09 综合类资料 文字讲义包 SPC Link-7

超级链接#7-1/4案例三: 公司名称: (课外作业) 作业学员: 某家抽电线工厂,其所生产的铜丝要求强度35kg以上,厂内制造部依据开发条件(技术)订出规格为5615kg,并规定在制程中时(每天一次)抽出5个样本测定拉断力,作X-R管制图来管理制程,依管制图之原理,一段时间后,制程有可能变化,必须重新计算管制界限,并且与规格比较,以协助我们明了质量状况。最近30组X-R管制图之记录如下:123456789101112131415X1485551505356455750545454575261X2535758545557465254566150545649X3514753515051485350605147585059X4545256495955505455555948555653X5505451495653495952525356525156X51.253.053.850.654.654.447.655.052.255.455.651.055.253.055.6R610759657581096612161718192021222324252627282930X1564955605452535956515752564853X2524656535059534958525951605351X3545753555158585253505458525854X4585257545551544863505453594955X5506049625256515457515561545751X54.052.854.056.852.455.253.852.457.450.855.855.056.253.052.8R81489587111025108104超级链接#7-2/4解 1.制程能力分析与规格的比较 51.2+53.0+53.8+ +52.8 X = 30 = 53.69 6+10+7+ +4 R = 30 = 7.67 R = = = d2 X-U - Ca = 100% = 100% T/2 /2 准确度 = % 级 T Cp = 6 = 6 精密度 = 级 Cpk = (1-Ca) . Cp = (1 - ) 制程能力指数评等 = 级2.不良率估计 Z1 = 3Cp(1+Ca) = 5.25 p1 = % Z2 = 3Cp(1-Ca) = 3.85 p2 = % P = p1+p2 = % ppm超级链接#7-3/43.新管制界限 按 原设定 UCLX = UCLR = CLX = CLR = LCLX = LCLR = 制程中 第 4点X = 50.6 第 7点X = 47.6 第25点X = 50.8 属X的异常点,应予排除(假设为非机遇原因)R则无异常点,将第4第7第25点舍去不计,重新计算及分析如下: 51.2+53.0+53.8+54.6+ +52.8 X = 27 = 6+10+7+9+6+7+ +4 R = 27 = UCLR = D4R =2.115 = CLR = R = LCLR = D3R = 0 = UCLX = X + A2R = + = CLX = X = LCLX = X A2 R = - =超级链接#7-4/44.产品保证能力分析:制程规格 35kg以上-5.7-3+3kg20 30 40 50 60 70 8020 30 40 50 60 70 80 质量规格53.7 53.7 35 Z = = 5.68 3.29 其低于35kg以下之机率 p = 0.0072ppm 0.01ppm 5.结论: 因Cpk = 1.29 ( 1.33 Cpk 1.00 ) 为B级能力,应加以注意,并维持或改善。设制程规格若需高成