Model for different Scheduling rule

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jeroenophetveld
Posts: 1
Joined: Tuesday 03 June, 2014 - 12:18

Model for different Scheduling rule

Post by jeroenophetveld »

Dear community members,

Currently I'm doing my graduation project at a furniture production company in Poland. I want to model a simple production environment that consists of the following parts:

1: Job Shop production, with 32 machines and different routings through component lines.
2: Assembly lines, sequentially consisting of 5 processes.

Now as I study Industrial Engineering and I learned from my statistics lecturer that there are 8 kind of scheduling rules which the production planner can use (Earliest Due Date, Shortest Operating Time, Least amount of Slack Time etc.), I want to compare the scheduling rule: Earliest Due Date (which the company uses now) with Shortest Operating Time (desired situation) and what the effects are on lead time, utilization rate and maybe other factors.

As I've read the basic tutorial of ED, I know that scheduling is part of input strategy. Now I have the following question:

1: Is it possible to model such scheduling situations?
If yes: can you please show me how I can do it?
If no: are there any alternatives available?

I collected already some amount of data including cycle times, set up times, routing scheme and BOM lines.

Thanks in advance.

Kind regards,

Jeroen
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Nienke Valkhoff
Posts: 20
Joined: Tuesday 11 January, 2011 - 09:23

Re: Model for different Scheduling rule

Post by Nienke Valkhoff »

Hi Jeroen,

Yes you can model any scheduling rule that you want. You write that you have read the ED Tutorial but I also recommend that you read and tryout examples of the Tutorial "A First start to 4DScript". For many models it can by very useful to know how to work with labels. So you should focus on understanding how to use these.

I have attached a very simple model.
2014_06_03_SPT.mod
Products sorted by ProcessTime
(7.55 KiB) Downloaded 331 times
In the Source I assign two labels to all products that are created. One label corresponds to the characteristic DueDate and the other to the characteristic ProcessTime. Each product will have its own values for these labels, i.e. its own ProcessTime and its own DueData. In the Queue the property 'QueueDiscipline' is set to "By Label ascending" and I changed the blue text in the logic such that the label ProcessTime is used, this way the products are sorted and if the product has a short process time it is put in front. In the Server the 'cycletime' property reads the value from the label named ProcessTime of the product.

In the model I do not use the label DueDate. These are only assigned to each product, but you can change the Queue Discipline of to use this label.

Later in your own model an ArrivalList atom, that can also be used to assign labels to products might be a useful atom to use instead of a Source.

Regards,

Nienke
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