Investigations of gluing quality of laminated window profiles

The issue of lack of high-quality wood as raw material for the timber industry is evident and well known not only in this country but throughout Europe and America. In order to increase the utilisation level of timber as a raw material (both in terms of quantity and quality) and in order to enhance physical and mechanical features of the products’ constructive elements, different techniques and technologies of wood processing have been developed. On the markets these products are known as “engineering wood” and they can be roughly classified as composite materials. Laminated elements belong to the products that substitute massive wood by ways of extension, widening and hardening of wood elements. In this way, reduction of deformation caused by humidity changes in wood such as twisting, winding and bowing can be reached or brought to tolerable levels. Laminated elements made of three laminates are commonly used for production of construction wood. Quality evaluation of laminated elements is usually carried out by visual control and the gluing quality is estimated based on the glue quality certificate. For assessing the gluing quality of laminated elements, the investigation of the strength of glued joints should be conducted on a regular or periodical basis, in order to have the confirmation of the right choice of glue and control of the production regime. In this manner justification and guarantee can be provided for the substitution of massive wood by laminated elements.