Quick answer: Shortlisting an industrial plastic case manufacturer starts with the quote, not the total. Demand five lines for tooling, material, moulding, secondary work and freight. The order below took 46 days from drawing to warehouse, settling minimum quantity, mould ownership, delivery and payment in that order.
Table of contents
- Why the first quote is not comparable
- Mould ownership and a three-page sign-off
- Minimum order, cycle time and delivery arithmetic
- What audits, payment terms and contracts miss
- FAQ
1. Why the first quote is not comparable
In March 2025 a client building assembly lines needed 800 partitioned cases: 600 × 400 × 280 mm outside, stacking four high. The same drawing went to four plants; quotes ran from 186 to 268 CNY, a 44 percent spread.
Four prices, one drawing. The gap was the number of lines in each quote.
| Quote line | Usual wording | What to ask |
|---|---|---|
| Tooling | 38,000 CNY one-off | Who holds title, mould number, storage address |
| Material | PP copolymer, per kg | Virgin content, regrind source, colour code |
| Moulding | Per piece, trimmed | Machine tonnage, cavities, cycle time |
| Secondary work | Holes, dividers, printing | Divider moulded in one shot or fitted later |
| Packing | Carton on pallet, ex-works | Freight included, stack height, wrapping |
Two sent one figure, 214 CNY, and nothing else. That may exclude tooling, or already spread it across 300 pieces.
Three differences hide below the surface: virgin resin or 30 percent regrind, a new tool or a modified common mould, a divider moulded in one shot or fitted later. Each moves unit price 10 to 20 percent and surfaces only when asked.
So the first move is not haggling but requesting five lines instead of one number. An industrial plastic case manufacturer that cannot produce them will recover the gap in tooling or modification fees.
2. Mould ownership and a three-page sign-off
Once structure is agreed, tool ownership decides your leverage for three years. A mould for a 600 × 400 body weighs about 1.85 tonnes, runs on a 320-tonne machine and costs roughly 38,000 CNY, which plants fold into the first run at 76 CNY per piece across 500 units.
Three clauses are possible: separate invoice titled to the buyer; amortised but still titled to the buyer; absorbed and titled to the plant. The third hands away your second round of bargaining.
Ask for five samples, not one. One sample says nothing about batch stability: keep two for destructive testing, send three to the line for a trial fit, and get the record signed.
Then compress the sign-off into three pages: the drawing with its 3.2 mm wall and 1.5° draft; material and appearance, colour difference inside ΔE 1.5; tooling title and storage, mould number and collection notice.
Most disputes start with one of those pages left blank, not with a bad part. An industrial plastic case manufacturer willing to fill them in usually has room left in the price.
3. Minimum order, cycle time and delivery arithmetic
Eight hundred pieces is not a large order. One cavity on a 320-tonne machine at a 210-second cycle yields about 130 cases a shift, so 800 takes six shifts and ties up a machine for a day and a half. Small runs drift to the back of the schedule.
The industrial plastic case manufacturer usually prices in bands: a 1.35 multiplier below 500 pieces, base price from 500 to 2,000, and 6 percent off above 2,000. At 800 you sit in the base band.
| Stage | Days | Deliverable | Payment |
|---|---|---|---|
| Tool design and build | 18 | Trial report, first-off sheet | 30% |
| Sampling and sign-off | 5 | 5 samples, three-page confirmation | 0 |
| Production | 16 | 800 pieces, batch record | 60% |
| Inspection | 7 | Full inspection record, packing list | 10% |
The stages add up to 46 days. Count delivery from the date the signed sample returns, not the purchase order, or 18 days of toolmaking land on your calendar.
4. What audits, payment terms and contracts miss
An audit of an industrial plastic case manufacturer is not about floor area. Ask three questions: does the tool store carry a numbered plate for your mould, does the machine tonnage list match the running schedule, and who controls the regrind bin. That filters out many trading companies.
The rest belongs in a contract annex.
- Tooling title: mould number, storage address, collection on 30 days' notice, freight and rigging.
- Regrind ceiling: virgin content at 85 percent or higher, with blend records per batch.
- Colour: ΔE within 1.5 under one light source, not by eye.
- Salt spray: 96 hours neutral salt spray without blistering for outdoor storage.
- Payment: 30 percent deposit, 60 percent against the bill of lading, 10 percent after acceptance.
- Delay: 0.3 percent of order value per day beyond 7 days late, capped at 5 percent.
Payment terms are the item most often traded for price, though sixty-day terms for 3 percent usually cost more in funding.
On audit day, walk to the tool store before the showroom. Showroom samples are chosen; numbered plates are not.
Conclusion
Across 46 days and 800 pieces, cost was set by three documents: a quote split into five lines, an annex naming the mould owner, and a delivery clause stating which date starts the clock. Choosing an industrial plastic case manufacturer comes down to who opens the quote, not to who quotes 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.
Related Reading
- Mould storage and numbering practice
- Factory tour checklist for case plants
- How to review a showroom sample
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