Composite formwork for sand casting

The utility model discloses a composite moulding board used for sand mould casting, belonging to a casting technique. Since the existing moulding board has a detachable structure and is made of wood, therefore the quality of cast parts can be affected. The composite moulding board is provided with a wood moulding board embryonic form fixed on a steel framework by a fastening piece, and a surface layer is covered on the wood moulding board embryonic form. The fastening piece is hid at the inner side of the surface layer, so that a plurality of fastening pieces can be used for avoiding centralized stress; meanwhile, the fastening pieces can be used for ensuring the bonding strength and do not affect the quality of the cast parts; the surface layer has good consistency, so as to be beneficial to guaranteeing the quality of the cast parts; a composite structure of glass fiber cloth is adopted by the surface layer, so that the surface layer has good strength and rigidity, is not easy to have the phenomenon of evap