JP2004524162A5 - - Google Patents

Claims (25)

A method of forming metal into a defined shape and lateral dimensions,
A hollow metal preform having a closed end, initially into the cavity of a mold which defines the lateral dimensions and the shape and the at least part of which is disposed away inwardly from the die wall ,
To stretch outwardly the preform until it contacts the almost completely the mold wall, said preform by adding internal fluid pressure, so by the defined shape and lateral dimensions to the preform Including
Cavity of the mold, the hollow metal preform having a closed end, with a punch located movably within said cavity at one end of the cavity, which is the necessary dimensions to surround laterally
The preform is located in the cavity such that the closed end of the preform is immediately opposite the punch;
The internal fluid pressure is applied to the preform to stretch the preform outward and to continuously apply the fluid pressure to the closed end;
Before or after the preform begins to stretch and before the preform has been stretched, the punch moves toward the one end of the cavity, and the closed end of the preform is moved over the fluid pressure. Retract in the opposite direction to the direction of the force applied by
A method of deforming the closed end of the preform while the preform extends outwardly until it substantially contacts the mold wall. Within said mold, the preform, a positive external fluid higher pressure positive internal fluid pressure and by applying a positive external fluid pressure according to claim 1, wherein said internal fluid pressure is applied Method. The method of claim 1, wherein heat is applied to the preform within the mold such that a temperature gradient occurs prior to subjecting the preform to the internal fluid pressure. 2. A method according to claim 1, wherein the preform is a long initially ordinary cylindrical workpiece having an extensible closed end and an open end opposite the closed end. The punch of the preceding claims, characterized in that the stretching of the preform even after said preform has begun extends is moved into said cavity prior to completion in step (b) The method as described in any one of these. The punch, the preform is moved into contact with the closed end before the start elongation of claims 1 to 4, the contact is characterized in that it is maintained between the preform is extended The method as described in any one of these. 7. The punch according to claim 1, wherein the punch has a contoured surface and the closed end of the preform is deformed to coincide with the contoured surface. the method of. The determined shape is a bottle shape including a neck portion and a body portion having a lateral dimension larger than the neck portion, the cavity of the mold has a major axis, the preform has a major axis, and 8. A method according to any one of claims 1 to 7, characterized in that in step (a) it is arranged coaxially with the cavity and the punch is movable along the long axis of the cavity. 9. The punch according to claim 8, wherein the punch has a dome-shaped contour, and the closed end of the preform is transformed into the dome-shaped contour in step (c). the method of. 10. A method according to any one of the preceding claims , wherein the mold wall comprises a separable separating mold for removing the container formed in the subsequent step (c). 11. A method according to claim 8, 9 or 10, wherein the defined shape is asymmetric with respect to the long axis of the cavity. Position of the punch, one of claims 1 to 11 and initially characterized in that it is initialized in the step (b) to limit axial stretching of the preform by the fluid pressure The method according to one. The preform is an elongated initially cylindrical workpiece having an open end opposite the closed end, the diameter of which is substantially equal to the diameter of the bottle-shaped neck portion. 13. A method according to any one of claims 8-12. 14. A method as claimed in any one of claims 8 to 13, wherein the workpiece has sufficient formability to be expanded to the defined shape by a single pressure forming operation. Prior to performing step (a), the workpiece is placed in a mold cavity smaller than the mold cavity, and the workpiece therein is defined as the defined shape at an intermediate size. 14. The method of claim 13, wherein the workpiece is subjected to internal fluid pressure to stretch to a shape smaller than the lateral dimension. The workpiece is initially a long normal cylindrical workpiece having an open end opposite the closed end, and is larger in diameter than the bottle-shaped neck.
Further comprising, after performing steps (a), (b), and (c), subjecting a proximate portion of the open end of the workpiece to a spin forming operation to form a neck portion having a small diameter, The method of claim 1. 17. A method according to any one of the preceding claims, wherein the workpiece is an aluminum workpiece. Has a recrystallization or recovered microstructure claims, characterized in that an aluminum sheet having a standard size ranging from about 0.25mm to about 1.5mm further comprising the step of making the preform Method according to 17. 19. The method of claim 18, wherein the preform is made as a closed end cylinder by drawing-redrawing or reverse-extruding the sheet. In the fluid pressure in the workpiece of step (b), (i) rising to a first peak before the workpiece begins to stretch, (ii) decreasing to a minimum value as it begins to stretch, iii) as the elongation proceeds until the preform is completely in contact with the mold wall, it rises to an intermediate value, and (iv) from the intermediate value during the completion of the preform elongation. The rising stage is continuously generated, and the punch deformation start in the step (c) for deforming by removing the closed end of the preform occurs almost simultaneously with the end of the stage (iii). 20. A method according to any one of claims 1-19. During the step (b), the closed end of the preform takes an enlarged regular hemispherical shape so that the portion of the preform first contacts the mold wall in step (b), Then, the deformation start of the punch in the step (c) in which the closed end of the workpiece is moved and deformed is started almost simultaneously with the closed end of the preform taking the shape. A method according to any one of claims 1 to 19. In order to change the difference between the internal fluid pressure and the external fluid pressure, the elongation rate of the preform is controlled by independently controlling the internal and external fluid pressures to which the preform is simultaneously exposed. The method of claim 2, comprising: 4. The method of claim 3, wherein heat is applied to the preform upward from the closed bottom by heating means in the punch to impart a temperature gradient to the preform. The heat of the preform according to claim 3, wherein heat is applied to the preform upward from the closed bottom by a heating means around an upper end of the preform to give a temperature gradient to the preform. Method. 25. A method according to claim 23 or 24, wherein heat is applied to the preform by heating means in the sidewalls of the mold.