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Value Stream Mapping Simulation

Creator
Creator

Hello everybody,

 

I had a problem modeling using this library. The attached model is a simplification of the model I'm building.

 

I understood by the Help Content and by studying the model, that the demand to be passed to Supplier by the PPS, should be result of the "existing base products in the first Inventory" subtracted "the production orders in the first Process".
However, in the models I built that two products are produced with a same base product, when the PPS calculates the demand to be passed to the supplier, it don't consider the current demand of the product with lesser amount requested by the customer. I.E. considering that there is 50 base products in the inicial inventory and that there is not any transformed products (Product_A or Product_B) available, being the daily demand 100 Product_A and 50 Product_B, the PPS should send a order to Supplier asking 100 base products, but it sends a order asking just 50 these (enough to atend the order of 100 Produc_A, product with higher amount request). This is my problem, the PPS don't ask products enough to produce all the products.

 

On the attached model is possible to observe this by the "PPS" Disposition Data, "Process1" Order table and "Inventory" Current Stock.

 

I guess it is a software's bug. Could someone help-me please?

 

Thanks in advance.

 

10 REPLIES

Re: Value Stream Mapping Simulation

Siemens Valued Contributor Siemens Valued Contributor
Siemens Valued Contributor

Hi ,

 

I am not sure if I understand the issue correct. The order numbers in the PPS Disposition Protocol look correct to me - they reflect the number of products Q missing at the time the next order is created by the customer taking in account the current number of remaining products Q.

If you change the amount of ordered products A at Customer to 100 you will notice that there are always 150 Q ordered by the PPS.

 

Hope this explains the behaviour a bit more...

 

Kind regards,

 

Holger-

Re: Value Stream Mapping Simulation

Creator
Creator

Hi HolgerLa,

 

Thank you for your answer. To you understand better the issue, I made some changes in the model, I decreases the packaging size of Supplier to 1 and I changed the amount of ordered products A at Customer to 100.
Now, if you run and then stop the simulation at 4:00:00:00.0001, will be possible to you see in the Process1 OrderTable the orders to be produced by this process on this day. The orders' sum is 300 products and the inicial inventory is empty, so I guess the PPS should order 300 parts to Supplier, but it orders just 200. Why it happens?

 

Besides, analysing when the orders could be produced, based on inventory levels and orders data in disposition log of PPS, I found that the ordens could be produced in the following way:
Day 0 - 700000001 and 700000002
Day 1 - 700000003
Day 2 - 700000004 and 700000005
Day 3 - 700000006, 700000007 and 700000008
Day 4 - 700000009 and 700000010 (would remain 50*Q at "Inventory")
But the orders aren't being produced in this way. They are delaying. Is it possible to analise if supplier is delivering less products than the ordered? If the supplier is delivering right, why are the orders delaying to be produced in "Process1"?  

 

Thank you again.

 

Dhiogenes.

Re: Value Stream Mapping Simulation

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi Dhiogenes,

 

following the theory of value stream mapping, in current implementation, the PPS assumes that there is only one product family which will be simulated. In your simulation model, there are two different products using the same base product. During disposition, this leads to an order quantity which is less than the curent demand.

We modified this behavior, now allowing several products using the same base product.

This feature will be available in VSM 11.0.16 and/or in version 12.0.2

 

Regards

 

GG

Regards
GG

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Re: Value Stream Mapping Simulation

Creator
Creator

Thank you so much.

 

When this update will be released?

 

Regards,

 

Dhiogenes.

Re: Value Stream Mapping Simulation

Experimenter
Experimenter

Hello everyone,

 

I updated the library, but for the attachment model I'm still having problems. Why the PPS orders 8400 products? It should order 6440 ((600LE+320LD) * 7days), shouldn't it?

 

Thank you,

 

Dhiogenes.

Re: Value Stream Mapping Simulation

Creator
Creator
Sorry, there were other people logged in this PC and I forgot to change the user account before send The message.

Dhiogenes

Re: Value Stream Mapping Simulation

Siemens Phenom Siemens Phenom
Siemens Phenom

Hello Dhiogenes,

 

no, you are not right.

the disposition does not work with the absolut number of products, it uses the cycletime of the products. Products LE has a cycletime of 144 seconds, product LD has a cycletime of 270 seconds. Because both products are based on the basic product BB this basic product has the minimum of the cycle time which is 144 seconds. So calculating the demand results in

2 products * 86400 secoods per day * 7 days / 144 secdonds per product = 8400 products.

 

This is more than necessary, but at the next disposition intervall, the products available in the Inventory will be taken into account and reduces the number of ordered base products.

 

Regards

 

GG

Regards
GG

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Re: Value Stream Mapping Simulation

Creator
Creator

Thank you GG and everybody for the help.

 

I had a new problem using this library. In the Customer object, if I don't check the box "Alow delay", the orders are created every day at midnight (having been defined the demand interval as 1:00:00:00) but even if I use a ShiftCalendar to define that the customer should not order on weakends, it happens. So, I tried to simulate with the box "Alow delay" checked, and thereby the customer don't order on weekends, but if the customer works 18 hours/day, the first order is created at 00:00:00, then the second order is created on the same day at 18:00:00, then the third order is created at 12:00:00 on the next day, and so on. So, is considerated that the demand should be generated each 24 working hours, considering the Customer's Shiftcalendar.
Thus, I also tried to change the demand interval to 18:00:00, and the model worked like it should, but the change also affected the disposition process, and the PPS started ordering to much products to supplier. I got solve this problem for now, changing the Customer's ShiftCalendar to it works 24 hours/day, but I don't think it's the right solution. Is there another solution for it?

 

Thank you again.

Dhiogenes.

Re: Value Stream Mapping Simulation

Siemens Phenom Siemens Phenom
Siemens Phenom

Hello Dhiogenes,

 

currently we don't have any solution for this. We will examine this in more detail and will modify the behavior of the customer object.

 

Regards

 

GG

Regards
GG

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