Structure and processing technology of school door leaf

1.1 Door Structure

Solid wood composite door leaves are typically made in a three or five-layer structure.

The intermediate layer forms the main structural layer, consisting of frames (skeleton) and door cores. The frames are made from prefabricated materials cut to the required dimensions to form the external skeleton. The door cores refer to the interior filling material of the door, which can be made of solid wood strips, particleboard, or honeycomb paper, among other materials.

The surface layer is a decorative veneer of 3mm or density board of 5mm, 7.5mm, or 12mm thickness. For a five-layer structure, decorative veneer can be applied to the surface of the thin density board. Additionally, the aesthetic appeal of the door leaf can be enhanced and the design can be diversified by inlaying various decorative strips in the center or on the surface of the door leaf.

1.2 Ingredients Process

The process of cutting materials that meet quality and material requirements into the required specifications as per the order is called "ingredient preparation." During ingredient preparation, attention must be given to leaving sufficient processing allowance, utilizing the wood rationally to ensure the quality of wooden doors, and improving the utilization rate of the wood. For components with texture requirements, the wood grain direction must be noted, meeting the drawing specifications, and corresponding markings made.

1.3.1 Compression Molding Process

The degree of deformation in finished wooden doors is closely related to the composite pressing process of frames and surface panels. To avoid or minimize door leaf deformation, strict control is required over the following aspects:

(1) Appropriate adhesive application with even distribution. Use an adhesive applicator to apply the adhesive, ensuring proper control over the amount. Insufficient adhesive application can lead to reduced bonding strength, adhesive shortage on the bonding surface, and localized separation. Excessive adhesive application results in a thick layer, requiring longer curing time and a higher risk of cracking.

(2) Appropriate hot pressing temperature. A low hot pressing temperature can cause the adhesive layer to delaminate and result in insufficient bonding strength; on the other hand, a high hot pressing temperature will lead to a longer cooling time after hot pressing and may cause plastic deformation of the material. Generally, the hot pressing temperature should be controlled within the range of 90-95°C. Additionally, it is crucial to ensure that the upper and lower pressure plates of the press are at the same temperature during hot pressing, so that both sides of the door panel have the same and uniform temperature rise.

The first piece test must meet the following criteria to be considered合格:

The product surface must not have any indentation, scratch, or bump damage.

Edge should be straight, corners slightly rounded, no burrs allowed.

(3) Edge strips must not protrude above the plane.

(4) The edges of the boards must be smoothly joined without any seams or overlaps.

(5) The edges of the edge banding must not have any adhesive overflow, nor should there be any glue lines or black lines.

(6) Edges are evenly coated with adhesive, ensuring strong bonding.

When sealing, first seal the two long sides, then the two short sides of the product. After sealing, conduct a full check of the quantity and quality to ensure they meet the工艺 standards, and then label accordingly.