The Use and Defects of Chemical Bonded Sand in Casting and Their Solutions
Introduction
Casting is a manufacturing process that produces metal parts by pouring liquid metal into a mold and letting it cool and solidify. The success of the casting process largely depends on the quality of the mold. Chemical bonded sand (CBS) is a common molding material used in the casting process for its many advantageous properties. This article will discuss the general use of CBS in the casting process, the types of problems which can arise from its defects and the potential solutions to address these issues.
Applications of Chemical Bonded Sand
The use of chemical bonded sand in the casting process has significantly improved throughput and efficiency as compared to other traditional foundry Sands. CBS is used to produce complex parts and shapes with tight tolerances, as well as to create smooth mold surfaces for superior surface finish and cosmetic details. CBS also has superior properties for sound attenuation, shock, and vibration which makes it beneficial for casting thin-walled parts or components.
Furthermore, the use of CBS can dramatically reduce the machining time for the part as well as reduce the cost and lead time for casting production. The sand used is reusable and recyclable, which reduces the use of limited natural resources for the same purpose.
CBS Defects and Their Solutions
Despite the advantages of using CBS in the casting process, there are some drawbacks and problems which can occur from the use of chemical bonded sand. The most common problems which arise from using CBS include sand attrition, sand shrinkage and sand burnout.
Sand attrition occurs when the particles of the sand become abrasive and the sand starts to wear itself away. This can be addressed by regularly inspecting the sand and replenishing it when necessary. Additionally using sand with a higher bond strength can help to reduce sand attrition.
Sand shrinkage occurs when the sand particles become too small, resulting in loose or cracked molds. This problem can be addressed by using core coatings and lubricants to ensure a tighter and stronger bond in the sand particles. This will help to prevent sand shrinkage and reduce the risk of cracks or other defects in the parts.
Finally, sand burnout can occur when high temperatures cause the sand to break down and disintegrate. To mitigate this problem it is important to use sand which has a higher heat resistance and to control the temperatures within the casting process. Additionally, core coatings and binders can also help to reduce the risk of sand burnout.
Conclusion
The use of CBS in the casting process provides many benefits and improves productivity and efficiency in the foundry. However, there are some drawbacks associated with this process and it is important to be aware of these potential issues in order to troubleshoot and prevent them. Regular inspections of the sand and the use of higher quality binders and coatings are some of the possible solutions to the challenge of CBS defects.
