{"id":857,"date":"2017-02-09T05:46:23","date_gmt":"2017-02-09T12:46:23","guid":{"rendered":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/?p=857"},"modified":"2017-02-09T05:46:23","modified_gmt":"2017-02-09T12:46:23","slug":"usllsl-need-cp1","status":"publish","type":"post","link":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/usllsl-need-cp1\/","title":{"rendered":"What USL\/LSL Do I Need for Cp>1?"},"content":{"rendered":"<p>Customer asked me what seemed like a strange question: What specification limits do I need to get a Cp greater than one? Usually her customer should set specification limits, but her boss wanted to know what they could deliver. Hmmmm!<\/p>\n<p>Then I realized that since QI Macros templates (e.g., XmR chart) calculate the average and sigma estimator, the LSL\/USL for Cp = 1.0 would be:<\/p>\n<p>LSL = Average &#8211; 3*SigEst\u00a0\u00a0\u00a0\u00a0 USL = Average+ 3*SigEst<\/p>\n<p>For Cp = 1.33, just change the 3 to a 4; Cp = 1.66, change the 3 to a 5. Here&#8217;s an XmR chart template with some sample data and calculations to reverse engineer spec limits:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-858\" src=\"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-content\/uploads\/Cp-to-LSL-USL.jpg\" alt=\"Cp-to-LSL-USL\" width=\"557\" height=\"351\" srcset=\"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-content\/uploads\/Cp-to-LSL-USL.jpg 557w, https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-content\/uploads\/Cp-to-LSL-USL-300x189.jpg 300w, https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-content\/uploads\/Cp-to-LSL-USL-115x72.jpg 115w\" sizes=\"auto, (max-width: 557px) 100vw, 557px\" \/><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Customer asked me what seemed like a strange question: What specification limits do I need to get a Cp greater than one? Usually her customer should set specification limits, but her boss wanted to know what they could deliver. Hmmmm! Then I realized that since QI Macros templates (e.g., XmR chart) calculate the average and [&hellip;]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,7,162],"tags":[195,223,225,168,224],"class_list":["post-857","post","type-post","status-publish","format-standard","hentry","category-qi-macros","category-six-sigma","category-statistics","tag-capability-analysis","tag-cp-cpk","tag-lslusl","tag-qi-macros","tag-specification-limits"],"_links":{"self":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts\/857","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/comments?post=857"}],"version-history":[{"count":1,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts\/857\/revisions"}],"predecessor-version":[{"id":859,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/posts\/857\/revisions\/859"}],"wp:attachment":[{"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/media?parent=857"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/categories?post=857"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.qimacros.com\/lean-six-sigma-blog\/wp-json\/wp\/v2\/tags?post=857"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}