"We were not chasing a new toy," says Aran Chai, production manager at AsiaCan in Rayong, Thailand. "We were chasing a reject rate that would not go below 6.8% on our paint bucket lines."
AsiaCan injection-moulds paint buckets for construction and DIY brands across Southeast Asia. The plant runs eight SKUs, three shifts, and a mix of virgin and recycled PP. In 2021, the team began testing in mould label technology on two cells before rolling it to the full line.
This article is based on a two-hour interview on the factory floor, plus production data from January 2022 to June 2023. It covers what worked, what did not, and where the numbers still depend on operator skill.
The Production Floor Before the Switch
Before 2021, AsiaCan applied pressure-sensitive labels after moulding. For in mould label for paint buckets, that old process meant extra handling, drying time, and scrap when labels wrinkled on curved surfaces. The plant also ran promotional lids on a separate line, which created scheduling conflicts.
Scrap averaged 7.2% across 14 months, with peaks near 11% during the humid season. The defects were not dramatic: slight label drift, a lifted edge, a smeared barcode. But at three shifts and eight SKUs, those small defects added up.
The team tried adjusting the robotic arm, swapping adhesives, and adding a static bar. Each fix helped for a week or two, then the same defects returned. The team also requested an in mold label quotation from three suppliers, but the quotes were hard to compare because tooling, robot interface, and resin compatibility were bundled differently.
Why In Mould Labels Made Sense for Paint Buckets
In-mould labelling places a printed film into the mould before injection. The resin fuses around it, so the label becomes part of the bucket wall. For paint buckets, that matters because the label has to survive drops, stacking, solvents, and UV exposure on a job site.
AsiaCan compared IML with heat-transfer decoration and pressure-sensitive labels. The sister plant in Chonburi uses in mold label automotive parts, where surface defects are tolerated even less, so AsiaCan borrowed its inspection protocol. The same supplier also had experience with in mold label for sauce bottles, which helped with food-safe ink questions even though paint buckets face different chemical exposure.
The decision was not universal. Low-volume custom colours stayed on pressure-sensitive labels because the label change cost was lower. IML made sense for the top six SKUs, which together represented most of the volume. The team set a rough rule: if an order was below 5,000 buckets, IML was usually not worth the changeover.
The Customized Heat Transfer Machine and Changeover Reality
The phrase customized heat transfer machine can be confusing in this context. At AsiaCan, it refers to a modified thermal transfer unit used for promotional lid graphics, not the bucket body IML cell. The project did not start with IML alone. The plant first modified the heat transfer machine to handle short runs of branded lids.
Changeover on that lid line started at 55 minutes. After new jigs, recipe storage, and operator checklists, it dropped to 28 minutes. That gain mattered because promotional runs often lasted only one or two shifts. But the customized heat transfer machine did not solve bucket body scrap. That came from IML tooling, robot placement, and film handling.
The biggest surprise was not the machine. It was incoming film width tolerance. A 0.4 mm variation caused wrinkles that looked like operator error. Once the plant added an incoming inspection step, the same operators produced fewer defects. It was a quiet fix, but it changed the daily rhythm on the line.
18 Months Later: Numbers, Limitations, and Next Steps
By June 2023, scrap on the IML lines had fallen to 3.1%. OEE moved from 65% to 74%. The project team calculated a payback period of 19 months, including tooling, training, and the customized heat transfer machine upgrade.
The limits are still real. When recycled PP content went above 30% on two SKUs, label adhesion became less predictable, so those SKUs stayed on pressure-sensitive labels. The plant also found that colour consistency across batches depended more on resin supplier changes than on the label film itself.
The next step is a pilot with higher recycled PP and a narrower film tolerance. For AsiaCan, in mould label is now the default for high-volume paint buckets, but it is not a universal answer. The production team keeps one rule: prove the changeover, prove the scrap data, then scale.
