Crate and tote box moulds.
Thin ribs, a stack rim that has to engage on the pallet, a handle that survives being dragged across a warehouse floor — crate tooling is a balance between stiffness and shot weight. We build 1 to 4 cavity tools that hit both numbers.
Stiffness comes from the rib, not the wall.
A 600 × 400 crate carries 20–25 kg with a wall of 1.8–2.4 mm. That only works if the rib pattern is right: ribs too thin starve during fill, ribs too thick sink on the visible face. We model the rib layout in the tool design and check the fill balance before cutting, so the base stays flat and the walls do not bow under load.
Stacking and nesting crates need two different things from the same tool. A stacking crate needs a rim and feet that locate positively; a nesting crate needs a taper and a stop that prevent over-nesting and jamming. The geometry lives in the tool, so it is worth getting the drawing argument settled before steel is ordered.
Folding and collapsible crates add hinges and snap locks, which means more slides, tighter tolerances and a longer trial. We build them, but we quote them honestly: a folding crate tool carries roughly 25–35% more tooling hours than the same size rigid crate.
Where the money goes
Most crate tools are 2 or 4 cavity, hot runner, with a hardened stack rim insert. That insert takes the wear from thousands of pallet engagements, and it is the first thing to erode — making it replaceable is cheaper than re-cutting a cavity block.
- Cavity and core: 718H or 2738, nitrided on the rim and handle faces.
- Stack rim: separate hardened insert, replaceable after wear.
- Gate: hot runner with 2–4 drops, or a direct gate on single-cavity tools.
- Cooling: conformal-friendly layout on the base, baffles in the core, 3–5 zones.
- Ejection: stripper plate or ejector sleeve, because a crate has no room for ejector pins in the base.
- Texture: VDI 3400 range, or a smooth finish for food-contact crates.
PP, HDPE, or recycled blends
PP gives the best stiffness-to-weight ratio and is the default for logistics crates. HDPE is tougher in cold rooms and outdoors. PCR and PIR blends are increasingly requested — they shrink differently and need a longer cooling time, which we build into the cycle estimate rather than discovering during the trial.
What we build to
| Typical part size | 300 × 200 mm up to 800 × 600 mm |
|---|---|
| Cavities | 1, 2 or 4 |
| Cavity steel | 718H / 2738, rim and handle faces nitrided |
| Gate | Hot runner (2–4 drops) or direct gate |
| Cooling | Baffled circuits, 3–5 zones, base-priority layout |
| Cycle time | 35–60 s depending on wall and cavity count |
| Tool life | 500,000–1,000,000 shots |
| Press tonnage | 400–1,600 t |
| Lead time | 10–12 weeks from design freeze |
Wall thickness, rib pitch and rim geometry decide both the tool price and the part price. If you are still choosing between a stacking and a nesting design, send both drawings — we will quote the version that costs less to run, not the one that costs less to cut.
Practical questions on crate tooling.
Can one tool make two different crate sizes?
Only by changing cavity inserts, which is a family-mould approach. It works when the two crates share the same footprint and differ in depth. It is rarely cheaper than two separate tools unless the annual volume of each is below about 20,000 pieces.
Why is my crate warping after demoulding?
Almost always differential cooling — the base cools slower than the walls, or the core circuit is undersized. The fix is in the tool: more baffles in the core, separate zones for base and wall, and a longer hold before ejection. It is worth fixing in the tool rather than slowing the cycle forever.
Do you build folding and collapsible crate moulds?
Yes, with the caveat that they carry more tooling hours: hinges, snap locks and additional slides. Expect 25–35% more tool cost and roughly two extra weeks compared with a rigid crate of the same size.
Can you mould from recycled PP?
Yes. Recycled material shrinks more and varies batch to batch, so we add cooling time and set the tool up with slightly larger shrinkage allowance. Tell us the material source at quotation stage — it changes the cavity dimensions, not just the process settings.
Send the crate drawing, get a real number.
Tell us footprint, wall thickness, load rating and annual volume. You get cavity recommendation, steel grade and lead time in the reply.