First, thickness deviation and density deviation
In general, artificial panels used in furniture manufacturing require surface processing. The commonly used surface processing methods include painting and veneering and mechanical processing. The first two are mainly to ensure the quality of surface processing. The most basic requirement is that the substrate thickness deviation should be uniform and the density should be uniform.
The smaller the deviation of the substrate thickness, the better the quality of the veneer processing.
In addition to the thickness deviation between the plates, it is also required that the thickness deviation within the plate is not greater than soil 02mm
The common method for determining the thickness deviation is to select several representative parts on the particle board, determine the thickness of the board (accurate to 0.lmm), calculate the average thickness of the board and its standard deviation, in order to assess the thickness deviation, and its calculation formula as follows:
As the substrate veneer is subjected to pressure, in order to ensure the quality and effect of the veneer, the density of the substrate is required to be uniform, and the density deviation is generally required to be less than 10% of the soil.
Second, formaldehyde emission
The adhesive used in the production of wood-based panels in China is mainly urea-formaldehyde resin. Because the release of free formaldehyde remaining in the panel will directly endanger human health, the amount of formaldehyde released is stipulated in the wood-based panel product standards, especially in developed countries. More stringent requirements
Third, other requirements
There are many items for assessing the quality of wood-based panels, in addition to the above-mentioned deviations in density deviation from the amount of formaldehyde released, there are also surface-quality glue properties (such as the flattened tensile strength of the bond strength), the static bending strength, the elastic modulus, the water absorption thickness expansion rate, the holding screw force, etc. Projects, quality indicators of these quality projects are stipulated in the wood-based panel standards, and are essential parameters for the design and manufacture of furniture. However, from the perspective of the modernization of furniture production, these quality projects are not complete and need to be supplemented and improved. There are some of the following items:
1, the surface quality
The surface quality of particleboard is an important key property for panel furniture. Surface quality of particle board means surface roughness Surface peel strength Surface porosity and absorption ability Surface pH Hardness Color etc.
As fine surface structure particle board, should avoid the rough shavings fall in some of the particleboard factory in our country, the phenomenon of coarse wood shavings falling on the surface or exposed on the surface is more common in foreign countries, only thin sparse large surface can be allowed on the particle board The shavings fall on the surface, strictly not even allowing a thick wood shavings like the matchstick to be produced. This rough wood shavings and fine wood shavings have a large amount of expansion when the board is wet, causing the surface shavings to swell irregularly. In the case of direct printing with a water-soluble coating, application of a thin material, or use of a water-soluble adhesive as a veneer adhesive, the effect is particularly severe. As a result, the surface is uneven.
The surface roughness of the particle board can be measured with a stylus detector. The detector moves on the surface of the particle board and records the height of the points on the surface contour. Based on this, the distance between the peak and the trough can be calculated.
The surface peel strength of the particle board surface porosity and absorption capacity are affected by the surface density of the board. From practical experience, it has been suggested that the surface density is best within the range of 800-900 kg/m3, although there are other influencing factors. (such as surface shavings size, surface shavings, moisture content, sizing amount, hot-pressing cycle, etc.), but if the supply of wood-based furniture particleboard can do this, it will provide excellent substrate conditions for furniture finishes.
The pH value of the board surface has an influence on the secondary processing methods of some surface decoration, for example, the surface pH of the primed board with impregnated paper should not be lower than 6, otherwise the melamine resin will be brittle and cracked during use; The PH value of the surface of the printed board printed by the water-soluble paint should not be less than 5, otherwise the urea-formaldehyde resin on the surface of the board will be hydrolyzed during the process of getting wet and dry, resulting in the defect that the surface layer is easy to peel off.
2, mechanical strength
It is generally accepted that the use of particle board in the panel furniture, the flat tensile strength and bending strength requirements do not require very high tensile strength requirements for the plane: when the particle board is used for wood trim and a single board or plastic paste In the case of panel overlays, 0.3 N/mm2 is sufficient; for direct printing or PVC film overlays, 0.4 N/mm2 should be used. Particleboards for structural applications (such as side panels) should generally have high The tensile strength, in the 0.4 ~ 0.9gN / / mm2 on the static bending (bending) strength requirements for the 16N / mm2, but it should be noted that the furniture for the use of particleboard bending properties are not static The bending load, which is the index of mechanical performance expressed by the static bending strength, is an index that needs the elastic limit.
If the internal bond strength of the chipboard is low, when the pin or screw is screwed into the edge, it will cause cracking of the edges; when the surface is covered with a plastic plywood, when they are placed in a dry environment, they will stress due to shrinkage. , leading to particle board core layering
3, holding nail force
The nail holding power of chipboard refers to the nail pulling force perpendicular to the board surface and the parallel board surface, the relationship between the nail holding force and the performance of the chipboard. The most important is the density and the plane tensile strength of the shavings. The increase in board density increases linearly or slightly. When the density of the board increases from 550 kg/m3 to 750 kg/m3, it increases by approximately 220%. The nail holding force parallel to the board surface is undoubtedly consistent with the flat pull of the board. Strength has a close relationship |
In panel furniture, the metal connection is directly connected to the chipboard. In order to ensure the nail holding force parallel to the plate surface, the stress should be distributed within the largest possible surface area.
4, dimensional stability
The characteristics of wood shrinkage and swelling are also reflected in the wood-based panels, which can easily cause changes in the dimensions of the panels and the deformation of the products. This is very unfavorable to the manufacture of furniture. The linear expansion rate of wood-based panels should be regulated to facilitate the design and processing of furniture.
5, surface absorption performance
This performance relates to the effect of painting and the amount of paint to be painted. It is closely related to the manufacture of furniture. The relevant performance parameters need to be specified.
6, sand content
In the manufacturing process of particleboard and medium density fibreboard, the use of large amounts of discarded residues will inevitably lead to the presence of sand in the panel. This is a detrimental effect on the cutter blade used in furniture processing, which affects its service life. Quantitative
The company Sports Equipment Co., Ltd. mainly produces outdoor slides, kindergarten toys, children's furniture, outdoor equipment, kindergarten rubber mats, naughty castles, etc. It is a science and technology enterprise integrating design, production, sales, and after-sales services. Website:. Advisory telephone. The company's pleasure and dedication to serve you! Factory address: No. 16, Chuangqiang Road, Lucheng District, Wenzhou City Light Industry Park.
bamboo fencing, solid bamboo fencing boards,durable bamboo fence,bamboo trellis
ZHEJIANG JIAHE BAMBOO TECHNOLOGY CO., LTD , https://www.zhuart-bamboo.com