JPH0735090B2 - Method for adjusting wall thickness of parison for manufacturing hollow molded article with composite material - Google Patents

Description

Detailed Description of the Invention a. OBJECT OF THE INVENTION <Industrial field of application> The present invention relates to a method for adjusting the wall thickness of a parison for producing a hollow molded article having a composite material.

<Prior Art> JP-A-63-104802 discloses an example of a method for adjusting the length and thickness of a parison of this type. In this publication, the length and the thickness of a parison made of a single synthetic resin are used. A thickness adjustment method is disclosed.

<Problems to be Solved by the Invention> However, the above publication does not disclose any method for adjusting the wall thickness of a parison for producing a hollow molded article including a composite material.

<Problems to be Solved by the Invention> The present invention provides a method capable of controlling the injection speed of each synthetic resin forming a parison having a composite material and appropriately changing the ratio of the composite material in the parison. To aim.

B. Structure of the Invention <Means for Solving the Problems> In order to solve the above problems, the present invention has at least a double resin supply passage communicating with a single parison outlet provided in a blow molding die head. An accumulator type injection machine is connected to each resin supply path, and an extruder for feeding molten resin is connected to each accumulator type injection machine to extrude a parison of a desired size in one cycle. At this time, a multi-point type parison wall thickness controller presets a speed pattern that is the sum of the respective speeds of the two accumulator type injection machines in one cycle corresponding to each designated point,
According to this speed pattern, the injection speed ratio of the two accumulator type injection machines is determined, and the synthetic resin of the inside and the outside is injected into the die head at the fixed injection speed ratio at the constant time intervals. And a method for adjusting the wall thickness of a parison for producing a hollow molded article including a composite material.

In order to solve the above-mentioned problems, the injection speed of each accumulator-type injection machine in this wall thickness adjusting method is detected and compared with the set injection speed, and the injection speed of each accumulator-type injection machine is fed back in accordance with the difference. It is preferable to control.

<Example> Next, a typical example of an apparatus for carrying out the method for adjusting the thickness of a parison according to the present invention will be described.

In FIG. 1, A indicates the entire hollow molded article manufacturing apparatus,
The blow molding die head 10 is provided with a single parison discharge port 11 similarly to the known one, and double resin supply passages 12 and 13 communicating with the parison discharge port 11 are provided in the die head 10. There is.

Further, to each of the resin supply passages 12 and 13, there are respectively connected accumulator type injection machines 14 and 15, and extruders 18 and 19 for feeding the molten resin to the accumulator type injection machines 14 and 15 are respectively accumulator type injection machines. Connected to machines 14 and 15, respectively.

A well-known 10-point type parison thickness controller 50 is provided, and a speed pattern which is the sum of the speeds of the two accumulator-type injectors 14 and 15 in one cycle corresponding to each designated point is preset 10 Point speed setting circuit
20, a speed distribution circuit 21 that determines the injection speed ratio X / Y of the two accumulator-type injectors 14 and 15 according to the speed pattern, and the predetermined injection speed ratio X / Y at the fixed time intervals. The degree of opening and closing is adjusted based on Y, in order to adjust the forward speed of the plungers 14a, 15a of the accumulator type injection machines 14, 15, that is, the amount of resin supplied to the inner and outer synthetic resin supply paths 12 and 13. Each accumulator type injection machine
Servo valves 16 and 17 connected to 14 and 15 are provided. Further, if necessary, the injection speed of each of the accumulator type injection machines 14 and 15, that is, the plungers 14a and 15a.
Linear potentiometer 2 for detecting the forward speed of
3, 24, compared with the forward speed of the plunger 14a, 15a detected by each linear potentiometer 23, 24 and the injection speed set in the speed distribution circuit 21, each accumulator-type injection machine 14 according to the difference, Comparison circuits 25 and 26 for feedback controlling the injection speed of 15 are provided.

Further, if necessary, each accumulator type injection machine
Command circuits 27 and 28 for issuing a command to switch the servo valves 16 and 17 to stop the advance of the plungers 14a and 15a in order to stop the injection of molten resin by 14 and 15 are comparison circuits 2
Connected to 5, 26.

The operation of the apparatus of the embodiment configured as described above will be described together with a representative embodiment of the method for adjusting the wall thickness of a parison for producing a hollow molded article including the composite material of the present invention.

Based on the point signal from the parison thickness controller 50, the die in the die head 10 is similar to the known one.
The gap between 30 and core 40 is adjusted to extrude the parison of the desired dimensions.

A speed pattern, which is the sum of the speeds of the two accumulator-type injectors 14 and 15 in one cycle corresponding to each point designated by the 10-point type parison thickness controller 50, is preset by the setting circuit 20. To do. According to this speed pattern, the injection speed ratio X / Y of the two accumulator type injection machines 14 and 15 is determined by the speed distribution circuit 21, and the determined injection speed ratio X / Y is determined at every fixed time.
Adjust the opening and closing degree of the servo valve 16, 17, based on
The advancing speed of each plunger 14a, 15a is adjusted to adjust the amount of resin supplied into the inner and outer synthetic resin supply paths 12, 13.

At this time, the forward speed of each accumulator type injection machine 14, 15 is detected by the linear potentiometers 23, 24, and the detected forward speed is compared with the injection speed set in the speed distribution circuit 21 by the comparison circuits 25, 26. The injection speed of each accumulator type injection machine 14, 15 is feedback-controlled according to the difference.

Next, when the injection of the molten resin by each accumulator type injection machine 14, 15 is stopped, the respective command valves 27, 28 are used to switch the respective servo valves 16, 17 and the plungers 14a, 15a.
Command to stop the forward movement of the
Stop forward movement of a and 15a.

C. Effects of the Invention In the method for adjusting the wall thickness of a parison for manufacturing a hollow molded article provided with a composite material which is the specific invention of the configuration, the injection speed of each synthetic resin constituting the parison provided with the composite material is as described above. The ratio of the composite material in the parison can be controlled and easily changed to obtain a desired parison, and a hollow molded article having a predetermined composite material can be molded.

The specific invention according to claim 2, wherein the injection speed of each accumulator type injection machine is detected and compared with the set injection speed, and the injection speed of each accumulator type injection machine is feedback-controlled according to the difference. In addition to the above effect, each of the above-mentioned inner and outer synthetic resins corresponds to the inside of the resin passage at an injection speed ratio determined by two accumulator-type injectors more accurately according to the ratio of the composite material at each point. Inject the molten resin.

<Effects Specific to Embodiments> In the above embodiments, each accumulator type injection machine 1
By switching the servo valves 16 and 17 when stopping the injection of molten resin by 4 and 15, and incorporating command circuits 27 and 28 that issue a command to stop the advance of the plungers 14a and 15a, the resin switching can be performed quickly. Can be done.

[Brief description of drawings]

The drawings relate to the present invention, and FIG. 1 shows the first of the present invention.
FIG. 2 is a schematic diagram showing an embodiment, and FIG. 2 is a block diagram showing the main part thereof. Explanation of main symbols in the figure 14, 15 …… Accumulator type injection machine, 16, 17 …… Servo valve, 14a, 15a …… Plunger, 27, 28 …… Command circuit.

Claims (2)

[Claims] 1. A blow molding die head is provided with at least double resin supply passages communicating with a single parison discharge port in the die head, and an accumulator type injection machine is connected to each resin supply passage. Extruder for feeding molten resin is connected to each accumulator type injection machine, and when a parison of a desired size is extrusion-molded in one cycle, a multi-point type parison thickness controller, each designated point The speed pattern which is the sum of the respective speeds of the two accumulator type injection machines in one cycle corresponding to is preset, and the injection speed ratio of the two accumulator type injection machines is determined according to this speed pattern, The compound resin characterized by injecting the inner and outer synthetic resins into the die head at the predetermined injection speed ratio every the predetermined time. The hollow molded article thickness adjusting method for manufacturing parisons of having the material. 2. The injection speed of each accumulator type injection machine is detected and compared with the set injection speed, and the injection speed of each accumulator type injection machine is feedback controlled according to the difference. A method for adjusting the wall thickness of a parison for producing a hollow molded article provided with the composite material as described above.