JP2010241023A - Resin molding crosshead device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the temperature after operation early while reducing the heating time before operation. <P>SOLUTION: In the resin molding crosshead device 101, thermocouples 3 and 4 are set in two positions of the vicinity of a heater 2 for heating a cross head 1 and the vicinity of a resin flow passage, and the heater 2 is controlled by a prediction heating control unit 10 which performs "prediction control adopting two-point temperature detection+cascade control". Accordingly, in a state before operation, the heater 2 can be made to generate a sufficient output to reduce the heating time. In a state after operation, the heater 2 can be made to generate an output just enough to stabilize the temperature early. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a crosshead device for resin molding, and more particularly to a crosshead device for resin molding that can shorten the heating time before operation and can stabilize the temperature after operation at an early stage.

  Conventionally, a band heater for heating the crosshead and a thermocouple installed at one location on the heat transfer path from the band heater to the resin flow path are used to control the band heater based on the temperature measured by the thermocouple. And the cross head of the hollow molding machine which performs heating control of a cross head is known (for example, refer to patent documents 1).

JP-A-10-329202

In the cross head of the conventional hollow molding machine, the band heater is controlled based on the temperature at one place where the thermocouple is installed.
However, if the thermocouple is installed at one place, there is a problem that it is difficult to perform smooth heating control. For example, if a thermocouple is installed in the vicinity of the band heater, heat is immediately transmitted from the band heater to the thermocouple, so the output of the band heater is immediately suppressed and it takes time until the entire crosshead is heated. Further, when the operation starts and the molten resin starts flowing through the resin flow path, the heat balance is lost, but it takes time to detect the change with a thermocouple far from the resin flow path. That is, the heating time before operation takes a long time and the temperature after operation cannot be stabilized early. On the other hand, when a thermocouple is installed in the vicinity of the resin flow path, there is a time delay in which heat is transmitted from the band heater to the thermocouple. It causes deterioration of the resin. In order to prevent this excessive heating, it is conceivable to perform step temperature raising in which the temperature is raised step by step, but it is difficult to set the set temperature and start time for each step.
Furthermore, in the multilayer cross head, since there are a plurality of annular resin flow paths having a heat insulating effect as compared with metal, heat transfer becomes complicated, and it is difficult to cope with the conventional technology.
Therefore, an object of the present invention is to provide a crosshead device for resin molding that can shorten the heating time before operation and can stabilize the temperature after operation at an early stage.

In a first aspect, the present invention provides a multilayer crosshead (1) in which a plurality of resin materials are supplied to a plurality of resin flow paths by a plurality of extruders, and heating for heating the multilayer crosshead (1). Means (2), upstream temperature measuring means (3) and downstream temperature measuring means respectively installed at two locations upstream and downstream of the heat transfer path from the heating means (2) to the resin flow path (4) and the heating by predictive control based on the upstream temperature (PVs) measured by the upstream temperature measuring means (3) and the downstream temperature (PV) measured by the downstream temperature measuring means (4). There is provided a crosshead device (101) for resin molding processing comprising a predictive heating control means (10) for controlling the means (2).
In the crosshead device for resin molding processing (101) according to the first aspect, in the heat transfer path from the heating means (2) to the resin flow path, an upstream temperature measuring means (in the vicinity of the heating means (2)) ( 3), and there is a downstream temperature measuring means (4) relatively close to the resin flow path. For this reason, even in the multilayer crosshead (1) with complicated heat transfer, the heat flow from the heating means (2) to the resin flow path in the state before operation can be predicted, and the heating means (2) can provide a sufficient output. The heating time before operation can be shortened. In addition, the thermal balance is lost when the molten resin starts operating and flows through the resin flow path. However, since there is a downstream temperature measuring means (4) relatively near the resin flow path, this change can be immediately detected. The heat flow from the heating means (2) to the resin flow path in the state after operation can be predicted, and the heating means (2) can provide an output with no excess or deficiency to stabilize the temperature after operation early. I can do it.

  According to the crosshead device for resin molding processing of the present invention, the heating time before operation can be shortened, and the temperature after operation can be stabilized at an early stage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory view showing a resin molding processing crosshead device according to a first embodiment; FIG. 6 is a configuration explanatory view showing a crosshead device for resin molding processing according to a second embodiment.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings. Note that the present invention is not limited thereby.

Example 1
FIG. 1 is a configuration explanatory view illustrating a resin molding processing crosshead device 101 according to a first embodiment.
The resin molding processing crosshead device 101 includes four types of six-layer crossheads 1 that extrude the parison P when four types of resin materials are supplied to a plurality of annular resin flow paths by six extruders E1 to E6. A heater 2 for heating the seed 6-layer crosshead 1, and an upstream thermocouple 3 and a downstream thermocouple respectively installed at two locations upstream and downstream of the heat transfer path from the heater 2 to the resin flow path 4 and a predictive heating controller 10 that controls the heater 2 by predictive control based on the upstream temperature PVs measured by the upstream thermocouple 3 and the downstream temperature PV measured by the downstream thermocouple 4. .

  The upstream thermocouple 3 is installed in the vicinity of the heater 2, and the downstream thermocouple 4 is installed in the vicinity of the resin flow path.

  The predictive heating control unit 10 outputs a difference calculator 11 that outputs the deviation between the target temperature SV and the downstream temperature PV, and the target upstream temperature SVs for reducing the deviation between the target temperature SV and the downstream temperature PV as “two points”. Master controller 12 calculated by “predictive control employing temperature detection + cascade control”, difference calculator 13 that outputs a deviation between the target upstream temperature SVs and the upstream temperature PVs, the target upstream temperature SVs and the upstream temperature A slave controller 14 for calculating a control amount MV for reducing the deviation of PVs by “predictive control employing two-point temperature detection + cascade control”, and a heater drive output HU corresponding to the control amount MV. 2 and a heater driving unit 15 for driving 2.

IS1
The transfer function of the master regulator 12 is, for example, K _P1 (1 + 1 / T _IS1 + T _DS1 ).
The transfer function of the slave adjuster 14 is, for example, K _P2 (1 + 1 / T _IS2 + T _DS2 ).

  According to the crosshead device 101 for resin molding processing according to the first embodiment, excessive or insufficient heating due to temperature transmission delay can be eliminated by “predictive control employing two-point temperature detection + cascade control”. That is, in the state before the operation, the heater 2 can output a sufficient output and the heating time can be shortened. Further, in the state after operation, the heater 2 can produce an output with no excess or deficiency to stabilize the temperature early.

-Example 2-
FIG. 2 is an explanatory diagram of a configuration of the resin molding processing crosshead device 102 according to the second embodiment.
The crosshead device 102 for resin molding processing has the same configuration as the crosshead device 101 for resin molding processing according to the first embodiment, except that the position of the downstream thermocouple 4 is changed.

-Example 3-
PID control may be further employed.

  The crosshead device for resin molding processing of the present invention can be used for, for example, molding processing of four types and six layers parison.

DESCRIPTION OF SYMBOLS 1 4 types 6-layer crosshead 2 Heater 3 Upstream thermocouple 4 Downstream thermocouple 10 Predictive heating control part 101,102 Crosshead apparatus for resin molding processing

Claims (1)

A multilayer cross head (1) in which a plurality of resin materials are supplied to a plurality of resin flow paths by a plurality of extruders, a heating means (2) for heating the multilayer cross head (1), and the heating means ( 2) upstream temperature measuring means (3) and downstream temperature measuring means (4) installed at two locations upstream and downstream of the heat transfer path from the resin flow path to the resin flow path, and the upstream temperature measurement. Predictive heating control for controlling the heating means (2) by predictive control based on the upstream temperature (PVs) measured by the means (3) and the downstream temperature (PV) measured by the downstream temperature measuring means (4) A crosshead device (101) for resin molding processing, comprising means (10).

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