Research on a wrinkle-free forming method using paraffin wax for sheet metal

This paper presented an effective method for sheet metal to prevent wrinkling and reduce machining allowance by using paraffin wax. The paraffin wax was used as pressure medium to transfer and exert a continuous and uniform forming pressure over the entire surface of the sheet being formed. Due to uniformly the forming pressure distributed, plastic instability and wrinkles during the forming process were suppressed. The proposed method can eliminate the machining allowance of the blank size and directly process the blank into the target shape piece, which also saves the trimming process time and improves the utilization ratio of the blank. The proposed forming method is applicable for blank with different shapes and thickness and has the advantages of strong flexibility and universality. The formability and thinning of the sheet, the forming error, were studied using ABAQUS numerical simulation software. The experimental results show that the proposed paraffin wax sheet forming method can significantly inhibit the wrinkling instability and improve the forming quality of the metal workpiece.