Influence of drawing process parameters on forming of micro copper tube with straight grooves

Using high-speed oil-filled spinning method, high quality micro copper tube with straight grooves (MCTSG) with an outer diameter of 6 mm was obtained. Then, MCTSG with an outer diameter of 3-6 mm was fabricated successfully by multi-pass drawing processing method. The influence of drawing parameters on the forming of micro straight grooves was investigated based on the forming mechanism. The results show that the values of groove depth and width decrease, while the wall thickness increases as the drawing diameter decreases. At the same time, the groove depth and width increase, while the wall thickness decreases as the die angle increases. The drawing force increases as the reduction increases. Excessive copper tube reduction may results in groove folding and segmental teeth. The drawing force decreases firstly and then increases with the increases in die angle. When the die angle α is 16°, the drawing force is the smallest, indicating 16° is the optimal angle.