How does the minimum order in custom color plastic box manufacturing tie to colour?

Answer: To the number of colours, not boxes: a new shade means one masterbatch buy and one purge, so 500 pieces is usual.

What does lot-to-lot Delta E 1.5 look like?

Answer: Side by side the eye resolves roughly 1.0 to 1.5, so a part passes alone and shifts next to another.

Why discount the load on a dark box?

Answer: Dark absorbs heat, the surface reaches 70 °C, modulus falls about 30 percent and creep speeds up.

How long does a colour change stop the press?

Answer: 30 minutes light to dark, 60 dark to light with three shots of scrap.

Can I order straight from a colour card number?

Answer: No. Cards differ from moulded parts in texture and gloss, so order by number plus a sealed sample.

Custom Color Plastic Box Manufacturing: Size, Wall, Load

Quick answer: Custom color plastic box manufacturing runs colour first, size second, load last. Fix the colour code and masterbatch ratio, 2.0 percent dark and 2.5 percent light, derive outside size from usable cavity, then hold load with 2.2 to 2.8 mm sides over a 2.6 to 3.2 mm base.

Why Custom Color Plastic Box Manufacturing Starts With Color
How Size and Wall Thickness Pair Up
Load Rating and Heat From Color
Color Codes, Delta E and Batch Consistency
Sampling and Production Acceptance
FAQ

1. Why Custom Color Plastic Box Manufacturing Starts With Color

In custom color plastic box manufacturing the first variable is colour, not size. Colour sets the masterbatch grade, let-down ratio and texture, and all three move shrinkage: dark and light differ by 0.3 to 0.5 percent, or 1.2 to 2 mm on a 400 mm body.

Item	How to write it	Typical value
Colour code	Code plus a sealed physical sample	One each of olive, navy, light grey
Masterbatch	Ratio to resin weight	2.0 percent dark, 2.5 percent light
Surface	Texture depth or gloss	Fine grain, 0.05 mm
Delta E cap	In-lot and lot-to-lot, separate	1.0 and 1.5

Surface finish is often dropped: on one grey, fine grain and gloss read further apart than Delta E 1.5.

2. How Size and Wall Thickness Pair Up

Size classes and wall thickness exist as pairs in custom color plastic box manufacturing; a wall figure alone means nothing. Bodies are graded by usable cavity, each grade carrying its outside size and walls.

Custom color plastic box manufacturing: navy case open on a wooden bench, dark foam in the lid, coiled cables and gloves beside it, grey bins

Usable cavity	Outside size	Sides	Base	Weight
350 × 250 × 120 mm	400 × 300 × 165 mm	2.2 mm	2.6 mm	1.4 kg
450 × 320 × 160 mm	500 × 370 × 210 mm	2.5 mm	3.0 mm	2.2 kg
560 × 400 × 200 mm	620 × 460 × 255 mm	2.8 mm	3.2 mm	3.1 kg

Work outwards from the cavity: both walls plus rib height give the outside. The middle grade takes 2.5 mm walls and a 22 mm rib, landing at 500 × 370 mm.

3. Load Rating and Heat From Color

Colour changes load capacity. A dark body in summer sun reaches 70 °C at the surface, polypropylene loses about 30 percent of its modulus, and a nominal 25 kg static rating reads as 20 kg.

Four high puts three loaded cases on the bottom one, and a dark case held 24 hours at 70 °C sags from 1.5 mm to over 2.5 mm. The load column in custom color plastic box manufacturing splits by shade, 25 kg light against 20 kg dark.

Two ways out: dark lid over a light base, or 0.2 mm more wall.

4. Color Codes, Delta E and Batch Consistency

Delta E needs two columns: in-lot measures one run, lot-to-lot measures drift. With one figure the moulder delivers loose and the buyer inspects tight.

Custom color plastic box manufacturing: closed navy case on a grey roller conveyor, vertical side ribs and a side handle, teal wall behind

Item	Condition	Limit
In-lot Delta E	D65, five parts side by side	Within 1.0
Lot-to-lot Delta E	Against the sealed sample	Within 1.5
Light fastness	Xenon arc, 300 hours	Within 3.0
Dispersion	300 lux at 500 mm, visual	No flow marks or specks

In-lot drift is nearly always dispersion: below 225 °C the masterbatch will not melt out, above 240 °C pigments break down. Keep three sealed samples per lot for 12 months.

5. Sampling and Production Acceptance

Sampling runs in three steps: three colour boards sealed and checked under daylight and shop lighting, five T1 parts judged on colour, then a first-article check.

Write the process window into the order: melt 225 to 235 °C, mould 45 °C, resin dried at 80 °C for 2 hours, 380-tonne press. A different press needs fresh colour confirmation.

Purge time gets cut first: 30 minutes light to dark, 60 minutes dark to light plus three shots of scrap.

Conclusion

Colour sets the masterbatch, the masterbatch sets shrinkage, shrinkage sets size, size sets wall, wall sets load. That chain runs one way in custom color plastic box manufacturing. Split Delta E into two columns, split load by shade, put the process window and purge time into the order, and custom color plastic box manufacturing finally has a spec it can ship against.

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.