What are pre-opened bags on a roll?

Pre-opened bags on a roll, also known as auto bags, are manufactured as a continuous roll with each bag already open on one side. An automatic bagging machine indexes the next bag and presents the opening ready for loading.

Once the product is inserted, the machine heat-seals the bag, separates it from the roll and advances the next one. Loading can be completed by an operator or an automated counting, weighing or feeding system.

Which machines use auto bags?

Pre-opened bags are used on compatible automatic bagging machines, including the SEVERN-DT tabletop bagging machine. Available in 200mm and 300mm configurations, it can run suitable poly or paper bags on a roll.

Bag dimensions, perforations, seals, roll construction and material behaviour all affect feeding, so the specification should be matched to the machine and tested before production quantities are ordered.

Why bag quality matters

Inconsistent perforations, excessive curl, poor winding, variable seals or material that does not open cleanly can cause stoppages. Severn Packaging supplies machine-ready auto bags for compatible vertical systems. Stock sizes cover common applications, while custom manufacture supports specific dimensions, thicknesses, colours, printing and specialist materials.

Are recycled-content options available?

Yes. Recycled-content LDPE options are available for many applications. The appropriate content depends on performance, appearance, traceability and regulatory requirements. Post-industrial recycled content or virgin material may be appropriate for sensitive applications requiring additional consistency or traceability.

Can auto bags be printed?

Bags can be pre-printed for branding, instructions and retail presentation, with options such as hanger holes and easy-open perforations. Variable information can also be printed inline by a compatible printer, including descriptions, part numbers, barcodes and batch information.

What specialist materials are available?

• VCI film for suitable metal components requiring corrosion protection.
• Antistatic material for electrical and electronic products.
• Mail-bag film for compatible fulfilment systems.
• Opaque or coloured film for privacy or identification.
• Vented bags that allow trapped air to escape.
• Paper bags on a roll for compatible applications.

Stock bags or custom sizes?

Stock bags suit common sizes, urgent requirements and initial trials. Custom bags are preferred where the product needs a closer fit, specific thickness, specialist features or branded printing. Testing a sample roll is the best way to confirm feeding, loading and seal quality.

Can loading be automated?

Where the product and volumes are suitable, automation options include the SEVERN-CC counting conveyor, SEVERN-CS counting scale and SEVERN-BF bowl feeder for integration with the SEVERN-DT.

Contact Severn Packaging to request samples or arrange a machine trial.