Engineering Change Order Process for BOMs: Change the Design Without Breaking Production

It is Thursday afternoon. Three field returns on the same valve, all leaking at the outlet joint. Engineering already knows the fix: add an O-ring and a leak test before pack-out. Everyone agrees. So why is it still not on the shop floor two weeks later?

Because in most small and mid-size plants, changing a bill of materials is not one decision. It is a scavenger hunt. Someone edits the BOM spreadsheet. Someone emails purchasing to stop buying the old part. Someone tries to remember which orders on the floor were released before the change and which after. Someone forgets. And in six months, a customer gets a valve that was built to the old recipe with a paperwork trail that says it was built to the new one.

An engineering change order process fixes that. This post walks through what one looks like when it lives inside your ERP, right next to the BOM, the open orders and the stock it affects, and how Qualis makes it feel like one confident click rather than a week of email.

Where the spreadsheet quietly breaks

You can run a BOM in a spreadsheet for years without noticing the cost. It shows up as small, unconnected incidents:

• Purchasing keeps buying the old part. The open purchase order still references the superseded drawing, so the supplier keeps shipping revision A long after engineering moved to B.
• The floor builds from the wrong revision. Nobody told the cell that the routing lost its welding step, so they weld the plate anyway and rework it later.
• Stock gets stranded. Five thousand bolts sit in a bin that no assembly consumes any more, and nobody made a decision about them until year-end count.
• The audit trail is a Slack thread. When quality asks who approved the change, when it took effect and what exactly moved, the answer is scattered across inboxes.

The research on this is not subtle. In a survey of 405 product companies, close to half managed their bill of materials in a spreadsheet or in nothing at all, and companies without connected change data reported ordering wrong parts, revision-control problems and scrap or rework as their top consequences. An earlier benchmark found that only a small minority of average manufacturers ran a formal change impact analysis at all, while the best performers did, and hit their change deadlines far more reliably as a result.

The pain is rarely the change itself. It is everything the change touches that nobody looked at.

What an engineering change order actually is

Strip away the acronyms and an engineering change order (ECO) is a single, numbered record that answers five questions about one change to a released bill of material:

1. What is changing? A one-line title a reviewer can scan.
2. Why? The one thing a diff can never show you.
3. Where does it start from? The exact released revision production is building today.
4. When does it take over? As soon as it is approved, or on a date you choose.
5. Who agreed? The approval, the apply, and the people who were told.

You may also hear ECR (a request, before anyone has decided) and ECN (a notice, after the decision, telling people it happened). Qualis folds the whole journey into one change order that moves through Draft, Approved, Applied and Closed, so you keep one reference number from the first idea to the archived record.

The other idea to hold onto is the revision. A revision is a new version of the same product's recipe: revision A becomes B becomes C. Each revision has an effective-from date and an expires-on date, and only one is active for production at a time. The change order is the governed way of getting from one revision to the next.

How the engineering change order process works in Qualis

Everything below lives under Bills of Material › Engineering Changes. The list gives you the state of every change at a glance, with quick filters for My change orders, Open, Awaiting my approval, To apply and Applied this month.

Step 1: start a revision from the released BOM

You do not edit the live BOM. You open it and click Start change order. Qualis asks for the title, the reason, the kind of change and the priority, then forks a fresh draft revision of that BOM for you to edit.

Two things happen quietly here:

• The next revision code is proposed for you from your organization's numbering: letters (A, B, C, skipping I, O, Q and S so they cannot be misread on a drawing) or plain numbers.
• Production keeps building the current revision. The draft carries an amber banner reading Draft revision C, not used in production and links back to the change order that owns it. The released BOM shows a chip saying a change is pending, and anyone raising a manufacturing order for that product sees the same notice.

Only one change order can be open per product and site at a time, so two people can never redline the same BOM in parallel.

Optional ceremony: if your quality system requires it, a single setting freezes released BOMs so edits and status changes can only land through a change order. Draft revisions stay freely editable either way.

Step 2: review exactly what changed

Edit the draft the way you always edit a BOM: operations, material lines, byproducts, attachments. Then open the change order's Changes tab. Qualis computes the difference between the released revision and your draft, section by section, and shows it unified or side by side.

Every changed cell shows before and after. A removed operation is struck through. An added component is green. You can toggle Only differences, or Export CSV to attach the change to a supplier email or a design review.

Below the diff sits Checks: what Qualis confirmed about the change before an approver ever sees it. Some checks block the approval (the draft is still identical to the release, the revision code is already taken, the base is no longer the active revision, a scheduled change has no date). Others warn (open manufacturing orders exist, a stranded component still has stock and no decision, a scheduled date has already passed). Errors disable the Approve button and say why in the tooltip.

Step 3: measure the impact before you approve

This is the part the spreadsheet never had. The Impact tab reads your live orders and stock and tells you what this one change touches, in seven scopes:

• Components: every part added, removed, used more or used less, with quantity before and after.
• Where used: the other bills of material that consume this product, so a change to a sub-assembly is not a surprise upstream.
• Manufacturing: open orders for this product, split into Already building the old revision and Will pick this change up.
• Purchasing and Sales: open purchase orders buying an affected component and open sales orders selling one.
• Stock: on hand, reserved and available for every affected component, across all locations.
• Dispositions: what happens to the parts this change strands (more on that next).

The manufacturing split matters. In Qualis, a manufacturing order freezes its bill of material the moment it is released. Orders already on the floor keep building the revision they were released with; orders released after the change apply pick up the new one. No order is silently rewritten mid-build. The Impact tab shows you both groups so you can tell the people running them, and a Notify responsible button sends an in-app notification to everyone who raised an affected manufacturing, purchase or sales order. People already told are skipped, so you can press it twice without spamming anyone.

The impact is measured live while the change is a draft, and frozen at submission so approvers see exactly the picture the author saw.

Step 4: decide what happens to stranded stock

Remove a component or use less of it, and the parts already in your bins need a decision. The Dispositions scope lists each one with its live on-hand and reserved quantity and five choices, each with a plain-English hint:

• Use up: keep building the old revision until the stock runs out
• Rework: modify what is on hand so it fits the new revision
• Scrap: write the stock off
• Return to vendor: send it back to the supplier for credit
• No action: looked at it; nothing to do

Each decision is stamped with who made it, when, and how much stock was on hand at the time. Scrap links you straight to a stock adjustment; rework links to a new manufacturing order. Recording the decision does not move stock by itself, which is exactly what you want: the change order is the record, the inventory transaction is the action, and both point at each other.

Step 5: approve, and choose when it takes effect

Click Approve. If an approval workflow applies to engineering changes in your organization, the change is submitted to the approvers instead and stays frozen until they answer, with the same rules, timeouts and audit trail as your purchase order approvals. If they send it back, the author is notified and the draft stays editable.

Effectivity is a single choice on the change order:

• On approval: the new revision takes over production the moment the change is approved.
• Scheduled: you pick the date. The change waits in Approved with a Pending apply state, and Qualis applies it automatically once the date arrives. Anyone trying to apply it early is told the date it is waiting for.

Step 6: apply, and let the timeline write itself

Applying does four coupled things in one motion: the draft becomes the active revision, the old revision is marked obsolete, the default flag and the product's default-BOM pointer move over, and the change order flips to Applied. The old revision's expires-on date and the new revision's effective-from date are the same instant, so there is never a gap or an overlap in your effectivity history. If anything fails, the whole flip is rolled back, the change order stays approved with a clear reason, and you get a Retry apply button rather than a half-applied BOM.

Open any revision of the product and its Revisions tab shows the whole family, oldest first: each revision's effectivity window, who created it, the reason, and the change order it came from. Pick any two revisions to compare them, months after the fact.

Close the change order when the paperwork is done. Applied and closed change orders are permanent records: they can no longer be edited, and every save along the way is kept in the version history.

What it prevents

• Wrong-revision builds. There is one active revision, orders freeze it at release, and everyone can see which orders are on which revision.
• Buying the old part. Purchasing sees the open purchase orders touched by a change before it is approved, and gets told when it goes live.
• Stranded inventory with no owner. Every removed or reduced component gets a recorded decision, with the stock count at the time of the decision.
• Two people changing the same BOM. One open change order per product and site, enforced.
• The audit trail question. Who raised it, why, what changed, who approved, when it took effect, who was notified: all on one numbered record, linked to the non-conformance or corrective action that triggered it.

There is a famous cautionary tale about a part being changed without changing its identifier, which left the company unable to tell old parts from new ones for years. Your revision letters, effectivity dates and change orders are the small daily habit that keeps that from ever being your story.

The process end to end

1. Draft: start the change from the released BOM, edit the forked draft revision.
2. Checks: the diff, the readiness checks and the impact panel tell you what will move.
3. Approve: with or without a formal approval workflow, the record is frozen for reviewers.
4. Apply: on approval or on the scheduled date, the new revision takes over and the old one retires.
5. Close: file it as a permanent record, with the revision timeline updated for good.

Frequently Asked Questions

What is the difference between an ECR, an ECO and an ECN?

An engineering change request (ECR) is a proposal, an engineering change order (ECO) is the approved instruction to make the change, and an engineering change notice (ECN) tells affected people the change happened. Qualis carries all three moments on one numbered change order: it starts as a draft, gains an approval, and notifies the people whose orders it affects.

What happens to manufacturing orders that are already in progress when a BOM revision changes?

They keep the revision they were released with. A manufacturing order in Qualis freezes its bill of material at release, so an applied change never rewrites an order mid-build. The change order's Impact tab lists those orders separately from orders that will pick up the new revision, so production knows exactly which is which.

Should a change take effect on approval or on a scheduled date?

Use On approval when the change should reach production immediately, such as a quality fix. Use Scheduled when the switch has to line up with a use-up plan, a supplier delivery or a customer commitment. In Qualis a scheduled change waits in Approved and is applied automatically once the date arrives, and the new revision's effective-from date is the date you chose.

What should we do with old parts after an engineering change?

Decide it per component before the change goes live: use up the remaining stock on the old revision, rework it to fit the new one, scrap it, return it to the vendor for credit, or record that no action is needed. Qualis lists every removed or reduced component with its live stock and stamps each decision with the person, the time and the quantity on hand.

How do we compare two BOM revisions to see exactly what changed?

Open any revision of the product, go to the Revisions tab and pick two revisions to compare. Qualis shows every added, removed and modified operation, material line, byproduct and attachment with before and after values, unified or side by side, and lets you export the difference as CSV.

Can a small manufacturer run engineering change orders in the ERP without a separate PLM system?

Yes. Because the change order sits beside the BOM, the manufacturing orders, the purchase orders and the stock in the same system, the impact analysis and the notifications come from live data instead of a synchronised copy. You can start with change orders as an optional habit and turn on the setting that requires them for released BOMs when your quality system asks for it.

The bottom line

A bill of material is a promise about how a product is built. Changing that promise safely means knowing what the change touches before you approve it, choosing when it takes over, deciding what happens to the parts it strands, and keeping a record that answers the auditor's questions without a treasure hunt.

Qualis puts that whole engineering change order process one click away from the BOM itself, with a live impact panel, a side-by-side revision diff, scheduled or on-approval effectivity and a revision timeline that writes itself.

If you have ever discovered a wrong-revision build after it shipped, see how engineering changes work in Qualis and start a trial. And if costing is your next question, our post on standard cost rollups shows how a new revision flows into what the product really costs, while production genealogy covers tracing every lot and serial forward and backward from the orders that built them.