What are the main factors affecting the dimensional stability of block board

Water content of raw materials
The dimensional stability of Block Board is closely related to the moisture content of raw materials. The core strips are generally made of natural solid wood. If the moisture content of the wood is too high, it is very easy to absorb moisture expansion or lose water shrinkage when the environmental humidity changes, causing the board to bend, warp or crack. In standard production, the core strip moisture content is required to be kept in the range of 8%-12%, which is closer to the use environment of furniture and interior decoration. If the raw materials are not fully dried, the plate will continue to release or absorb moisture during use, which will directly affect dimensional stability.

Core strip arrangement and splicing process
Whether the core strips are arranged in a regular manner directly determines the internal stability of the Block Board. The core strips are arranged too loosely, which easily creates gaps, resulting in local deformation when subjected to stress or moisture. Improper splicing process will cause the core materials to be bonded firmly, and displacement and irregular expansion are more likely to occur under changes in temperature and humidity during use. Strict process requires that the core strips be arranged in parallel and spliced ​​closely, and the uniformity of the overall structure is ensured through cold pressing and hot pressing processes.

Adhesive properties
Adhesives are the key to the structural stability of Block Board. Inadequate glue strength will lead to degumming between the panel and the core plate, which will cause bulging of the board or separation between layers. Different types of adhesives have significant differences in water resistance and heat resistance. Low-quality adhesives are prone to failure in humid environments, affecting dimensional stability. In production, urea-formaldehyde resin modified glue, phenolic resin glue or polyurethane glue are usually selected, which are more reliable in terms of bond strength and durability.

Pressing process
Block Board needs to go through cold pressing and hot pressing during the forming process. Insufficient pressure will lead to uneven glued layer, hollow or weak points inside, which will easily cause local deformation during environmental changes in the later stage. Unreasonable control of the hot pressing temperature and time will also affect the curing effect of the adhesive. Only through stable pressure and scientific hot pressing time can the core material be closely integrated with the panel, thereby improving dimensional stability.

Panel material
Block Board’s panels are generally made of veneer or thin layer of plywood. The density, hardness and moisture content of different materials will affect the overall size performance of the board. Panels with lower density are prone to deform under humidity changes, and insufficient hardness will lose their flatness under external forces. High-quality panels should have the characteristics of fine texture and balanced moisture content to ensure the balance between surface tension and internal stress of core material and reduce dimensional changes.

Ambient humidity and temperature
The Block Board’s usage environment plays a decisive role in dimensional stability. When the ambient humidity is too high, the board will absorb moisture from the air, causing expansion and bulge; when the humidity is too low, the wood will lose water and cause shrinkage and cracks. Severe changes in temperature will also accelerate the migration of moisture inside the wood, causing size fluctuations. Therefore, in practical applications, it is necessary to reduce the impact of the environment on the board by maintaining the indoor humidity stable.

Storage and transportation conditions
During the storage and transportation of Block Board after delivery, improper protection will also affect dimensional stability. If the storage environment is too high or the air is not circulated, the board will absorb moisture and expand. If moisture-proof measures are not taken during transportation, the plate is very susceptible to moisture and deformation during long-distance transportation. Scientific storage methods should keep the environment dry and ventilated, and stack the plates horizontally to prevent local pressure from causing warping.

Machinery and post-processing
Block Board If the operation is not standardized during sawing, grooved, hole drilling and other processing, it may damage the internal stress balance and cause dimensional changes. If the surface after processing is not protected by paint, veneer or edge sealing, the internal core strips are more likely to expand or shrink due to humidity. Through the complete post-processing process, the surface and edge of the sheet can be effectively closed, reducing the risk of dimensional instability.

Life and ageing factors
As the usage time increases, the internal structure of Block Board will gradually age. Decreased adhesive performance and slack core fibers will lead to reduced dimensional stability. Especially in high temperature and high humidity environments, the aging speed is accelerated, making it easier to show problems such as warpage and cracking. Choosing high-quality raw materials and processes, combined with reasonable use and maintenance, can delay the impact of aging on dimensional stability.