II. Match the English terms with their Ukrainian equivalents.

1. shavings a) клей

2. residues b) площина

3. chips c) середній шар

4. sawdust d) шліфувати

5. density e) пласке пресування

6. adhesive f) тріска

7. flat pressing g) щільність

8. plane h) тирса

9. core i) відходи

10. batch pressing j) вібросито

11. progressive pressing k) завантажувати

12. to charge l) стружка

13. drum dryer m) барабанна сушарка

14. vibrating screen n) безперервне пресування

15. to sand o) періодичне пресування

III. Read and translate the sentences into Ukrainian.

1. Particleboards are made of wood residues.

2. Wood particles are glued together with adhesives.

3. From the chipper, wood particles are fed into a hammer mill.

4. The adhesives must answer certain requirements.

5. Hydrophobic additives are used to reduce swelling of particleboards.

6. There are two types of pressing mats: batch pressing and progressive one.

7. Pre-pressing makes the mat denser and transportable.

8. The particles are dried in a drum- or in a belt dryer.

9. By the batch pressing the mats are placed on pallets and charged into the press.

10. Pressure is required in all types of particleboard production.

IV. Read and translate the text.

The Manufacture of Particleboards

Wood particleboards belong to the family of wood-based composite materials. Particleboards are of panel form material and are made of residues from woodworking

enterprises, which come in the form of chips, shavings, slabs, sawdust, edgings. Particleboard is also made from a variety of agricultural residues. Low-, medium-, and high-density panels can be produced with cereal straw particles. These particles are glued together with adhesives (binding agent) under pressure and with heat.

Pressure is required in all types of particleboard production. There are two basically different methods of pressing: flat pressing and extrusion.

In flat-pressed boards, the wood particles are arranged in the plane which is parallel with the board plane. In the case of extrusion, the wood particles are oriented in a plane perpendicular to the plane of the board. The properties of particleboards which are made with flat pressing, are different from those produced with extrusion.

Particleboards are typically made of three layers. The faces of the board consist of smaller wood particles and the core is made of larger particles.

To produce a particleboard, the raw material must be chipped into small particles in special chipping machines (chippers). The size and geometry of wood particles influence the quality of the particleboard. From the chippers, wood particles are fed to a hammer mill for further grinding. Then the particles are dried. The drying operation is a very important stage in the manufacturing composite products. The particles are dried in the drum dryers or belt dryers. To separate coarse particles and dust from standard-sized particles, the fractions are fed to the vibrating screen.

The dry standard-sized particles are directed to a blender. In the blender, the wood particles are mixed with an adhesive (usually these are organic resins). The adhesive must answer certain requirements: it must make the particleboard strong, must not change the colour of the wood, must be resistant to fungi and insects, must be cheap.

To reduce swelling and water absorption of particleboards, hydrophobic additives must be used. This is usually wax.

The resultant mixer is moved onto a belt conveyor where it is formed into mats. The forming of mats also requires even distribution of wood particles.

Mats are often pre-pressed. Pre-pressing makes the mat denser and helps to keep its form when transporting to the hot press.

After pre-pressing, the mats are hot-pressed into panels. There are two types of pressing mats: batch pressing and progressive one. The batch pressing is more popular. It is done in hot hydraulic presses. By the batch pressing the mats are placed on pallets and charged into the press. When the pressing cycle is over the particleboard is discharged from the press and cooled. So the press is periodically charged and discharged.

When the mixture of wood particles and adhesives is fed into the press continuously, the pressing is called the progressive one. After pressing, the board is

trimmed to get desired length and width. After trimming, the boards are sanded or planed. They may be also finished with lacquer or paint, or treated with fire-resistant chemicals.