Solid Wood Particle Board Testing

Solid wood particle board testing is conducted in accordance with relevant standards and industry specifications. Scientific testing and analysis are performed on formaldehyde emission, modulus of rupture, internal bond strength, water absorption thickness swelling, surface bonding strength, and screw holding power, objectively assessing the product quality grade. A detailed test report is issued within 7-10 working days, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Formaldehyde emission: This is a core indicator for measuring the environmental grade of solid wood particle board, mainly limited in accordance with the national standard GB 18580-2025. Depending on the place of use, it is divided into E1 grade (≤0.124 mg/m³) and ENF grade (≤0.025 mg/m³). The test result is directly related to whether the product can be used in interior decoration and furniture manufacturing.

Modulus of rupture: This indicator reflects the ability of the board to resist bending failure under load and is key to evaluating its structural load-bearing performance. The higher the test value, the less likely the board is to break or bend excessively when used as horizontal components such as tabletops and shelves, directly affecting the service life and safety of furniture.

Internal bond strength: An indicator for measuring the firmness of bonding between the wood particles inside the board and the adhesive. If the internal bond strength is too low, the board is prone to delamination and cracking when subjected to tension perpendicular to the board surface, and the risk increases significantly especially during secondary processing such as grooving and drilling.

Water absorption thickness swelling: Evaluated by measuring the thickness change of the specimen after immersion in water for a specified time. This indicator reflects the moisture resistance and dimensional stability of the board. If the swelling rate is too high, the board tends to absorb water, swell and deform in humid environments, affecting its application in high-humidity places such as kitchens and bathrooms.

Surface bonding strength: Specifically designed to test the firmness of bonding between the surface decorative layer (such as impregnated paper and PVC) and the substrate board. Insufficient strength will cause the surface layer to peel and blister, seriously affecting the appearance quality and service experience of the finished product. It is an important item in finished board testing.

Screw holding power: Simulates the pull-out resistance after a screw is driven into the board in actual use. This indicator directly affects the connection strength and stability of furniture components joined with screws and is a direct basis for evaluating the secondary processing performance and connection reliability of the board.

Moisture content: A control indicator for the moisture content of the board during production, storage and use. Too high moisture content tends to cause board deformation, mold growth and reduced bonding strength; too low may increase the brittleness of the board. An appropriate moisture content (usually 6%-12%) is the basis for ensuring the stability of the physical properties of the board.

Testing Scope

Boards for furniture manufacturing: Covers the substrates used in various panel furniture such as wardrobes, bookcases, cabinets and beds. Testing focuses on mechanical properties (modulus of rupture, internal bond strength), environmental grade (formaldehyde emission) and subsequent processing performance (screw holding power) to ensure the structural safety and healthy use of the furniture.

Boards for interior decoration and renovation: Mainly includes boards used for non-structural purposes such as wall substrates, partitions and ceiling lining panels. Testing of such boards focuses on environmental indicators (formaldehyde), moisture resistance (water absorption thickness swelling) and fire resistance (if required) to meet the health and safety specifications of the indoor environment.

Boards for custom home and whole-house customization: Because large-scale personalized processing and installation are involved, extremely high requirements are placed on the physical performance stability and environmental consistency of the board. The testing scope needs to cover everything from the substrate to the finished board after surfacing, ensuring that the performance still meets requirements after edge banding and grooving.

Boards for export trade: Depending on the target market, mandatory standards of different countries or regions must be met, such as the CE certification of the EU (EN 312 and EN 13986 standards), the CARB certification of the United States, and the JIS standards of Japan. The testing scope needs to be expanded according to the regulatory requirements of the target market.

Boards with special functions: Including fire-retardant boards (combustion performance grade testing), moisture-proof boards (strengthened water absorption thickness swelling testing) and high-load-bearing boards (strengthened modulus of rupture testing). Their testing scope adds the corresponding special performance tests on the basis of general items.

Raw materials and production process control: The testing scope extends to the front end of production, including inspection of the wood raw materials and adhesives used (such as urea-formaldehyde resin and melamine-modified resin), as well as monitoring of hot-pressing process parameters (temperature, pressure and time), so as to control the quality of finished products from the source.

Testing Methods

Formaldehyde emission testing (1 m³ chamber method): This is currently the arbitration method in China (GB 18580-2025). The specimen is placed in a 1 m³ climate chamber with constant temperature, humidity and air exchange rate. After continuous operation for a period of time, air in the chamber is collected and analyzed for formaldehyde concentration by the acetylacetone spectrophotometric method or high-performance liquid chromatography, with the result expressed in mg/m³.

Modulus of rupture testing (three-point bending method): In accordance with GB/T 17657-2022. A rectangular specimen is simply supported at both ends and a vertical load is applied at a constant rate at the center of the span until the specimen fails. The maximum load is recorded and the modulus of rupture (MPa) is calculated by formula. This method simulates the working condition of the board under transverse load in actual use.

Internal bond strength testing (perpendicular tensile method): In accordance with GB/T 17657-2022. Metal blocks of specified size are bonded to the upper and lower surfaces of the specimen with high-strength adhesive, and then tension is applied perpendicular to the board surface on a universal testing machine until internal failure of the specimen occurs. The strength (MPa) is calculated from the maximum tensile force at internal delamination or fracture.

Water absorption thickness swelling testing (immersion method): In accordance with GB/T 17657-2022. After measuring the initial thickness of the specimen, it is completely immersed in distilled water at (20±1) ℃ for a specified time (usually 24 hours), then removed, surface moisture wiped off, and the thickness is measured again. The percentage increase in thickness is calculated to evaluate its water resistance.

Surface bonding strength testing: In accordance with GB/T 17657-2022. Dedicated cutters are used to cut a square groove of specified size on the surface of the decorative board, with the depth reaching the substrate. A test block is bonded to the grooved area with high-strength adhesive, and after curing, a perpendicular tensile test is performed to measure the force at which the surface layer is pulled off, and the strength (MPa) is calculated.

Screw holding power testing: In accordance with GB/T 17657-2022. A pilot hole is pre-drilled in the specimen, and a wood screw of specified specification is driven in at a specific depth and torque. A tensile testing machine pulls the connecting device out along the screw axis, and the maximum tensile force (N) at which the screw is pulled out is recorded to evaluate the holding capacity of the board for screws.

Moisture content testing (gravimetric method): In accordance with GB/T 17657-2022. A small test piece is cut from the specimen and its initial mass (wet weight) is immediately weighed, then it is dried in an oven at (103±2) ℃ to constant weight and weighed again (dry weight). The moisture content of the test piece is obtained by calculating the percentage of mass loss, and the result represents the overall moisture condition of the board.

Testing Standards

Domestic Standards:

1. GB 18580-2025, Indoor decorating and refurbishing materials — Limit of formaldehyde emission of wood-based panels and finishing products

2. GB/T 17657-2022, Test methods of evaluating the properties of wood-based panels and surface decorated wood-based panels

3. GB/T 1931-2009, Method for determination of moisture content of wood

4. GB/T 1936.1-2009, Method of testing in bending strength of wood

5. GB/T 4823-2013, Defects in sawn timber

International Standards:

1. ISO 12460-1, Determination of formaldehyde emission of wood-based panels — Part 1: 1 m³ chamber method

2. ISO 527, Plastics — Determination of tensile properties

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

1 m³ climate chamber system: Core equipment for formaldehyde emission testing. The system includes a constant temperature and humidity climate chamber, a clean air supply unit, an air sampling system and an analysis unit. The inner wall of the chamber is required to be made of inert material, and the temperature, humidity and air exchange rate must be precisely controlled to ensure that the test environment conforms to the standard requirements and the data are accurate and reliable.

Universal mechanical testing machine: Key equipment for multiple mechanical property tests such as modulus of rupture, internal bond strength, surface bonding strength and screw holding power. It has a high-precision load sensor and displacement measuring system, can programmably control the loading rate, automatically record the load-displacement curve, and calculate the maximum force and strength.

Constant temperature and humidity conditioning chamber: Standard environmental equipment for conditioning specimens before testing. According to GB/T 17657, specimens usually need to be balanced to constant weight in an environment of temperature (20±2) ℃ and relative humidity (65±5)% to eliminate the interference of environmental factors on test results and ensure the uniformity of test conditions.

Spectrophotometer or high-performance liquid chromatograph: Core analytical instruments in formaldehyde emission testing. The spectrophotometer (commonly the acetylacetone method) quantifies the formaldehyde concentration by measuring the absorbance at a specific wavelength and is economical and practical. The high-performance liquid chromatograph (HPLC) has good separation effect, high sensitivity and strong anti-interference ability, and is commonly used for precise analysis and arbitration.

Precision thickness measuring instrument: Used to measure board thickness, water absorption thickness swelling and other dimensional change indicators. A digital micrometer or a dedicated thickness gauge is usually adopted, with a spherical or circular flat measuring head, applying standard pressure to ensure consistent contact at the measuring point and a reading accurate to 0.01 mm, so as to ensure the accuracy of dimensional data.

Blast drying oven and precision balance: Supporting equipment for moisture content testing. The drying oven needs to stably control the temperature at (103±2) ℃ with a blower to ensure uniform internal temperature. The accuracy of the analytical balance needs to reach above 0.001 g to accurately measure the mass difference of the specimen before and after drying, so as to calculate the precise moisture content.

Standard cutters and sample preparation equipment: Including universal circular saws, pre-adjusted grooving cutters, standard drill bits, etc. They are used to precisely prepare the specimens required for each test according to standard dimensions. The dimensional accuracy and