D.C.MONTGOMERY.J.B.KEATS,G.C.RUNGER.AND W.S.MESSINA provement process,while EPC is often n "bottom 1.Leave the funnel fixed and aimed a the rgel up"procedure,driven by process control or mnn- engineers.In effect,the role of SPC is 2.If the distance from the resting place of the marble to the target isY,then move the funnel n distance rom its current position cess to counteract ongoing forces that 3.The same rule2,but move the funnel adistance process to drift off-target if compensations are no -y from the target e,SPC does not control the process,but olinleOoorioctnhatsgua ova of the root the hand,EPC does not remove the root or assignable these four rules.Rule 1 alw Rule produces a ingooo process var tained with rule 5之 plodes. sin th 8na h integration is useful becnuse im awny from the target,but it m cly result. An and behaves like a random walk. the cffect itor the process for detectio to mon to de happen when one“tampers'”with a stable p sultinadditionalroductionofovcrallvariability.in- this con- ess,and when do and Doganaksoy (1992). and Ia assignable cnuscs (and make adjustmcuts)audwe (1990)have emphasized the importanceof to leave the process alone trated by simulation thnt if the process mean fixed,control ctions will be worse than no coutrol, even rule in a reasonably geuernl situntio showed that the minimum mean square extreme cases,al. utpe situation to th 2hefnamdpositioimned sum of all The Process Model control rule is what is referred to as inte MacGregor(1990)presented an instru of gain of unity.Integral coo aplication ong beer industries.In 1950) In this exp a ring stand is placed over coutrol for of cve"A funel is with a ized by rapid gnin,that is,quick res arcdopolhroughuhcfmnaclAaraClilrori crs ol on th according to one of several rules. e proposed by Deming re the following. chlorine gas flow to pulp mnss in a blench lant.In Joural of Quality Technology Vol.26,No.April 1994