During the manufacturing process of the counterweight blocks for forklifts, various problems may arise. Common issues include sand holes and sand sticking. For these frequently encountered problems, corresponding solutions have been compiled. 

Measures to avoid loopholes: 

(1) Strictly control the properties of the molding sand, enhance the surface strength and compactness of the sand cores, reduce burrs and sharp edges, and minimize sanding. 

(2) Before boxing, thoroughly clean the surface of the cavity and core of the mold to remove any loose sand. Ensure a smooth and stable box closure. If there is a visible riser or an open vent hole, avoid allowing loose sand to fall into the mold cavity. After boxing, the mold should be filled with molten material as soon as possible. 

(3) Set up a correct and reasonable gating and risering system to avoid excessive erosion of the mold walls and sand cores by the molten metal. 

(4) The surface of the gate cup should be smooth and there should be no loose sand. 

Measures to avoid your sand sticking: 

(1) Select sand with high refractoriness to improve the refractoriness of the molding sand and core sand. The SiO2 content of the raw sand should be above 96% (by mass fraction), and the sand particles should be coarser. The higher the pouring temperature of the weight blocks and the thicker the wall thickness, the higher the requirement for the SiO2 content in the raw sand. 

(2) Appropriately lower the pouring temperature and increase the pouring speed, thereby reducing the thermodynamic and physicochemical effects of the molten metal on the sand mold. 

(3) The compactness of the sand mold should be high (usually greater than 85%) and uniform, reducing the gaps between the sand particles; the mold and core should be properly repaired without any local looseness. 

(4) Use coatings that do not crack or fuse into cavities even at high temperatures.