JPH035295B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for easily measuring parison cross-sectional area swell in a blow molding machine.

[Prior Art] A general blow molding machine will be explained with reference to FIG. 4. A mandrel 3 that is raised and lowered by a servo actuator 2 is housed in a cylindrical head 1, and a nozzle is installed at the bottom of the head 1. The main body 4 is attached and a nozzle 6 is formed between the nozzle main body 4 and the mandrel 3, and the nozzle 6 is moved up and down by the actuator 5 into the gap between the head 1 and the mandrel 3.
injection plunger 7 for extruding parison 8 from
are slidably fitted together.

The parison cross-sectional area swell R in such a blow molding machine is determined by where the parison cross-sectional area is A _P and the nozzle diameter is
When D _N and the nozzle gap are S, it is expressed as R=A _P /πD _N S (i), where the parison cross-sectional area A _P is the parison moving speed, ν _P is the parison moving speed, and the extrusion amount by the injection plunger 7 is G.
Then, A _P = G / ν _P ... (ii) The amount of extrusion G by the injection plunger 7 is expressed as follows, where A _I is the cross-sectional area of the injection plunger and ν _I is the moving speed of the _injection plunger. _I ...(iii) Then, by inserting this equation (iii) into equation (ii), we get A _P = A _I · ν _I / ν _P …(iv).

For this reason, conventionally, when measuring the parison cross-sectional area swell R, the moving speed ν _I of the injection plunger 7 and the moving speed ν _P of the parison 8 are detected by speed detectors, and the parison cross-sectional area is calculated from equation (iv). Find A _P ,
The parison cross-sectional area swell R is determined from the parison cross-sectional area A _P using equation (i). Note that in formula (i), π,
D _N and S are constants.

[Problems to be Solved by the Invention] However, in the method of measuring the parison cross-sectional area swell described above, both the moving speed ν _I of the injection plunger 7 and the moving speed ν _P of the parison 8 must be detected. Therefore, the work becomes complicated, and there is a problem that the detector for determining the moving speed ν _P of the parison 8 is expensive and lacks reliability.

The present invention has been made in view of the above-mentioned circumstances, with the object of making it possible to easily measure the parison cross-sectional area swell.

[Means for Solving the Problems] The first invention provides a blow molding machine in which a parison is injected from a nozzle by sliding an injection plunger. The position of the injection plunger is detected by a position detector connected to an actuator that raises and lowers the injection plunger, and the position of the injection plunger is detected when the lower end position of the parison extruded from the nozzle is detected by a phototube placed at a required position below the blow molding machine. Find the stroke amount of the injection plunger from the detected positions of both plungers, divide the stroke amount by the nozzle gap, parison length, and nozzle circumference, and multiply this value by the plunger cross-sectional area to calculate the parison cross-sectional area swell. The second invention provides a blow molding machine in which a parison is injected from a nozzle by sliding an injection plunger, in which the lower end position of the parison extruded from the nozzle is located at a required position below the blow molding machine. The position of the injection plunger when detected by the phototube provided is detected by a position detector connected to an actuator that raises and lowers the injection plunger, and the position of the lower end of the parison is detected by a phototube located below the phototube. detecting the position of the injection plunger when the injection plunger is pressed by the position detector;
The stroke amount of the injection plunger is determined from the detected positions of both plungers, the stroke amount is divided by the nozzle gap, the parison length, and the nozzle circumference, and this value is multiplied by the plunger cross-sectional area to determine the parison cross-sectional area swell. The third invention is
In a blow molding machine in which the parison is injected from the nozzle by sliding the injection plunger, the injection plunger when the side of the parison extruded from the nozzle is marked with a marker placed below the blow molding machine. The position of the injection plunger is detected by a position detector connected to an actuator that raises and lowers the injection plunger, and the position of the injection plunger when the mark is detected by a phototube disposed below the marker is detected by the position detector. The stroke amount of the injection plunger is determined from the detected positions of both plungers, and the stroke amount is divided by the nozzle gap, parison length, and nozzle circumference, and this value is multiplied by the plunger cross-sectional area to determine the parison cross-sectional area swell. It is.

[Operation] In the present invention, in any of the inventions, the injection plunger stroke amount when the parison is injected for a predetermined length is determined, and the parison cross-sectional area swell is determined from the stroke amount, the nozzle gap, and the mechanical constant. .

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which a phototube 9 for detecting the passage of the lower end of the parison 8 is provided at a required position below the nozzle body 4, and a position detector 10 is attached to the actuator 5. from the phototube 9 and the position detector 10 to the arithmetic and control unit 11.
A detection signal can be sent to the servo actuator 2, and a command signal can be given from the arithmetic and control unit 11 to the servo actuator 2. In the figure, the same reference numerals as those shown in FIG. 4 indicate the same elements.

The principle of measuring the parison cross-sectional area swell R in this example is as follows. That is, the parison cross-sectional area Swell R is expressed by equation (i) as described above, and the parison cross-sectional area A _P in equation (i) is
The parison length determined by the set position is L _P ,
Letting the parison volume be V _P , A _P =V _P /L _P …(v), and the parison volume V _P is as follows: Letting the injection plunger stroke amount be X _S , and as mentioned above, let the injection plunger cross-sectional area be A _I , From the principle of constant volume, V _P = A _I・X _S …(vi).

Therefore, by substituting equations (v) and (vi) into equation (i) and rearranging, R=A _I・X _S /L _P /πD _N S=A _I /L _P πD _N ×X _S /S...
(vii) holds true. In this equation (vii), the injection plunger cross-sectional area is
A _I , parison length L _P , and nozzle diameter D _D are all mechanical constants determined by the blow molding machine, and the nozzle gap S is a set value, so if the injection plunger stroke amount is measured, (vii) The parison cross-sectional area swell R can be measured from the formula. Note that πD _N is the circumference of the nozzle, which is not circular but flat, and for an oval nozzle, the circumference is (vii)
You can use it with

During blow molding, a command signal is given from the arithmetic and control unit 11 to the servo actuator 2, the mandrel 3 is raised and lowered by the servo actuator 2, the nozzle gap S is set to a predetermined value, and the actuator 5 is operated. Injection begins. The position _X1 of the injection plunger 7 at the start of injection is detected by the position detector 10, and the detection signal is stored in the arithmetic and control unit 11.

When injection starts, the parison 8 is extruded from the nozzle 6 by the descent of the injection plunger 7, and the parison 8 gradually becomes longer as the injection progresses. At this time, the position signal X of the injection plunger 7 is continuously input from the position detector 10 to the arithmetic and control unit 11 . When the lower end of the parison 8 passes through the phototube 9, a pulse signal is sent from the phototube 9 to the arithmetic and control unit 11. Injection plunger 7 when passes through phototube 9
The position of X ₂ is stored.

Once the positions X ₁ and X ₂ of the injection plunger 7 are determined, the injection plunger stroke amount X _S is determined by the arithmetic and control unit 11 from X _S =X ₂ −L ₁ , and the determined injection plunger stroke amount X _S and mechanical constants that have been input into the arithmetic and control unit 11 in advance.
The parison cross-sectional area swell R is calculated by (ii) based on A _I , L _P , and D _N . When injection is completed, the device stops, but when calculating the parison cross-sectional area swell R for two or more types of nozzle gaps S, a command signal is output to the servo actuator 2 by the arithmetic and control device 11, and the nozzle gap S is The settings are changed, the above-described operation is repeated again, and the parison cross-sectional area swell R is measured.

Immediately after the start of injection of the parison 8, there is a possibility that an error due to an unsteady state such as the lower end of the parison 8 being thin may occur. Therefore, as in the embodiment shown in FIG. When the parison cross-sectional area swell R is measured, there is a possibility that the error becomes large. Therefore, the system shown in FIG. 2 eliminates such disadvantages and makes it possible to measure the parison cross-sectional area swell R with high accuracy.

In another embodiment of the invention shown in FIG. 2, another phototube 12 is disposed between the phototube 9 and the lower end of the nozzle body 4, and the parison length determined by the position of the phototubes 12, 9 is set to L. It is called _P. The distance from the lower end of the nozzle body 4 to the photocell 12 is parison 8.
This is the distance at which the parison 8 ejected from the nozzle gap can remain in a steady state when passing through the phototube 12 from the lower end.

When injection starts and the parison 8 is extruded from the nozzle 6, and its lower end passes the phototube 12, its pulse code is sent to the arithmetic and control unit 11, and the injection plunger 7 is detected by the position detector 10 at that time.
The position X ₁ of is stored in the arithmetic and control unit 11. When the lower end of the parison 8 passes through the phototube 9, its pulse code is sent to the arithmetic and control unit 11, and the injection plunger 7 is detected by the position detector 10 at that time.
The position X ₂ of is stored in the arithmetic and control unit 11.

Once the positions X ₁ and X ₂ of the injection plunger 7 are determined, the arithmetic and control unit 11 determines the injection plunger stroke amount X _S by X _S =X ₂ −X ₁ , and this value is expressed in equation (vii) Then, the parison cross-sectional area swell R is calculated. When the injection is completed, the device stops, but when determining the parison cross-sectional area swell R for two or more types of nozzle gaps S, the nozzle gap S
The parison cross-sectional area swell R is measured by changing the setting and repeating the above-mentioned operation again.

FIG. 3 shows still another embodiment of the present invention. In contrast to the embodiments shown in FIGS. 1 and 2 in which the parison cross-sectional area swell is measured using one type of nozzle gap in one injection, In this embodiment, it is possible to continuously set the parison cross-sectional area swell using two or more types of nozzle gaps in one injection.

13 in FIG. 3 is supported by an arm 14,
A marker 16 is a phototube arranged below the marker 13 at an interval of L _P , which can be attached to the mark 15 on the parison 8 .

In this embodiment, prior to injection, the number of times the parison cross-sectional area swell R is measured and the nozzle gap at each time are input into the arithmetic and control device.
When injection starts, the mandrel is raised and lowered by the servo actuator in the same manner as shown in FIGS. 1 and 2, the first nozzle gap is set, and the nozzle gap is set by the injection plunger. Parison 8 is extruded from the parison 8.
When the mark 15 is lowered by a predetermined amount, a mark 15 is engraved on the side surface of the parison 8 by the marker 13, and a pulse signal is sent from the mark 13 to the arithmetic and control unit, and the position of the injection plunger when the mark 15 is affixed is determined.
X ₁ is stored in the arithmetic and control unit.

Parison 8 descends again and marks 1 for the first time.
5 passes through the phototube 16, a pulse signal is sent from the phototube 16 to the arithmetic and control unit, and the position _X2 of the injection plunger at the time when the mark 15 passes through the phototube 16 is stored in the arithmetic and control unit, and the positions _X1 ,X ₂ , the injection plunger stroke amount X _S is determined from X _S =X ₂ -X ₁ , and this value is entered into equation (vii) to measure the parison cross-sectional area swell 6.

When the first measurement of the parison cross-sectional area swell R is completed, the signal activates the servo actuator to raise and lower the mandrel, and the second nozzle gap is set. The cross-sectional area swell R is measured.
The injection ends when the number of measurements of the parison cross-sectional area swell reaches the set number of times.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the method for measuring parison cross-sectional area swell in a blow molding machine of the present invention, an excellent effect can be achieved in that the parison cross-sectional area swell can be easily measured.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the method for measuring parison cross-sectional area swell in a blow molding machine of the present invention, FIG. 2 is an explanatory diagram of another embodiment, and FIG. 3 is an explanatory diagram of another embodiment. FIG. 4 is an explanatory diagram of a method for measuring parison cross-sectional area swell in a conventional blow molding machine. In the figure, 1 is the head, 2 is the servo actuator,
3 is a mandrel, 4 is a nozzle body, 5 is an actuator, 6 is a nozzle, 7 is an injection plunger, 8 is a parison, 9 is a phototube, 10 is a position detector, 11
is an arithmetic control unit, 12 is a phototube, 13 is a marker,
14 is an arm, 15 is a mark, and 16 is a phototube.

Claims (1)

[Scope of Claims] 1. In a blow molding machine in which a parison is injected from a nozzle by sliding an injection plunger, the position of the injection plunger at the start of injection is detected by connecting it to an actuator that raises and lowers the injection plunger. The position of the injection plunger is detected by the position detector, and the position of the injection plunger when the lower end position of the parison extruded from the nozzle is detected by the phototube disposed at a predetermined position below the blow molding machine. A blow molding machine characterized by determining the stroke amount of the injection plunger from the plunger position, dividing the stroke amount by the nozzle gap, parison length, and nozzle circumference, and multiplying this value by the plunger cross-sectional area to determine the parison cross-sectional area swell. A method for measuring parison cross-sectional area swell. 2 In a blow molding machine in which the parison is injected from a nozzle by sliding an injection plunger, the injection occurs when the lower end position of the parison extruded from the nozzle is detected by a phototube placed at a required position below the blow molding machine. The position of the plunger is detected by a position detector connected to an actuator that raises and lowers the injection plunger, and the position of the injection plunger when the lower end position of the parison is detected by a phototube disposed below the phototube; The stroke amount of the injection plunger is determined from the positions of both plungers detected by the position detector, and the stroke amount is divided by the nozzle gap, parison length, and nozzle circumference, and this value is multiplied by the plunger cross-sectional area to determine the parison cross-section. A method for measuring parison cross-sectional area swell in a blow molding machine, characterized by determining area swell. 3 In a blow molding machine in which the parison is injected from the nozzle by sliding the injection plunger, the injection when the side of the parison extruded from the nozzle is marked with a marker disposed below the blow molding machine. The position of the plunger is detected by a position detector connected to an actuator that raises and lowers the injection plunger, and the position of the injection plunger when the mark is detected by a phototube disposed below the marker is detected by the position detector. The stroke amount of the injection plunger is determined from the detected positions of both plungers, and the stroke amount is divided by the nozzle gap, parison length, and nozzle circumference, and this value is multiplied by the plunger cross-sectional area to determine the parison cross-sectional area swell. A method for measuring parison cross-sectional area swell in a blow molding machine, characterized in that: