What a pre-shipment inspection is and is not
A pre-shipment inspection, often shortened to PSI, is a check of a finished, packed lot before the balance is paid and the goods leave the plant. The inspector draws a random sample of cartons, opens them, checks the pairs against the signed golden sample and the spec sheet, runs agreed functional tests, and reports defects by severity. If the lot fails, it is sorted or reworked and inspected again.
A PSI is not a substitute for testing during development. It cannot tell you whether a model passes FCC Part 15 or CE RED, whether a cell survives UN 38.3 or whether a lens meets ISO 12312-1; those come from lab reports on the design. What it tells you is whether this lot was built like the approved sample, works out of the box and is packed and labelled to ship. Development testing is covered on testing and inspection.
Sampling and acceptance rules
Most buyers use a sampling plan based on ISO 2859-1, with an acceptance quality limit (AQL) for each defect class. A common structure is shown below; the actual levels are stated working defaults, confirmed per order.
| Defect class | Examples in smart glasses | How it is usually treated |
|---|---|---|
| Critical | Swollen or damaged cell, exposed conductor, sharp edge, missing recording indicator on a camera model, missing battery marks | Zero accepted; any finding fails the lot |
| Major | Will not pair or charge, one speaker silent, hinge does not hold, lens scratch in the viewing zone, wrong firmware version | Tight AQL agreed per order |
| Minor | Small cosmetic mark outside the viewing zone, slight print offset, carton scuff | Looser AQL agreed per order |
Functional tests take time per pair, so some buyers run appearance checks on the full AQL sample and functional tests on a smaller special sample. Agree this in writing before the inspection so the report can be read against it.
The inspection checklist
Appearance and fit
- Frame color, finish and logo against the golden sample; no flash, sink marks or plating defects.
- Lens tint, coating and cleanliness; scratches or inclusions in the viewing zone.
- Frame measurements - lens width, bridge, temple length - within the tolerance on the spec sheet.
- Hinge opening force and alignment; temples sit level when the frame is open on a flat surface.
Electronics and function
- Power and pairing. Power on, device name as approved, pairing to a reference phone, reconnection after power cycle, multipoint where specified.
- Audio. Both speakers play, no distortion at the agreed volume, balance between sides; a quick leak check where an acoustic fixture is available.
- Calls. Microphone pickup on a test call, with noise reduction behaviour per firmware.
- Controls. Touch strip gestures and buttons, voice prompts in the right language.
- Charging. Pogo pin contact on the cable or case, charge indicator, charge start within the expected time.
- Firmware version. Read the version from the app or test tool and match it to the approved release. This one check catches many quiet changes.
- Line extras. Camera models: photo and video capture, recording indicator LED visible and working. AI and translation models: app connection and a short session, noting that languages and latency depend on the app and translation engine.
Packaging, labels and shipping marks
- Box, insert, case, cable, manual and accessories complete and as approved.
- Barcodes scan; retail labels, compliance marks and FCC ID or CE mark present where required.
- Export cartons: correct counts, weights and carton marks; lithium battery marks for shipments under UN3481; the UN 38.3 test summary available for the forwarder.
- Carton drop test on one or more cartons if agreed per order.
Common findings and their causes
Patterns repeat across programs, and knowing them helps you write the spec sheet so they are caught early.
- Wrong firmware version. Often a late fix applied on the line without a change notice. Prevent it with a written release rule and a version check at final test.
- Weak or noisy charging. Dirty or misaligned pogo contacts, or a cable from a different batch. Check contact plating and sweat resistance in development; see smart glasses not charging.
- Hinge feel varies. Screw torque not controlled, or a mixed batch of hinge parts.
- Lens marks. Lenses handled without protective film during assembly.
- Cells at high charge. IATA recommends a state of charge of no more than 30 percent for lithium-ion cells packed with or in equipment under PI 967; it is a recommendation rather than a rule, but many forwarders ask for it.
Reading the report and deciding
A good PSI report lists the sample size, the defects found by class with photos, the functional test results and a clear pass, fail or pending verdict against the agreed AQL. If the lot fails, the options are to sort the full lot and reinspect, to rework a defined defect and reinspect, or, for minor cosmetic issues only, to accept with a written concession. Do not accept a lot with a critical finding on a battery or electrical safety point.
Who should inspect
The inspection is most useful when it is independent of the production team. Options include the plant's own outgoing QC with a buyer review of records, the sourcing desk's inspector, or a third-party inspection company commissioned by the buyer. Whoever inspects needs the golden sample or a set of reference photos and measurements, the spec sheet, the test steps, a reference phone with the app installed and, ideally, simple fixtures for speaker and charging checks. An inspector who arrives with only a generic consumer electronics checklist will miss the eyewear points - hinge feel, frame measurements, lens zones - and the battery paperwork. Brief them on the product before the visit, and ask for photos of every defect and of the carton marks.
Build the inspection into the timeline: book it when the plant confirms the lot is at least 80 percent packed, and allow a few days for a possible reinspection before the vessel or flight cut-off. Typical batch and shipping times are on MOQ and lead time, and shipping paperwork is covered on logistics and shipping. To include inspection in your program, use the quote form.