I. Wood-based Sheet Forming Processes

Wood-based sheet forming mainly includes two mainstream technologies: fiberboard and particleboard. In the production of fiberboard, wood is first chipped and the fibers are separated. Then, adhesives and waterproofing agents are added. After high-temperature and high-pressure treatment, a sheet with a uniform structure is finally formed. Its performance depends on the quality of the fibers and the amount of adhesive used. For particleboard, wood is processed into particles, dried, and then glued. The particles are laid in a mold and formed, followed by hot pressing. The gluing process usually uses roller coating or spray gluing methods to ensure the bonding strength between the particles. The temperature and pressure in the hot pressing stage directly affect the density and stability of the sheet.

CNC Press Brake

II. Metal Sheet Forming Technologies

The processing of metal sheets covers key steps such as rolling, stamping, and surface treatment. The rolling process is divided into hot rolling and cold rolling. In hot rolling, steel billets are treated at high temperatures and continuously rolled into steel sheets of the required thickness. It is highly efficient but produces sheets with a relatively rough surface. Cold rolling is carried out at room temperature and can produce products with high precision and a smooth surface. Stamping forming includes processes such as deep drawing and bending. Deep drawing uses a mold to stretch a flat blank into a hollow part and is suitable for parts with complex structures. Bending achieves angle forming through press bending or roll bending techniques. Outer tensile and inner compressive stresses need to be controlled to avoid cracking. Surface treatment often uses galvanizing, phosphate, or chromate processes to improve corrosion resistance and adhesion.

 

III. Plastic and Foam Sheet Forming Methods

Plastic sheets are generally formed by the extrusion process. The dried plastic raw materials are melted under high temperature and high pressure and then extruded through a mold for shaping. Foam plastic sheets are divided into compression molding foaming and internal foaming technologies. In the former, polystyrene particles are placed in a mold cavity, and steam is introduced to make them bond and solidify. In the latter, a special flow channel is used to form a uniformly foamed internal structure in a single step under pressure and temperature. Polyurethane rigid foam sheets are produced on a continuous production line. The foaming raw materials are sprayed on the surface of the substrate film and quickly shaped by a pressing machine to obtain high-strength sheets with rough surfaces on both sides.

 

IV. Processing of Composite Sheets and Special Materials

The molding of epoxy resin composites relies on the pultrusion process. The fiber-reinforced materials are impregnated in a glue tank and then gradually shaped through a pre-forming mold and a forming mold. A traction device ensures continuous production. Carbon fiber profile sheets use a gradual hot pressing technology. The sheet is deformed in stages to approach the ideal cross-section and ensure uniform wall thickness. Plant fiber or straw sheets are made by mixing materials such as magnesium sulfate and fly ash, pouring them into a mold for curing, and combining with a polyvinyl alcohol-based environmentally friendly adhesive to achieve waterproof and flame-retardant functions.

 

V. Innovative Processes to Improve Efficiency and Performance

High-temperature gas jet hot pressing forming rapidly heats fiber materials through compressed gas, significantly shortening the hot pressing cycle and is suitable for the efficient processing of non-plant fibers. Shot peening forming technology uses high-speed steel shots to impact the metal surface, generating compressive stress to form a curved surface. It is commonly used in the manufacturing of aircraft wall panels and has the dual advantages of forming and enhancing fatigue strength. Stretch bending forming involves bending the profile after pre-stretching, which improves the stress distribution and is suitable for manufacturing high-precision aircraft components such as ring frames and stringers.

 

Through the reasonable selection and application of the above processes, sheet metal forming technology can meet the diverse needs of industries such as construction, aviation, and automotive, and promote the continuous optimization of material performance and production efficiency.