The Work Order Is Open. Where Is the WIP—and Why Has It Stopped?
Open work orders do not explain whether electronics WIP is queued, waiting for material, under test, on quality hold, in rework or sitting between operations. EMS control needs operational status at the point where work is actually waiting.
The short answer
EMS WIP visibility means knowing not only that a work order is open, but where the physical build is, which operation owns it, what status blocks it and what must happen next. A useful WIP model distinguishes queued, running, waiting for material, quality hold, test, rework, engineering hold, subcontract and complete-awaiting-release states.
Without that state, management sees backlog but not flow.
The same question belongs to the wider High-Mix EMS Changes Every Day. How Do You Keep Production Under Control? operating picture: WIP visibility has to remain connected to the decisions made before and after it, rather than becoming a separate local control.
Open is not a production status
An open work order can be:
- not started;
- partially complete;
- waiting between operations;
- blocked;
- under repair;
- physically outside the plant.
Treating all open work equally creates misleading priority lists. Use operation-level status. Show the last completed operation and next required operation.
This gives planning and supervisors a common view of progress.
It also helps identify where queues are forming. Add blocking reason. A job waiting should have a reason.
Examples include:
- material;
- quality;
- test;
- engineering;
- machine;
- operator;
- subcontract;
- priority hold.
A reason code is useful only if it leads to ownership. Use WIP age. Track how long work has remained in the current state.
Old WIP deserves attention.
A two-hour wait may be normal.
A three-day wait between test and rework can indicate hidden control failure.
Preserve lot and serial identity. Electronics WIP can contain trace-controlled lots or units.
Movement should not lose genealogy.
Barcode-driven execution can connect physical WIP to the work-order state. Distinguish queue from active work. A job can sit at a station without being worked.
Separate queue, active and hold where useful.
This prevents management from assuming that physical location equals progress.
Include quality hold
Quality disposition can stop WIP.
The production view should show that status rather than leaving the job apparently waiting for the next operation.
This allows supervisors to escalate correctly. Include rework loop. Rework is not a normal forward operation.
Show when a unit has entered repair and when it has returned to the standard route.
This keeps lead-time and yield analysis honest. Include test queue. Functional test can become the real bottleneck.
If WIP accumulates before test, the system should expose the queue and age.
This is more actionable than overall work-order completion percentage. Include engineering hold. NPI and complex products may pause for technical decision.
Record the owner and expected action.
Otherwise “waiting for engineering” can become an indefinite state.
Include outside processing. When WIP leaves the plant, keep the same operational thread.
Show quantity sent, due back and status.
The job has not disappeared merely because it is off-site. Use WIP visibility for customer service. Customer service often asks, “Where is my order?”
A useful answer should not require phone calls around the factory.
The system should provide the current state and whether the customer date remains credible.
Avoid excessive status complexity
Too many states can confuse operators.
Use a practical set that supports decisions.
Detailed technical data can exist underneath without turning the main WIP view into a coding system. Use event capture close to the work. Status improves when operators or devices record start, complete, hold and move events at the operation.
End-of-shift manual updates create stale WIP.
Epicor Mars-style execution can capture these events while keeping Epicor as the enterprise work-order foundation. Reconcile physical and system WIP. Periodically test whether the system matches the floor.
Select WIP and verify:
- physical location;
- quantity;
- status;
- revision;
- next operation.
Differences indicate transaction discipline or process design issues. Use WIP states in daily capacity decisions. If the test queue is already large, releasing more upstream work may only increase WIP.
Production control should use current queue state when deciding what to start.
This prevents local efficiency from worsening total flow.
Set escalation thresholds by state. Different states can have different acceptable ages.
A two-day subcontract wait may be normal.
A two-day hold after final test may not be.
Use thresholds that reflect the process. Make hold ownership explicit. Every held WIP item should have an owner and next action.
A reason without ownership becomes a parking lot.
Show whether purchasing, quality, engineering, production or supplier action is required.
Preserve quantity through splits and merges
Electronics work can split for rework, partial shipment or external processing.
WIP tracking should maintain quantity integrity.
Unexplained split quantities often become inventory reconciliation later. Use location only when it supports action. Physical location can be useful, but location alone is not status.
A pallet at test can be waiting, running or passed.
Combine location with operational state. Review stale transactions. Sometimes the physical WIP moved but the system event did not.
Identify stale or impossible states.
Frequent corrections indicate that the capture method is too difficult or poorly placed in the workflow. Define the WIP unit of control. Some products can be tracked effectively by work order.
Others need batch, panel or serial-level status.
Choose the unit that supports the operational and traceability decision.
Too coarse hides problems; too detailed creates unnecessary transaction burden.
Make quantity status explicit. One work order can contain:
- not started quantity;
- completed quantity;
- failed quantity;
- rework quantity;
- quantity at subcontractor;
- quantity waiting final release.
A single percent-complete figure hides these states.
Use quantity buckets where they support control. Show next action, not only current reason. “Quality hold” explains why the job stopped.
“Awaiting MRB decision” or “awaiting incoming inspection” gives the next action.
The WIP view becomes more actionable when the reason and expected decision are both visible.
Use stale-status alerts
If a job shows “running” for twelve hours on a two-hour operation, something is wrong with the process or transaction.
Identify stale status automatically where possible.
This is a practical way to improve data reliability. Track WIP handoff responsibility. When one operation completes, define who owns the move to the next step.
Ambiguous handoffs create physical queues.
The system status should reflect when ownership transfers. Use WIP to estimate remaining lead time. Current operation and queue position provide better promise evidence than work-order release date alone.
Combine WIP state with the remaining routing.
This supports more accurate customer updates. Review WIP accumulation by root cause. If one area accumulates WIP, determine whether the constraint is:
- equipment;
- labor;
- quality;
- missing material;
- information;
- scheduling.
Adding capacity will not solve an information hold.
WIP analysis should identify the cause before investment.
Use WIP visibility to reduce unnecessary release. Releasing more work can make management feel that the backlog is progressing.
If downstream queues are already blocked, additional release simply creates more WIP.
Use current queue and hold status to decide whether another job should enter the floor.
This can reduce congestion, material movement and the number of partially completed orders competing for attention. Give customer service a controlled WIP summary. Commercial teams do not need every station event, but they do need a reliable current state and reason for delay.
A concise WIP summary can reduce phone calls and manual status chasing while keeping detailed execution data with operations.
What management should measure
Useful indicators include:
- WIP age by operation;
- quantity on hold;
- rework WIP;
- test queue;
- engineering hold age;
- unlocated WIP;
- off-site WIP;
- jobs with stale status;
- manual WIP corrections.
These measures show where flow is breaking.
A practical review
Choose the ten oldest open work orders.
For each one, identify exact current operation, blocking reason, owner and next action.
If the answers require a meeting to reconstruct, WIP visibility is not yet operational.
Where Epicor Mars fits in WIP visibility
For WIP visibility, the key system-design question is how to keep enterprise control and electronics-specific execution on the same operating thread. Epicor provides the enterprise-grade ERP foundation for customer orders, purchasing, inventory, planning, costing, finance, approvals and governance. Epicor Mars extends that foundation with the EMS industry context needed at the point of work, including material identity and readiness.
That connection is directly relevant to The Work Order Is Open. Where Is the WIP—and Why Has It Stopped?. Open work orders do not explain whether electronics WIP is queued, waiting for material, under test, on quality hold, in rework or sitting between operations. EMS control needs operational status at the point where work is actually waiting. When the Epicor Mars execution record stays tied to the Epicor work order, material and customer context, management can compare the business commitment with what the factory actually executed without maintaining a second source of truth.
For WIP visibility, that complementary positioning is the point: Epicor remains the enterprise-grade foundation, while Epicor Mars adds the EMS workflows needed to make this particular control operational on the factory floor. Explore Epicor Mars for electronics manufacturing.
Frequently asked questions
Is WIP visibility the same as real-time machine monitoring?
No. Machine data can help, but WIP visibility focuses on the job/unit state and reason for waiting.
Should every unit be tracked individually?
Only where product and traceability requirements justify it. Other products may use lot or work-order-level WIP.
Can ERP completion percentage replace WIP status?
Usually not. Completion percentage does not explain where or why the job is waiting.
What is the most useful WIP metric?
Age by state or operation is often very revealing because it surfaces hidden queues.