 I am S.R. Doolange, working as an associate professor in the Department of Mechanical Engineering at Vulture and the Institute of Technology, in this video we will discuss on process capability for variables. Learning outcome At the end of this session, students will be able to apply and analyze the process capability for variables which are associated with quality. Contents Process capability for variables Example and all Process capability for variables References Process capability for variables Process limit Which is also called as the vice of the process Or the vice of the data Based on natural, that is common cause of variation So in the last video we have seen variability is bound to happen in the process. It could be due to material, machines, man, equipment. So this is the process limit is nothing but vice of the process or vice of the data. Based on different causes of the variation. Tolerance limit It is called as the vice of the customer Or the customer requirement The customer used to give the specification limits or the tolerance for a particular product That is nothing but a specification limit or the tolerance limit Process capability is a measure of how capable the process is to meet customer requirements Compare Compares processes limits to tolerance limits Process capability is also called as six sigma or six sigma dash So there should be a relation between the six sigma dash and the tolerance limit or the specification limit And that relation is to be established by means of process capability for variables Process capability for variables Now these are the four parameters The first figure shows specification limits That is nothing but upper specification limit minus lower specification limit In accordance with the common variation that is six sigma or six sigma dash Now the USL minus LSL is higher than six sigma dash So the process is within control Now in the second, the specification that is nothing but USL minus LSL Is smaller than the six sigma dash In the third, specification is equal to common variation That is USL minus LSL is equal to six sigma dash In the fourth, the specification has got the different center And the common variation has got the different center The process is not centered according to the specifications and the common variations Think which is better Now in the four options which are given for the process capability Or the relationship between the USL minus LSL with respect to six sigma dash Which is better Naturally the first one specification limit USL minus LSL is greater than six sigma dash is better And it should be centered and both should be centered at one point Now let us take one example in order to understand the relationship between The tolerance limit, that is specification limit And the six sigma dash A certain product has been statistically controlled At a process average of 36 And a standard deviation of 1 The product is presently being sold to two users Who have different specification requirements User A has established a specification of 38 plus minus 4 For the product And user B has specifications of 36 plus minus 4 Now based on the present process setup What percent of the product produced will not meet the specification setup by User A and user B Now here the percentage is to be calculated based on the statistical tables Now here we will just see How much portion is out of the upper specification or lower specification Now in the second B Assuming that the two user needs are equal A suggestion is made to shift the process target to 37 At the suggested value What percent of the product How much area we can say Produce will not meet the specification setup By user A and B Now here user A Is having the specification of 38 plus minus 4 So I will say that USL is equal to 42 that is 38 plus 4 And LSL is equal to 38 that is minus 4 That is 38 minus 4 is 34 The process average is 36 That is the center of the process Based on the process setup What percent of product will not meet the specification setup By user A and B Let us take user A first So this is the upper specification 42 This is the lower specification limit 34 And the process average is 36 So this is the process average Now one is the standard deviation Means 6 sigma dash is equal to 6 into 1 That is 6 So here it is 2 Here it is This is 36 process average So here we can say that So something like this So this is the upper specification limit This is going below the lower specification limit This is USL This is LSL So upper specification, lower specification So this lower specification is called as scrap Now if we take user B For user B Upper specification limit is That is user B 36 plus minus 4 Upper specification limit is 40 That is 36 plus 4 Lower specification limit is 36 minus 4 that is 32 36 minus 4 that is 32 Now here I will know 40 Process average is 36 And this is 32 Now 6 sigma dash is like this Now process is at the center This is 6 sigma dash Here this is 6 sigma dash Now when the process average is 36 Some portion is scrap For user A And for user B There is no scrap or no rework Now let us shift the process average to 37 Now here B is assuming the needs are equal Suggestion is made to shift the process average to 37 This is 37 So what will happen? It will move like this So this is 6 sigma dash Now the process is centered The process is centered And we are getting all the components Within the upper specification and lower specification In the second case If it is shifted that is for user B 37 So what will happen? Some portion may go out For user B That is a rework is to be carried out So keeping the process average at 36 What will happen? There will be scrap for user A And there is no scrap or rework for user A When we shift the target to 37 There will not be any rework or the scrap And when we move the process average From 36 to 37 In that case For user B There is a possibility of some rework So based on this If we calculate the area we will find out How much area is out of the Upper specification limit Or lower specification limit Based on that We can calculate the percentage of components Which are coming Above the upper specification Or lower specification limit So there is a relationship between This is a relationship between The process capability And the upper specification and So in a nutshell We can say that it should be greater than 6 sigma dash These are the references which are used For creating this particular video Thank you