Abstract:

High-quality copper tube with micro straight grooves,which is less than 6mm in outer diameter,was fabricated via the composite process of high-speed oil-filled spinning and multi-pass drawing.Then,the corresponding machining mechanism was analyzed,and the influences of machining parameters on the quality of the product were investigated.The results indicate that,during the machining,excessive drawing reduction may result in groove folding and crack,and excessive roundness error may lead to crinkle even depression;and that,when the entry cone angle of the drawing die is 16°,the length of sizing region is 4mm and the exit cone angle of the drawing die is 30°,high-quality copper tube with micro straight grooves can be machined under good lubrication condition and small residual stress.Moreover,it is found that stable-quality copper tube with micro straight grooves,which is less than 6mm in outer diameter,can be machined by controlling the drawing parameters and the roundness error.The inner grooves of the product tend to close,just like a dovetail,which benefits the improvement of capillary force of the tube.

Key words: micro groove, oil-filled spinning, multi-pass drawing, drawing parameter, heat pipe