OEE calculation for line with more than 1 tact

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• #23751

Yibra
Member

Hello,
I am trying to calculate OEE and I have a question. In any calculation template I saw, the determination of the Ideal Run Rate of a line (that’s how many pieces it assemble per minute /PPM/) is considered if I manufacture products that have the tact of production. But what if I have an assembly line that assemble more types of products within 1 shift with different Ideal Run Rate?
For example: Within 1 shift (8 hours) I will assemble 2 hours product type A with ideal Run Rate of 60 PPM, then 3 hours type B with Ideal Run Rate of 40 PPM and 1 hours with type C of ideal run rate 80 PPM). How can I calculate the Ideal Run Rate if the ration between type A : type B : type C is not constant? Sometimes I only assemble type A or B&C.
Does anybody know a simple method to caluclate the OEE for such a line?
Thanks alot.

0
#56830

Paul Gibbons
Participant

Yibra,
The easiest way is to have a different OEE table for each product made during that shift. From this you will also be able to see, from the failure modes, if there is any correlation between the different products produced and your OEE level.
To gain the overall OEE for the whole shift I would take the average % of the performance element and calculate the other elements based on your actual numbers to get an overview. I have used this approach successfully.
Here is your example using my approach……

Product

A
B
C
Total

Base Hours
Standard minutes available
120
180
60
360

Planned Downtime
0
0
0
0

120
180
60
360

Availability
Waiting setter
0
0
0
0

Maintenance
0
0
0
0

No Programme
0
0
0
0

No Operator
0
0
0
0

Waiting Material
0
0
0
0

Waiting Toolroom
0
0
0
0

Total Downtime
0
0
0
0

Running Time
120
180
60
360

Downtime Efficiency
100%
100%
100%
100%

Performance
120
80
70
270

Cycle Time (minutes)
1
1.5
0.75

Performance Efficiency
100%
67%
88%
85%

Quality
Quality Test Sample
0
0
0
0

Total lost for Quality Reason
0
0
0
0

Purity
100%
100%
100%
100%

OEE
Overall Equipment Efficiency
100%
67%
88%
85%

Paul

0
#56831

Yibra
Member

Thanks alot Paul. I thought it could be calculated that way, but I wanted another opinion. I’ll try to calculate it that way. Thanks alot.
Kamil

0
#56853

Eugenio Quintero
Participant

Hope this helps….
Eficiency by =  S[cycle std/pz 1 ][Production Total 1 ] +  + [cycle std/pz n ][Production Total n ]
machine                                       S Uptime 1-nn

Eficiency by =  n[cycle std/pz  ][Production Total ]
product                        Uptime

FTQ        =      Sn[Good Parts1 ] + ¡K. + [Good Partsn ]
machine          S [Good parts+ Scrap + Rework] 1-nn

FTQ by =             n             [ Good Parts ]
product             Good Parts + Scrap + Rework

Availability =         Sn[Uptime 1 ] + ¡K. + [Uptimen ]
by machine              S [Uptime+ Downtime] 1-nn

Availability =             n[ Uptime ]
by product              Uptime+ Downtime

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#56866

Andrew Rice
Participant

Hi there,
The simplest way to calculate the OEE would be as follows
Calculate the Ideal Time for each product (say in minutes):
((Good Units A)/Ideal Rate A) + ((Good Units B)/Ideal Rate B) + ((Good Units C/Ideal Rate C) = Ideal Time
In your example the above will be in minutes
8 hours = 480 minutes = scheduled time
OEE Rate = Ideal Time / Scheduled Time as a percentage.

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#57464

Arusei
Participant

The best way is to set your machine Oee Calculation on your most produced product then when you change over to another product use a conversion factor based on the cycle times of the two products. If you still dont understand I may provide an example next time

0
#57594

Burns
Member

The best way to calcuate an Ideal cycle time with multiple part numbers is to use a waited average. If you have any questions please feel free to contact via email. [email protected]

0
#57723

Anoop
Participant

Can OEE concept be applied on manual Assembly lines. If yes, then how to monitor in case of Multi-models having different Standard Times & ratio also varies on daily basis leading to variation in Takt Time.

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