Bi-normal distribution for processing time

General Questions
1

Hi

In my model, I would need a bi-normal distribution as a machine process time. However, there is no such option in VC default. Kindly would like to ask you if there is an Add-On to add bi-normal distribution? Or if there are any other workarounds.

Thanks

2

Could you specify what you mean by bi-normal? How would you apply a bi-normal distribution function to a process time in a machine?

3

It is two normal distribution combination. for example, machine has 50 percent process product A, the process time around 2 hours; the other 50 percent process product B, the process time around 10 hours.

4

To add producttype specific process times with normal distribution, you can do the following:

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  1. Add the product property “ProcessTime” and “Deviation” to your product types
  2. In your process add a delay (if there is not one already)
  3. Set the TimeSource to Expression
  4. Add this as Expression:
    normal(0, ProductIn.ProcessTime, ProductIn.Deviation)
    You can find more about the normal distribution in the online helpfile:
    Functions
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5

Thank you. Is it possible if there is only product type, 50% process time is normal (60s, 2s); 50% process time is normal (5s, 1s)?

6

In that case you can use the if statement.

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Add two delay statements in Then and Else.
In the condition the uniform function will generate a random number from 0% to 100%.

  • If that number is lower than 50%, the process time is normal(60s, 2s).
  • If that number is higher or equal to 50%, the process time is normal(5s, 1s).
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7

You can also write that in just one line:

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uniform(0,0,100) < 50 ? normal(0,60,2) : normal(0,5,1)

Here are some info about how the conditional operators work: Grouping Operators

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