Shop Order re-explosion of materials on Lot Size change

Hi ​@OllieByrne ,

Yes — what you are seeing is standard behavior in IFS Cloud, and it is related to how Shop Order structure is regenerated (re-exploded) when key parameters like lot size are changed.

 What is happening

When you:

1. Manually modify shop order materials
   • Add / remove / replace components
2. Then change the lot size

 IFS triggers:

Re-explosion of the shop order structure based on the effective revision

This means:

• System rebuilds material requirements from:
  • Product structure (BOM)
  • Revision
  • Lot size

 Result:

• Your manual changes are overwritten
• Structure returns to standard BOM definition

 Why this happens

IFS treats lot size change as a structural recalculation trigger because:

• Component quantities depend on:
  • Lot size
  • Scrap factors
  • Scaling logic

 So system ensures:

Structure = consistent with engineering definition

 Important Behavior

Manual changes are not permanently stored as overrides

 They are:

• Temporary adjustments
• Lost when:
  • Re-explosion is triggered

 Was this different in 22R2?

From practical experience:

• This behavior already existed in earlier versions (including 22R2)
• However:
  • It may have been:
    • Less noticeable
    • Triggered less aggressively
    • Dependent on how change was done

 In 25R1:

• Behavior is more consistent/strict

 How to Handle This

 Option 1: Make changes after lot size update

Best practice:

1. Change lot size first
2. Then adjust components

 Avoids re-explosion overriding your changes

 Option 2: Use Alternate/Engineering Structure

If changes are permanent:

• Update:
  • Product structure (BOM)
• Or:
  • Use alternate structure

 Option 3: Lock Structure (if applicable)

• Some setups allow:
  • Preventing re-explosion

 Depends on configuration

 Option 4: Use Shop Order specific changes carefully

• Treat manual edits as:
  • Temporary

 Key Insight

Lot size change = system assumes structure must be recalculated

 So it prioritizes:

• Engineering accuracy
  over
• Manual adjustments

​@OllieByrne what you are seeing is NOT standard behavior. Shop Orders can be manipulated to any extent and will not revert to the content of the original structure/routing revision if the Lot Size is changed.

Do you have a customization that is resetting the Materials list when the Lot Size is changed?

In 25.1.2 Here is a released shop order with its standard materials list. Lot Size = 10.

Change the QPA of the component from 1 to 4.

Add a component, QPA = 3.

Lot Size is still 10.

Change the Lot Size to 20. Manual changes to the components list and QPAs stay in effect. As expected, the Required Qty is updated accordingly.

Another way to know this is not standard behavior - recall the setting on a routing operation for ‘Increase Lot Size on Scrap’. Imagine if this were ‘on’, multiple scraps were performed, and the Lot Size kept changing with each scrap. Should we expect the materials list to keep reverting with each scrap?