Manufacturing Chipboard

Raw material, currently around 98% recycled wood waste, is stored in 2300 tonne enclosed silos to minimise environmental impact.  Recycled material is screened, cleaned and any contaminants removed before being blended and fed into a Recalor dryer.  With an hourly capacity of 45-55 tonnes this is the largest dryer in the UK.

In the control room the Dieffenbacher continuous press is configured to produce boards from 1,830mm and 2,540mm in width and in thicknesses from 6 to 40mm. 

After cutting the board is rapidly cooled before sanding.  Board is stored in a intermediate storage facility prior to finishing and despatch. 

Melamine Faced Chipboard

The board is transferred to two Dieffenbacher short cycle laminating lines for application of printed papers.  Each line has a capacity of 180 cycles per hour enabling the board to be cut immediately without bowing. 

The board is cut and despatched to meet customers requirements.

Quality at Sonae Knowsley

Knowsley is a modern plant with state of the art plant and monitoring equipment. The factory produces wood particle board to meet the criteria of both, BS EN 312, (physical requirements for Particleboard) and also the site Quality Management System, which operates to ISO 9001.

The philosophy is to produce product ‘right first time’ and to enable this, the manufacturing system is arranged as a series of linked processes, all of which operate within set ‘recipes’. This arrangement is essential in the control of a naturally occurring but variably presented raw material, such as wood fibre.

The Quality Management System (QMS) is initiated at the point of raw material collection from supplier premises. Tight specification is imposed to limit particle size and contamination levels. This is checked on receipt at the Knowsley site by selective and also random sampling, where the moisture content is also confirmed satisfactory.

Significant investment has been made in the automated handling and cleaning of the raw wood chip, prior to controlled size reduction to produce engineered flakes for storage, pre-drying.

The drying process, in common with all board mills is critical and here the final moisture content is carefully monitored and the drying process controlled, to produce flakes at the correct moisture level for further processing. As with all the processes, this operation runs 24 hours a day and 7 days a week. All the control measures are pre-set and automatic adjustments are made to the process to maintain the ‘recipe’ compliance.

After drying the quality ethic is maintained by screening the material into controlled fractions for use in the core of the board and also the surface. Any over or undersize material is rejected at this point for rework or use as fuel for the process heat requirement. Again, the system is set to operate with minimal operator intervention, to maintain pre-set parameters. The screened fractions are delivered to storage silos and then drawn on demand for the next linked process.

The separate core and surface fractions are now weighed and blended with the exact quantity of resin (glue) required to produce the desired properties for the grade of board intended. This part of the process is where the inbuilt quality system is at it’s most dramatic, as it monitors the flow of wood required by the press, the balance between, surface and core fractions and intermediate silo levels to maintain the glued material at the optimum level prior to pressing.

The glued material is spread evenly over a running belt, similar to a paper making operation and a continuous ribbon of glued woodchip is prepared and taken to the press. Here again the inbuilt monitoring is essential as the weight, both across, the ribbon of wood chip (the mat) and down the length is held in tight tolerance to produce a consistent product.

The mat is delivered to the continuous press which is 42 meters in length and here the ‘cooking’ of the glued chips is carefully linked to the application of pressure to collapse the material to the required density and thickness. The variation of weight and thickness will control the final board properties and if the glue is also varied, we can significantly influence the board properties. To control this, we have established ‘recipes’ for all board types which when entered at the start of a production run, will maintain the production output at the required quality level.

The board exits the press hot and is allowed to cool prior to sanding to calibrate the board to final thickness.

All the above, linked processes are subject to operator oversight to maintain the required ‘recipe’ compliance and random sampling of both the final product and the material in intermediate stages, is maintained to create an auditable quality cross check to verify compliance to the ISO 9001  and BS EN 312 requirements.

Quality cannot be delivered by final inspection. It is matter of philosophy, engineering expertise and attention to detail.

The most important part of the Sonae quality system, is customer awareness and response. It is our practise to listen to our customer comments and respond positively. It is our goal to anticipate the requirement and deliver the response before the request.