FAQ
FAQ: What Is a Double Backer Machine?
Direct answers on double backer machines, how they combine flute layers into multi-wall corrugated board, and what buyers should specify.
Quick Answer
A double backer is the corrugating machine that bonds a second liner sheet to single-face board—or combines multiple flute layers—into double-wall or triple-wall corrugated board. It controls heat, pressure, and glue application so multi-layer board exits flat and ready for slitting and scoring.
FAQ 1: Where does the double backer sit on the line?
It is positioned after the single facer and preheaters, before the slitter-scorer and stacker, in typical corrugating line layouts.
FAQ 2: What problems indicate double backer misalignment?
Board warp, delamination between liners, uneven glue lines, and thickness variation across the web often trace to double backer heat or pressure settings.
FAQ 3: Do all carton factories need a double backer?
Only plants producing multi-wall board on-site need one. Buyers purchasing pre-made board or running single-wall programs may not require this machine.
FAQ 4: What should buyers specify when sourcing a double backer?
Web width, design speed, heat source compatibility, glue system type, and integration with existing single facer and reel stands.
FAQ 5: How does adhesive choice affect double backer performance?
Adhesive gel temperature and viscosity must match line speed and paper grade. Mismatched glue causes soft boards, bubbles, and converting jams downstream.
PackTrades Recommendation
Learn more about corrugating line components in Knowledge articles on single facer machines and production line buying, and compare machinery suppliers on PackTrades under Packaging Machinery.