What does the lowest band of case tooling cost buy?

Answer: CNY 35,000 buys one cavity, no slides, 718H at 30–34 HRC, 120 h of machining and one trial, which suits a case without side recess and holds 250,000 shots.

Why is a two-cavity tool only 1.55× the price?

Answer: Steel and base double, but machining rises only from 120 h to 195 h and trials do not change, so roughly CNY 19,000 of the CNY 54,000 is steel and plate.

Who should pay for three trials?

Answer: The first trial sits in the tool price, a tool-fault trial stays with the toolmaker, and a customer-change trial is billed at CNY 950 each.

What is tool cost per part at 20,000 pieces?

Answer: CNY 35,000 divided by 20,000 is CNY 1.75, roughly 12% of unit cost. At 5,000 pieces it becomes CNY 7.

Does a 250,000-shot life matter on a small order?

Answer: Rarely. 20,000 parts uses 8% of life, so only programmes above 50,000 parts a year need the limit.

Case Tooling Cost: Tooling Cost for Small and Mid Cases

Quick answer: Case tooling cost for a 400 mm case spans CNY 35,000 to 90,000, a 2.5× spread set by cavities, machining hours, trials and texture.

Three quote bands
One cavity versus two
What 120 hours of 718H buys
Who pays for three mould trials
Amortising over 20,000 parts
FAQ

1. Three quote bands

One 400 mm × 300 mm × 160 mm PP case, quoted at CNY 35,000 by one moulder and CNY 90,000 by another. Line by line both tools are 718H, both weigh about 380 kg, and the steel line differs by under CNY 4,000. The spread sits in five places: cavities, slides, base size, trials and texture.

718H at CNY 40/kg puts the steel at CNY 15,200, which is 43% of the CNY 35,000 quote and 21% of the CNY 90,000 one. Hours and services downstream dilute that bill, so shopping on steel grade is the wrong first move.

Slides hide best on a quotation. A case with side recesses and latch seats cannot strip on a straight pull. One slide adds 18 h, CNY 2,400 of rails and a base one size up; the four slides on the CNY 90,000 tool add CNY 14,000.

Item	CNY 35,000	CNY 60,000	CNY 90,000
Cavities	1	1	2
Slides and lifters	0	2	4
Mould base	400 mm × 350 mm	450 mm × 400 mm	550 mm × 500 mm
Trials	1	2	3
Texture	one in-house pass	one outsourced pass	two outsourced passes
Lead time	25 days	32 days	42 days

The steps are not linear. From 35,000 to 60,000 the buyer gains two slides and one trial; from 60,000 to 90,000 a cavity, two more slides and a second texture pass. Two tools can both be called a 400 mm case mould and differ by a whole part per shot.

Ask for cavity and slide counts before haggling, because a saving on the tool returns later as a modification invoice.

2. One cavity versus two

Two cavities do not double the quote. The CNY 35,000 tool becomes CNY 54,000, a factor of 1.55: base from 400 mm × 350 mm to 550 mm × 500 mm, steel from 380 kg to 620 kg, machining from 120 h to 195 h, trials unchanged.

Case tooling cost comparison: olive green case open on a steel bench, black egg-crate foam, blue pouches and paper sacks, empty grey racking behind

Item	One cavity	Two cavities
Tool quote	CNY 35,000	CNY 54,000
Steel and base weight	380 kg	620 kg
Machining hours	120 h	195 h
Trials	3	3
Shots for 20,000 parts	20,000	10,000
Cost per part at 20,000	CNY 1.75	CNY 2.70
Cost per part at 80,000	CNY 0.44	CNY 0.68

Amortisation follows parts, not shots. On 20,000 parts the single cavity carries CNY 1.75 and the two-cavity tool CNY 2.70, so the single is cheaper per part. Two cavities save press time, not tool money.

At 80,000 parts they are CNY 0.44 and CNY 0.68 and the gap narrows to CNY 0.24: the only crossover, where tool cost falls below CNY 1 per part.

Below 20,000 parts, quote one cavity. Lifting case tooling cost above CNY 50,000 for a second cavity and discounting the part by CNY 0.20 never pays back.

3. What 120 hours of 718H buys

718H pre-hardens at 30–34 HRC, so it machines, polishes and ships without quenching. The saving is not only 3–5 days of heat treatment but the 0.08 mm of flatness a 400 mm block loses in the quench, worth about CNY 4,000 of re-grinding.

The 120 h is 42 h roughing, 38 h finishing, 24 h electrodes and EDM, 16 h polishing, or CNY 10,800 at CNY 90/h, which is 31% of a CNY 35,000 quote. Hours are the easiest line to squeeze and the easiest to recover later.

Electrode count drives the EDM block: 18 for the cavity side, 14 for the core, because every corner radius, rib root and latch seat needs its own burn. Skip one and the cell loses 1.5 h, or an R0.5 corner stays sharp and costs 0.03 mm of tolerance in polishing.

At 90 mm of draw a long-reach cutter deflects 0.05 mm and the polisher spends 6 h flattening it.

Texture runs CNY 1,200–3,000/m² plus 5 days outsourced. A 0.12 m² lid is CNY 360 for one pass and CNY 720 for a redo.

4. Who pays for three mould trials

One trial costs about CNY 950: 2 h of press time at CNY 300/h, 8 kg of material at CNY 12/kg, two people for 2 h, plus scrap handling. Three trials reach CNY 2,850, or 8% of a CNY 35,000 quote.

Case tooling cost by cavity count: four open tool cases on a wood-grain bench, dark EVA cut-outs, one white liner, numbered recesses at right

Ownership needs three lines in the quotation. The first trial sits inside the tool price; a trial caused by a tool fault stays with the toolmaker; a trial caused by a drawing, colour or insert change is billed at CNY 950 each.

Modification sits outside the five-line breakdown: CNY 400–600 per added or removed spot, CNY 6,000 for a slide, CNY 1,200 for an insert, from CNY 2,000 to re-texture, CNY 300/h to polish.

One change is avoidable before steel is cut: the lid gap. Drawn at 0.3 mm it scuffs at 60 ℃ and opens to 0.45 mm, two spots of added material, CNY 1,000 and 3 days.

5. Amortising over 20,000 parts

CNY 35,000 over 20,000 parts is CNY 1.75 each. Over 5,000 parts it is CNY 7, and the tool share of unit cost climbs from 12% past 40%. That bracket deserves more time on the tool band than on the moulding rate.

718H running PP at 60 ℃ wears 0.02–0.03 mm across 250,000 shots, and texture depth falls from 0.05 mm to 0.03 mm, so a cosmetic part needs a re-texture or a new insert at 15%–20% of the original price, CNY 5,000–7,000.

That limit barely constrains mid volume. A 20,000-part order uses 8% of life and needs 12 years of repeat business to exhaust it.

Five lines make a quotation negotiable: steel and base, hours, standard components, trials and modification, texture. With five lines two quotes align item by item; with one lump sum the buyer cannot see where the 2.5× went.

Conclusion

Judge case tooling cost on five lines, never on a lump sum. Spread the two quotes out and steel plus base moves from CNY 15,200 to CNY 19,000, a gap of CNY 3,800, while machining moves from CNY 10,800 to CNY 34,200, more than three times. Push on hours and slides; push on steel and a supplier buys a cheaper grade until the 250,000-shot life drops to 150,000. Fix the cavity count first, because CNY 35,000 buys one cavity and CNY 54,000 buys two, and haggling across the two strips slides and trials that come back as modification. Three moves before signing: demand a five-line quote, write the ownership of three trials into the order, and run the amortisation at 20,000 parts. Those three shrink the 2.5× spread to under 1.4×, and what remains is the honest premium for cavities and life.

Line	CNY 35,000 tool	CNY 90,000 tool	Basis
Steel and base	15,200 (43%)	19,000 (21%)	weight × rate
Machining hours	10,800 (31%)	34,200 (38%)	hours × rate
Standard components	4,200 (12%)	16,200 (18%)	slide, lifter, guide count
Trials and modification	2,800 (8%)	12,600 (14%)	count
Surface texture	2,000 (6%)	8,000 (9%)	area × rate

This article discusses container-side specifications and design implications only, and does not cover any handling, loading or use of the contents.