minimizing costs and purchase of the raw materials
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Zerotel Corp
Mar 26, 2011, 3:15:45 PM3/26/11
to frepple users
A similar question I have already asked.
I have set Size Maximum qty for the purchase operation to be enough for 4 days
of work. I can see that instead of several purchases on different dates there
are several purchases on the same date before starting of production. I want to
distribute the costs of the raw material over the production period. As far as I
can see the only way to do this is to set "A maximum quantity for
operationplans" in the operation producing the end product.
I remember an answer telling that materials are consumed at the start of the
operation.
I have set Size Maximum qty for the purchase operation to be enough for 4 days
of work. I can see that instead of several purchases on different dates there
are several purchases on the same date before starting of production. I want to
distribute the costs of the raw material over the production period. As far as I
can see the only way to do this is to set "A maximum quantity for
operationplans" in the operation producing the end product.
I remember an answer telling that materials are consumed at the start of the
operation.
Are there any plans to change this to allow for more accurate raw material
planning?
Johan De Taeye
Mar 27, 2011, 3:09:34 AM3/27/11
to freppl...@googlegroups.com
>>I can see that instead of several purchases on different dates there
>>are several purchases on the same date before starting of production.
>>are several purchases on the same date before starting of production.
Try using a buffer of type "procurement" instead of an explicit purchase operation.
The procurement buffer has specific modeling and solving capabilities: reorder-point, reorder quantity, purchasing lead time, min&max purchase quantity, min&max time between purchases, ...
>>I want to distribute the costs of the raw material over the production period.
>>As far as I can see the only way to do this is to set "A maximum quantity for
>>operationplans" in the operation producing the end product.
>>I remember an answer telling that materials are consumed at the start of the
>>operation.
>>I remember an answer telling that materials are consumed at the start of the
>>operation.
Material production and consumption is always happening at discrete points in time.
The inventory profile in frePPLe will look as a step:
---+
+--+
+----+
+--+
+--------
You can influence the height of the steps by controlling the size of the operationplans.
>>Are there any plans to change this to allow for more accurate raw material
>>planning?
>>planning?
A continuous material consumption as you are wishing doesn't look like a step:
---\
\
\
\--------
This can be implemented by coding a new buffer type with specific modeling and solving capabilties. It is pretty complex to code, and is not on the roadmap. Unless a customer sponsors this development activity, it won't happen any time soon.
Johan
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