Ask two operators on different shifts how much edge paint to apply and you will often get two different answers, both delivered with confidence. Neither is lying. The instruction was given verbally by a supervisor who has since moved to another line, and it has drifted.
This is the mechanism behind a large share of the variation that buyers experience as inconsistent quality: the first bulk lot matches the sample, the second is slightly different, and by the fourth the edge gloss has changed. Nothing was decided. The construction simply drifted because the method was never written down in a form that could be controlled.
What a Work Instruction Has to Contain
A work instruction is not a tech pack. The tech pack describes the product; the work instruction describes one operation, for one operator, at one station. Conflating the two produces documents nobody reads at the bench.
A usable instruction fits on one page or one screen per operation and answers six questions.
- **What is being made** — the panel or sub-assembly, with a photograph of the operation in progress, not just the finished part.
- **Which materials and components** — reference numbers, so a substitution is visible rather than assumed.
- **Which machine and settings** — stitch type, stitch density, thread ticket, needle size, foot pressure, temperature for fusing or edge painting.
- **The sequence** — the order of steps within the operation, including which seams are closed first.
- **What good looks like** — a close-up photograph of an acceptable result, and a photograph of the three most common defects.
- **Cycle time** — the target time per unit, which is what allows the line to be balanced and costed.
Paper, Laminated Cards or Screens
The format matters less than whether the instruction is present at the station and current. Three formats are in common use and each has a clear place.
| Format | Strength | Weakness | Best for |
|---|---|---|---|
| Laminated card at the bench | Always visible, no power or network needed | Hard to update, versions proliferate | Stable operations and small factories |
| Printed job packet per order | Travels with the bundle, includes order-specific detail | Consumed and discarded, no revision control | Colour and material variations per order |
| Screen at the workstation | Always current, revision controlled, can show video | Requires infrastructure and discipline | Programmes with frequent changes and multiple styles |
A hybrid works well in practice: a laminated standard card for the operation, plus a printed job packet for anything that varies by order — colour, hardware, logo placement.
Programme parameters at a glance
| Parameter | Commitment |
|---|---|
| Minimum order quantity | 500 pieces per style / colourway |
| Sampling lead time | 6–10 working days (12–15 days for complex constructions) |
| Bulk production lead time | 35–50 days after sample approval |
| Inspection standard | AQL 2.5 (ISO 2859-1), single sampling, general level II |
| Incoterms | FOB Xiamen — EXW, CIF and DDP available on request |
| Payment terms | T/T 30% deposit / 70% before shipment; L/C at sight for container loads |
| Verified production floor space | 4,950 m² (SGS-verified) |
| Team | 137 staff across 7 production lines |
| Equipment | 149 machines including computerised saddle-stitch and edge-painting units |
| Monthly capacity | 200,000 pieces |
| Entity | Founded 2014; principal has worked in bag development since 2004 |
Revision Control Is the Whole Point
An instruction that exists but is not version controlled is worse than no instruction, because it creates false confidence. The control mechanism needs four elements: a revision number on every document, a master copy held in one place, a change log recording what changed and why, and a withdrawal step that removes superseded copies from the floor.
The withdrawal step is the one that fails. New instructions are issued; old ones stay pinned to the bench because nobody removes them. A simple discipline fixes it: the revision number is written in large type on the card, the supervisor checks the number at the start of each shift, and any card with a superseded number is removed on sight. It takes two minutes a day.
The test that reveals whether control exists
Ask three operators on different shifts what revision of the instruction they are working to. If the answers differ, or if nobody knows, the factory has documents but no control.
Where Drift Originates
Variation enters at predictable points, and knowing them tells you which operations need instructions and which can be left to skill.
- **Shift handover.** The supervisor explains something verbally at the end of a shift and it is never written down.
- **New operator onboarding.** A new hire is trained by whoever is available, who may themselves be using a drifted method.
- **Substitution under pressure.** A material runs short, an equivalent is used, and the instruction is not updated to reflect what is now being run.
- **Machine change.** A different machine has different settings; the instruction still specifies the old ones.
- **Colour and material variation.** A construction that works in one leather requires a different skive or stitch density in another, and the difference is not recorded.
Cycle Times Make the Instruction Commercial
The cycle time on a work instruction is what links the method to the price. Without it, capacity planning is guesswork and line balance is impossible. With it, a supervisor can see immediately that one operation is running at twice its standard time and intervene before the line falls behind.
Cycle times should be measured, not estimated, and should reflect a normal operator at normal pace rather than the fastest person on the line. A useful practice is to time the operation five times on three different operators and take a median, then review it once the first bulk lot is complete. The revision that follows a bulk run is usually the most accurate document in the factory.
Training Records and Competence
An instruction is only effective if the operator has been trained against it and that training is recorded. For most programmes a simple competence matrix is enough: operators down one axis, operations across the other, with a mark for trained, assessed and authorised.
The matrix earns its keep at two moments. It tells the supervisor who can be moved to a bottleneck operation without a quality risk, and it answers a customer audit question about how the factory ensures competence at critical operations. Factories without one usually discover the gap when a key operator leaves and nobody else can run the operation to standard.
What Buyers Should Ask For
A buyer does not need to specify the factory's documentation system, but three questions will establish whether one exists.
- Show me the work instruction for the hardest operation on my bag.
- Which revision is it, and when was it last changed?
- Show me the revision history and the training record for the operators running it.
Building It Into a Programme
QUANZHOU JUNYUAN BAGS issues an operation-level instruction for each construction step, with photographs of acceptable and rejected results, machine settings and target cycle times, and holds the revision history with the tech pack so that any change to the product is traceable to a change on the floor. With 7 production lines and 149 machines, the instruction set is also what allows a style to be moved between lines without re-learning it.
For a buyer, the practical benefit is stability: the fifth bulk lot looks like the first, because the method was written down and controlled rather than carried in someone's memory.
Make the method repeatable
Send the construction and the operations that worry you most. The programme team will show how the instruction set and revision control apply to your style.
Frequently Asked Questions
What is the difference between a tech pack and a work instruction?
A tech pack describes the finished product: materials, dimensions, construction and tolerances. A work instruction describes a single operation for a single operator, including machine settings, sequence, photographs of acceptable results and a target cycle time.
Do small factories need written work instructions?
They need them for any operation where drift would be costly: hand operations, new materials, and anything running across multiple shifts. A ten-person workshop can often rely on proximity; a multi-line factory cannot.
What should a work instruction include?
The part being made, the materials and component references, the machine and its settings, the sequence of steps, photographs of a good result and the common defects, and the target cycle time.
Why does quality drift between shifts?
Because verbal instructions change with each retelling and are rarely written down at handover. A written, revision-controlled instruction removes the mechanism by which drift occurs.
How do I control document revisions?
Put a revision number in large type on every document, hold a master copy in one place, keep a change log, and remove superseded copies from the floor. The removal step is the one that usually fails.
Should instructions be paper or digital?
Either, provided they are present at the station and current. Laminated cards work for stable operations; screens work where styles and colours change frequently. A hybrid of a standard card plus an order-specific packet is a practical compromise.
What is cycle time and why does it matter?
The standard time to complete one operation. It links the method to the price and allows the line to be balanced. Without it, capacity planning is guesswork and an operation running at twice standard is invisible until the line falls behind.
How are cycle times set?
By measurement, not estimation. Time the operation five times across three operators and take a median, then revise once the first bulk lot is complete. The post-bulk revision is usually the most accurate version.
What is a competence matrix?
A grid of operators against operations, marked for trained, assessed and authorised. It shows who can cover a bottleneck operation without quality risk and provides evidence for customer audits.
What should a buyer ask to see?
The instruction for the hardest operation on the product, its revision number and last change date, and the training records for the operators running it. A factory that answers all three quickly has a working system.