This lecture covers the fundamentals of sand casting, focusing on non-permanent molds and sand quality indicators. It explains the classification of sands, different hardening methods, and the importance of mold quality in the casting process. The instructor discusses the properties of green sands, chemically hardened sands, and the use of resins for mold creation. Additionally, the lecture explores the challenges related to humidity in molds and the advancements in additive manufacturing processes like 3D printing for metal casting applications.