A buyer with twelve SKUs across three formats and four pack counts is not buying twelve products. They are buying one production schedule with eleven interruptions in it. The interruptions are real cost, and they are almost never itemised.
What a changeover actually involves
Stopping a pad line is the quick part. Restarting it correctly is not. A format change typically touches:
- Material rolls. Topsheet, backsheet, core, adhesive, release paper — each change is a thread-up and a registration reset.
- Cutting and forming tooling. Swapped, aligned and trialled.
- Sealing parameters. Temperature, pressure and dwell, re-established for the new material combination.
- Packaging line. Film, fill count, seal settings, coding.
- Quality release. First-off samples checked and approved before the run is allowed to continue.
The last item is the one buyers most often underestimate. Lines do not restart into full production; they restart into a hold while samples are checked. That hold is scheduled time that produces nothing.
How the cost reaches the unit price
There are two honest ways to handle changeover cost, and a third that is not honest.
Absorbed into unit price. The factory divides total changeover time by projected volume and adds it to every unit. This rewards volume and penalises small runs, which is usually correct.
Charged per run. A fixed set-up charge appears once per production run. This is transparent and easy to audit, and it makes small runs visibly expensive — which they are.
Not charged at all. This happens more than buyers expect on first orders, where a factory absorbs changeover to win the business. It reappears at the first reorder, usually as a price increase that the buyer experiences as a supplier behaving badly.
Designing a range that does not fight itself
Four levers reduce changeover cost without reducing commercial coverage:
- Consolidate formats. Two pad lengths that differ by ten millimetres may be one product in the market and two changeovers on the line.
- Vary the pack, not the product. Pack count changes are far cheaper than format changes. A range built on pack variation carries most of its complexity on the packing line instead of the main line.
- Sequence by material family. Grouping SKUs that share topsheet and backsheet reduces thread-ups significantly.
- Commit to run lengths. A firm twelve-month volume commitment per SKU buys a better schedule than an indicative total across the range.
This is the same logic that sits behind SKU and pack planning, and it is worth running before a range is finalised rather than after the first quotation comes back higher than expected.
The question to ask at quotation stage
Ask how many production runs the order will be split into, and how long each changeover takes on the line being quoted. A factory that can answer precisely is quoting from a schedule. A factory that answers vaguely is quoting from an average, and the average will not be your experience.
The manufacturing process page shows the line sequence these changeovers interrupt, and the OEM services page sets out how we schedule multi-SKU programmes.
