Prefabricated House Stair Mold Design

The design of prefabricated house stair molds requires a comprehensive consideration of materials, structure, precision, efficiency, and safety. The key points are as follows:

1. Material Selection

• Steel Molds: The main body is made of high-strength Q235 steel plate with a panel thickness of 3-5mm. Key load-bearing parts (such as step corners and side plate connections) are reinforced with angle steel ribs through welding to enhance resistance to deformation. The surface of the steel mold needs to be sandblasted for rust removal and coated with an epoxy resin coating, providing excellent rust resistance and a long service life.
• Composite Material Molds: These molds are injection-molded from a composite of high-strength ABS resin and glass fiber, with each set weighing between 8-15 kilograms, facilitating manual handling and lifting. They have an impact strength of 15kJ/m² and can operate stably in environments ranging from -20℃ to 70℃, making them suitable for construction scenarios with low temperatures or large temperature variations.

2. Structural Design

• Modular Assembly: The mold consists of step modules, side plate modules, and end plate modules, which are quickly assembled using bolts or clips. Seams are sealed with rubber strips to prevent concrete leakage. For example, Nantong Keda's patented mold uses adjustable围板块 (surrounding panels) and step blocks to accommodate different step sizes.
• Split Design: The step plate and side plate are connected with clips, with a splicing error of ≤0.5 millimeters, ensuring that the height difference between prefabricated stair steps is ≤2 millimeters, meeting building code requirements.
• Reserved Functional Slots: The inner walls are equipped with steel bar positioning slots and pre-embedded part installation holes to accurately fix the positions of steel bars, preventing displacement during concrete pouring and ensuring structural safety.

3. Precision and Performance

• Dimensional Accuracy: The mold must ensure that the dimensional deviation of prefabricated stair components is ≤2 millimeters, with a surface flatness of ≤3 millimeters over a 2-meter straightedge, achieving a 'plaster-free' effect and reducing post-construction repair work.
• Demolding Performance: The inner walls of steel molds are coated with a special release agent or use a wet demolding technique (such as wing-shaped torsion spring positioning and lubrication in sliding slots) to reduce concrete demolding resistance by 40%. Composite material molds rely on the self-lubricating properties of the material to enhance demolding efficiency.
• Durability: Steel molds can be reused 200-300 times with a component wear rate of less than 5%. Composite material molds have strong anti-aging properties, with a single-use cost that is only one-third of that of traditional steel molds.

4. Versatility and Reusability
By adjusting the height of the side plates or combining modules, the mold can accommodate different step sizes (thickness 50-150 millimeters, width 260-300mm, height 150-180mm), meeting diverse architectural needs and reducing mold development costs.

5. Safety and Convenience
The design should consider the convenience of formwork installation and removal, reserving space for steel bar installation and concrete pouring. Composite material molds are lightweight and can be quickly rotated with lifting equipment. Steel molds reduce the burden of single operations through modular design, enhancing construction safety.