Choose Between In-Process and Pre-Shipment Inspection

Suppose heat treatment for an order of undercarriage parts is performed by a subcontractor, but packing has not started. An inspection now can check evidence created around that process while correction is still possible. An inspection near shipment can examine the finished quantity, markings and packing, but it may be too late to correct a repeated process problem without sorting, rework or delay. These inspections answer different questions.

Choose the stage around the risk in the specific order. First identify where a defect can arise, when reliable evidence of it becomes available and how the cost of correction changes after the next operation. Then define the inspection scope, sampling basis, reporting path and shipment-release authority in the order plan. A satisfactory result at either stage is evidence from that inspection; it is not a guarantee that every unit is defect-free.

Broader supplier selection, commercial sourcing and order preparation belong in the neighboring bulk excavator parts sourcing guide. This page deals only with choosing the quality-inspection stage for a defined order.

Identify defects that become harder to correct later

Begin with the process route, not a generic percentage-complete rule. For each important requirement, name the operation that can create or conceal the defect. Examples might include a dimension produced during machining, a property associated with an outsourced treatment, a surface condition changed by coating, or an identification mark applied before packing. These examples are prompts for analysis, not claims that every part or process needs the same test.

Next, locate the last useful correction window. A machining issue found before coating may allow affected work to be isolated and the remaining production settings to be reviewed. The same issue found after the order is complete may require finished parts to be sorted or reworked. Conversely, carton count, shipping marks and protection between parts cannot be evaluated properly before the relevant packing is available.

This is why an in-process inspection is most useful when it can observe a meaningful production state after the risk-producing operation and before later work makes correction harder. ECQA’s comparison of during-production and pre-shipment inspection describes the earlier stage as offering more opportunity for corrective action, while the final stage concentrates on finished goods and shipment readiness. Its stated completion ranges are the provider’s service description, not a universal trigger for industrial-parts orders.

For each risk, record four facts before choosing a stage: the operation that creates the exposure, the evidence needed to evaluate it, the earliest time that evidence is valid, and the last time corrective action remains practical. If any of those facts is unknown, keep the row open. “No defect found” is not a valid conclusion when the requirement, test method or relevant production lot has not been identified.

Compare the evidence available at each stage

In-process inspection can look at work-in-progress units, production records that exist at that point, the consistency of repeated operations and whether an agreed corrective action has reached later units. It may also reveal whether material, tooling, instructions or subcontracted work differ among batches. Its limitation is equally important: some units do not yet exist, later operations may introduce new defects, and final packaging may be unavailable.

Pre-shipment inspection has a different evidence set. Finished units can be compared with the order specification, and the inspector can examine available quantities, identification, accessories, packing configuration, carton markings and general readiness for dispatch. Axoha’s stage comparison notes both this stronger view of the finished order and the narrower correction window after production is substantially complete. It also explains that inspections normally use samples, so the buyer must define the sampling plan rather than treat inspection as proof about every unit.

The following decision matrix turns those differences into order-specific fields. It is a working record, not a universal inspection plan. The two example rows are hypothetical.

A fillable version of the inspection-stage decision matrix is available with normal, missing-information and conflicting-stage examples. A blank, unknown or contradictory required field produces a hold status; it never becomes an automatic pass.

Some checks can appear at both stages, but the evidence population changes. Dimensions measured on completed units during production do not establish the condition of units made afterward. Measurements at pre-shipment do not reconstruct a process record that was never retained. When the buyer needs both early process visibility and final shipment evidence, use two linked inspections and give each a separate acceptance question.

Build a sequence for a specific order

Turn the process map into a sequence before production reaches the first planned observation point.

1. Define the order population. Record the purchase-order line, part and drawing revision, quantity, supplier site, planned lots and any subcontracted operation. Mixed production batches should remain identifiable; otherwise an acceptable sample cannot be tied confidently to the population it is meant to represent.
2. Rank the order’s failure exposures. Consider the consequence of a nonconforming part, the chance that one cause could affect repeated units, the supplier’s relevant performance history, and whether later operations conceal evidence or add substantial correction cost. A new supplier or a critical outsourced operation can justify earlier evidence, but neither automatically dictates the same inspection timing for every order.
3. Place the in-process point after evidence becomes valid. “Inspect early” is too vague. For the hypothetical outsourced heat-treatment case, the planned point would be after a traceable treated batch and required records are available, while the affected material can still be isolated before coating, assembly, mixing or packing. The actual evidence and acceptance criteria must come from the order’s approved specification.
4. Define the response before a finding occurs. State who stops or segregates affected work, who receives the report, how the affected range will be traced, what correction evidence is required, and whether a follow-up inspection is needed. An early inspection has little value if production continues across an unresolved repeated defect.
5. Place the pre-shipment point when its target evidence exists. Identify the finished population that must be available, what packing state is needed, and which labels, quantities, documents and tests will be reviewed. Do not copy an inspection company’s default percentage into the purchase order unless the buyer has evaluated and adopted it for this order.
6. Link both records. The final inspector should be able to identify the earlier lot, finding, containment and corrective evidence. If the final shipment combines lots, the report should show which lots were available and sampled. A missing link between the early finding and the offered shipment remains an unresolved condition.

The right sequence may therefore be in-process only, pre-shipment only, or both. An established, stable order with risks visible only in finished packing may place most value on the later check. A new or changed process with a costly, repeatable defect may justify an in-process point plus a final check. If the evidence needed for a risk is destructive, laboratory-based or otherwise outside an on-site inspector’s capability, the plan must identify the appropriate test and responsible party rather than forcing it into a visual inspection.

Confirm readiness and release responsibilities

Inspection readiness is a factual status agreed for the specific task. Before the visit, provide the purchase order, current specifications and drawings, approved references where applicable, defect definitions, test methods, sampling basis, available lot identities, packing requirements and report recipients. Tetra Inspection’s description of its pre-shipment process similarly calls for order details, specifications, approved references and inspection criteria. Its 80% threshold and stated AQL defaults describe that provider’s offering; they are not adopted here as universal requirements.

The buyer’s plan should state the actual readiness condition. For an in-process visit, that may be a named operation complete on a traceable set of units with the required records available. For a pre-shipment visit, it may be a defined quantity complete and a stated portion packed, with the remaining packing work explicitly identified. If the factory reports a different completion basis, or the available goods do not match the declared population, the inspector should record the difference and the buyer should decide whether to proceed, reschedule or narrow the inspection. The inspector should not silently redefine the population.

Sampling also requires an order-specific basis: the lot or batch to sample, selection method, sample size or governing plan, defect categories and acceptance criteria. If the contract invokes a standard, record its exact edition or agreed reference and any buyer-selected parameters. If no sampling basis has been approved, the result is pending rather than passed. Sampling evidence cannot support units that were unavailable, excluded or added later without an agreed extension of the decision.

Finally, separate reporting from release. The inspector records observations and the result against the assigned criteria. The supplier identifies and contains affected work and provides correction evidence. The buyer’s named quality or commercial authority reviews deviations, concessions and unresolved items. The person authorized under the purchase terms then releases the specified shipment population—or keeps it on hold. A service provider’s “pass” label does not replace that buyer decision unless the contract explicitly grants that authority.

Write the notification deadline, recipients and release evidence into the plan before inspection. If a report is missing, a requirement conflicts with the offered goods, corrective evidence is incomplete, or the release authority is unknown, the shipment remains on hold. That explicit unresolved state is what makes the sequence usable: each inspection contributes the evidence it can actually see, and no unknown is converted into approval.