When preparing the tung oil core sand applied to the welding platform, the following points should be noted: For machine tool castings, 1. It is necessary to pay attention to whether the quality of tung oil or linseed oil is qualified. 2. To improve the wet strength, attention should be paid to adding an appropriate amount of dextrin or bentonite and other additional binders. 3. Under the condition of ensuring the strength requirement of the core sand, the usage of tung oil, linseed oil, and water should be minimized as much as possible, and the original sand with less mud content should be selected. 4. The mixing process should vary according to the added substances and the type of the sand mixer.