Veneering is the most effective and economic way to produce high quality decorative wooden face material. Modern production technologies make exploitation of wood to veneer possible in many ways. Between 800 to 1000 sq m of veneer is produced from one cubic meter of lumber. No other kind of woodworking renders such a yield.
The production of veneer is described below briefly :

1. Procurement of logs

Veneer is produced by slicing, peeling or sawing thin layers of wood from high quality logs. Sawing veneer was invented as far back as 3500 years by the Egyptians and has been the only method used for many centuries after that. Today peeling and slicing are the most commonly used techniques to produce veneer.

Preparation on the logs:

The use of a veneer log depends upon the following factors which have to be assessed in the round log form:
• Heart and tension cracking
• Visible faults (knots, pin-knots, decay)
• Dimension
• Color
• Texture
• Shape
To meet present day quality and decorative standards, a veneer surface has to be defect free as far as possible, uniformly colored and evenly textured.This necessitates a very great deal of experience and knowledge of veneer to ensure correct and optimal conversion.

There are various methods of slicing which give different surface effects to the veneer (also see the graphic diagram on the methods of slicing). Thorough and skilful assessment of the log with due consideration to achievable quality and grain structure form the basis for deciding the method of slicing the log. After debarking, the veneer flitch is cut on the band saw depending on its preparatory indications.

2. Cooking

The next step in the production process is the cooking of the fitches. The exceptions are species such as Sycamore or White Beech where light or white coloring is desired.

Basically cooking of logs in hot water is done for two purposes. Firstly , the wood gains necessary suppleness (softness) by this process which would ensure smooth slicing. The softness of wood is essential to achieve perfect quality in production. Secondly, the color of the produced veneer could be influenced by the cooking time. For example, the color of original white beech could be changed by cooking to a pink or salmon-colored hue.
Depending upon the species of wood and color demands of the market, cooking periods vary from one day to one week.

A different temperature profile is given for the various species of wood for the respective cooking period. This profile has to be kept precise to avoid color defects. The temperature profile for different species of wood varies according to the geographical location of the operation. The primary reason for this variation is the variation in the quality of water (hardness, chemical composition) which plays a considerable role in the course of the cooking operation.

3. Slicing

For the actual slicing operation the flinches are planed on one or both sides to ensure that the flitch can be laid perfectly flat on the slicing bed.
Differentiation of slicing can be made based on type of the veneer slicing machine
• Slicing machine, horizontal or vertical.
• Peeling machine, rotary cutting, eccentric peeling or stay-log.
Different results are achieved depending on the machine and slicing method used.
Quality of the slicing depends on decisive factors such as the exact knife and pressure bar settings to an accuracy of 0.1 mm. Another important factor to ensure optimal quality slicing is the grinding of the knives at different angles (this can vary from specie to specie).
Generally a heating system is installed on modern slicing and peeling machines. The heating system is meant to dry the water which comes out during the slicing operation and the moisture that stems from condensation. This water content has to be eliminated as quickly and uniformly as possible to avoid blue stains on the wood.

Possible slicing defects:

1. Scratches:

These occur as a result of fine knots (for example, in Sycamore), contamination in or on the trunk (grains of sand, little stones) or ingrown metal in the wood (nails, etc.). These things will chip the cutting edge of the knife and thus cause scratch marks in the veneer leaf. Such chips are either ground out by using sandstone or the knife will have to be changed depending on the depth of the chip.

2. Deviating thicknesses:

Thickness of the leaves can differ as a result of the log being clamped wrongly in the machine or a wrong setting of the pressure bar. Another cause could be that the flitch is not lying perfectly flat on the slicing bed.

3. Chatter marks:

Chatter marks are regular ribs of different thickness which run across one part of the veneer sheet. Causes are the same as those mentioned under "deviating thicknesses".

4. Drying

In many "state of the art" veneer plants, the still moist veneer leaves are dried in the jet drier which also has a flattening effect. Bundles of 24 or 32 sheets each are taken out of the drier to facilitate handling in the warehouse later on. The diagram below shows how such a drier operates:

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Different drying programs must be run depending on the specie of wood. In these drying programs, belt speed and temperature specifications should be strictly adhered to. Veneer leaves that are over dried become brittle and are no longer useful. On the other hand veneers which are too moist can cause bubbles in the final product. A final moisture content of approx. 10-14% is aimed for and considered to be the average value as a result of correct drying.

Since many veneers tend to buckle after drying due to the different densities given in the veneer leaf, these veneers have to be flattened in the past by means of an extensive additional pressing operation. Over the period a press dryer has been developed which both presses and dries the veneer. However, this is only suitable for slightly buckled veneers. Veneers which are severely buckled (For example Beech) have to be pressed again to meet quality requirements.

5. Clipping

Finally the veneer bundles are clipped on the clipper in rectangular dimensions to finish it into ready for sale material.

Grading:-
After clipping, the ready for sale veneers are graded into different qualities. Generally, a difference is made between:
• Interior quality
• Panel quality
• Door quality
• Corpus quality
These grading standards vary from manufacturer to manufacturer in terms of length, width and quality. Sub-grades can also be different within the grading standards.

6. Measuring

Bundle by bundle the veneers move over photocells on a conveyor belt. The system measures the width of the bundle in centimeters, registers and then calculates figures to the average width and also records the length of each bundle.

After this a computer calculates the square meter content of each bundle on account of its length, number of sheets and average width and stores these figures which eventually can be printed out on measurement lists.

7. Cutting