Every buyer has heard “we have strict quality control”. Almost none has seen it turned into documents that can be checked. The difference between the two is not effort — it is whether the process leaves evidence.
A custom backpack factory that can be audited runs on a four-document system: the tech pack, the inspection checklist with AQL levels, the test reports, and the corrective action log. Here is how each one works and what belongs in it.
The tech pack is the contract your QC department enforces
The tech pack is not artwork. It is the specification that inspection compares against, and if a dimension is missing here, there is nothing to inspect against.
It should carry, at minimum: a measured spec sheet with tolerances for every critical dimension; the bill of materials naming fabric, thread, zipper, webbing, buckle and logo method with supplier and reference number; construction notes including stitch type and stitches per inch; a colour lab dip card; the label and hangtag placement drawing; and the packaging specification. Anything written as “good quality” is a defect waiting to be argued about — replace it with a number and a tolerance.
AQL turns opinion into a decision rule
Acceptable Quality Limit is the standard language of inspection, and it exists so that “pass” and “fail” stop being a negotiation.
The usual starting point for bags is ISO 2859-1 general inspection level II, with a common split of AQL 2.5 for major defects and AQL 4.0 for minor defects. A major defect is one that makes the product unsaleable or unsafe — a broken stitch, a stuck zipper, a label on the wrong side, an incorrect dimension beyond tolerance. A minor defect does not stop the sale: a stray thread end, a slight stitch wobble, a fold in the lining. The inspection sample is drawn to the lot size, and the number of allowable defects follows from the tables — not from how the factory feels that afternoon.
Define the defect classification in writing before the first production run, not after the first dispute.
Three inspection gates, each with a hold point
Quality cannot be inspected into a bag at the end. It is built at three gates, and each gate must be able to stop the line.
- Incoming material inspection: fabric width, weight, colour, and zipper function checked against the tech pack before anything is cut. Once material is cut, defects become permanent.
- In-line inspection: during sewing, at defined intervals, checking seam strength, stitch density, symmetry and logo position. This is where a drift is caught while it costs one piece instead of one thousand.
- Final random inspection: a sample drawn from the finished, packed lot and measured against the AQL plan. This is the gate that issues the release note.
Test reports the buyer can read without a translator
Fabric and hardware claims should arrive as reports, not adjectives: zipper cycle testing for the pull count agreed in the PO, hardware salt spray results in hours, fabric tensile and tear strength in the standard units, colourfastness to rubbing and to light, and seam peel strength in N/15 mm. Each one names the standard it follows — ISO, ASTM or GB — and each one carries a date and a sample reference that matches the shipment.
Anything that arrives without a standard reference is marketing.
The corrective action log is the proof of improvement
Defects will occur. What separates a factory that improves from one that repeats itself is a log: what was found, how many, which lot, root cause, the corrective action taken, and the verification that the same defect did not return in the next shipment.
Ask for the last three entries. A factory that can show them is a factory that actually uses the data. A factory that cannot produce the log has been inspecting without recording — which means improvement is left to memory.
Make the paperwork part of the PO
The cheapest way to guarantee auditability is to write it into the purchase order: approved tech pack attached as a controlled document, named inspection gates and hold points, agreed AQL levels for major and minor defects, required third-party test reports, and corrective action log for the previous two shipments reviewed before the balance payment releases. Nothing here adds cost per unit. Each line removes a reason for the goods to arrive wrong.
Quality control that cannot be audited is a promise. Quality control that leaves documents is an agreement. Send SimiBag your spec and target market, and we will send back the tech pack structure, inspection plan and test reports we run for custom backpack production at https://simibag.com.