A packaging moulder’s deep PP container had a core that drilled channels could not cool. A 3D-printed conformal cooling insert cut the cycle from 27 to 21 seconds, reduced warpage by two thirds and paid for itself in five months.
Key numbers
A packaging moulder produced a deep polypropylene container on a high-volume tool. The cycle time was 27 seconds, and the parts warped more than the customer liked. Every attempt to shorten the cycle made the warpage worse. The core was the problem: tall and narrow, it could only be cooled by a single drilled channel and baffle, which left most of its surface running hot.
What the data showed
Cooling made up 17 of the 27 seconds, 63% of the cycle. Thermal imaging after mould opening showed uneven core temperatures, with the upper part of the core much hotter than the base. The hot areas shrank later than the rest of the part, causing warpage of around 1.1 mm. This was exactly the type of tool described in conformal cooling: is it worth it?, where conventional channels cannot reach the areas that need cooling most.
What changed
- Simulation compared the existing conventional cooling with several conformal designs, predicting core temperature distribution, cycle time and warpage for each.
- A new core insert was 3D-printed in maraging steel, with cooling channels following the shape of the core about 4 mm below its surface.
- Water treatment and filtration were added, because narrow conformal channels are vulnerable to scale and blockage.
- Cooling time was then reduced step by step, with dimensional and warpage checks at each stage.
Results
Cycle time fell from 27 to 21 seconds, with cooling reduced from 17 to 11 seconds while fill, pack and ejection stayed the same. Warpage dropped by two thirds, from 1.1 mm to 0.35 mm, because the core now cooled evenly. At the tool's volumes, the insert paid for itself in five months.
Why it worked
The conformal channels removed heat evenly from the whole core, including the tall upper section that conventional cooling could not reach. Even cooling meant even shrinkage, which reduced warpage, and faster cooling meant a shorter cycle. Unlike many process changes, it improved both quality and productivity at once, much like the core cooling changes in our earlier closure cycle time case study.
Lessons for your operation
- Break down cycle time. If cooling dominates, look at the hardest-to-cool areas.
- Thermal imaging quickly shows hot spots that drive cycle time and warpage.
- Simulate before committing to a conformal insert.
- Protect narrow channels with water treatment and filtration.
- Reserve conformal cooling for tools where volume justifies the cost.
