Abstract

A device for producing a tubular object from thermoplastic material includes a die, a plunger, and a withdrawal unit. The movements of the withdrawal unit, plunger and die body are controlled such that the movement of the withdrawal unit is carried out according to a freely adjustable velocity profile over the path of the withdrawal unit. Movement of the plunger is carried out according to a freely adjustable velocity profile over the plunger path and movement of the die body is carried out according to a freely adjustable position profile over the path of the withdrawal unit or plunger. In this manner, the wall thickness of the tubular object may be adjusted with high accuracy over its length.

IPC Classes  ?

• B29C 49/04 - Extrusion blow-moulding
• B29C 49/30 - Blow-moulding apparatus having movable moulds or mould parts
• B29C 49/32 - Blow-moulding apparatus having movable moulds or mould parts moving "to and fro"
• B29C 49/78 - Measuring, controlling or regulating

Abstract

A method and a device are disclosed for producing a tubular object from thermoplastic material, for example a bellows. The device comprises a die with a movable die body for altering the cross-sectional surface of the die opening, a plunger for extruding a specific quantity of plastic material through the die, and a withdrawal unit for guiding the tubular plastic object emerging from the die. The movements of the withdrawal unit, the plunger and the die body are controlled such that the movement of the withdrawal unit is carried out according to a freely adjustable velocity profile over the path of the withdrawal unit, the movement of the plunger is carried out according to a freely adjustable velocity profile over the path of the plunger and the movement of the die body is carried out according to a freely adjustable position profile over the path of the withdrawal unit or of the plunger. In this manner, the wall thickness of the tubular object may be adjusted with high accuracy over its length.

IPC Classes  ?

• B29B 11/10 - Extrusion moulding
• B29C 49/04 - Extrusion blow-moulding
• B29C 49/72 - Deflashing outside the mould

Goods & Services

Machines for processing thermoplastic material.