有偏,2 单侧规格,界,界限,（1）仅给出规格上,限,限,T,U,（2）仅给出规格上,限,限,T,L,二 记数值,1记件值,2记点值,5,1计量值双,侧,侧规格界限,双侧规格界限,是,是指既具有规,格,格上限(,T,U,)要求，又有,规,规格下限(,T,L,)要求的情况,(1)无偏,规格中心,T,m,与分布中心,重,重合,计算公式：,工序不合格品,率,率,p,的估计：,直接根据规,格,格上、下限,T,U,、,T,L,以及工序分布,的,的数字特征，,估,估,计 和,S,进行计算,根据工序能,力,力指数,C,p,计算。,由式:,因此有,例1,P,1,P,2,T,L,T,U,T,m,f（x）,T,6,例1,根据某工序加,工,工零件的测试,数,数据计算得出,，,，,=6.5,S,=0.0055，规格要求,为,为,。,。,试求该工序的,工,工序能力指数,及,及不良品率。,解：,7,计算公式：,绝对偏移量,：,(图中曲线1),偏移系数,：,工序能力指数,：,：,或：,当,k,，即,eT/2,时，,规定,C,pk,=0(图,中,中，曲线2),不合格,品,品率估,计,计：,采用,“,“用,C,p,和,k,值估计,不,不合格,品,品率”,例2,f（x,）,）,有偏时,工,工序能,力,力指数,与,与不合,格,格品率,e,1,2,e,T,L,T,U,P,1,P,2,T,m,x,T,(2),有,有偏,规格,中,中心,T,m,与分,布,布,中心,不,不,重,重合,计量,值,值,双,双侧,规,规格,界,界限,8,例2,测试,一,一批,零,零件,外,外径,尺,尺寸,的,的平,均,均值=19.0101，,S,=0.014,3，,规,规格,要,要求,为,为,，,，试,计,计算,工,工序,能,能力,指,指数,并,并估,计,计不,合,合格,品,品率,。,。,解：,由,由题,意,意：,计算,C,pk,或由,C,p,=0.816,，,，,k,=0.145,查,查表,得,得不,良,良品,率,率估,计,计约,为,为2.1%2.3%,9,用,C,p,和,k,值估,计,计不,合,合格,品,品率,C,p,k,0.03,0.04,0.08,0.12,0.16,0.20,0.24,0.28,0.32,0.36,0.40,0.44,0.48,0.25,.0.50,13.86,13.34,13.64,13.99,14.48,15.10,15.86,16.75,17.77,18.92,20.19,21.58,23.09,24.71,0.60,7.19,7.26,7.48,7.85,8.37,9.03,9.85,10.81,11.92,13.18,14.59,16.51,17.85,19.69,0.70,3.57,3.64,3.83,4.16,4.63,5.24,5.99,6.89,7.94,9.16,10.55,12.10,13.84,15.74,0.80,1.64,1.69,1.89,2.09,2.46,2.94,3.55,4.31,5.21,6.28,7.53,8.98,10.62,12.48,0.90,0.69,0.73,0.83,1.00,1.25,1.60,2.05,2.62,3.34,4.21,5.27,6.53,8.02,9.75,1.00,0.27,0.29,0.35,0.45,0.61,0.84,1.14,1.55,2.07,2.75,3.59,4.65,5.94,7.49,1.10,0.10,0.11,0.14,0.20,0.29,0.42,0.61,0.88,1.24,1.40,2.39,3.23,4.31,5.66,1.20,0.03,0.04,0.05,0.08,0.13,0.20,0.31,0.48,0.72,1.06,1.54,2.19,3.06,4.20,1.30,0.01,0.01,0.02,0.03,0.05,0.09,0.15,0.25,0.40,0.63,0.96,1.45,2.13,3.06,1.40,0.00,0.01,0.01,0.01,0.04,0.07,0.13,0.22,0.36,0.59,0.93,1.45,2.19,1.50,0.00,0.01,0.02,0.03,0.06,0.11,0.20,0.35,0.59,0.96,1.54,1.60,0.00,0.01,0.01,0.03,0.06,0.11,0.20,0.36,0.63,1.07,1.70,0.00,0.01,0.01,0.03,0.06,0.11,0.22,0.40,0.72,1.80,0.00,0.01,0.01,0.03,0.06,0.13,0.25,0.48,1.90,0.00,0.01,0.01,0.03,0.07,0.15,0.31,2.00,0.00,0.01,0.02,0.04,0.09,0.20,2.10,0.00,0.01,0.02,0.05,0.13,2.20,0.00,0.01,0.03,0.08,2.30,0.01,0.02,0.05,2.40,0.00,0.01,0.03,2.50,0.10,0.02,2.60,0.00,0.01,2.70,0.01,2.80,0.00,单位,：,：,%,10,(1),仅给,出,出规,格,格上,限,限,T,U,计算,公,公式,：,：,当,T,U,时,时，,p,50%,，,，则,规,规定,C,p,0,不合,格,格品,率,率估,计,计：,例,某,某零,件,件质,量,量要,求,求加,工,工后,不,不得,大,大于71g，,测,测试,部,部分,数,数,据后,得,得,70.2g，,S,0.24g,，,，试,计,计算,工,工序,能力,指,指数,C,p,及不合格,品,品率,p,。,解：,2计量,值,值单侧,规,规格界限,f（x）,T,U,x,11,计量值,单,单侧规格,界,界限,(2)仅,给,给出规格,下,下限,T,L,计算公式,：,：,当,T,L,时,时，,p,50%,，,，则规定,C,p,0,不合格率,估,估计：,例3,要求零件,淬,淬火后的,硬,硬度,HRC,71，实,测,测数据后,计,计算,得 ,HRC,73；,S,1，试计算,工,工序能力指数,C,p,及不良品率,p,。,解：,f（x）,T,L,x,-,T,L,12,计数值计件,值,值,计算公式,以不合格品率,上,上限,p,U,作为规格要求,：,：,(1)取,k,个样本，每个,样,样本的样本容,量,量分别为,n,1,，,n,2,，,n,k,，每个样本中,的不合格品,数,数为,d,1,，,d,2,，,d,k,。,(2)计算平,均,均不合格品率,及,及平均样本量,(3)计算工,序,序能力指数,C,p,例1,某产品规格要,求,求,p,U,0.1，现,取,取5个样本，,n,1,n,2,n,5,100,各,各样本,中不合格品数,为,为：,d,1,7，,d,2,5，,d,3,6，,d,4,2，,d,5,4，求工序,能,能力指,数,C,p,。,解：,13,计数值计点,值,值,计算公式,规格要求是单,位,位产品平均缺,陷,陷(或疵点数)上限或不合,格,格品率,很小时的样本,中,中不合格品数,上,上限,C,U,(1)取,k,个样本，每个,样,样本的样本容,量,量分别为,n,1,n,2,，n,k