Litho-laminating process

The litho-laminating process is a means of creating corrugated board that has a high quality, litho printed surface. The process may use a reel  or individual sheets of corrugated board as the carrier, while the top liner is normally coated paper fed from a pre-printed reel or a stack of individual printed sheets.

The litho-laminating process can be sub-divided into three main types - inline, offline, and sheet to sheet. Some litho-laminating equipment can also be used for stand-alone  single-face corrugated production or sheeting.

The capabilities of any litho-laminating line will depend on the exact configuration of units included. In broad terms a line will consist of some combination of three main elements:

• Wet end: for single-face corrugated production,
• Laminating section: for adhering the printed paper to the corrugated substrate
• Delivery section

Not all litho-laminating lines feature a wet end. Each section may require additional handling and processing units which might include sheet feeders, rewinders, sheeters, tear tape applicators, and centerslit units, among others.

The key element of a litho-laminator wet end is the single facer group. This creates single face corrugated from reels of liner and fluting papers. The group is made up of several components including reel stands, splicers, pre-heaters, conditioners, and the corrugating single facer itself, often called a module facer, which creates the fluting and glues it to the liner.

The laminating section of a litho-laminator brings together the corrugated substrate, whether formed inline by a single facer, supplied on a reel, or fed as individual sheets, with the printed top paper, which may have been fed as a reel of pre-print or as individual sheets. A gluing unit applies adhesive to the flute tips of the corrugated carrier which the printed top paper is aligned with, and then adhered to. If the litho-laminate is to be delivered as sheets it will then be cut to the required length.

In the delivery section of a litho-laminator the laminated board passes through two drying stages - a single sheet compression process, where the sheets are pressed between two conveyors, and a belt press which results in good final bonding. The resulting litho-laminate is then delivered to a stacker or rewinder, depending on whether it is a web or a sheet.