Does a plastic case supplier quote include mould amortisation?

Answer: Look for a separate mould line. When listed, the price covers resin and operations. When not, the tool sits inside the price.

Can the 400-piece minimum go lower?

Answer: Yes, at the cost of spreading colour changes over fewer units. Natural or black resin runs at 200 pieces; custom light grey carries a 20 percent premium.

How long should a factory visit take?

Answer: One day covers machine tonnage, the mould register, resin receiving records and a wall measurement on the floor.

What if mould ownership stays vague?

Answer: You re-tool to move, queue behind other orders for changes, and pay for repairs. One move costs the tool again.

Plastic case supplier: 2.4 mm walls, 400-piece MOQ, 45-day terms

Quick answer: Quotes only compare against a complete RFQ. A plastic case supplier that lands 18 percent low is cheaper in wall, regrind or hardware, not overhead. Settle the mould clause, five checkpoints and the sampling credit before arguing price.

Nine fields that make a quote comparable
Where an 18 percent cheaper quote comes from
Mould ownership: three clauses that move the cost
Splitting 45 days into five checkpoints
Payment terms, sampling fees and quote validity
FAQ

1. Nine fields that make a quote comparable

Three quotes on one desk can differ by 30 percent without anyone cheating you. The gap starts in the RFQ: "500 grey cases" gets read three ways, and each plastic case supplier prices the version it imagined.

Field	Specify	Risk if blank
Dimensions	Inner clearance, three axes, 1 mm	Near-match mould, will not fit
Wall	2.4 mm plus or minus 0.2 mm, five points	Quoted at 2.0 mm, strength drops a third
Resin	Grade plus a virgin floor, say 80 percent	Unknown blend cracks in the drop test
Hardware	Latch material, count, salt-spray hours	304 swapped for zinc, rust in months
Packing	Bag per unit, layers per pallet	Billed on volume, two extra pallets
Volume	First order, quarter, year, separately	Mould loaded onto first order

Dimensions and wall are the lines most often left vague. Name inner clearance and its tolerance, measure the outer size at the highest rib, or one drawing yields two incompatible cases.

Volume decides amortisation. A 400-piece first order leaves the plastic case supplier spreading a 46,000 yuan tool across it.

2. Where an 18 percent cheaper quote comes from

Two quotes for one drawing, 18 percent apart, differ in material and operations, not profit.

Plastic case supplier: eight grey hard cases stacked four high on a wooden pallet, wrapped in clear stretch film, pale grey studio backdrop

Wall: 2.4 mm delivered at 2.0 mm saves 0.17 kg per case and cuts drop-test height from 1.2 m to 0.8 m.
Regrind: virgin content cut from 100 to 60 percent saves 3.2 yuan per kg and greys the colour.
Hardware: a 304 latch replaced by zinc plating takes salt spray from 72 hours to 24.
Finishing: foam, labels and relief valves left out of the price, then billed later.

Regrind is the hardest to detect afterwards. A batch record can be produced; colour and toughness cannot be restored.

Turn those into four checks: caliper readings at five wall points, a batch certificate, a salt-spray report, an itemised finishing price. A plastic case supplier that accepts all four is telling you how it builds.

3. Mould ownership: three clauses that move the cost

Mould cost is the vaguest line in most plastic case supplier quotations. The same 46,000 yuan tool yields a three-year cost that differs by a factor of two, because ownership decides who may move it and who pays for repairs.

Model	Payment	Portable	Fits
Buyer-funded	100 percent before tooling	Yes, against a removal fee	Long-life product
Amortised	Inside the unit price, title at a volume	Negotiable after the threshold	Small first order
Shared	Half each	With written consent	Two suppliers

Write the threshold as a cumulative count. At 9 yuan per unit a 46,000 yuan mould clears at 5,100 pieces, which is enforceable and a three-year clause is not. Add the 300,000-shot design life and the 3,200 yuan charge per change.

4. Splitting 45 days into five checkpoints

Forty-five days describes a repeat order. A first order adds 32 days of tooling and 5 of trial shots, near 82 days.

Plastic case supplier: long white case on a galvanised rack, lid ajar over black inserts, five latches and two folding handles

Checkpoint	Days	Document
Material	7	Resin grade and batch certificate
Moulding	12	First-off sample, five wall readings
Finishing	9	Foam assembly, latch torque record
Packing	5	Packing list, pallet photos
Inland freight	4	Signed delivery note

Put the checkpoints in the contract with a payment on each, or the dates are decoration. At material, reject a wrong grade on the spot. At moulding, keep the first-off sample and wall readings on file. At finishing, check latch torque and foam assembly: an under-pressed latch lifts the lid seam. At packing, count pallet layers: five down to four saves freight and raises crush damage. At freight, collect the signed note; impact before handover belongs to the supplier. The eight-day buffer covers tool changes and rework, and whoever consumes it should say why.

Pay 30, 40 and 30 percent across those checkpoints.

5. Payment terms, sampling fees and quote validity

Three clauses belong in the annex. The amounts are small, the disputes are not.

Sampling fee: 1,200 yuan per sample, credited against a first order of 400 pieces.
Terms: 30 percent deposit, balance at 45 days, or checkpoints. Pick one.
Validity: 20 days. PP resin can move 300 yuan per tonne in a week.

The sampling credit is the clause most often missed on trial orders.

Terms affect cash flow, not unit cost. Using them as a bargaining chip returns as cheaper resin or a thinner wall. A plastic case supplier handed a clear schedule quotes decisively.

Conclusion

Buying from a plastic case supplier is mostly turning a vague RFQ into verifiable conditions: nine fields decide whether quotes compare, four concessions decide whether a low price can be trusted, and the mould clause plus five checkpoints decide the cost three years out. That separates a workable plastic case supplier from an expensive lesson.

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.