Nest Depth on Egg Trays: Why 2 mm Changes the Whole Stack

One Dimension, Three Effects

Nest depth is how far one tray sinks into the tray below. It affects stack stability, total stack height and denesting force simultaneously.

A 2 mm increase can improve stability while raising denesting force beyond the line limit and reducing the trays per pallet.

That is why nest depth changes should never be made to fix one problem in isolation.

Measuring It

Measure the height of a stack of 30 trays and divide by 30, then subtract the single tray height difference.

Measure with trays loaded as they ship, since loaded trays deflect and nest deeper.

Record both empty and loaded values. They differ, and the loaded value is the one that matters for the pallet.

The Working Range

A typical 30-egg tray nests 4 to 8 mm. Below 4 mm the stack is unstable laterally; above 8 mm the denesting force rises sharply.

The range is set by post height and rim geometry, which are tool features.

A tray at 10 mm nest depth can require a magazine height limit to keep denesting force in range.

Effect on Stability

Deeper nesting constrains lateral movement, which is why tall stacks of deeply nested trays are more stable.

But it also means a misaligned tray cannot settle into position, so a poor stack stays poor.

Shallow nesting allows self-alignment, which is an advantage on manual stacking.

Effect on Stack Height

Trays per pallet is stack height divided by the nested height per tray. A 2 mm increase on a 30 mm tray is a 7 percent loss of trays per pallet.

On a full container that is a real freight cost, and it is usually not included in the tool change decision.

Calculate trays per pallet before accepting a nest depth change.

Effect on Denesting

Contact area rises with nest depth, so friction rises. A tray that nests 2 mm deeper carries proportionally more denesting force.

This is the effect that stops packing lines, and it appears at the bottom of the magazine first.

Measure denesting force at the bottom of a full magazine after any nest depth change.

Specification

Write the nest depth range, the stack height for 30 trays and the denesting force range at the line humidity.

Add the trays per pallet as a commercial requirement, since it can be affected by the other three.

Review all four numbers together at first article. They are one system, not four specifications.

Questions Buyers Ask

What is a normal nest depth for an egg tray?

Four to eight millimetres for a 30-egg tray. Below 4 mm the stack is unstable; above 8 mm denesting force rises sharply.

How much stack height does 2 mm of nest depth cost?

About 7 percent of trays per pallet on a 30 mm tray, which is a real freight cost on a full container.

Why does nest depth affect denesting force?

Contact area rises with nest depth, so friction rises. The effect appears at the bottom of the magazine first.

Does loaded nesting differ from empty nesting?

Yes. Loaded trays deflect and nest deeper, so the loaded value is the one that determines pallet height.

Can nest depth be changed to fix stability alone?

No. It changes stack height and denesting force at the same time, so all four numbers must be reviewed together.

Next Step

Send the tray drawing and the line magazine height. You will receive a nest depth recommendation with the three side effects quantified, in one reply.

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