Paper production process
A step-by-step guide to our papermaking process:
Paper for recycling is mixed with processed water and then stirred in a giant stainless steel vat, called a pulper, to make a fibre suspension. Impurities are removed using a series of screens, to ensure that we only produce high quality paper that can be used to make high performance packaging.
Our paper machines remove water from the fibre solution. At the start of the papermaking process, the solution comprises of roughly 1% fibre and 99% water.
Diluting the paper fibres this way allows us to make thin, uniform paper.
At the wet end of the paper machine sits the headbox, which distributes a uniform jet of watery stock.
The liquid falls onto the wire or forming fabric. Beneath the wire, foils (short for hydrofoils) remove water and improve fibre uniformity, ensuring that the fibres weave together in a tight mat.
The wire passes over suction boxes that vacuum out the water, leaving a soft mat of pulp that forms the paper sheet, also known as the paper web. By now the wire has travelled 30-40 meters. In a couple of seconds, the water content has dropped to 75-80%, and the web has lost its wet sheen.
The next stage of water removal consists of passing the paper web through a series of nip rollers that squeeze the water out of the pulp mat. This pressure also compresses the fibres so they intertwine to form a dense, smooth sheet. At this stage, the water content has reduced to between 45 and 55%.
The paper web now travels through an enclosed space containing a number of steam-heated drying cylinders. They are warmed up to 130ºC using steam heat to ensure that the paper is now 80 to 85% dry.
Wet sizing solution is now applied to the paper in order to add a thin layer of starch to the surface. Starch contributes to stiffness and the bonding of the fibres within the sheet of paper.
After the sizing is applied, the paper passes through another set of heated drying cylinders. In all, the paper web may travel 400 meters through the dry end. In the process, it will lose roughly 93% of its water.
To give the containerboard a smooth and glossy surface to optimise it for printing, the paper passes through a set of smooth rollers, which can be hard or soft, that press the paper, embossing a smooth face on the paper surface.
Real-time quality control
Producing high-quality paper depends on maintaining extremely fine control over the variables in the manufacturing process. The sheet of paper is now inspected by an automated measuring device that detects imperfections.
After completing its 500-metre journey, the paper exits from the paper machine and is automatically wound onto a jumbo reel, which can weigh 50 tonnes and be up to eleven metres wide.
The jumbo reel is lifted by crane to a nearby winder, where the paper is unwound and cut into smaller rolls as ordered by the customer, then labelled for shipment.
On a regular basis, samples of containerboard are taken to our Quality Control laboratories, to ensure that our paper is the highest quality possible.