Manufacturing Buffer

Manufacturing Buffer is a value set to protect production order deadlines. The buffer is set to allow enough time to complete the Production Order when something goes wrong. Manufacturing buffer also provides a delivery buffer according to component lead times.


Prerequisites:


Table of Contents:


How to set Manufacturing Buffer

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Manufacturing Buffer is a value set in the Production BOM to protect production order deadlines. It is set as a percentage of production time and component lead time. 



If Ignore cumulative lead time is checked, you can enter a lead time for components (in days) on the Production BOM of a product. 


If Ignore cumulative lead time is unchecked, component lead time will be taken from the values specified on the Suppliers tab of a product. See Setting Lead, Safety and Reorder quantity for more information.



How Manufacturing Buffer is calculated

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The manufacturing buffer is set in percentage terms to define how much production time is needed as a buffer. It is calculated as: 


  • (CRITICAL PATH FOR LEAD TIME FOR ALL COMPONENTS OR SUM OF CYCLE TIMES OF ALL OPERATIONS IN PRODUCTION ORDER) X BUFFER %

or

  • (CRITICAL PATH FOR LEAD TIME FOR ALL COMPONENTS OR CRITICAL PATH FOR PARALLEL OPERATIONS + CYCLE TIMES OF ALL OPERATIONS IN PRODUCTION ORDER) X BUFFER %


Buffer is considered for the calculation of timelines upon Production Order authorisation (or when Production Order is auto-planned and/or auto-released. The calculation is as follows for each Capacity Calculation method:

  • From Planned Date Forward: Planned date + critical path for lead time for all components x buffer % + sum of all operations in production order + sum of all operations in production order x buffer %
    • Thus, the Release Date for the order = Planned date + critical path for lead time for all components x buffer %
  • From Required by Date Forward: Required by Date - critical path for lead time for all components x buffer % - (sum of all operations in production order + sum of all operations in production order x buffer %)
    • Thus, the Release Date for the order = Required by Date - (sum of all operations in production order + sum of all operations in production order x buffer %)


When the Production Order timelines are calculated, the buffer is applied to both: 

  • Sum of all operations in the order
  • Lead times for the delivery of the components.

Thus, Release Date will be a bit later than the longest lead time of the components. 


In the Scheduler, the buffer shown will not contain buffer for lead time components delivery, as this has already been used in order to set the Release Date. 


Leather Chair manufacturing buffer is set to 40%. This means that we suppose that the production of an order of chairs may be longer to 40% than we planned initially. No matter how many chairs the order contains, we plan that any number of chairs can take 40% longer than the calculated production time.  


Production Runs do not have their buffer. Buffers are applied only to Production Order.


Example:

  • The Production Order for 10 chairs takes 40 hours of production time. Production time is subject to operational hours of 8 hours a day, 7 days a week. Thus production time is 5 days. 
  • The longest lead time for components is 3 days. 1 day = 24 hours. (Buffer to protect lead time considers that 1 day = 24 hours (regardless of the operational hours). Weekends 
  • The manufacturing buffer to protect components delivery is 24 x 3 x 40% = 28.8 hours. Thus, the buffer to protect lead time is 1.2 days.
  • The buffer to protect manufacturing is 40 x 40% = 16 hours. This buffer is subjected to operational hours of 8 hours per day 7 days a week. Thus buffer to protect manufacturing is 2 days.
  • So, the timeline for the Production Order will be: Required by date - 2 days (manufacturing buffer) - 5 days (sum of all operations) - 1.2 days (lead time buffer) - 3 days (lead time).
  • Let's assume that Required by date is 13.03. And the available capacity of the resource for the day is 8 hours per day. Thus, the timelines for the order will be 13.03 - 2 days (manufacturing buffer) - 5 days (sum of all operations) - 1.2 days (lead time buffer) - 3 days (lead time)= Planned date = 01.03
  • The Release date in this case is calculated as 01.03 + 3 days (lead time) + 1.2 days (lead time buffer) = 4.2 days = Release Date =5.03


This means that a Production Order for 40 chairs takes 11.2 days hours with manufacturing buffer and lead time where only 40 hours is "pure" production when there are no problems.


How Manufacturing Buffer is used

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The manufacturing buffer is added to the Release date of the order. The manufacturing buffer is visible on the Planning view, Production Orders view and Sales Orders view of the Scheduler


In the Scheduler, the buffer shown will not contain buffer for lead time components delivery, as this has already been used in order to set the Release Date. The manufacturing buffer shown in the Scheduler represents buffer for production time only. 


Each delay causes a reduction of the total buffer percentage. There are 3 manufacturing buffer zones:

  • Green- Safe zone (66.6+%): There is plenty of time to complete the Production Order.
  • Yellow - Warning zone (33.3-66.6%): There is time to complete the Production Order. Production should not be delayed any further.
  • Red - Urgent zone (0-33.3%): The Production Order can't be delayed anymore and should be processed urgently. 


The Scheduler allows filtering by Priority/Buffer % so you can see which orders require attention. 



Total Manufacturing Buffer is applied to the whole Production Order.

  • Example: The Manufacturing buffer for the finished good Chair is set to 40%. A Production Order for 10 chairs takes 40 hours of pure production time. The Manufacturing buffer for the order is 40% x 40 = 16 hours. The total time calculated for the Production Order is therefore 40 (Production time) + 16 (Buffer) = 56 hours. 


NOTE: The manufacturing buffer is not applied to individual production operations or production runs. 

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