IFS Cloud Lead Time: Purchase, Manufacturing and Expected

IFS Cloud defines purchase lead time, manufacturing lead time and expected lead time for an inventory part, and it treats safety lead time separately. The table gives what the page says about each.

Purchase lead time is the time from when the part is ordered until it is available in inventory. The page builds it from the primary supplier’s manufacturing lead time, the external transport lead time, the transport lead time, the internal transport lead time and the internal inspection lead time. It adds a note: safety lead time will not be considered as a component in purchase lead time.

The components sit in different places and use different calendars. You can specify a supplier manufacturing lead time and an internal inspection lead time per combination of supplier and purchase part. Supplier manufacturing lead time is measured in supplier calendar days, or in calendar days if no supplier calendar is defined, and internal inspection lead time is measured in distribution calendar days. The external transport calendar is defined by the Ship Via Code, and internal transport lead time is measured in site distribution calendar days.

Two further statements affect dates on orders. The total purchase lead time shown on the Inventory Part page is used for calculating dates when, for example, a purchase requisition is entered without a supplier. When a supplier is identified, the system sets dates from the lead times configured in the Supply Chain Matrix and on Supplier for Purchase Part. And on a purchase order, neither internal transport lead time nor external transport lead time is saved. The supplier side of this is covered in IFS Cloud sourcing rules and multi-supplier ordering.

You can calculate the total lead time of a purchased part in the Calculate Purchase Lead Time dialog box, and the result is presented in the Acquisition tab of the Inventory Part page when using the Update option. The 25R2 page on the calculation gives a worked example: a supplier manufacturing lead time of 10, an external transport lead time of 2, a transport lead time of 0 and an internal transport lead time of 1, together with an internal inspection lead time of 1, give a total purchase lead time of 14 days.

The page names four update options: Update, Update Also Expected, Do Not Update, where there is no update in the system and only a report is created, and Update Using Average Historical Lead Time. The last option does not use the standard set-up lead times. When it is used, the standard set-up lead times on Supply Chain Matrix and Supplier for Purchase Part are not applied, and the purchase lead time is calculated from the actual received and approved dates of the historical receipts.

For the historical average, the page offers start date options and excludes outliers: values with a Z-score higher than 2.5 are excluded by default, and the threshold can be adjusted to 2 or 3. In the page’s example the average of 4.166 days is rounded up to the nearest full day, 5 days. Whether to use actual receipts or the standard lead times is a decision for purchasing, and the supplier behaviour behind such numbers is discussed in supplier behaviour change signals.

Manufacturing lead time can be calculated using the lead time calculations found in Manufacturing Standard/Calculation or in the Routing page. The routing page of the documentation separates a fixed part from a variable part, and the sums hold for a routing alternate having no parallel or overlapping operations: the fixed lead time is the sum of setup time, transport time and queue time for all operations, and the variable lead time is the sum of machine or labor time for all operations.

The calculation depends on further inputs. The lot size is normally the standard lot size specified on the inventory part. The calculation can be based on machine time, labor time or the maximum of the two. For parallel operations only the operation that takes the longest to complete is considered when calculating the fixed and variable lead time.

The page works one example without overlap: a fixed lead time of 7h, a variable lead time of 4h and a lot size of 5 pieces give 7h + (4h * 5 pcs) = 27h. A second example, with overlap between operations, uses a variable lead time of 2h and gives 7h + (2h * 5 pcs) = 17h. Routing lead time is used in several places, among them MRP and Master Scheduling. The planning side is covered in dynamic structures in MRP.

Expected lead time is the time, in days, that it takes to receive the parts into inventory, assuming that not all component parts are in inventory. The default value of the Expected Lead Time field is 0 (zero). If no expected lead time is entered in the inventory part record, the expected lead time is the same as the purchase or the manufacturing lead time.

The page explains why the field exists. The manufacturing lead time of the part can be incorrect because it assumes that all parts are available from inventory, so you should use the Expected Lead Time field to help ensure that a part can be delivered in time. Order promising is covered in high-fidelity discrete order promising and, for capable-to-promise, in CTP in IFS Cloud.

For purchased parts MRP uses the lead time defined for the primary supplier, including supply chain matrix and inspection lead time. If no valid routing exists or no primary supplier for a purchased part, the lead time specified on the Inventory Part page is used. For a manufactured or remanufactured part, MRP calculates the lead time for a supply from the valid routing.

The order of preference matters for data maintenance: the supplier’s data comes first for a purchased part, and the Inventory Part value is the fallback. Check for each purchased part which of the two MRP will read before deciding where to maintain the value. The reorder point side of planning is covered in reorder point planning in IFS Cloud.

Purchasing owns the supplier-side components and planning owns the manufacturing and expected values, and both own the review date. Purchasing maintains the supplier manufacturing lead time per supplier and purchase part, and the transport lead times. Planning maintains the routing and the expected lead time. Agree how often each value is reviewed, and who decides whether to replace standard lead times by the historical average.

Test lead time data with one part per type and write down the expected planned date before the planning run. The table gives four parts that follow from the documentation.

Lead time data is ready for go-live when each of the checks below has a record behind it.

1. The five components of purchase lead time are maintained where the page places them, in the calendars it names.
2. Safety lead time is kept out of purchase lead time.
3. Primary suppliers are set, so that MRP reads the supplier data and not the part field.
4. Routings are valid for manufactured parts, and their standard lot size is set.
5. Expected lead time is set where components can be missing, and its default of 0 has been checked.
6. The update option used for calculating purchase lead time is decided.
7. The four test parts are recorded with expected dates.
8. Each value has an owner and a review date.

Dariusz Myśliwiec: 18 years hands-on with IFS, including IFS Cloud. Based in Kraków, delivering remotely across Europe and globally through an independent practice. You talk to the consultant who does the work, not a sales layer.

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