Calculation of supply quantity, number of signals, and average daily demand

The calculation of the supply quantity for kanban loops, the number of kanban signals, and the average daily demand is performed in the Item Data by Warehouse (whwmd2110s000) session.

LN calculates the default supply quantity for kanban loops by multiplying the signal supply quantity with the number of kanban signals.

The number of kanban signals is specified or calculated by LN. If calculated, this formula is used:

Number of kanban signals = D * T * (1+B/100)/Q
Legend
DAverage Daily Demand
TStock Coverage
BBuffer
QSupply Quantity

 

Average daily demand

The average daily demand for (end) items from the current warehouse is based on Job Shop Control production orders. The items supplied by the kanban order are used to assemble or produce the (end) items. The average daily demand is used to calculate the number of kanban signals required to effectively supply a shop floor warehouse.

The value of the Average Daily Demand field can be manually specified or calculated. If calculated, LN determines this demand for the period defined by the future and history horizons specified in the Horizon for Historical Demand and Horizon for Future Demand fields.

For the future horizon, LN checks the planned issues for production orders in the Planned Inventory Transactions (whinp1500m000) session. Planned issues with a date in the past are also included.

For the history horizon, LN checks the completed issues for production orders in the Item - Warehouse - Inventory Transactions (whinr1510m000) session.

The demand quantity thus found is divided by the number of work days with or without planned or completed issues for production within the horizons defined.

The Use Zero-Usage Days for Average Daily Demand field in the Warehouse Master Data Parameters (whwmd0100s000) session determines whether work days without production can be included in the calculation of the average daily demand.

For example, if the future and history horizons span five days, but there is planned or actual production on four days within these horizons, the average daily demand is based on 4 days if zero production days are not included. If included, the average daily demand is based on 5 days.

If zero-production work days are included, the average daily usage is lower than it would be without including zero-production work days.

Stock coverage

This is the number of days within the future horizon, which usually represents the lead time of an end product for which the component demand is covered by the available stock. The lead time is the transport time added with the production time.

The stock coverage is used to calculate the number of kanban signals. The value in the Stock Coverage field is manually specified.

Buffer

A percentage of the average daily demand used to calculate the number of kanban signals and the default supply quantity of kanban orders. This percentage is added to the average daily demand, which results in a higher default supply quantity for the kanban orders. This is used to prevent underdeliveries.

Percentages in excess of 100% are allowed.

Offset date

For the future horizon, you can specify an offset date.

The offset date is the starting point for the future horizon. For example, the current date is January 10th and the future horizon is 14 days. If you specify offset date January 24th, the future horizon spans from January 24th up to February 7th. The default offset date is the current date added with the Stock Coverage.

The offset date helps you identify a peak or a slump in demand for a future period, so you can adjust the supply quantities in advance.

Signal supply quantity

The quantity of items that must be supplied by a kanban signal. This quantity is manually specified.