The Corrugator

A corrugator is a set of machines designed to bring together three, five, or seven sheets of paper to form a single, double, or triple wallboard in a continuous process.

The 3 key stages:

• Corrugating the flutes and gluing to a single liner
• Gluing the outside liner to make a rigid board
• Cutting the board to the desired size

Three sheets of paper (containerboard) are unrolled simultaneously on the corrugator: the inner liner, the outer liner, and in the middle, the medium (also called fluting).

The medium sheet is given a “wave”. This corrugation is obtained by pressing the sheet under heat through grooved metal rolls. This operation gives the paper its fluted shape in the single facer.

Starch is applied to the tips of the flutes on one side, the outer liner and the inner liner are glued to the tips of the corrugated medium sheet of paper from the outer and the inner side respectively.

The Corrugated board comes out of the corrugator as a flat board sheet.

Converting of the corrugated board

The converting of the corrugated board includes all processes of transformation from a flat board to a finished product (mainly packaging). These processes consist of printing, die-cutting, folding and gluing (taping or stitching).

Different operations are carried out based on the customer’s specification and according to the type of packaging.

The converting process varies according to the type of packaging.

Printing

Whatever the type of packaging, printing on corrugated sheets is always possible.

The flexographic print process is commonly used for printing on corrugated. In recent years the digital direct print is entering the market offering new possibilities.

Printing can be done « in-line » or « off-line ».

Die-cutting, folding, gluing

Most of the corrugated containers are manufactured on the Flexo-Folder-Gluer (FFG) machines which are combining printing, die-cutting, folding, and gluing. Those processes can be also performed on separate machines.

The packaging is then palletized and ready to be shipped flat to the customer.

COVID-19 has not affected our production