so today we're going to understand what is this Process Yield now what is the First Time Yield
and how it is different from the First Pass Yield we'll also look at what is Rolled Throughput Yield
and we will understand all these three terms first time yield, first pass yield and the Rolled
throughput yield with the help of unlimited examples so please watch this video till the end
so if you are watching this video for the first time on my youtube channel then please make sure
that you hit that subscribe button and please press that bell icon so that you are notified
whenever i post a new video on my youtube channel so in this channel i post videos
related to six sigma clean manufacturing project management and business management
so let's first understand the term Yield so yield is the percentage non-defective items of all the
item that are produced it is used in manufacturing to measure the performance of a process
it is defined as the ratio of the number of non-defective item produced divided by the total
item that are produced let's understand this with help of some animated example here assuming that
we have a machine for which we have 10 parts that will be processed through this machine
so once it is processed we get eight good parts and two bad parts
so your number of non-defective items will be eight and total item that are ten
so the yield will be eight that is your good parts or the non-defective items
divided by total item that are produce is 10 so you get a yield of 0.8 or 80 %
yield are normally of three types first time yield and also known as fty
road throughput yield rty and first pass yield fpy
Let us understand all these three one by one with the help of animated examples
Let's understand the term first time yield so first time yield is defined as the number of
units leaving the process as good parts which include some of the those which have been reworked
divided by the number of units put into the process let's understand through this example
where we have 10 parts which have been processed and we get eight good parts and two bad parts
so after those eight two were those parts which have been reworked and put it back
as good parts . So we'll put the formula it is number of units leaving as good parts
which includes rework divided by total item produce so in this case you have number
of good parts as 8 which includes 2 rework divided by 10 that is a total item produced
so your first time yield will be 0.8 or 80 percent so in this case the first time you takes only
what went into the process and what comes out so which includes what have been reworked as well
Now let us look at what is first pass yield so the first pass shield is defined as the number of
units leaving the process as good parts but with no rework divided by the number of units
put into the process so first pass yield is also known as the throughput shield
let's understand this with the help of the same example so we have 10 parts so we will process
all these 10 parts so we get eight good parts and two rework and two as bad parts or rejected parts
now the first pass yields is the number of units leaving as good parts but without rework so in
this we have eight good parts but out of these eight good parts two-way rework so we'll subtract
those as well so eight that is good part minus two that is reworked divided by the total items that
are produced so we get a first pass yield as 0.6 or 60 percent so that is it is that is it is how
it is different from first time yield where you take the constitution of rework now let us see
what is rolled throughput yield before that we have just learned what is first pass yield
which is only used for individual sub processes but if there are more than two process or three
process or n number of processes for that we have a Rolled Throughput yield so roll throughput yield
is the probability that the process with more than one step will produce the defect free unit
It is a product of each process throughput yield or the first pass field it is given by process
one throughput yield X by Process 2 throughput yield X Process 3
throughput yield and so on depending upon how many process you have let's understand this also with
the example so assuming that we have three process process one two and three so we'll take those tens
parts will process it through first process prawn we get eight good parts and two rejected parts and
out of those eight good parts to a rework we will calculate now the tpy or the throughput yield for
process 1 which is 10 good parts or total parts minus 2 rework minus 2 rejected divided by 10
so we get 0.6 as your throughput yield for process 1. now we take those eight good parts from process
one and process it through process two we get zero rejected parts eight good parts but one rework
so in this case your throughput yield for process 2 would be 8 minus 1 rework minus 0
injected parts so you get 8 by 7 by 8 and 0.87 as your throughput yield for process two
now you take these parts and process it to process three you get one rejected part and then eight
good parts out of which one is rework so you calculate the tpy for process three as eight
minus one minus one so you which comes up to be 0.75 so now that you have individually calculated
tpy for each process now it's a time to calculate the rolled throughput yield the formula is given
the top so we'll put that in the formula and we'll add multiply all these three we get 0.6
multiplied by 0.875 multiplied by 0.75 and we get 0.39 or approximately 40 percent so your rolled
throughput for all entire process is 40 percent so if you are still watching this video please make
sure you hit that subscribe button and do press that bell icon as well and you can also watch
my other videos as well but before that please don't forget to hit that like button as well