How is Plywood made : The Full Process Explained | Part-1
Part 1 of this series focuses on raw log preparation and the foundational processes of the plywood industry. It also explains key wood properties and common defects, introduces the concept of short-rotation timber, and outlines the machinery used during the log preparation stage.
Wood plays a huge role in our daily lives. We use it to build houses, make furniture, manufacture paper,
transportation, decorative work etc. Since ancient times, wood has served as one of the essential materials
in human lives.
However, despite its wide range of uses, it has few shortcomings.
Heterogeneity : which means that structure and composition of wood is not uniform throughout
Anisotropy : which means that physical properties of wood, such as strength, color, density and hardness, vary from point to point, even within the same piece of wood log
Dimensional instability and warping due to the presence of water
Decay
Termite attack
Also, to obtain high-quality wood, the tree should ideally be more than 50 years old. However, due to deforestation,
the excessive exploitation of natural forests and the government restrictions, the availability of such mature
timber has become limited.
As a result, short-rotation timber — trees cultivated through agricultural methods and harvested within 2-15
years — is commonly used.
These drawbacks have led to the development of engineered wood products such as Plywood, MDF and Particle Board,
which aim to retain/enhance the benefits of natural wood while minimizing its weaknesses.
In this article series, we will explore how plywood is manufactured, the machinery involved in the process,
and the key factors considered during its production.
Let’s Begin
The process of plywood manufacturing consists of the following stages
Plywood Manufacturing Stages Flow
Chart
This blog covers the following stages. The remaining stages will be explored in subsequent articles.
Log Harvesting
Log Moistening
Log Debarking
Log Conditioning
Log Cross Cutting
Log Harvesting
In the first stage, large timber trees are harvested from agricultural plantations after a thorough
evaluation of its diameter, straightness of the trunk, branch characteristics and maturity.
These factors ensure that only suitable trees with minimal defects and optimal fiber quality are selected.
The machine used for harvesting/cutting the logs is called Chain Saw.
Log Harvesting (AI generated
image)
Log Moistening
After harvesting, the logs are stored in the log yard. At this stage, the logs naturally contain moisture
within their fibers. However, if left exposed, this moisture gradually evaporates, causing the wood to develop
internal cracks, lose its elasticity, and become deformed.
To prevent such deterioration and maintain the desired moisture content, the logs are moistened regularly — either
by sprinkling water over them or by immersing them in a water reservoir or pond. This process keeps the logs in
optimal condition until they are ready for further processing.
Log Moistening (AI generated
image)
Also, it is essential to treat the log yard with appropriate insecticides and anti-fungal solutions. This prevents
attacks from wood-destroying organisms such as insects, borers, and decay-causing fungi.
Log Debarking
The following image illustrates the various layers which comprises a wooden log -
Wooden Log
Anatomy
The outermost layer of the log, known as the dead bark, serves as a protective covering that shields the inner,
living tissues of the wood.
At this stage, the entire dead bark and a small portion of the inner bark are removed to expose the clean wood
surface underneath.
This operation is known as debarking, and the machine used for this is called Wood Debarking Machine.
Log Debarking (AI generated
image)
Note :
In certain cases—especially when the bark is extremely hard or tightly bonded
to the wood—the debarking process is carried out after the log conditioning
stage.
Conditioning softens the bark and makes its removal easier and more efficient.
Log Conditioning
After debarking, the logs are transferred to steam vats (or conditioning chambers). Here, the logs are
immersed in hot water or exposed to steam at higher temperatures. This process softens the wood fibers and
lignin, making the logs easier to peel into veneers.
Steam Vats (AI generated
image)
The temperature and duration of conditioning depend on the species and density of the wood. Softer woods require
lower temperatures and shorter times, while denser hardwoods need higher heat and longer soaking periods.
Type of Wood
Medium
Temperature Range
Duration
Softwood
Hot Water Bath
80 °C – 90 °C
6 – 12 hours
Medium Hardwood
Hot Water Bath
90 °C – 100 °C
10 – 20 hours
Dense Hardwood
Steam (Pressurized Chamber)
100 °C – 120 °C
20 – 36 hours
Log Cross Cutting
When the logs reach the processing section, the long, cylindrical wooden logs are cut into smaller,
manageable sections of specific lengths—typically slightly longer than 8 feet or 4 feet.
This extra length ensures allowance for trimming and removal of defects during later processing.
Log Cross Cutting (AI generated
image)
This operation of cross cutting the logs is carried out using a Log Cross-Cut Saw Machine.
Conclusion
In the first part of this series, we explored the stages involved in preparing the log for further processing.
In the next part, we will look at how these prepared logs are transformed into long, thin veneer sheets.
