In plastic case pictures, what should I check first?

Answer: Latch spacing on the long side. Two latches at the ends and a bare middle means a light injection part; three to five with a centre latch suggests thick walls.

Can wall thickness be measured from a photo?

Answer: Only estimated. Scale from flange width: 8 to 12 mm suggests 3 to 5 mm walls, 14 to 20 mm suggests 6 mm.

Is a rotomoulded case always stronger?

Answer: No. It spreads thickness evenly and absorbs impact, but is less stiff than an injection case of equal weight.

How far off are published load ratings?

Answer: The gap is in test conditions. A 200 kg figure is static, so cut it by a 1.5 safety factor when stacking.

How do I avoid picking wrong on a small order?

Answer: Get three views, a wall section and a video of the real part, then ship one empty case.

Plastic Case Pictures: Types, Materials and Selection

Quick answer: Five case families compared by moulding method, wall thickness, outer size and load, plus the cues in plastic case pictures that turn one photo into a specification.

Reading the Five Case Types in Plastic Case Pictures
Telling Molding Methods from Structural Cues
Five Views and What Every Drawing Must Call Out
Four Misreads Buyers Make from Photos
A Selection Index by Total Weight and Shipping Mode
FAQ

1. Reading the Five Case Types in Plastic Case Pictures

Two black cases look alike at thumbnail size yet differ threefold in wall thickness and twofold in price. Shape is the residue of a process.

Type	Moulding	Wall	Outer size	Empty weight	Load
Hard injection case	Two-piece	3.0–5.0 mm	500×350×220 mm	3.2–5.0 kg	60–90 kg
Rotomoulded case	Single shell	6.0–12 mm	620×450×320 mm	8–14 kg	120–200 kg
Trolley case	Injection, metal handle	2.2–3.2 mm	560×400×250 mm	4.5–7.0 kg	35–50 kg
Stacking tote	Injection, ribbed base	2.5–4.0 mm	600×400×280 mm	2.6–4.2 kg	300 kg static
Wheeled body	Injection plus castors	3.5–6.0 mm	700×480×360 mm	9–16 kg	80–120 kg

Injection tooling runs RMB 120,000 to 300,000 on a 1,200-tonne press; rotomoulding costs RMB 30,000 to 80,000 and reaches 12 mm walls.

2. Telling Molding Methods from Structural Cues

Raking light shows the parting line, the lid step shows flange width, latch spacing shows the load path. Those cues in plastic case pictures settle process without opening the box.

Plastic case pictures: a khaki rotomoulded case on a table, a pressure relief valve centred on the front flanked by latches, fabric rolls behind

Rotomoulded shells show no parting line, only a gate witness; injection cases carry a mid-height seam and bolt-on bumpers. Flange width scales from a photo: 8 to 12 mm injection, 14 to 20 mm rotomoulded.

Cue	Injection	Rotomoulded
Parting line	Seam at mid-height	Gate witness only
Flange width	8–12 mm	14–20 mm
Latches	2–4 near the ends	3–5 with a centre unit
Seal groove	Insert lip	Moulded double lip
Pressure valve	Rare, drilled later	M12 threaded, common
Hinge pin	3–4 mm metal	6–8 mm stainless

3. Five Views and What Every Drawing Must Call Out

One frame in a set of plastic case pictures is useless for assembly planning. Handle retraction and castor overhang decide whether a case fits a rack or a van.

View	Must state	Often omitted
Front	Length and height	Handle retraction 25–40 mm
Side	Depth and lid height	Castor overhang 60–80 mm
Top	Internal length and width	Corner radius 8–15 mm
Bottom	Foot spacing, stack lip	Landing pad 3–5 mm
Isometric	No dimensions	Latch and valve positions

Retraction protrudes even when stowed. Castor overhang runs 60 to 80 mm, so two cases need 150 mm extra.

4. Four Misreads Buyers Make from Photos

Renders passed off as photography, unmarked scale, accessories left out of net weight and internal sizes quoted as external cause most disputes over plastic case pictures.

Plastic case pictures: a worn olive grey case on a workshop bench, scuffed corners and latches, wooden crates, fabric rolls and tape behind

Misread	Real gap	Check
Render read as photo	0.3 mm sink marks, flash	Unretouched raking-light file
Disguised scale	Looks 20 percent larger	Three views with scale bar
Accessories excluded	Wheels and foam add 1.5–3 kg	Weigh the complete case
Internal read as external	Two walls plus ribs	Ask which dimension

Drop height is often just a claim. Checkable wording names 1.2 to 1.8 m, six faces, three edges and one corner at rated load.

5. A Selection Index by Total Weight and Shipping Mode

Packed weight is the fastest entry point in plastic case pictures: it settles type, wall thickness and handling.

Under 15 kg a hand-carried injection case with 3.0 mm walls is enough. Between 15 and 40 kg use a trolley case, handle tube at least 1.2 mm, wheels 75 mm or more. Above 40 kg add forklift pockets and 100 mm clearance under the base.

Conclusion

Line the five families up by process, wall thickness, size and load, and one frame becomes a checklist. Watch four things: parting line, flange width, latch spacing, handle retraction. Read the next set of plastic case pictures with that filter.

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.