Solution To The Problem of Rough Surface of Castings

The rough surface of castings not only affects the appearance, but may also reduce the wear resistance and sealing of the parts, and even affect the subsequent assembly accuracy. If not resolved in a timely manner, it may lead to the scrapping of the parts. Based on the characteristics of casting technology, starting from the causes, solutions, and preventive measures of the problem, we will quickly solve the surface roughness problem and ensure that the castings meet the requirements for use.

1、 Identify the core reasons for surface roughness

There are three main reasons for the rough surface of castings: firstly, poor quality of molding sand, with particles that are too coarse or contain impurities, resulting in sand marks on the surface of castings; Secondly, improper pouring process results in poor flow of molten metal, which cannot fully fill the mold cavity and form a rough surface; The third issue is surface wear and sanding of the mold, or improper use of release agents, which can lead to impurities adhering to the surface of the casting. In addition, insufficient purity of the molten metal and low pouring temperature can also exacerbate surface roughness.

2、 Targeted solutions

Optimize the quality of molding sand: Select molding sand with fine particles and fewer impurities, add an appropriate amount of binder to improve the flowability and formability of the molding sand, and avoid sand particles from adhering to the surface of the casting.

Standardize the pouring process: control the pouring temperature of the metal liquid to ensure its fluidity and avoid insufficient filling due to low temperature; Adopting a smooth pouring method to reduce surface defects caused by metal splashing.

Mold and demolding treatment: Regularly inspect the surface of the mold, timely polish the worn parts, apply special demolding agent, and avoid mold sand sticking; If the mold is severely aging, replace the mold in a timely manner.

Post processing: For slightly rough castings, fine polishing (using soft tools) can be used to remove surface floating sand and burrs; When the roughness is severe, it needs to be recast to avoid forced use.

3、 Preventive measures

Strictly control the quality of molding sand and pouring temperature during daily casting, and avoid using metal raw materials with excessive impurities; Regular maintenance and upkeep of molds, timely cleaning of residual sand particles on the surface; After pouring, do a good job of cooling the casting to avoid surface cracking and roughness caused by uneven cooling, and reduce surface roughness problems from the source.