Our improvement on the pre-opened bag converting machine perforation

What the Perforation Improvement Does

The improvement adds one extra perforation line below the main perforation line on pre-opened bags made on a roll. This additional line is created by an extra pre-cut blade on the machine, enabling easier opening after sealing without compromising seal integrity.

How the Extra Perforation Line Works

The main perforation line allows the bag top to pre-open when fed through the rubber roller. The second, lower perforation line is created using a partial cut—50% to 80% open—achieved by fitting fewer blades to the perforating blade holder. This partial cut maintains sealing strength while allowing the bag to open smoothly.

Why Partial Cutting Is Used

A full 100% cut would weaken the seal and reduce the bag's load-bearing ability. By using a partial cut of 50% to 80%, the machine balances easy opening with strong sealing and reliable performance during filling and handling.

Where This Machine Is Used

This improved pre-opened bag making machine is used by poly bag makers producing bags on a roll for autobaggers, and by e-commerce fulfilment and 3PL operators who need reliable, easy-to-open packaging for high-speed lines.

How the Machine Processes the Bag

The machine unwinds a poly film or laminated film reel, applies the main perforation line for pre-opening, then adds the secondary partial perforation line below it. The bag is then folded, sealed, and rewound into a roll ready for use on an automated bagging line.

Comparison of Bag Types

The left bag has two perforation lines—one main line and one secondary partial line. The right bag has only the main line. The extra line on the left bag allows easier opening after sealing, while maintaining the structural strength needed for filled bags.