Can we order drilling only?

Answer: Yes, the stages are independent. Drilling alone carries about ¥800 in jig and programming, which is ¥0.27 per unit at 3000.

Is ±0.2 mm on hole position necessary?

Answer: Only for a gland that must hold IP67. A cable pass-through is fine at ±0.5 mm and saves about ¥1.5 per hole.

Why switch to UV digital above four colours?

Answer: Five colours mean five screens and four registration steps, and 0.3 mm of drift shows. UV digital prints in one pass at ¥9 per case.

Are jig and screen charges refundable?

Answer: They carry your drawing number once made, so no. Recovery is a separate clause, usually a per-unit credit on the repeat order.

How long does a label stay on?

Answer: Five years indoors with 468MP tape, a wiped surface and 0.2 MPa of roller pressure. Skip the wipe and the edges lift in three months. ---

Protective Case Secondary Operations Cost

Quick answer: Case Secondary Operations price by hole type, colour count and label material, not by the box: at 3000 units an 8 mm hole runs about ¥3.2, one-colour printing ¥3.4, a PET label ¥1.2, with jigs amortised separately.

Why Case Secondary Operations Are Quoted by Line
Drilling: Tooling, Tolerance and Re-sealing
Screen Printing: Colours and Minimum Runs
Labels and Nameplates: Adhesion and Weathering
Price Bands and Jig Amortisation
What Doubling the Batch Does
FAQ

1. Why Case Secondary Operations Are Quoted by Line

A quotation that lumps Case Secondary Operations into ¥18 per unit leaves both sides arguing over which part of that 18 moves when a hole shifts. Split the lines and every change has a home: holes by count, printing by colours and screens, labels by piece.

The stages also run at different rates: a CNC centre at ¥60 per hour, a screen press with set-up at ¥45, a labelling bench at ¥25. Blending them averages cheap labour with expensive labour, and hides risk: 3 percent scrap sits in drilling, 8 percent in printing.

2. Drilling: Tooling, Tolerance and Re-sealing

A round port from 6 mm to 12 mm is cut with a step drill in 8 seconds through a 3 mm wall. A USB cut-out or valve seat needs a CNC router and a jig that pins the shell flat, or the hole walks with the draft angle.

Case Secondary Operations result: a pink case upright, moulded handle in the lid, one latch each side, blank front panel, white background

Tolerance follows the fixture. A jig-held hole holds ±0.2 mm on position and ±0.1 mm on diameter; a hand drill wanders to ±0.8 mm. Waterproof glands seal on an O-ring, and 0.5 mm of offset pinches one side, the most common rework item on a sealed case.

Re-sealing is where the money goes. Once a hole is cut the IP67 rating is gone, and it returns only through a gland at ¥8 to ¥12 per hole, a vent, or a 0.2 mm membrane patch at ¥2 to ¥4 that stops splashes only. A full unit then holds 0.3 bar for 60 seconds at ¥8 per case.

3. Screen Printing: Colours and Minimum Runs

Printing splits into a one-off and a per-unit charge. A single-colour screen in a 300 mm by 200 mm frame costs ¥120 to ¥180; four colours need four screens at ¥480 to ¥720. That cost does not move with volume, so spreading it over 300 units instead of 3000 multiplies its share by ten.

The per-unit charge tracks colours, not area. One pass lands at ¥3.4 per case at 3000 units; four passes with three registration steps reach ¥12. Past four colours the error shows at 0.3 mm, and UV digital at ¥9 is cheaper.

Set-up sets the minimum. A screen change takes 40 minutes, colour matching wastes 30 g of ink, and the first 20 units go to proofing, so shops quote from 300 units. Curved walls need a cylindrical machine and 40 percent more money.

4. Labels and Nameplates: Adhesion and Weathering

A 50 mm by 80 mm PET label costs ¥1.2 to ¥2.5 and holds colour indoors for 3 years, but yellows and lifts its corners after 18 months in sun. An anodised aluminium plate of the same size runs ¥6 to ¥12 and lasts beyond 5 years.

Case Secondary Operations output: a red case closed, flat front panel with no holes or label, handle and two latches, grey background

Adhesion fails more often than material. Polypropylene sits at 29 mN/m of surface energy and ordinary adhesive will not wet it; 3M 468MP works, but only after an isopropanol wipe and 10 seconds of rolling at 0.2 MPa.

Weathering follows the route. A case that enters a −20 °C freezer cracks standard PET within two cycles, while 0.15 mm low-temperature film adds ¥0.6.

5. Price Bands and Jig Amortisation

Case Secondary Operations only compare cleanly in one table. The figures assume a 3 mm polypropylene wall, a 2.8 kg case and 2026 labour rates in southern China, before tax.

Operation	Unit	300 units	3000 units
8 mm round hole	¥/hole	6.0	3.2
Shaped cut-out	¥/hole	32	18
One-colour print	¥/case	7.5	3.4
Four-colour print	¥/case	26	12
PET label	¥/label	1.9	1.2
Aluminium plate	¥/plate	14	9

One-off costs need their own lines, with the amortisation basis written into the quotation. A ¥680 jig is ¥2.27 per unit over 300 pieces and ¥0.23 over 3000, which is why two quotes for the same drawing can differ by ¥6.

One-off item	Cost (¥)	Over 300 units	Over 3000 units
Drilling jig	680	2.27	0.23
Cut-out program	120	0.40	0.04
Four-colour screens	600	2.00	0.20

Ownership follows payment: a buyer who pays for the jig usually owns it, while a shop that absorbs the cost recovers it later.

6. What Doubling the Batch Does

Volume does not act evenly, so a single discount factor misleads. A jig is set once, so a round hole falls 47 percent between 300 and 3000 units.

Printing gains from screen life, dropping 55 percent on one colour; four colours stop four times for registration and drop 54 percent, though the cash saved is largest. Labelling gains least at 37 percent.

Batch (units)	Drilling	Printing	Labelling
100–300	Hand drill with jig	Flatbed screen	By hand
300–1000	Single-spindle CNC	Flatbed screen	Hand plus board
Above 5000	Multi-spindle head	Pad or UV digital	Semi-automatic

The break point sits at 5000 units, where each stage wants a machine of around ¥20,000 that only 12 months of orders can absorb.

Conclusion

A Case Secondary Operations quote holds up when four things are visible: holes split into round and shaped, tolerance tied to IP67, printing priced by colours and screens, and the amortisation batch of every jig in the contract. With those on the page, the ¥5 gap between a 300-unit and a 3000-unit order is arithmetic.