Time period grouping feature


The time period grouping feature is a feature to generate auto-replenishment orders by grouping raw materials required by operations assigned to a certain time period.

You can use the following properties of the item class for this feature.

 Lot sizing startTime type 
 Lot sizing cycleEnum typeNone/Day/Week/10 days/Month
 Lot sizing periodTime span type 

The property "Lot sizing period" is used

when you want to make further groupings by time periods within the Lot sizing cycle, or

when you want to group time periods without depending on "Day", "Week", "10 days", and "Month" (i.e. when the property "Lot sizing cycle" is set to "None".)


Example

  Lot sizing startLot sizing cycleLot sizing period
(1)8:00:00 on the first day of every month2005/10/1 8:00:00MonthBlank or a time period of 32 days or more
(2)8:00:00 on Mondays2005/10/3 8:00:00WekBlank or a time period of 7 days or more
(3)8:00:00 on Mondays and Thursdays2005/10/3 8:00:00Wek4 days
(4)8:00:00 on the days of which the last digit is 1 (i.e. 1st, 11th, 21st, 31st)2005/10/1 8:00:0010 daysBlank or a time period of more than 10 days
(5)8:00:00 and 20:00:002005/10/1 8:00:00Any option12 hours
(6)Every four days starting from 2005/10/12005/10/1 12:00:00 AMNone4 days

Remarks

For the above (2) and (3), you can specify any day that is Monday for the property "Lot sizing start".

For the above (4), the lot sizing period is supposed to be 11 days considering months that have 31 days.

Also, the lot sizing start is not limited to 2005/10/1 but any date of which the last digit is 1, such as 2005/11/1.

For the above (5), the lot sizing start part (2005/10/1) can be replaced with any date.For auto-replenishment orders generated using the time period grouping feature, Production lot size MAX, Production lot size MIN, and Production lot size UNIT will be considered.



Time period grouping feature generates auto-replenishment orders based on the scheduling result of the next process of the item for which the time period grouping feature is used and according to the settings of "Lot sizing start", "Lot sizing cycle", and "Lot sizing period".
Therefore, the next process needs to be assigned before using the time period grouping feature.

For example, for item B1 of operations assigned to resource M3 in the diagram below, the property "Lot sizing cycle" is set to "Week" and "Lot sizing period" to "7D". Therefore, manufacturing orders are generated and assigned to produce the item by grouping by a week according to the next process operations (Item B) that are assigned to resource M4.Before assigning operations for item B1, operations for item B need to be assigned.

For the above reason, you need to compile commands in the scheduling parameter so that order explosion and backward assignment will be repeated using the command loop feature for each low level code from the smallest low level code (the finished item side) to the largest (raw material side).

When commands are repeated for each low level code, "Low level code MIN" and "Low level code MAX" in the Filter tab of the scheduling parameter settings will be used for "Loop initialize expression" and "Loop increment expression" in the Loop tab of the scheduling parameter settings.

For a specific example as to the command structure of the scheduling parameter and so on, please refer to Sample J-2.




No' grouping cycle and 'No' (a start date is reset every time)

For item C, the following period grouping are set up

 Production lot size MAX100
 Grouping cycleNone(a start date is reset every time)
 Grouping period7days
 Grouping start date6/5/2005

The following image represents the assignment result. Blue dotted line indicates the grouping start date which is reset dynamically.
For a short while, a lot size does not exceed the lot size MAX and the period is grouped within the 7 days grouping period. However, the demand becomes large after the 19th and it exceeds the production lot size MAX before reaching the days for the grouping period. As a result, the replenish order is generated for the production lot size MAX and the next grouping period begins immediately.


The following image represents the assignment result when the grouping cycle is set up 'None' based on the above setup. The grouping period is divided on a fixed basis.


When a grouping cycle is set 'None (a start date is reset every time),' the grouping may occur while some order is being added. On that occasion, the grouping may start on its half way through.
Under the following example, the order "104"indicates that 10 is pegged from M0007 against the demand quantity 30 and the remaining 20 is pegged from M008.



In case that the lot size MIN or the lot size UNIT is set up while the grouping bundle is applied

When the lot size MIN or the lot size UNIT is set up while the period grouping is applied. On that occasion, the remaining occurs the size of generated replenish order mostly becomes large against the demand of the demand volume within the grouping period.
Whether or not this remaining is to be pegged with the succeeding period's demand is set up, using the "period bundle roundup quantyty pegging type"property.

Under the item B1, the following period grouping is set up.

 Production lot size UNIT40
 Grouping cycleNone(a start date is reset every time)
 Grouping period7days
 Grouping start date6/5/2005

According to the default, the "period grouping rounding quantity pegging type" is defined as "no pegging."This generates the remaining 10 against the demand volume of 30 from the 5th day through 12th day.


When the "period grouping rounding quantity pegging type"is set up as "pegging," the remaining quantity is pegged against the succeeding period, as shown below.


The replenish order for the succeeding period is pegged as follows:


When the "period grouping rounding quantity pegging type"is set up as "no pegging," the ultimate inventory becomes large as the remaining will not be used.On the other hand, when it is set up as "pegging,"there occurs no remaining.Thus there will be possibility that the number of replenish order will reduce and the inventory will be as minimum as required.



Peg to output instructions in future lot sizing period

If the "Peg to output instructions in future lot sizing period" property of the item table is set to "Not pegged", pegging that would cause time constraint violation will not be performed.

For example, below is the schedule result when time period grouping is performed by setting "Lot sizing cycle" of item C to "1 day". In the period between June 10 and 14, replenishment orders (P0000, P0001, P0002) are generated ignoring the inventory order on June 15.

 

If the result of backward scheduling is to be considered final, this property should be set to "Not pegged". But in that case, the schedule would generate surplus inventory. In the example above, the schedule would cause 20 remainders of item C.

On the other hand, if the "Peg to output instructions in future lot sizing period" property of the item table is set to "Pegged", pegging will be performed even when time constraint violation would occur as shown below.

 

If the result obtained by backward scheduling is reassigned with forward scheduling to resolve operations assigned to the past and operations that would cause time constraint violations, delivery delays will occur. In contrast, setting this property to "Pegged" would simply eliminate surplus inventory.



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