Лесотехнически Университет

Summary

Тhe aim of the research presented in this paper is to study the water resistance of experimental plywood bonded with alcohol-soluble phenol-formaldehyde resin. The evaluation of water resistance is made on the basis of the obtained data for the changes of the physical properties of plywood after exposure to prolonged water treatment. Tests for the thickness swelling, volume swelling and water absorption are made after immersion in water for prolonged period in controlled laboratory conditions. The measuring of thickness, length, width and mass of plywood specimens for determination of these properties is made after immersion in water for the period of 1 day (24 hours) to 52 days (1248 hours).

The experimental plywood model was made from peeled beech veneers. Pure alcohol-soluble phenol-formaldehyde resin is used as plywood binder.

The research results showed that the plywood model has uniform density; it is dimensionally stable during and after prolonged water treatment, without any deformations of the shape of the test specimens. The changes of the values of thickness and volume swelling, as well as the values of water absorption in the analyzed period are proportional to change of the duration of the period of water treatment. According to the obtained data from the tests of these properties the plywood model meets the requirements of the standard for load-bearing plywood for use in construction.

Summary

On the basis of performed literature overview and analysis of the effect of production modes on physical indices of fibreboards, following variable factors were determined: pressing temperature, board thickness and binder content.

In this paper, the results of the performed analytical and empirical investigations with respect to the effect of pressing temperature, board thickness and binder content on physical properties of MDF-type boards (medium-density fibreboards manufactured after the dry method) made of hard hardwood species are presented. Regression models showing the effect of variable factors on board indices were derived. The changes in the values of those indices in case of combinations of levels of production factors were examined. Analysis of the result was made, with the respective conclusions having been drawn.

Summary

Determination of quality of production of the same kind is performed in its predominant part by means of sampling test. This also applies to manufacture of particleboards (PBs). Statistical methods allow assessing and comparing the quality of products. To assess and compare the quality of individual manufacturers with respect to standard requirements, an interval estimate of the arithmetic mean value of indices has been used, and to compare the quality between different manufacturers, a test of hypothesis with respect to mean values of two samples has been used.

After performed tests of laminated particleboards (LPBs) of different manufacturers, statistically significant differences in the quality level between individual manufacturers have been established.

The aim of the investigation is approval of methods for application of statistical methods when selecting a manufacturer / supplier of PBs according to objective criteria related to production quality.

Summary

The quality of each product is a set of a great number of indices and characteristics that define its ability to meet the consumers’ requirements.

By means of survey of specialists, the more important indices determining the quality of particleboards were ranked and weight factors for each index were calculated. With these weight factors, the determination of composite quality index of PBs will be possible. The results also give guidelines for improvement of the quality of this type of material.

Summary

The main factor defining the performance of the hard thin FBs is the pressure applied in the process of piezothermal treatment. In order to manufacture a product designed by engineering, the pressing pressure should be with a specific value determined in advance. The latter is in correlation dependence on the tree species, the characteristics of the wood-fibre mass and of the wood-fibre carpet. Determining, out of these factors, is the resistance that the carpet shows under the applied external load, with it depending mainly on the characteristics of the mass and, to a determining degree, on the tree species used for the manufacture of the boards.

In this paper, an investigation on the effect of pressure during manufacture of thin FBs on the basis of beech and cerris oak wood is presented. Derived are the main dependences of the performance of FBs on the factors examined in case of application of the methods of regression analysis, with use of the least squares method. Established are the optimum values of pressure depending on the thickness of the boards and the design thickness set.

Summary

Quality of products manufactured takes an extremely important position in all types of manufacture today. This is necessitated by the continuously growing competition at market level – customers value more and more quality products and turn to those companies that can give them the necessary thing according to their requirements. This applies especially to furniture-manufacturing companies.

That is why of extreme importance is to find the exact approaches and methods for quality management and assurance. One of those methods is the FMEA (Failure Mode and Effect Analysis) method that is an analytical engineering method used to examine and eliminate potential discrepancies, problems, faults and errors.

The aim of the paper is to establish the possibility of application of the FMEA method in increasing the quality of cabinet furniture manufactured, with following tasks having been carried out: an assessment of the risk of allowing potential discrepancies, problems, faults and errors during manufacture of cabinet furniture in specific company has been performed, by characterising the reasons leading to them by means of application of the FMEA method; the necessary actions for improvement have been determined; a new assessment of the risk of potential discrepancies, problems, faults and errors after performance of the outlined improvements by means of the FMEA method has been made.

Summary

The free movement of goods is the cornerstone of the single market. The mechanisms that are necessary to achieve this goal are based on prevention of technical obstacles to trade, on mutual recognition and on technical harmonisation.

In order to improve the functioning of the internal market in construction products, in May 2008 the European Commission proposed replacing the Directive on Construction Products (89/106/EEC) with a new regulation intended to eliminate the still existing regulatory and technical obstacles to the free movement of construction products in the European Economic Area.

The new Regulation laying down harmonised conditions for the marketing of construction products was adopted by the European Parliament and the Council on 9 March 2001. The Regulation repeals the so far effective Directive 89/106/EEC on Construction Products and enters into force 20 day following its publication in the Official Journal of the European Union on 04.04.2011, i.e. on 24.04.2011. After this date, it becomes binding and shall be applied directly in all Member States.

It is necessary that the manufacturers of wood-based products are made acquainted in time with the novelties in this field because a great part of their produce is put into construction sites and comes under the scope of the European technical legislation.

A review of the main requirements of Regulation No. 305/2011 laying down harmonised conditions for the marketing of construction products has been made in the paper.