The mold decides cycle time more than the PLC. A poorly cooled 40-cavity tool on an FS-8556 (850×560 mm, 180 mm depth) will lose to a well-cooled 24-cavity tool on a smaller press. Brief the toolroom with CAD, material, and target cpm — not “copy this sample.”
| Press (from spec sheets) | Max area | Max depth | Do not assume |
|---|---|---|---|
| FS-7836 | 780×360 mm | 120 mm | “36” ≠ 36 drink cups |
| FS-7842 | 780×420 mm | 150 mm | Deep cups eat pitch |
| FS-7856 | 780×560 mm | 150 mm | Water jackets need space |
| FS-8556 / HSS-8556 | 850×560 mm | 180 mm | Depth is useless without cooling |
| FS-8560 | 850×600 mm | 180 mm | Largest FS area, not automatic extra cavities |
Cooling, cut, changeover
Independent circuits for cavity and plug keep PP from warping. Size the chiller to the mold — a 24-cavity PP yogurt tool can dump more heat than a 32-cavity shallow water cup. In-mold cut gives a cleaner rim; offline bottom cutters are for multi-part cups. If you run three SKUs a day, specify locating keys and hose quick-connects so changeover stays under an hour in year one.
Pitch math is unforgiving: forming area ÷ (rim + jacket + steel). Buyers who order “40 cavities because the competitor quoted 40” get a tool that cannot freeze and a press that never hits the cpm on the invoice.
Worked pitch check
780×420 mm area, 75 mm rim pitch, water jacket ~8 mm: you do not get a 10×8 grid of tall yogurt cups. We return a cavity map before steel. See mold and tooling and samples.
Fault map — what the line is telling you
| Symptom | Likely cause | First check |
|---|---|---|
| 40-cavity tool slower than the old 24 | Pitch ate the water jacket; cavities cannot freeze | Cavity map before steel — count is not a slogan |
| PP yogurt cups oval after two hours | Shared cooling on cavity and plug | Independent circuits; size the chiller to this tool |
| Changeover half a shift on a three-SKU day | No locating keys or hose quick-connects | Specify hardware now if you run more than two sizes/week |
| Rim ragged; extra bottom-cut station added late | In-mold cut never scoped | Say drinking rim vs multi-part cup before the quote |
| Aluminum trial tool dies in month four | High annual shots on soft metal | Steel when Ramadan repeats on the same SKU |
RFQ checklist — send this in one email
Fill what you know; blank is better than a guess. Attach it on Get a Quote with photos of resin or flake.
- CAD or a physical sample (rim, undercut, wall)
- Material and target cpm — not “as fast as possible”
- How many sizes per week and who changes the tool
- Press family / forming area (780×360 up to 850×600, depth 120–180 mm)
- In-mold cut vs offline bottom cutter; IML or print
- Aluminum trial vs hardened steel and estimated shots/year
Frequently asked questions
Aluminum or steel?
Aluminum for trials and low annual shots. Hardened steel when you will run the SKU for years at high cpm.
Does in-mold cut always win?
Cleaner rim, fewer stations. Not always right for multi-part cups — say so before we quote.
Why did my 40-cavity mold run slower than 24?
Cooling and pitch. Cavities that cannot freeze will force you to drop cpm.
What data do you need?
Material, wall, undercut, print/IML, target cpm, and which press family.
Can I copy a competitor’s cavity count?
Only if forming area, pitch, and cooling match. Count without a cavity map is how 40-cavity tools miss the cycle time.
How long is mold lead after CAD freeze?
Typical steel is weeks after the drawing lock, on a separate clock from the 35–45 day machine lead. Freeze both in the same week.