What is a normal minimum order for small batch case customization?

Answer: 200 to 300 units for an injection moulded body, about 800 with a new tool, from changeover hours and machine rate.

Can an order be as small as 50 units?

Answer: Yes, by changing route. A stock mould with sprayed or wrapped colour accepts 50, though geometry stays fixed.

The quote says six hours, so why did it take nine?

Answer: Heat soak and trials. Shooting early brings back shrink and flash, and counts climb from five to twelve.

Can one batch carry two colours?

Answer: It can, but it is two colour changes; dark to light adds 70 minutes, so 150 units each nears 8 CNY.

Is a small batch always more expensive?

Answer: Per unit yes, in total not always. 200 units tie up 11,600 CNY against 106,000 for 2000, so at 300 units a year the larger lot costs more than the 5 CNY saved, which is why small batch case customization suits spare parts.

Small Batch Case Customization: What Sets the Minimum Order

Quick answer: In small batch case customization the minimum order is a division problem, not a policy. A mould swap costs six to eight hours of press time however few parts you buy, and that block spreads across 200 or 2000 units at about 5 CNY.

Small Batch Case Customization Starts at the Changeover
What a Changeover Costs in Hours
Colour and Foam Inserts Add a Floor
The Cost Curve From 200 to 2000
Four Ways to Shrink the Changeover
FAQ

1. Small Batch Case Customization Starts at the Changeover

Small batch case customization is charged per tool, not per unit: aligning, clamping, plumbing and ejector travel take as long for 100 units as for 5000.

The quote is a division. Changeover hours times the machine rate, plus trial scrap, over margin. Six hours at 180 CNY is 1080 CNY, and at 4 CNY of margin 270 units recover it, hence the 200 to 300 floor.

Order size	Amortisation (CNY)	Landed cost (CNY)	Slot
200	5.4	58	Inserted, waits
500	2.2	55	Shared colour run
2000	0.5	53	Priority
5000	0.2	53	Dedicated

The curve flattens: 200 to 500 removes 3.2 CNY, 2000 to 5000 only 0.3.

2. What a Changeover Costs in Hours

Seven steps: 45 minutes stripping the old mould, 50 aligning to 0.05 mm, 20 for water and sensors, 60 to 90 for heat soak to 50 degrees Celsius, 40 purging, 40 for trials, 25 for the first article, totalling 4.7 to 5.2 hours.

Heat, not the crane, is the bottleneck. Preheating 40 minutes early is the only free compression, and five scrapped trials cost 2 kg.

Step	Minutes	Constraint	Overlap
Old mould out	45	Sticking ejectors	No
Alignment	50	0.05 mm parallelism	No
Heat soak	60 to 90	2.5 to 3.5 mm wall	Preheat
Trials and first article	65	Shrink, flash	No

3. Colour and Foam Inserts Add a Floor

Colour and mould changes stack. Charcoal to black is a 40 minute purge; to a light tone, three passes of 8 minutes plus hopper cleaning, so 70 minutes. Colour is judged on Delta E, where 1.5 is visible, so one masterbatch lot is required. For small batch case customization that means 25 kg, enough for 3000 units at 380 grams and 2% letdown.

Foam adds a floor. An EVA die costs 1800 CNY and three days, or 18 CNY per set across 100 sets; CNC cutting skips it at 12 minutes per set, holding radii to R3 or above.

4. The Cost Curve From 200 to 2000

Material and moulding scale linearly at about 26 CNY per unit; changeover is one 1080 CNY batch charge; finishing drops from 4 to 3.4 minutes after 500 units. The gap sits in the middle line: 5.4 CNY per case at 200 units against 0.5 at 2000, a share of 9% against 1%.

Cost line	200 units	2000 units	Behaviour
Material and moulding	26	26	Linear
Changeover	1080	1080	Fixed
Landed unit cost	58	53	5 CNY gap

The break is near 800 units: below it, recolouring an existing mould beats a 28,000 CNY tool, and in small batch case customization that is the line worth arguing over.

5. Four Ways to Shrink the Changeover

A quick-change platen with hydraulic clamps locks four points at once, cutting alignment from 50 minutes to 12. It costs about 16,000 CNY and pays back in forty changeovers.

Preheat costs nothing: warm the next mould during the previous job and save 40 to 60 minutes.

Colour batching covers three jobs with one purge, at two to three days of slippage.

Standard body plus finishing sprays a stock mould at 6 CNY per case, or wraps it in 0.4 mm PVC at 3.5 CNY, pushing the floor to 50 units.

Stacked, they bring a changeover in small batch case customization to 3.5 hours and amortisation on 300 units from 5.4 to 3.2 CNY.

Conclusion

A minimum order looks commercial but behaves like a process calculation. The changeover does not shrink with quantity while the amortisation does, and the whole 5 CNY gap comes from that line. Move the floor by sharing a changeover or compressing it below 3.5 hours, and a quote for small batch case customization stops being a yes or no answer.

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.