Where Four Double Walls Make Sense
Rigid bases for premium retail
The double walls on all four sides hide the raw edges of the paperboard or micro-flute, creating a clean, finished rim. This makes it an excellent base for premium goods, cosmetics, or confectionery when paired with a clear sleeve or a telescopic lid.
High-speed automated tray forming
Because it ships as a completely flat blank, it maximizes pallet density. It is built for operations that use mandrel formers to erect and glue trays at high speeds directly before the filling station.
Bottom components for telescopic boxes
This tray is frequently used as the rigid bottom half of a two-piece telescopic box, where a separate lid slides over the top. The four double walls provide a strong foundation that resists bowing under the lid's friction.
Containment for dense or heavy goods
The folded-over inner flaps reinforce the primary vertical structure, giving the tray excellent stacking strength and resistance to outward wall splay when loaded with dense items.
Retail and Automated Packing Contexts
Confectionery and cosmetics
These sectors often prioritize structural rigidity to protect delicate items and the clean visual presentation that folded-over inner walls provide.
Consumer electronics and hardware
Heavy or high-value components benefit from the reinforced corners and double-thick walls, which help maintain the tray's shape during handling and unboxing.
Contract packing facilities
Facilities equipped with automated tray formers can use the flat-blank delivery to reduce inbound freight and storage space, erecting the trays only as needed on the line.
When to Consider Pre-Glued or Lighter Trays
Hand-packing and low-volume runs
If the packing team erects trays by hand, manually folding and gluing four corners is very inefficient. A pre-glued 4-corner tray (like the B30 series) that opens by hand is usually a better fit.
When high rigidity is unnecessary
Four double walls consume a large amount of board. If high rigidity is not needed on all sides, a two-double-wall tray can reduce material usage while still providing strong primary walls.
Machine Fit and Board Selection
Tray former and mandrel compatibility
The specific make and model of the tray former dictates the blank dimensions and glue application zones. Confirming these details early ensures the corner tabs and inner flaps are sized correctly for the equipment.
Board grade and fold resistance
Every wall features a 180-degree fold. The chosen board or micro-flute should have excellent score-cracking resistance to prevent the surface from splitting when folded flat against itself.
Grain direction planning
To assist the 180-degree folds and minimize stress on the fibers, the grain direction is usually planned to run parallel to the longest wall creases.
Outer shipper or lid pairing
As an open-top tray, this package cannot ship independently through parcel networks. It is typically paired with a secure lid, inserted into a sleeve, or placed inside a master shipping carton for transit.
Clearances and Flap Adjustments
Inner flap tapers
The inner flaps that fold down to create the double walls can be tapered, meaning they are angled slightly at the ends. This prevents them from colliding in the corners, especially when using thicker board grades.
Caliper offsets for perfect corners
The height of the inner flaps is precisely offset based on the exact thickness of the board. Proper offsets ensure the flaps do not bind and the tray forms a clean 90-degree corner.
Inner flap height reduction
While the standard template folds the inner flaps all the way to the base, the flap height can be reduced to save material or accommodate specific internal inserts, provided the tray former can handle the shorter fold.
Board and packing details
Inbound freight efficiency
Because these blanks have no pre-glued joints or diagonal creases, they stack perfectly flat. This allows for maximum blanks per pallet, reducing inbound shipping and warehouse storage space compared to pre-glued styles.
