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MANUFACTURING

    Kerto® products are manufactured in Metsä Wood Lohja and Punkaharju Kerto Mills in Finland.

The commercial production of Kerto LVL started year 1981 in Lohja Mill. Thus Metsä Wood is the first LVL manufacturer in Europe and yet today has the largest annual LVL production capacity in Europe.

 

WOOD SUPPLY  

 

Over 90 % of the wood raw material used in Kerto manufacturing originates from the Finnish forests of the owner members of Metsäliitto Cooperative (Metsä Group). The wood supply is controlled by certified quality and environmental management systems including chain of custody of the wood origin. Metsä Group wood supply is controlled by followind quality and environmental management systems:

ISO 9001 Quality management system

ISO 14001 Environmental management system

Chain of custody: - PEFC (Programme for the Endorsement of Forest

Certification) - FSC (Forest Stewardship Council)

The vast majority of raw material used in Kerto manufacturing is PEFC certfied. The availability FSC certified raw material is limited.

PRODUCTION PROCESS

Kerto production is managed according to principles of ISO 9001:2008 standard. The quality and conformity of the product is controlled by a third party, VTT Expert Services Ltd, with reqular site inspections and audits.

Kerto LVL is manufactured by gluind rotary peeled softwood veneers. The main raw material is spruce (Picea abies), but the product may contain small shares of pine (Pinus sylvestris). Kerto products are CE marked according to standard EN 14374 for structural LVL. The system of assessment and verificationof constancy of performance AC1 is followed in Kerto production which requires eg. external quality control.

TABLE 1. BASIC FIGURES OF KERTO PRODUCTION

Lohja Mill

Punkaharju Mill

Number of production lines 2 2

Starting years 1986, 1998, 2017 2001, 2006

Annual production capacity 100 000 m3 130 000 m3

Maximum product length (m) 25 m 24,5 m

Maximum product width (m) 1,8 m 2,5 m

Product thicknesses (mm) 21 – 75 mm 21 – 75 mm

Products Kerto-S, Kerto-T,

Kerto-Q Kerto-S, Kerto-T,

Kerto-Q

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This document is property of Metsäliitto Cooperative (Metsä Wood) and is only applicable when used along with products produced by Metsä Wood. Use of the document for other manufacturer's product is prohibited. Metsäliitto Cooperative is not responsible for application of documents or possible faults in documents. This clausul must not be removed. Metsä Wood and Kerto are registered trademarks of Metsäliitto Cooperative (Metsä Wood). 

The logs are measured, debarked and soaked in warm water and cut to right length for the lathe

The lathe blocks are peeled to 3 mm thick continuous veneer mat, which is then cut to veneer sheets.

Veneer sheets are dried and graded based on strength and visual quality.

Glue is spread on top of the veneers and the veneers are laid up to continuous 1,8 m or 2,5 m wide billet.

- Weather resistant, dark-brown colored phenol-formaldehyde adhesive is used.

- In scarf-joints of the surface veneers on top side of the product a colorless melamine adhesive is used for better appearance.

The billet is hot-pressed, when the glue lines are cured

After hot pressing the billet is cut and rip sawn to order-specified dimensions

Finished products are packed in plastic wraps.

Kerto product thicknesses vary between 21 - 75 mm, standard thicknesses in steps of 6 mm

- Over 75 mm thick products are possible to produce by multiple gluing.

MORE INFORMATION

Further processing

Multiple gluing

Tolerances

Certificates and approvals