Should tooling be amortized into the price quoted by an injection molded plastic case manufacturer?

Either works if every quote uses the same method. Pull tooling out, divide by planned volume, compare molding prices.

Is a four-cavity tool always cheaper than a single cavity?

No. It costs more than twice as much and needs a larger press. The saving appears above roughly five thousand units a year.

Does a freezer application need a different material?

PC/ABS handles sustained -20°C duty. If forklift contact is expected, thickening corners to 3.5 mm costs less than changing compound.

How do I test whether a 25-day lead time is real?

Ask for the schedule split into tool making, trial and molding, then the machine number.

Injection molded plastic case manufacturer quote for -20°C

Quick answer: Cold-store cases fail on two lines of the quote, tooling ownership and wall thickness. Estimate clamping force from projected area, fix the wall at 2.0 to 3.0 mm with one to four cavities, then spread tooling over the volume you will really order.

Quote Sheet From an Injection Molded Plastic Case Manufacturer
Tonnage From 400 to 1300 and One to Four Cavities
Wall From 2.0 to 3.0 mm and 0.5 Percent Shrink
Who Owns the Mold When You Want a Second Supplier
Lead Time and Payment Terms in 25 Days
FAQ

1. Quote Sheet From an Injection Molded Plastic Case Manufacturer

Three quotes from an injection molded plastic case manufacturer, one drawing. The case rides a trolley inside a -20°C freezer, carries 18 kg of tools, ships sixty units at a time over 400 km plus a feeder leg. The spread between highest and lowest was 41 CNY per unit.

The gap is not in the molding but in what each quote folded into the unit price.

Quote line	Often buried in unit price	Pin down before comparing
Material and molding	Yes	PC/ABS grade, masterbatch ratio, net weight, regrind allowance
Tooling	Listed or amortized	Cavities, mold base steel, hot runner, guaranteed shot life
Secondary work	Depends on plant	Drilling, printing, foam cutting, assembly, scrap liability
Packaging	Usually ignored	Individual bag or pallet wrap, returnable pallet
Freight and tax	Written as delivered	Delivery point, Incoterm, separate mold clearance

One quote listed tooling separately, the second divided it by three thousand pieces, the third omitted it. Every injection molded plastic case manufacturer structures the sheet differently, so normalize all three into five rows before comparing totals.

2. Tonnage From 400 to 1300 and One to Four Cavities

Clamping force stops being improvised once the footprint is fixed: projected area times 0.5 tonnes per square centimetre, plus ten percent.

Injection molded plastic case manufacturer: grey lidded totes stacked two and three high on steel shelving, two latches per lid, wooden pallets behind

Case footprint	Projected area	At 0.5 t per sq cm	Machine	Cavities
350 x 230 mm	805 sq cm	403 t	400 t	2
450 x 300 mm	1,350 sq cm	675 t	700 t	2
530 x 360 mm	1,908 sq cm	954 t	1,000 t	1 to 2
620 x 420 mm	2,604 sq cm	1,302 t	1,300 t	1

The last column is what buyers skip. A four-cavity tool counts the runner in the projected area, so the press climbs past 1,300 tonnes and fewer plants can run it.

Cavities also set molding hours: one cavity runs 55 seconds, two stretch to 68, yet unit cost drops by a third.

Ask three questions: how many cavities, which tonnage, what cycle. Numbers that disagree with the drawing will not survive production.

3. Wall From 2.0 to 3.0 mm and 0.5 Percent Shrink

Wall thickness is the easiest line to blur on a quote from an injection molded plastic case manufacturer. On a nominal 450 x 300 x 180 mm body, going from 2.0 mm to 3.0 mm lifts bare weight from 2.4 kg to 3.5 kg. At 24 CNY per kilogram of PC/ABS compound, material alone differs by 26 CNY.

That is only the opening: a thicker wall lengthens cooling past 70 seconds, so the same drawing moves by thirty percent.

Under 2.0 mm looks cheaper until the freezer answers: a 1 kg ball dropped one metre onto a corner at -20°C cracks a 1.8 mm wall far more often.

Shrinkage belongs on the drawing too. PC/ABS shrinks 0.5 to 0.6 percent, or 2.3 to 2.7 mm across a 450 mm body, enough to turn a smooth lid fit stiff or leave a gasket groove uneven.

Ask the injection molded plastic case manufacturer what shrink value is compensated in the cavity, and what happens if trial parts deviate by 0.15 mm.

4. Who Owns the Mold When You Want a Second Supplier

Tooling on a case this size runs into six figures in CNY. Once paid, the name on the mold decides your leverage.

Injection molded plastic case manufacturer: a cream lidded tote rides a roller conveyor, orange racking and stacked cartons behind it, strip lights overhead

Buyer pays in full, buyer holds title, plant stores and maintains
Amortized per piece, title transfers after an agreed quantity
Plant funds the tool, plant keeps title, buyer holds use rights
Split model: buyer funds the base, plant funds the cavities

All four appear as one line reading tooling extra, and only the first lets you walk away cheaply.

Moving a two-cavity tool costs 30,000 to 40,000 CNY and about fifteen days: stripping, crating, freight, re-alignment, trial.

Settle three points: title and transfer, maintenance duty, and how the tool leaves.

5. Lead Time and Payment Terms in 25 Days

An injection molded plastic case manufacturer quoting twenty-five days to first delivery is realistic. Anything shorter invites a question about whether an existing mold is modified.

Twelve days go to the tool, four to the T1 trial, nine to production and finishing. Payment is usually 30 percent deposit against 70 percent before shipment, tooling at 50 percent on signature. Sixty-day terms add three to five percent, the plant's cost of money.

Sampling costs 1,500 to 2,500 CNY and is credited against volume, the only chance to check fit before the tool is cut.

Conclusion

Buying a cold-store case is a translation exercise: working condition into clamping force, force into wall and cycle, volume into amortization. Align the three and price stops being a matter of haggling. Title, transfer cost and schedule belong on paper before signature. The right injection molded plastic case manufacturer opens those accounts with you instead of quoting lowest.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.