Smart Lock Pre-Shipment Inspection Guide: AQL, Defects & Final Shipment Checks

A smart lock order may look finished when hundreds of cartons are stacked in the factory warehouse.

But for the buyer, one important question remains:

Does the finished shipment actually match what we approved?

This is where pre-shipment inspection becomes important.

A final inspection can identify problems such as the wrong mortise, mixed Tuya and TTLock versions, missing accessories, cosmetic defects, incorrect firmware, damaged packaging, or incomplete quantities before the goods leave the factory.

For importers, distributors, private-label brands, and project buyers, a pre-shipment inspection is not the same as production quality control.

Production QC asks:

Was the product controlled correctly during manufacturing?

Pre-shipment inspection asks:

Does the finished shipment meet the agreed requirements before we release it?

This guide explains how to build a practical smart lock pre-shipment inspection plan, how AQL sampling fits into the process, what defects should be classified, and what buyers should do when an inspection fails.

1. What Is a Smart Lock Pre-Shipment Inspection?

A pre-shipment inspection, often shortened to PSI, is a final verification of finished goods before shipment.

For smart locks, the inspection can cover several areas:

product identity → appearance → mechanical operation → electronic functions → software configuration → accessories → packaging → quantity

The purpose is not to repeat every test performed during production.

Instead, PSI provides a final checkpoint between:

finished production

and:

shipment release.

SEGULOCK's existing Smart Lock Quality Control Guide already covers incoming inspection, production control, functional testing, packaging, and final inspection as part of the wider QC process. This PSI guide focuses specifically on the final finished batch.

2. PSI Is Not a Replacement for Production QC

A final inspection cannot fix a weak manufacturing process.

Imagine a batch of 1,000 smart locks.

If the wrong firmware was loaded into all 1,000 units, a final inspection may identify the issue.

That is useful.

But it would have been much better to prevent the mistake during production.

This is why a stronger purchasing process is:

Approved Sample → Frozen Specification → Production QC → Packaging Control → Pre-Shipment Inspection → Shipment

Each stage answers a different question.

Sample testing determines whether the product is suitable.

Production QC controls consistency.

PSI verifies the finished batch before release.

Do not treat the final inspection as the only quality-control activity.

3. Freeze the Approved Specification Before Inspection

An inspector cannot determine whether something is wrong unless the buyer has first defined what “correct” means.

Before inspection, provide the approved specification.

For a smart lock order, this may identify:

Inspection ItemApproved RequirementModelExact model numberFinishBlack / Satin Nickel / otherAppTTLock / Tuya / otherMortiseExact typeDoor configurationApproved specificationFirmwareApproved version where controlledLogoApproved position/versionManualApproved language/versionAccessoriesApproved packing listPackagingApproved artworkLabelApproved SKU/barcodeQuantityPurchase-order quantity

A phrase such as:

“Inspect our black smart locks.”

is not enough.

The inspector needs to know which black smart lock, which app, which mortise, which accessories, and which packaging version.

4. Use the Golden Sample as a Reference

Where practical, an approved sample can serve as a physical reference.

This may help compare:

• Surface finish

• Logo

• Panel construction

• Handle

• Display

• Accessories

• Packaging

• Product configuration

However, the golden sample should not replace written specifications.

Some important characteristics are difficult to verify visually.

Examples include:

• Firmware

• App platform

• Internal configuration

• Gateway compatibility

A strong inspection uses both:

approved sample + written specification.

5. What Does AQL Mean?

AQL stands for Acceptance Quality Limit.

Acceptance-sampling systems use a sample from a larger lot to support an accept/reject decision instead of inspecting every unit.

ISO published ISO 2859-1:2026 in January 2026. It defines sampling schemes indexed by AQL for lot-by-lot inspection by attributes. The previous 1999 edition has been withdrawn.

ANSI/ASQ Z1.4 is another widely used acceptance-sampling standard for inspection by attributes and provides normal, tightened, and reduced sampling plans.

The important practical point for a smart lock buyer is:

AQL is a sampling and acceptance framework. It is not a promise that the entire shipment contains exactly that percentage of defects.

6. Do Not Copy a Random AQL Number from Another Product

Buyers often see examples such as:

Critical 0 / Major 2.5 / Minor 4.0

and assume these numbers must be used for every order.

That is not a good approach.

The appropriate sampling plan and acceptance criteria should depend on factors such as:

• Product risk

• Customer requirements

• Order value

• Market

• Previous supplier performance

• Project requirements

A hotel project may have different risk tolerance from an inexpensive consumer accessory.

A smart lock installed on a building entrance may deserve different attention from a cosmetic accessory.

Therefore, SEGULOCK buyers should agree the inspection standard before the inspection takes place rather than arguing about acceptance criteria after defects are discovered.

7. Define Critical, Major and Minor Defects

Defect classification is one of the most important parts of the inspection plan.

The exact definitions should be agreed for the specific order.

A practical framework is:

Critical Defect

A defect that creates an unacceptable safety, security, regulatory, or fundamental-use risk.

Examples depend on the product and application.

Major Defect

A problem that significantly affects normal use or means the unit does not match the approved specification.

For a smart lock, possible examples might include:

• Main unlocking function fails.

• Motor does not operate.

• Wrong mortise supplied.

• Mechanical key cannot unlock.

• Wrong app platform.

• Essential installation component missing.

Minor Defect

A workmanship or appearance issue that does not prevent normal intended use but does not meet the agreed quality standard.

Examples may include certain small cosmetic imperfections where the buyer has defined them as acceptable or unacceptable.

The key is to classify defects before inspection.

8. Start with Quantity and Carton Verification

Before opening products, verify the shipment structure.

Check whether the finished quantity corresponds to:

• Purchase order

• Packing list

• Model mix

• Color mix

• Carton quantity

For mixed orders, confirm that cartons are clearly identified.

For example:

ConfigurationPO QuantityModel A – TTLock – Black300Model A – Tuya – Black200Model B – Outdoor100TTLock Gateway20

A shipment containing the correct total number of boxes can still be wrong if the configuration mix is incorrect.

9. Verify Product Identity Before Function Testing

An inspector should confirm that the sampled products are actually the products ordered.

Check items such as:

• Model

• Finish

• Front panel

• Rear panel

• Mortise

• Label

• App platform

• Logo

This may sound obvious, but visually similar versions can create serious problems.

A TTLock lock and a Tuya lock may use almost identical housings.

The difference may only become obvious when the app is tested.

That is why product identification and electronic configuration should be checked together.

10. Inspect Appearance and Workmanship

Appearance matters because the customer sees the product before experiencing any electronic function.

Typical areas include:

• Scratches

• Dents

• Color consistency

• Coating

• Plating

• Panel gaps

• Handle finish

• Display window

• Keypad

• Camera area

• Logo

• Protective film

Compare the finish with the approved sample or specification.

Avoid vague inspection criteria such as:

“Appearance should be good.”

If cosmetic requirements matter to your brand, define them clearly.

Private-label distributors may have tighter appearance expectations than project buyers installing locks in back-of-house service areas.

11. Check Mechanical Operation Before Electronics

A smart lock is still a mechanical locking product.

Before focusing on the app, inspect:

• Handle movement

• Handle return

• Mortise movement

• Latch

• Bolt

• Spindle

• Cylinder

• Mechanical key

• Clutch where applicable

The mechanism should operate without abnormal friction.

If the motor is tested against a mechanically binding lock body, the inspector may incorrectly conclude that the electronic motor is weak.

Mechanical operation should therefore be separated from electronic activation.

12. Test the Access Methods Included in the Order

The test plan should match the exact model.

Possible access methods include:

• Fingerprint

• PIN

• RFID card

• Mechanical key

• Bluetooth

• App

• Face recognition

• Palm recognition

Do not test features simply because another SEGULOCK product includes them.

Instead, use the purchase specification.

For example, if the buyer ordered:

Fingerprint + PIN + RFID + TTLock

those functions should be reflected in the inspection checklist.

If the product is PIN-only, fingerprint testing is irrelevant.

13. Verify App and Firmware Configuration

Software errors are especially dangerous because a lock can look perfect and still be commercially wrong.

A final inspection should confirm, where relevant:

• Correct app

• Correct product registration

• Bluetooth connection

• Remote functions where applicable

• Gateway compatibility

• Language

• Firmware/configuration identification

For TTLock projects, review the TTLock Gateway Guide if remote management is part of the product promise.

The PSI should not assume that “TTLock compatible” automatically means every remote function is available.

Test the functions included in the approved configuration.

14. Test Low-Battery and Emergency Access Requirements

Do not inspect only normal unlocking.

A buyer should also consider how emergency access has been specified.

Depending on the product, this might include:

• Mechanical key

• Emergency USB/Type-C power

• Low-battery warning

• Backup credential

The exact test procedure should follow the model specification.

Do not invent a universal low-voltage test threshold for every smart lock.

The objective is to verify that the agreed emergency-access design is present and works as expected.

15. Inspect the Mortise, Spindle and Screw Configuration

Small installation components create large field problems.

During the PSI, confirm the correct:

• Mortise

• Backset

• Faceplate

• Spindle

• Mounting screws

• Strike plate

• Cylinder where included

A perfect electronic lock with the wrong spindle can still be unusable.

This is especially important when the same model supports multiple door thicknesses or lock-body configurations.

If your team regularly encounters fit problems, also review the Smart Lock Installation Problems Guide.

16. Packaging Inspection Must Check Contents, Not Only Artwork

A beautiful color box does not mean the package is correct.

The inspector should verify both:

what the packaging says

and:

what is actually inside.

Typical checks include:

Packaging CheckQuestionBox artworkCorrect approved version?ModelCorrect?LogoCorrect?App informationCorrect?QR codeCorrect destination?ManualCorrect model/language?MortiseCorrect type?SpindlePresent and correct?ScrewsComplete?CardsCorrect quantity?KeysCorrect quantity?LabelsCorrect SKU/barcode?

This connects directly with the Smart Lock Packaging Guide.

Packaging errors should be treated as configuration errors, not merely cosmetic issues.

17. Scan QR Codes During Inspection

QR codes are easy to print and easy to overlook.

But a wrong QR code can affect an entire batch.

During inspection, scan the codes printed on:

• Box

• Manual

• Label

• Warranty card

Confirm that they lead to the correct:

• App

• Manual

• Product page

• Support resource

This is particularly important for products available in multiple software ecosystems.

A TTLock model should not accidentally contain Tuya setup instructions.

18. Check Outer Cartons and Shipping Marks

The inspection should also verify the master cartons.

Depending on the order, check:

• Carton condition

• Model marking

• Quantity

• Gross weight information where specified

• Carton dimensions where specified

• SKU

• PO number

• Carton number

• Destination marks

This becomes particularly useful when the shipment contains several models.

Correct product boxes inside incorrectly marked master cartons can still create warehouse problems after arrival.

19. Random Sampling Should Actually Be Random

Inspection loses value if the supplier prepares only a few “inspection units” in advance.

The inspector should select samples from the finished lot according to the agreed inspection procedure rather than accepting only units handed over for testing.

The objective is to obtain a useful representation of the shipment.

Acceptance-sampling standards such as ISO 2859-1:2026 and ANSI/ASQ Z1.4 are designed around formal sampling and acceptance rules rather than simply choosing several convenient products.

20. AQL Does Not Mean “These Defects Are Okay”

This misunderstanding is common.

Suppose an inspection plan permits a certain acceptance number under the chosen sampling system.

That does not mean:

“The buyer wants defective locks.”

Acceptance sampling is a statistical method used to make a lot-level decision based on a sample.

ASQ describes acceptance sampling plans as defining the sample sizes and the associated acceptance or non-acceptance criteria.

It should not replace:

• Process improvement

• Supplier corrective action

• Root-cause analysis

If the same defect keeps appearing in multiple orders, the buyer should investigate the process rather than simply accepting repeated defects because a lot happens to pass sampling.

21. Inspect High-Risk Features More Carefully

Not every function carries the same commercial risk.

For example, if a project specifically depends on:

• TTLock gateway

• Outdoor protection

• Temporary PIN

• Face recognition

• Camera

• Special mortise

these should receive additional attention in the inspection plan.

The inspection scope should reflect the reason the buyer selected the product.

For an outdoor gate lock, the buyer may care strongly about:

• Correct model

• Sealing components

• Outdoor configuration

• Finish

• Battery cover

For an apartment project, the priority may be:

• Door configuration

• App

• Mortise

• User-management functions

Use case should influence inspection priorities.

22. Check OEM and Private-Label Details Separately

Private-label projects add additional inspection points.

Check:

• Logo

• Logo position

• Brand name

• Product model

• Color box

• Manual

• Label

• Barcode

• Warranty card

• Master carton

Do not assume that correct physical hardware means the OEM order is correct.

A batch can function perfectly but still be commercially unusable if it carries:

• Wrong brand

• Old artwork

• Incorrect model number

• Another customer's manual

For OEM projects, packaging and branding are part of the product specification.

23. What Should Be in the Inspection Report?

A useful PSI report should make the release decision understandable.

It may include:

• Order identification

• Product

• Quantity

• Sample quantity

• Inspection criteria

• Defect findings

• Photos

• Functional test results

• Packaging findings

• Quantity/carton checks

• Overall result

• Inspector comments

A real 2026 smart-lock PSI sample report published by inspection provider SILQ, for example, includes product conformity, workmanship, measurements, packing audit, inspected quantity and defect categorization.

The buyer does not need exactly the same format.

But the report should provide enough evidence to understand what was actually checked.

24. What Happens If the Inspection Fails?

A failed PSI should trigger a controlled decision.

Do not immediately ship simply because the vessel booking is approaching.

First determine:

What failed?

Then determine:

How much of the batch may be affected?

Possible next actions may include:

Sorting

Separate defective products.

Rework

Correct the problem.

Replacement

Replace affected units or components.

100% Check

Useful for certain clearly identifiable defects when agreed.

Reinspection

Perform another inspection after corrective work.

Commercial Decision

In some situations the buyer and supplier may agree on another solution, but the risks should be understood clearly.

The appropriate response depends on the defect.

25. Reinspection Should Verify the Corrective Action

A second inspection should not simply repeat the first report without understanding what changed.

Suppose the original PSI finds:

Wrong Spanish manual in multiple cartons.

The supplier says:

“We replaced all manuals.”

A reinspection should verify that the correction was actually completed.

Likewise, if the issue is:

Wrong TTLock firmware.

the corrective process must address the relevant batch, not simply the sampled pieces that failed.

Ask:

• What was the root cause?

• Which units were affected?

• How were they corrected?

• How was the corrected batch verified?

26. One Repeated Defect May Matter More Than Several Random Minor Issues

Imagine an inspection finds five unrelated small appearance issues.

Now compare that with another inspection finding five units with the exact same motor problem.

The second situation may deserve more attention because it suggests a systematic issue.

When defects repeat, ask:

Could the same cause exist in the rest of the shipment?

This is where PSI should connect back to production quality control.

Inspection should not only count defects.

It should help identify risk patterns.

27. Decide Who Is Authorized to Release the Shipment

A common process problem occurs when:

• Inspector finds defects.

• Factory wants to ship.

• Freight forwarder has booking.

• Buyer has not reviewed the report.

Before production begins, define who has shipment-release authority.

For example:

Factory completes goods → PSI completed → Buyer reviews report → Buyer releases shipment

The inspector does not necessarily make the commercial decision for the buyer.

The buyer should know what result triggers:

• Release

• Correction

• Reinspection

• Hold

28. Third-Party Inspection vs Factory Inspection

Both can have a role.

Factory Final Inspection

Advantages can include:

• Faster communication

• Familiarity with product

• Integrated production process

Third-Party Inspection

May be useful when:

• Buyer is overseas.

• Order value is significant.

• New supplier relationship.

• Buyer policy requires independent verification.

• Project risk is high.

SEGULOCK's QC article already notes that buyers may use their own inspector or third-party inspection company for higher-risk orders.

A third party does not remove the need for a clear inspection specification.

An inspector can only check effectively when the buyer defines what was ordered.

Smart Lock PSI Checklist

Before shipment release, confirm the following areas:

CategoryMain ChecksQuantityPO quantity and model mixProductCorrect model/configurationFinishCorrect color and appearanceMechanicalHandle, latch, bolt, keyElectronicMotor, keypad, sensorsAccessFingerprint, PIN, RFID, etc.AppCorrect platformFirmwareCorrect configuration where controlledEmergencyKey/emergency powerMortiseCorrect lock bodySpindleCorrect configurationScrewsCompleteAccessoriesCompleteBrandingCorrect OEM logoManualCorrect model/languageQRCorrect destinationPackagingApproved artworkLabelsSKU/barcodeCartonsQuantity and markingsDefectsClassified to agreed standardReportPhotos and findingsReleaseBuyer approval before shipping

Adapt the checklist to the exact product.

A simple fingerprint lever lock and a WiFi video smart lock should not use identical test plans.

Sample Testing vs QC vs PSI

These stages have different purposes.

StageMain QuestionSample TestingIs this product suitable for our market?Production QCIs production reproducing the approved product consistently?Packaging ControlIs the final product packed and identified correctly?PSIDoes the finished shipment meet the approved order before release?

If you are still selecting models, start with the Smart Lock Sample Testing Guide.

If production is beginning, use the Smart Lock Quality Control Guide.

If private-label packaging is being prepared, use the Smart Lock Packaging Guide.

Then use PSI as the final shipment-release checkpoint.

Common Pre-Shipment Inspection Mistakes

One of the most common mistakes is scheduling PSI without giving the inspector an approved specification. Another is copying AQL values from an unrelated product without considering the buyer's risk requirements.

Buyers should also avoid inspecting only appearance while ignoring firmware, app platform, mortise, accessories, and emergency functions.

Another frequent mistake is allowing the supplier to select only specially prepared samples instead of following an agreed sampling procedure.

Finally, do not treat “PASS” as proof that every single unit is perfect. Sampling supports a lot-level decision. It does not mean every unit in the shipment was individually inspected.

FAQ

What is a pre-shipment inspection for smart locks?

It is a final inspection of finished smart locks before shipment to verify the product, functions, appearance, configuration, accessories, packaging, quantity, and other agreed requirements.

Is PSI the same as smart lock quality control?

No. Quality control covers a broader manufacturing process. PSI is the final verification of the finished shipment.

What does AQL mean in product inspection?

AQL means Acceptance Quality Limit and is used within acceptance-sampling systems to support lot acceptance decisions based on sampled units.

What is the current ISO standard for AQL sampling?

ISO published ISO 2859-1:2026 in January 2026 for lot-by-lot inspection by attributes. The previous ISO 2859-1:1999 edition has been withdrawn.

What AQL should be used for smart locks?

There is no single universal AQL setting for every smart lock order. The buyer, supplier, and inspector should agree appropriate sampling and defect criteria based on product risk, application, contract requirements, and quality expectations.

Should every smart lock be tested before shipment?

That depends on the agreed QC process and product risk. Some functions may be tested during production on every unit, while a PSI typically uses an agreed sampling plan for final verification.

What should be checked during a smart lock PSI?

Typical areas include model, finish, mechanical operation, unlocking methods, app configuration, emergency access, mortise, accessories, packaging, labels, manuals, cartons, and quantity.

What happens when a PSI fails?

The buyer should review the defects and determine whether sorting, rework, replacement, additional inspection, reinspection, or another corrective action is required before shipment release.

Is third-party inspection necessary?

Not for every order, but it can be useful for larger orders, new suppliers, high-risk projects, or buyers that require independent verification.

Inspect Before the Goods Leave the Factory

The most expensive place to discover a smart lock configuration error is usually after the products have already:

shipped → cleared customs → entered your warehouse → reached installers → reached customers.

A stronger B2B process catches problems earlier:

Approve Sample → Freeze Specification → Control Production → Approve Packaging → Inspect Shipment → Release Goods

Pre-shipment inspection should answer one final question:

Is this finished batch the product we agreed to buy?

SEGULOCK supplies smart locks for distributors, importers, private-label brands, and project buyers with different product, app, mortise, packaging, and OEM configurations.

When preparing a bulk order, send:

your target model, destination market, app requirement, door specification, quantity, OEM requirements, packaging requirements, and inspection requirements.

You can also request the SEGULOCK product catalog and B2B quotation before starting sample evaluation and bulk-order planning.

Discuss Your Smart Lock Inspection & Bulk Order Requirements

Get in touch

Address

Room 3060, Area C, No. 544 YaYun Avenue, Dalong Street, Panyu District, Guangzhou, Guangdong Province, China

Contacts

Whatsapp+8613711061941

sales@segulock.com