2. Translate from Russian into English using the vocabulary of the Unit.

1. Фанера обычно состоит из нечетного числа слоев, склеенных различными клеями.

2. Слои для изготовления фанеры получают (изготовляют) путем лущения шпона.

3. Бревна раскалываются для получения узкой полосы (ленты) толщиной 2-4 мм.

4. Фанера структурно подходит для использования в качестве панелей в различных компонентах.

5. Увеличение деформации фанеры обуславливается совместным эффектом ползучести и влаги.

6. Фанера более склонна к ползучести, чем цельная древесина.

7. Благодаря своим свойствам и оригинальной текстуре фанера широко используется в мебельной промышленности.

8. Клееная ламинированная древесина имеет более высокую прочность, чем сырьевой материал.

9. Сегодня клееные ламинированные материалы производятся во всем мире.

10. Ламинированные материалы используются как балки, плиты, элементы рам (ферм) и обшивки.

11. В Америке пиломатериалы с параллельными слоями используются в строительстве жилых домов.

12. Преимущества альтернативных древесных материалов - в их архитектурных визуальных характеристиках, огнестойкости и легкости методов их крепления.

V. Speak about:

1. Plywood and its utilization.

2. Glued laminated timber and its advantages.

Unit 9 Revision

Grammar:

Wood-based panels: Fibreboard, Particle board

I. Answer the questions.

1. What wood-based panels have you got acquainted with in the previous unit?

2. What other wood-based panels do you know?

3. Where are wood-based panels used?

II. Read the text and try to understand it.

Wood has been designed in nature to meet very specific engineering and environmental needs, but man seeks to adapt it to a very much wider range of uses. In order to overcome the shortcomings of timber in size and anisotropy, new man-made forms of wood have had to be introduced. Glulam and plywood developed with the advent of structural glues and the rotary peeling process. More recently, developments have concentrated on reconstituted forms of wood such as particle boards, OSB (Oriented Strand Board), fiberboards and parallel strand lumber. These developments contribute much to improving the efficiency of the forest resource. More energy is consumed in the conversion process but this is far outweighed by the benefits of using either waste or fast growing small timbers and in fabrication costs. The main use of this reconstituted or composite wood is in wood-based panels.

Production and consumption data show a marked increase in the use of wood-based panels in the last decade. 30 million cubic meters were consumed in the 12 EC countries in 1929 and of this more than two thirds was

particle board.

Furthermore, Europe is self sufficient in particle boards and fibreboards but imports nearly two thirds of the plywood used. Wood-based panels are very versatile and are used in many different industries including furniture, wall paneling, packaging and do-it-yourself, 50% of the product is used structurally, principally in the construction industry. Structural uses include flooring and roofing, wall sheating, formwork and special structural uses such as web members in I and box beams. Internal fitments such as doors and stair units represent a further major market for wood-based panels.

A particleboards may be defined as a panel material manufactured under pressure and heat from particles of wood (wood flakes, chips, shavings) with the addition of an adhesive.

Chipboard dates from the 1940s and was originally developed to utilize waste timber, it was generally of low quality. After a slow start, growth has been tremendous and quality and finish have been improved and can be designed to suit end use by varying the materials, the lay up of the board and the pressing cycle. The wood chips form 85% of the board and are normally from coniferous softwoods such as spruce and pine although hardwoods such as birch may be used for heavy duty boards. The chips are cut by a series of rotating knives to produce thin flakes/chips which are screened, dried and then sprayed with adhesive. The chips are next blown on to a forming platten and, by using different sized chips stored in separate hoppers, a multi-layered matt can be built up. Fine chips at the top and bottom of the matt provide a smooth surface suitable for painting. The common binders are synthetic resins, either urea formaldehyde (UF) for boards intended for use only in dry conditions or the more expensive melamine urea formaldehyde (MUF) for boards with enhanced moisture resistance properties. The layered matt is cut to length before passing into the press at the temperature of up to 200º C. Press sizes allow boards up to 5 m long and 2,5 m wide but these will normally be cut down depending on end uses.

General understanding

Answer the questions:

1. Does wood meet all the engineering and environmental needs?

2. Why does man seek to adapt it to a very much wider range of uses?

3. What materials appeared with the advent of glues and rotary peeling process?

4. What man-made materials were introduced later?

5. Why did the appearance of these reconstituted materials contribute much to improving the efficiency of the forest resource?

6. Did the production and the consumption of wood-based panels increase in the last decade?

7. Why are wood-based materials considered to be versatile?

8. What do structural uses include?

9. What are particle boards made of?

10. What are chipboards developed for?

11. What species are used for the production of chipboards?

12. What provides a smooth surface of a chipboard?

13. How are layered matts cut?