| 摘要 |
The invention relates to a method for injection moulding of a moulded part (1), which has at least two different sections (2, 3) being different in the outer diameter (D1, D2), wherein a void (4) is produced in the inner of the moulded part (1) by causing a projectile (5) in the direction of a longitudinal axis (L) of the moulded part (1) through the still molten injection mouldable material in a direction of flow (F), whereto a pressurized fluid is exerted in the void (4) in the direction of flow (F) behind the projectile (5) which moves the projectile (5) into the direction of flow (F). To obtain constant wall thicknesses in the case that the outer dimensions of the moulded parts are changing the invention is characterized in that a projectile (5) is used which comprises at least one elastic or plastic section (6), which section (6) is delimited by a space (7) in which the pressurized fluid can enter when causing the projectile (5) to move, wherein the volume (V) of the space (7) and for this reason the effective outer diameter (d1, d2) of the projectile (5) can be changed in dependency of the fluid pressure (p), wherein the pressure (p) of the pressurized fluid and/or the pressure in the melt or a process factor being dependent from the pressures is controlled in such a manner that the space (7) and for this reason the effective outer diameter (d1, d2) of the projectile (5) is enlarged and/or reduced in such a way that the effective outer diameter (d1, d2) of the projectile (5) has a predetermined value at least in sections along the feeding path (x) in the direction of flow (F). Furthermore, the invention relates to an apparatus for injection moulding of a moulded part.
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