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Process parts by weight

Hi Sim Superusers,

 

I am trying to process parts based on weight of the part. A heat treat furnace can handle 1000 pounds of parts at a time. But each part type has different weight. No matter what the part type is, the total weight should add upto 1000 pounds to start processing. 

 

Please share your thoughts on this scenario. 

 

Thank you!

 

Karthik Murugan

15 REPLIES

Re: Process parts by weight

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
I guess, you have some tolerance (-).
First you need to define the weight as an attribute for all parts (user defined attribute).
You could do it with an exit control. Check, if the weight of the batch including @ is above 1.000 pounds --> if yes: move the filled batch to heat treatment and get a new batch container --> (wait for the container) move @ to the empty container; else -> move to the container
so, the first part, that would cause an overload, will start the heat treatment process
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Process parts by weight

Hi Steffan,

 

Thanks for the reply. I tried as per your method, but I am getting some error. Obviously my coding is wrong and I have attached model here for your reference. 

 

I am using buffer to represent a Heat Treat. So when first part arrives, the exit is locked and parts are loaded until weight becomes 60 pounds and entrance is closed. Now the loaded parts stay in buffer for a given time and then unloads together at once. 

 

The reason to use buffer for Heat Treat is for flexible lot size. Please let me know if there are any other easy way to simulate this. Attached is my model with few errors am i am not able to fix. 

 

Appreciate your help!

 

Thank you!

Re: Process parts by weight

I am not able to attach the file, getting an error message "The contents of the attachment doesn't match its file type"

 

Re: Process parts by weight

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
zip it
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Process parts by weight

Attached!!

Re: Process parts by weight

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

some issues

- creation table of the source: the column no 4 needs to be table, just type someting into this column and press F2 (or double click into the cell) --> sub table; here you define the attributes of the MUs: first column --> name (weight is reserved for the data type weight) and the value in the same row and the column with the right data type

 

- I have changed your entrance control: I included a global variable to calculate the total weight, so you only need to handle the case, that the batch is full

- you cannot change the dwell time, if the part is already on the station; you need to set it before --> I have included a wait command to model the dwell time in the heat threatment

- you need to close/open both: the entrance and exit

- you need an init method to start with an open entrance and closed exit

 

Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Process parts by weight

Siemens Phenom Siemens Phenom
Siemens Phenom

Hello,

 

you could also consider using the Parallel Station for such an application, as with a buffer you would have later onwards an issue getting a proper statistical evaluation of your model, as a buffer per se is not “working”. Attached you can find a model where something similar is implemented using a Parallel Station. This is a rough setup where parts get a random number assigned to their user-defined attribute "weight". This attribute is added to a global variable which keeps track of how much weight has been already loaded into the station. Should there be a part waiting in line which would make the batch exceed the weight of here 1000, then process gets started. The part in the meantime waits until the previous batch is finished before being loaded into the station. Otherwise the part is moved into the Station and its weight added to the global variable. Here you can see that there are several points which you would have to specify according to your use case. For example whether your process load definitely must not exceed 1000 pounds or whether you have some tolerance and can start your process. You also would have to use only one part type here, as the Parallel Station does not process different types in a batch at once. You could still introduce another user-defined attribute like "part-type" to distinguish your parts and if need be write methods to e.g. record the throughput for each part type.

 

Kind regards,

Igor
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Re: Process parts by weight

Hi Steffan,

 

When I open the sub table, it looks like this. Not sure why,,

 

Thank you

 

Karthik

Re: Process parts by weight

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
set the table as MU-source for the source and confirm the changes; Plant Simulation will format the table (and the sub table)
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net