| 摘要 |
PURPOSE:To eliminate the necessity of aligning work for a high precision tube with its unevenness amount equal to or less than that of an extrusion head with an aligning mechanism and carry out extrusion molding without generating the material loss generated by aligning. CONSTITUTION:Mounting sections 1a, 4a and 5a of same outer diameter are formed integrally on a die 1, a spider holder 4 and point holder 5 respectively, and said sections are centered by means of opening face reference of a circular opening 9 formed on a head main body 8 to improve the concentricity of the die 1, a spider 2 and a point 3. Also, if required, centering accuracy is further enhanced by minimizing the clearance of outer peripheries of the mounting sections 1a, 4a and 5a by means of linear expansion difference at the time of using or by one chuck processing the inner and outer diameter faces of respective parts to eliminate the axis deviation within a single part, and make the thickness unevenness of a tube T less. Further, the mounting sections 1a, 4a and 5a are formed in the structure of having the end faces perpendicular to the axial center and placed in line with in an opening 9 and fixed by a box nut 7 to simplify the manufacturing, assembly and disassembly and the like and simultaneously reduce the cost. |
