High Density® bamboo production
The High Density® bamboo production process includes all the steps to create a material that is harder, stronger and more durable than almost any wood. The material is produced from bamboo strips (fibres), which are compressed into beams or panels as a base material for many products. Compared to standard strand woven bamboo, High Density® is far more stable and environmentally friendly. Below we explain how bamboo flooring, beams and boards are produced out of hollow bamboo stems, to reach the highest quality products:
1. Harvesting the right bamboo
Endless forests in Eastern-Chinese mountainous regions are covered with bamboo. Bamboo stems have an expiry date when talking about MOSO® bamboo products: ideally, the stems are harvested when they are 5 years old. Younger stems are not completely lignified and older stems become grey. The best base material will result in the best final product. The quality of the bamboo stems can be determined when purchasing the stems, but is difficult to see in the final product. Poor quality of the base bamboo material can still become apparent in the final product in an unexpected way later on.
2. Making bamboo strips from hollow stems
The freshly harvested bamboo stems are cut into strips. This production process entails more than just slicing the hollow bamboo stem into pieces. The inner and outer skins have to be removed, to obtain the best surface for glue bonding. Better quality bamboo strips mean more waste, since more bamboo is sliced from the strips to make sure there is no skin left. The quality of the strips can be determined when purchasing strips, but you may not directly see the difference in the final product. MOSO® only accepts high quality strips for its bamboo products.
3. Crushing the strips for further bamboo production
The bamboo strips are crushed to open up the material for further processing. The crushed bamboo strips become bundles of fibres. The quality of the crushing will determine the quality of the glue impregnation and bonding in the next production steps. Better crushing of the strips requires more precise processing, and therefore higher costs.
4. Thermal treatment to alter the stability and colour
Bamboo products are available in three standard colours: Natural, Caramel and Chocolate. Natural is the colour of the material without any treatment. When the bamboo strips are steamed, they become brown: Caramel. With a thermo treatment of ca. 200°C the colour changes into a dark brown Chocolate. The treatment alters the material: the sugar component of the bamboo is caramelised or broken down, making the material more durable and stable. The treatment can be executed at various temperatures for a shorter or longer time. Lower temperatures and shorter times usually result in lower costs, a preferred option for some manufacturers. MOSO® always focuses on the optimal durability and stability of the final bamboo product.
5. Bamboo products contain bamboo and glue
The crushed bamboo strips are glued and compressed to bond the bamboo fibres. MOSO® wants to replace chemical resins with bio-glues. Because the quality of the final products is most important to MOSO®, this is not possible yet. To date, no bio-glue can match the high requirements necessary to deliver the best quality products. Until bio-glues can be used in production, without impairing the quality, we continue to use glues from top international brands. This ensures the lowest quantity of emissions.
The type and the amount of glue applied during the production is very hard to determine once the final product is manufactured. Nevertheless, this is one of the key differences between High Density® and Strand Woven Bamboo. The costs for glue are significant in the total production costs. Many factories make their own glue or use glue from a local supplier to reduce the costs, while MOSO® chooses to work with respectable brands like Dynea.
6. Compressing bamboo can be done in various ways
Depending on the type of product, the dimensions, and the required colour of bamboo, compression can be done in cold-press or hot-press systems. Each type of glue needs a certain temperature during compression to cure. Additionally, the way bamboo strips are placed in the molds has an effect on the stability and look of the final product. Well-trained MOSO® quality controllers test the material after this important production step, to ensure the quality of the final product. It is hardly possible to do this without laboratory tests.
7. Moisture content defines the stability of bamboo products
Bamboo, like any other natural material, is affected by moisture: it expands when its moisture content increases and contracts when its moisture content decreases. It is crucial that, within each production step , the moisture content is lowered and controlled in drying rooms. The moisture content of the final product, supplied from the factory, determines significantly the way bamboo products behave after installation. A higher moisture content in the product during production usually results in more problems at a later stage when the product is exposed to changes in humidity.
Since Strand Woven Bamboo or High Density® Bamboo are very dense and hard, it is difficult to determine the moisture content of the final product. Through continuous product development during the last 10 years, MOSO® has mastered the method to control the moisture content of each final product. To ensure the high quality of the bamboo products in their final application, local MOSO® quality inspectors monitor the moisture content during and after production of each production batch.
Final High Density® bamboo product
The last step in the High Density® bamboo production is the final profiling of the material. A material as hard and dense as High Density® bamboo requires a lot from the tools used for profiling. By using high quality, often European made machines, MOSO® ensures the right way of processing the material into final products. A good example is the way click systems are profiled into the material. The best machines create the best surface finishing. Depending on the product, MOSO® uses High Density® bamboo as a top layer for panels and flooring, or as solid beams or flooring.