ECMA B20.04.00.00

Unglued Webbed-Corner Tray

The Unglued Webbed-Corner Tray is a one-piece folding carton designed to prevent minor leaks of crumbs, powders, or grease. Instead of standard cut corners, it uses continuous webbed corners that bellows-fold inward, creating a solid barrier at the base.

Because it uses no glue, it is delivered completely flat. The short end walls fold over 180 degrees to trap the webbed corners, locking securely into base slots for a clean, double-wall presentation.

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  • Nationally competitive pricing & delivery costs.
  • Available in a wide variety of configurations.

At a glance

  • Continuous webbed corners prevent bottom leakage
  • Unglued, self-locking assembly
  • Double-thickness end walls for a premium look

Common uses

  • Bakery and pastry trays
  • Confectionery packaging
  • Retail display trays for small parts
  • Food service and catering

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Bakery, Confectionery, and Retail Display

Bakery and Pastry Packaging

The continuous corners keep crumbs, sugars, and minor grease contained within the tray, making it a strong choice for baked goods when paired with the right board coating.

Retail Display for Small Parts

The double end walls provide a clean, substantial look on the shelf, while the webbed corners ensure small components do not slip out during handling.

Confectionery and Sweets

For loose candies or powdered sweets, the webbed corners prevent fine particles from escaping the bottom edges during transit and display.

Food Service and Catering

Useful for serving dry or mildly greasy foods where a continuous corner barrier helps maintain a clean presentation.

Hand Packing and Automated Tray Forming

Hand-Packing Operations

Because this tray is entirely self-locking, it bypasses the gluing stage during manufacturing. This can be advantageous for short digital runs or operations that prefer to erect trays on demand.

High-Volume Packing Lines

While it can be folded by hand, this style is frequently erected by automated plunger-and-die tray formers on high-speed packing lines.

Short-Run and Digital Print Programs

The unglued format makes it easier to produce small batches or prototypes without needing folder-gluer setup time.

Comparing Cut-Corner and Pre-Glued Trays

When corner leakage is not a risk

If you are packing solid, contained items where crumbs or powders are not an issue, a standard cut-corner tray offers a simpler fold and less material bulk at the corners.

When vertical stacking is required

Open-top trays have limited vertical compression strength. If the trays will support weight in transit, they usually need an outer shipping carton or a switch to a rigid lid system.

Board Caliper, Grain Direction, and Lock Fit

Board Caliper and Flexibility

The webbed corners involve the board folding back on itself multiple times. Thick or brittle materials, such as micro-flute corrugated, can crack or create too much bulk, preventing the end walls from locking. Standard folding boxboard is usually preferred.

Packing Line Setup

Hand packing involves coordination to gather the webbed corners while folding the end walls over. If your volume is high, verify that your automated tray formers are compatible with this specific fold-over locking sequence.

Moisture and Grease Resistance

While the physical corners prevent dry leaks, the board itself needs appropriate barrier coatings if the tray will hold greasy or moist foods.

Grain Direction and Corner Cracking

The multiple converging creases in the webbed corners are susceptible to cracking. Discussing board grain direction and scoring profiles with your converter can help minimize this risk.

Locking Tab Sizing, Webbed Flap Angles, and Base Slots

Locking Tab Sizing

The tabs that secure the fold-over walls should be precisely sized to match the base slots and the board thickness. If the board changes, these clearances should be recalculated to ensure the tray stays locked.

Webbed Flap Angles

The angle of the webbed corner creases can be adjusted to change how the material gathers, improving the fold for different tray depths.

Base Slot Clearances

The receiving slots in the base panel can be widened or narrowed depending on the friction needed to hold the fold-over flaps securely.

Board and packing details

Print Surface and Presentation

The exterior of the base and long walls, as well as the interior of the short end walls, are formed from the same side of the blank, allowing for continuous branding.

Friction Flap and Crescent Slot Variants

B20.04.00.00.a (Friction Flaps)

Uses a different locking logic, relying on trapezium-shaped friction flaps rather than explicit locking tabs and base slots.

B20.04.00.00.b (Crescent Slots)

Features crescent-shaped locking cuts in the base panel and a modified inner wall profile for a different locking engagement.

Additional notes

Automated tray forming

While this tray can be erected by hand, high-volume operations often use plunger-and-die tray formers. Check with your equipment manufacturer to ensure compatibility with fold-over webbed corners.

FAQs

Assembly and Route

Does this tray need glue or tape?

No. It is a one-piece, self-locking design. The short end walls fold over the gathered corners and lock into slots in the base.

Product Fit

Is this tray liquid-tight?

No. While the webbed corners prevent dry powders and crumbs from escaping, the tray is not sealed for liquids. Moisture resistance depends entirely on the board's coating.

Materials

Can I use corrugated board for this tray?

It is usually a poor fit. The webbed corners need the material to fold tightly. Corrugated board is often too bulky and may crack or prevent the locking tabs from seating properly.

Assembly and Route

How is it delivered?

Because it uses no glue, it is delivered completely flat, which maximizes shipping and storage efficiency.

Product Fit

Can I stack these trays?

Open-top trays do not bear vertical weight well. For shipping or palletizing, they usually need to be placed inside a master shipper or fitted with a structural lid.

Materials

Why does board thickness matter so much for this design?

The locking tabs rely on precise friction and clearance to stay in their slots. If the board is thicker or thinner than specified, the lock may fail or the board may tear during assembly.

Product Fit

What coatings work well for bakery use?

Grease-resistant or poly-coated boards are often used to prevent butter or oils from soaking into the paperboard, keeping the tray looking clean.

Assembly and Route

How does the webbed corner fold?

As the side and end walls are raised, the corner material folds diagonally inward like a bellows, resting flat against the inside of the short end walls before being trapped by the fold-over flap.

Review your product's containment needs and your packing line's capabilities to determine if a webbed-corner tray is the right fit.

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