News release | August 2026

ZRAY has signed partnership agreements with two corrugated packaging manufacturers to co-develop flap folding alignment standards for sustainable board grades. The goal: make next-generation recycled and lightweight boards run as reliably on automatic case formers as traditional virgin-fiber boards do today.

The Problem with “Green” Board Grades

Sustainable corrugated is not a marketing problem — it is a mechanical one. Recycled board and lightweight flutes behave differently on a case former:

• Higher caliper variance. Recycled linerboard can vary in caliper by ±0.3 mm between batches, while virgin fiber typically holds ±0.15 mm. On a fixed-gap flap folder, that variance shows up as mis-folded flaps.
• Lower stiffness. A 100% recycled single-wall board may be 15–25% less stiff than the virgin equivalent at the same grammage, so the flap crease creeps during folding and the case comes out slightly out of square.
• Crease memory issues. Overly deep creases from the die cutter cause the board to split at the crease line under the folder’s pressure, producing micro-cracks that weaken the case’s stacking strength.

These three factors are the top causes of flap-folding misalignment jams on lines that have already switched to recycled board.

What the Partnership Covers

The cooperation has three workstreams:

1. Joint Test Protocol for Flap Folding

ZRAY and the two mills have agreed on a standard test protocol for board samples before they go into production:

• Flap folding angle test — a 20-sample set is folded 90° on the ZRAY test erector and the fold angle measured against the target ±1°.
• Crease depth gauge check — crease depth is measured against board caliper to flag over-creased blanks.
• Grain direction verification — folds are checked parallel to the corrugation direction, since cross-direction folds on recycled board crack more easily.

2. Adjustable Folding Geometry on New Machines

Based on the partners’ board data, ZRAY has added a flap folding pressure profile adjustment to its case formers. Instead of a fixed folding shoe, the machines now accept a per-recipe folding force and timing profile stored in the PLC. When a customer changes board supplier or grade, the recipe is re-tuned in minutes rather than requiring mechanical shimming.

This applies across the range, including the single-piece case erector, three-piece case erector, and double-head high-speed case former.

3. Field Data Exchange

The mills share their board property statistics (caliper, stiffness, crease depth) for new grades, and ZRAY feeds back machine-side jam and fold-quality data. This closes the loop: board developers see how their grades perform on real equipment, and ZRAY tunes default recipes before a new grade ever reaches a customer line.

Early Results

In a 90-day pilot with one partner mill’s 100% recycled linerboard:

• Flap folding misalignment rate on the test erector: 2.1% → 0.4% after recipe tuning.
• Case squareness deviation improved from ±4 mm to ±1.5 mm on 500 × 350 × 250 mm cases.
• No crease-splitting was observed across 40,000 test cycles on B-flute recycled board.

What This Means for Your Line

If you are already running — or planning to run — recycled or lightweight board on an automatic case former, you can now:

• Send ZRAY a board sample pack (20 blanks) for a free folding alignment test.
• Receive a pre-tuned PLC recipe for that specific board grade with your machine.
• Get a written recommendation on crease depth limits to share with your die cutter.

Availability

The folding pressure profile adjustment is standard on all new ZRAY case formers and available as a software/actuator upgrade for machines installed since 2023.

Ready to test your recycled board grade on a ZRAY case former? Book a free flap folding alignment test or message us on WhatsApp at +86 13681839278.