Quality Control

Pre-Shipment Inspection for Custom Pins: AQL Questions to Ask

Q: The sample looked good. Why inspect again before shipment?

A pre-production sample proves the factory can make one acceptable pin under controlled conditions. It does not prove that 20,000 finished pieces were stamped, plated, enamel-filled, soldered, packed and counted correctly. A buyer may approve a 30 mm hard enamel pin with a 1.6 mm iron base, shiny gold plating, two butterfly clutches and a retail backing card, then receive cartons where 4% have low enamel, 2% have bent posts, 1% are missing clutches and several inner bags contain the wrong SKU. Those defects rarely appear in one couriered approval sample.

Pre-shipment inspection is the control point between finished goods and freight release. For enamel pins, brooches, challenge coins, keychains and small metal badges, ZheCraft normally recommends final inspection when 100% of production is complete and at least 80% is packed. At that stage, the inspector can verify workmanship and logistics accuracy: carton quantity, retail card, barcode, clutch type, polybag strength, inner-pack ratio, carton marks and packing list consistency. Inspecting at 60% completion may catch plating scratches, but it will not confirm carton counts or mixed-assortment accuracy.

The commercial risk is larger than the unit price suggests. A 5,000 piece soft enamel order at FOB USD 0.42 to 0.95 per piece is only USD 2,100 to 4,750 in goods value, but a failed event delivery can cost more in airfreight, replacements, chargebacks and lost promotion time. If a lot fails inspection, sorting and reinspection usually add 3 to 7 calendar days. Replating can add 5 to 12 days if the base metal is recoverable. Remaking can add 10 to 20 days, or longer if new tooling, special enamel colors or compliance testing are involved.

Q: What AQL level should I put in the purchase order?

AQL means Acceptable Quality Limit. It is not a quality promise and it does not mean defects are acceptable to the brand. It is a sampling rule that defines when a production lot passes or fails. For custom metal promotional products, the practical baseline is ANSI/ASQ Z1.4 or ISO 2859-1, General Inspection Level II, with Critical 0, Major 2.5 and Minor 4.0. Tighten the levels for premium retail, child-facing products, licensed brands, safety-sensitive attachments, retailer direct-ship programs or any order that cannot be rechecked after arrival.

Under General Level II, a 3,201 to 10,000 piece lot normally uses a 200 piece sample. At AQL 2.5 for Major defects, the common accept/reject number is Ac 10 / Re 11. At AQL 4.0 for Minor defects, it is Ac 14 / Re 15. Critical defects should always use acceptance number 0: one exposed sharp post, loose magnet, failed restricted-material claim or hazardous small part issue is enough to stop shipment until contained.

Lot quantity	General Level II sample size	Typical AQL setting	Typical MOQ and FOB context
100 to 499 pcs	Usually special Level or 100% check by agreement	Critical 0 / Major 2.5 / Minor 4.0	Low-MOQ custom pins; often FOB USD 0.85 to 2.20 depending on mold, plating and colors
500 to 1,200 pcs	80 pcs	Critical 0 / Major 2.5 / Minor 4.0	Common MOQ tier for event pins; standard clutch and opp bag packing
1,201 to 3,200 pcs	125 pcs	Critical 0 / Major 2.5 / Minor 4.0	Distributor orders; FOB often USD 0.45 to 1.20 for 25 to 35 mm soft enamel
3,201 to 10,000 pcs	200 pcs	Critical 0 / Major 1.5 or 2.5 / Minor 4.0	Brand campaigns, multiple colorways, retail cards or barcode labels
10,001 to 35,000 pcs	315 pcs	Critical 0 / Major 1.5 / Minor 2.5 or 4.0	Large promotions; higher risk of mixed cartons and visual drift between batches
Premium retail or child-facing items	By lot size; Level II or tightened inspection	Critical 0 / Major 1.0 or 1.5 / Minor 2.5	Use for magnets, safety claims, licensed IP, retailer chargeback exposure or USD 8 to 20 retail pins

Q: Which defects should be Critical, Major and Minor?

The weakest inspection instruction is “good quality, no scratches.” It creates disputes because the factory, inspector and buyer may judge the same mark differently. A better PO includes a defect classification sheet, approved sample photos and measurable limits. The front logo face should be stricter than the reverse side or an area hidden by a clutch. Retail-packed pins should be stricter than bulk giveaway pins because the consumer sees the product before touching it.

Critical defects are safety, legal or compliance failures. Examples include burrs or sharp edges likely to cut skin, a post tip piercing the bag or card, detached magnets, broken needles, failed lead-free or nickel-free claims, and small parts risk when the order is marketed to children. Major defects make the item unsellable, unusable or brand-damaging: wrong logo, wrong plating color, missing enamel color, detached post, weak clutch, wrong backing card, incorrect barcode, size outside tolerance, or low enamel across a visible logo area.

Minor defects are workmanship issues that do not affect function and are not obvious at normal viewing distance. Examples include a light polishing line under 3 mm on the back, a small enamel pinhole under 0.30 mm away from lettering, slight plating cloud on a hidden edge, or a minor opp bag wrinkle. If the brand sells pins at USD 8 to 15 retail, move more cosmetic issues into Major. If the pins are free conference giveaways, a realistic Minor allowance avoids rejecting usable goods for imperfections customers will not notice.

• Critical: exposed sharp edge, loose magnet, broken pin tip, hazardous small part failure, failed restricted-material claim, or post protruding through retail packaging.
• Major: wrong design, wrong Pantone beyond agreed tolerance, missing fill, detached post, weak clutch, wrong backing card, wrong barcode, wrong carton mark or low enamel visible on the front face.
• Minor: light back-side scratch, small plating cloud on hidden area, enamel dot under 0.30 mm, slight polishing line, minor opp bag wrinkle or small non-logo speck.
• Inspection conditions: review appearance at 30 to 40 cm under 600 to 1,000 lux neutral white light; use magnification only for agreed technical checks.
• Color tolerance: define Pantone code and acceptable range, for example Delta E under 2.0 for retail brand colors or under 3.0 for promotional giveaways when measured on cured enamel.
• Surface priority: front logo and lettering are strict; reverse side, edge wall and clutch-covered areas may allow minor marks if they do not affect safety or presentation.

Q: What product specs should the inspector physically measure?

A useful inspection is not only visual. The inspector should verify dimensions, thickness, weight, attachment position, enamel quality and packaging counts against the approved artwork, golden sample and purchase order. For die-struck iron, brass or zinc alloy pins, practical dimensional tolerance is usually ±0.20 mm on length and width for pieces under 40 mm, and ±0.30 mm for 40 to 70 mm pieces. Designs with deep cutouts, irregular silhouettes or cast zinc alloy may need a wider tolerance agreed before tooling.

Metal thickness deserves a written specification because it changes perceived value and attachment strength. Common enamel pin bases are 1.2 mm, 1.5 mm, 1.8 mm or 2.0 mm before plating. Heavy brooches, medals and challenge-style badges may use 2.5 to 3.0 mm. A reduction of 0.20 mm can be visible on a 35 mm pin and may weaken solder contact if the post base is not adjusted.

Plating thickness cannot be verified reliably by eyesight. If corrosion resistance matters, require XRF testing or a factory plating record. Economical decorative plating on iron or zinc alloy is often 3 to 5 microns total. A better target for gold, nickel, black nickel, antique brass or antique copper is 5 to 8 microns. Outdoor use, sweat exposure, high-humidity storage or premium retail may require salt-spray testing, sealed plating or a clear electrophoretic coating rather than relying on AQL visual checks alone.

Check item	Practical tolerance or target	How to inspect	Reject when
Length and width	±0.20 mm under 40 mm; ±0.30 mm for 40 to 70 mm	Digital caliper on random pieces; compare with approved drawing	Repeated samples are outside tolerance or silhouette is visibly inconsistent
Metal thickness	±0.10 mm for 1.2 to 2.0 mm pins; ±0.15 mm for thicker badges	Caliper on flat base area, avoiding raised logo and solder pad	Under-thickness affects weight, rigidity or attachment strength
Single pin weight	±5% from approved sample with same attachment and finish	0.01 g scale; average 10 pieces per SKU	Consistent underweight indicates thinner base, wrong alloy or missing component
Post or brooch position	±0.50 mm from approved centerline for most lapel pins	Measure from edge or centerline; check wearing angle	Pin tilts, rotates, feels imbalanced or post shows through front design
Plating thickness	3 to 5 microns standard; 5 to 8 microns improved	XRF if specified; otherwise process record plus visual inspection	Finish is thin, uneven, stained, peeling, mismatched or tarnished
Enamel fill	Hard enamel flush after polishing; soft enamel recessed but even	Visual and fingertip check across front face	Low fill, overflow, missing color, bubbles, contamination or rough logo surface
Retail card placement	Pin centered within ±1.5 mm unless buyer specifies tighter	Ruler or template against approved card	Tilted pin, off-center display, blocked barcode or wrong orientation

Q: How should attachment strength be checked without damaging the lot?

Attachment failures are one of the most common complaint categories for lapel pins, brooches and keychains. A pin can look perfect in a photo but fail after first wear if the solder area is too small, overheated, contaminated by plating residue or placed on a thin section of the design. For a 25 to 35 mm lapel pin with one post, a practical pull target is often 5 to 7 kgf. For heavier 40 to 55 mm pins, double posts or brooch bars, 8 to 10 kgf is safer. Very small 15 to 20 mm pins may use lower values, but the buyer should approve the target before production.

The inspection plan must state whether pull testing is destructive. If an inspector pulls to failure, those pieces should not ship. For most B2B orders, a sensible plan is 5 destructive pull tests per SKU plus non-destructive manual checks across the AQL sample. The inspector should rotate the clutch, press and remove it several times, and check whether the post bends, spins or separates from the solder pad.

Magnetic attachments need separate checks. The magnet should not detach from its housing, the adhesive should not lift after moderate twisting, and the holding force should suit the garment thickness. Strong magnets can increase cost, create child-safety concerns and complicate air shipping declarations, so they are not automatically better than butterfly clutches or rubber clutches for every campaign.

• Specify attachment type: butterfly clutch, rubber clutch, deluxe clutch, safety pin brooch, magnetic back, split ring, lobster clasp, ball chain or key ring.
• State pull-test target: pin post minimum 6 kgf for 30 mm lapel pins, brooch bar minimum 8 kgf for 50 mm badges, split ring connector minimum 10 kgf for metal keychains.
• Confirm test quantity: for example, 5 destructive pull tests per SKU and manual tightness checks on the full AQL sample.
• Reject rotating posts, cold solder marks, cracked solder pads, loose clutches, bent needles, open split rings, sharp brooch catches or adhesive squeeze-out around magnets.
• For keychains, check split ring closure gap under 0.30 mm and jump rings fully closed with no visible opening at normal viewing distance.

Q: What should be checked on packaging, cartons and labels?

Many shipment disputes are not caused by the pin itself. They come from mixed SKUs, missing clutches, wrong backing cards, short carton counts, unreadable barcodes or cartons that collapse during freight. Packaging inspection should verify the unit pack, inner pack, master carton and shipping mark. It should also confirm that the packing list matches the physical cartons ready for pickup.

A common economical pack is one pin plus one clutch in an individual opp bag, then 50 or 100 pieces per inner bag or small box. Retail programs may require a 300 gsm to 400 gsm backing card, Euro hole or round hang hole, barcode label and outer polybag. Backing card checks should include card size, paper weight, print color, coating, hole position and pin placement. A 1.0 to 1.5 mm hang-hole shift is often acceptable, but a visibly tilted pin on a retail card should be Major if it harms shelf presentation.

Cartons must suit the weight of metal goods. For enamel pins, coins and zinc alloy keychains, ZheCraft normally keeps master cartons under 15 kg gross weight where possible and uses 5-ply export cartons for heavy items. If one carton holds 1,000 pins at 12 g each plus cards, clutches and bags, the gross weight can exceed 14 kg quickly. For LCL sea freight or courier shipments, carton compression, corner strength and tape quality matter as much as the pin finish.

• Verify unit pack: correct pin, clutch, backing card, barcode, warning label, instruction insert and country-of-origin marking if specified.
• Count inner packs: 50, 100 or agreed quantity per bag or box; no mixed designs unless the PO defines the assortment ratio and tolerance.
• Check master carton: SKU, PO number, quantity, gross weight, net weight, carton number, destination code and buyer-required shipping mark.
• Measure carton dimensions within about ±10 mm of the packing list unless freight booking, palletization or retailer routing guides require tighter control.
• Control heavy cartons: request stronger cartons, dividers or lower carton weight for coins, zinc alloy keychains and metal sets above 15 kg gross weight.
• Define shortage rule: for event orders, even 1% shortage may be Major; for replenishment orders, a commercial debit note may be acceptable if agreed before shipment.

Q: When should I use factory QC, third-party inspection or both?

Factory QC and third-party inspection solve different problems. Factory QC is faster and better for process control because it happens during tooling, stamping, casting, polishing, plating, enamel filling, curing, soldering and packing. Third-party inspection is useful when the buyer needs independent reporting, the supplier is new, the order ships directly to a distributor or retailer, or the shipment cannot be rechecked at destination.

For a reorder of 1,000 simple pins at FOB USD 0.35 to 0.70 per piece, factory final QC plus detailed production and packing photos may be enough if previous lots were stable. For a first order of 10,000 retail-packed pins, or a kit containing pins, patches, lanyards and coins, independent AQL inspection is usually worth considering. Inspection cost is commonly quoted per man-day. In China and Southeast Asia, many general inspection firms quote roughly USD 180 to 350 per man-day depending on city, travel and report requirements. One inspector can usually cover a 200 to 315 piece sample plus packing checks in one day if SKU complexity is moderate.

Lead time also affects the inspection plan. Normal custom pin production is often 12 to 18 days after artwork approval for simple soft enamel, 18 to 25 days for hard enamel or multiple plating colors, and 25 to 35 days for complex retail packaging, epoxy, special attachments or compliance testing. Reserve third-party inspection 3 to 5 days before expected completion and keep at least 2 to 4 days between inspection and freight pickup for sorting or corrective action.

Q: What should I confirm before releasing balance payment?

Do not wait until the forwarder asks for pickup details to define inspection rules. Add the AQL level, defect classification, tolerances, packaging counts, photo requirements and rework process to the purchase order or approved production sheet. If the shipment is event-critical, state the latest acceptable inspection date, latest ship date and whether failed lots may be sorted, reworked, discounted or must be remade. A vague promise to “fix if needed” is not enough once cartons are sealed.

Before paying the balance, request a complete final QC package: overall production photos, close-up front and back photos, failed-sample photos if any, packing photos, carton marks, quantity summary by SKU, attachment test results and any material or plating test reports agreed in the PO. If a third-party report rejects the lot, ask for a corrective action plan with exact affected quantities, rework method, responsible party and reinspection date. Accepting a discount on defective goods only makes sense when defects do not affect safety, brand presentation, barcode scanning, retail display or the end user’s ability to wear the pin.

• Send the approved artwork, golden sample photos, Pantone list and tolerance sheet to both factory and inspector before mass production.
• Use General Level II with Critical 0, Major 2.5 and Minor 4.0 as a baseline; tighten for retail, premium, child-facing or compliance-sensitive orders.
• Define measurable specs: size, thickness, weight, plating finish, plating thickness if required, enamel level, attachment strength, Pantone tolerance and packaging count.
• Require photos of passed and failed samples, not only a one-line pass result; include ruler, caliper, XRF or scale readings where relevant.
• Do not release shipment until critical defects are cleared, major defects are within AQL, and carton quantities match the packing list and PO.
• For new projects, ask the factory to review the checklist before quoting because tighter plating, stronger posts, retail cards, AQL sorting and testing can affect MOQ, unit price and lead time.

Have a project? Send your artwork and target quantity and we’ll reply with a detailed quotation within 12 working hours.