Tahara Machinery Limited

Kao Corporation

Kao Corpoation

Masayuki Akimoto

Mitsuo Yamanoi

Masashi Ogura

Yutaka Saito

Atsushi Sugiyama

Tokuji Noguchi

Minoru Oizumi

Minoru Ohizumi

Masashi Yano

A parison length control method for a blow molding machine in which a parison is extruded vertically, the end of the parison is closed, and a blowing gas is blown into the closed parison. The method includes the step of deriving a relationship between parison length and extruder screw rotation speed during a test molding process. Current parison length is then detected during normal molding operation, and the difference between the current parison length and a target parison length is derived. The extruder screw rotation speed is then controlled by calculating a correction amount for the extruder screw rotation speed based on the parison length difference in combination with the relationship between parison length and extruder screw rotation speed. The extruder screw rotation speed is then adjusted by the correction amount so as to attain the target parison length.

Parison length control method for blow molding machine

The invention resides in a rotary blow molding machine in which under an extruder for extruding a parison, a turntable is arranged which has plural sets of molds mounted thereon for holding the parison therebetween and blow-molding the parison, the turntable is rotated by a motor, an annular driven gear is provided on the turntable, and one pair of idle gears are made to intervene between the driven gear and a driving gear for transmitting the rotation of the motor so as to intermesh with both the gears.

Molding machine

A parison thickness control system includes an extruder die and a mandrel which are movable relative to each other to change wall thickness of a parison extruded between the extruder die and the mandrel during an extrusion or forming cycle of the parison. A parison control pattern is derived by manually inputting master points each defined in terms of a target parison wall thickness and an elapsed time during the parison extrusion cycle. A further parison control pattern is derived by performing the spline interpolation to interpolate between the master points. A still further parison control pattern is derived by correcting the above-noted further parison control pattern to allow the maximum or minimum value of the master points to indicate a limit value for the target parison wall thickness during the parison extrusion cycle. The parison extrusion cycle is divided into a given number of equal time intervals to define cycle points. The target parison wall thickness is derived for each cycle point based on the above-noted still further parison control pattern. The relative movement between the extruder die and the mandrel is controlled based on the derived target parison wall thickness for each cycle point. At least one of the cycle points may be used for triggering operation of an associated device.

Parison thickness control method

Growing community of inventors

Kaminokawa, Japan

Masayuki Akimoto