JPH0825464A - Apparatus and method for molding cylindrical member - Google Patents

Abstract

PURPOSE:To immediately correct the thickness of a cylindrical member within a deformable period by converting electrostatic capacity measured by electrostatic capacity meter provided in opposed relation to the opposed electrode assembly attached to the leading end part of a die core rod to thickness and correcting the thickness of the cylindrical member to a desired value on the basis of the measured thickness. CONSTITUTION:The core rod 213 of the die 211 provided to the leading end of an extrusion molding machine is attached by support members 214 and an opposed electrode assembly 215 is attached to the leading end of the core rod 213 to be connected to earth. The electrode assemblies 221-224 of an electrostatic capacity meter are attached to the die in opposed relation to the opposed electrode assembly 215. Therefore, the electrostatic capacity of the cylindrical member issued from a cylindrical passage 212 in a deformable state is measured in four directions. The measured electrostatic capacities are converted to thicknesses by an operation device. The measured thicknesses of the respective places of the cylindrical member are corrected to correct thickness by a control means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a capacitance meter to
The present invention relates to a tubular member forming apparatus and a tubular member forming method capable of accurately forming the thickness of a tubular member such as a pipe. In recent years, pipes made of vinyl chloride or the like have become popular in place of metal pipes. And these pipes tend to be used in many new applications in various fields. The present invention relates to a tubular member forming apparatus and a tubular member forming method for forming a tubular member with high thickness accuracy that can also be used for the new application.

[0002]

2. Description of the Related Art FIG. 4 is a schematic block diagram for explaining a process of forming a tubular member in a conventional example. In FIG. 4, the tubular member molding method comprises: an extrusion step 41 of extruding a heated molten material with an extruder; a molding step 42 of molding the extruded material into a desired shape with a die; The correction step 43 for correcting a tubular member having an undesired shape at a deformable time, the cooling step 44 for cooling the tubular member formed into a desired shape so as not to deform, and the thickness of the finished tubular member. A measuring step 45 for measuring pod defects and the like by ultrasonic waves, a size regulating step 46 for forming a tubular member of a desired length, a cutting step 47 for cutting to a regulated length, and a cut tubular shape. And a deposition step 48 for depositing the member.

Further, in the straightening step 43, since the tubular member has not yet been hardened, the tubular member having a desired shape can be obtained by, for example, straightening the shape with a stamping machine and adjusting the arrangement of dies. Allow the member to be made.
Further, the thickness and defects of the cylindrical member cured by the cooling process 44 are measured by ultrasonic waves.
Then, the measured value is used as a control signal for eliminating defective products or stopping the operation of the extruder.

[0004]

The tubular member coming out of the die of the extruder is heated and in a deformable state. Conventionally, a tubular member forming apparatus corrects a deformed tubular member by utilizing the deformable state. However, since the conventional tubular member forming apparatus does not measure the thickness of the tubular member in a deformable state, it merely straightens a bent and formed product. In addition, the thickness of the deformable tubular member cannot be measured by the ultrasonic waves that are in direct contact, and the thickness thereof is measured after being cooled. For example, when a tubular member with high thickness accuracy is required, even if a tubular member with an undesired thickness is detected in the measuring step, the tubular member that has already completed the correction step and the cooling step is However, it is not corrected and becomes a defective product.

Then, the discovery of defective products after cooling is
Instead of correcting defective products, the only option was to stop the extruder and adjust the dies and correction devices to reflect them in the next product. In recent years, the development of new uses of tubular members has progressed, and the uniformity of the wall thickness of tubular members has been required. However, the conventional tubular member forming apparatus cannot accurately control the thickness of each tubular member one by one.

In order to solve the above-mentioned problems, the present invention relates to each of the tubular members in a deformable state by at least one capacitance meter. It is an object of the present invention to provide a tubular member molding apparatus and a tubular member molding method capable of immediately correcting the thickness of a tubular member by measuring To do.

[0007]

[Means for Solving the Problems]

(First Invention) In order to achieve the above object, a tubular member molding apparatus of the first invention is a die for extruding a molten plastic member to mold a tubular member (211 in FIG. 2).
And at least one counter electrode assembly (215 in FIG. 2) attached to the tip end of the mandrel (213 in FIG. 2) of the die (211) and being at ground potential, and the counter electrode assembly (215). A main electrode provided opposite to
An electrode assembly (221 to 224 in FIG. 2) of a capacitance meter comprising a flat guard electrode and a flat ground electrode;
A calculation means (139 in FIG. 1) for converting the capacitance measured by the capacitance meter into a thickness, and the calculation means (139)
And a correction means (134 in FIG. 1) for correcting the thickness to a desired thickness based on the thickness calculated by.

(Second Invention) A tubular member molding method of the second invention comprises a step of extruding a molten plastic member from a die to mold the tubular member, and a capacitance meter.
A step of measuring the capacitance of the tubular member, and the thickness is calculated based on the capacitance measured in the step,
A step of determining whether or not the thickness is a desired thickness, a step of correcting the thickness to a predetermined thickness when the thickness is not a predetermined thickness, and a step of cooling the tubular member after being corrected to the predetermined thickness. It is characterized by having.

[0009]

[Work]

(First Invention and Second Invention) The applicant of the present invention is that the capacitance meter can accurately measure the thickness in a non-contact manner, and measures the capacitance of the tubular member in a deformable state by being heated. Then
The thickness of each tubular member is calculated based on this capacitance, and the thickness of each tubular member is calculated by using this value for control to correct the thickness of the tubular member. I found that I could control it accurately. That is, the present invention measures the capacitance with respect to the wall thickness of each tubular member in a non-contact state using a capacitance meter in a deformable state after being molded in the molding process. To do. And the measured capacitance is
The thickness of the tubular member is calculated by the arithmetic device. Also,
The counter electrode assembly of the capacitance meter is attached to a die in a molding process, and a required number of main electrodes can be provided facing the counter electrode assembly. Therefore, after the wall thickness of each of the tubular members is calculated while still in a deformable state, it is accurately corrected at any part of the thickness. The tubular member whose thickness is accurately controlled is then cooled and cut into a predetermined size.

[0010]

EXAMPLE FIG. 1 is an example of the present invention and is a schematic view for explaining a manufacturing process of a tubular member. In FIG.
The tubular member forming method includes an extruding step 131 for extruding a heated material in a molten state by an extruder and a forming step 13 for extruding the extruded material into a desired shape with a die.
2 and a measuring step 133 for measuring the capacitance of the cylindrical member that is deformable, and in the deformable state,
Correction process 13 for correcting the undesired shape and thickness of the tubular member
4, a cooling step 135 of cooling the tubular member formed into a desired shape so as not to deform it, a size regulating step 136 for making the tubular member of a desired length, and cutting into a regulated length. A cutting step 137 for cutting, a deposition step 138 for depositing the cut tubular member, an arithmetic unit 139 for performing an operation for converting the capacitance measured by the capacitance meter in the measurement step 133 into a thickness, and an operation And a control means 140 for controlling the correction device for correcting the deformable tubular member to a predetermined thickness based on the determined thickness. In addition, the cylindrical member formed by the die is in a deformable state, its capacitance is measured, the thickness is immediately calculated from the measured value, and then the cylindrical member is corrected by this value. Therefore, there is no waste and accurate control is possible.

FIG. 2A is an embodiment of the present invention, and is a perspective view for explaining a die and an electrode assembly and a counter electrode assembly of a capacitance meter provided on the die, and FIG. 2B is the same. FIG. 2A and 2B, a die 2 is attached to the tip of a well-known extrusion molding machine not shown.
11 is attached. And the die 211 is
For example, the mandrel 2 so that a cylindrical passage 212 is formed.
13 is attached by a support member 214. When the molten plastic member (not shown) is passed through the cylindrical passage 212, a part of the cylinder is separated by the support member 214. Become a state.

At the tip of the mandrel 213, a counter electrode assembly 21 is provided by a screw 216 and a screwing part 217 of the mandrel 213.
5 is attached. The counter electrode assembly 215 is, for example, a quadrangle and has an entire surface made of a conductive member, and is connected to a ground (not shown) via the mandrel 213 and the support member 214. Opposed to the counter electrode assembly 215, the capacitance meter electrode assemblies 221 to 224 are mounted by a device (not shown). Therefore,
The capacitance of the deformable tubular member coming out of the cylindrical passage 212 is measured in four directions without contact. Each measured capacitance is converted into a thickness by a calculation device (139 in FIG. 1). Then, the measured thickness of each part of the tubular member is controlled by the control means (1 in FIG. 1).
40), in the straightening step (134 in FIG. 1),
Corrected to the correct thickness. After that, the tubular member is cooled, and the process similar to the conventional process is performed.

2 (a) and 2 (b) are emphasized to explain the principle of the present invention.
11 and the attachment of each electrode assembly 221-224 has not been described in detail. However, the die 211 and each of the electrodes 221 to 224 can be attached by well-known or well-known fixing means. And the dice 21
1 and each of the electrode assemblies 221 to 224 are attached by
It does not matter whether the die 211 is in contact or not. Also,
When the die 211 and the electrode assemblies 221 to 224 are attached in a non-contact manner, the electrode assemblies 221 to 224
Is preferably attached to a position that is not affected by the heat of the die 211 as much as possible.

Next, an example of the electrode assembly of the capacitance meter will be described. FIG. 3 is a diagram for explaining an electrode assembly for measuring thickness using a capacitance meter used in the embodiment of the present invention. In FIG. 3, the main electrode 1 has a flat lower surface and an electrode terminal 111 protruding upward and screwed with a main electrode nut 121.
The guard electrode 2 is provided with a recess 21 for accommodating the main electrode 1 covered with the insulating member 3, a through hole 22 for inserting the electrode terminal 111 of the main electrode 1, and a screw portion 23 on the upper part of the guard electrode 2. The recessed portion 24 and the screw hole 25 are formed. The insulating member 3 is made of, for example, an insulating member having a small thermal expansion such as polycarbonate or ceramic, and is formed as thin as possible in the vertical direction with respect to the main electrode 1.

The connector 4 is formed with a connector terminal 41 in the lower part thereof insulated from the outside of the connector 4. Also,
The connector 4 includes a connector holder 42 and an engaging portion 4 that is integrally provided with the connector holder 42 and is provided in a lower portion.
3. A connector nut 44 is formed. And
The electrode terminal 111 and the connector terminal 41 are electrically connected by the lead wire 5. The inner holder 6 is a cylindrical body made of metal, and a screw portion 61 is erected on the lower portion of the inner holder 6 and screwed with the screw portion 23 of the guard electrode 2. Further, a locking portion 62 protruding inward is formed on the upper portion of the inner holder 6. The insulating plate 7 is, for example, an insulating member having a small thermal expansion like the insulating member 3 and is placed on the upper portion of the guard electrode 2 and has a holder opening and a screw opening.

The ground electrode 8 is made of a metal plate, and like the insulating plate 7, has a holder opening and a screw opening. The inner holder 6 is a cylindrical body made of the same member as the insulating member 3, and is fitted into the holder openings of the inner holder 6 and the ground electrode 8. The outer holder 10 has a flange portion 101 formed on the lower portion. Main electrode 1 and insulating member 3
The guard electrode 2 is fixed by the main electrode nut 121 via the main electrode bush 11. Further, in the flange portion 101 of the guard electrode 2, the insulating plate 7, the ground electrode 8 and the outer holder 10, the screw 12 is the bush 13 for grounding.
It is screwed and fixed to the screw hole 25 via.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. And
Various design changes can be made without departing from the present invention described in the claims. For example, the tubular member described in this embodiment has a cylindrical shape in FIG. 2, but may have a polygonal shape other than the cylindrical shape. Further, in this case, the number of electrode assemblies is arbitrary,
Its shape can also be adapted to a cylinder or a polygon. Also, the counter electrode assembly and the electrode assembly are
It is attached by a known or known attachment means. Further, as the extruder, the die, the straightener, the capacitance meter, the arithmetic unit, the control unit, and the like described in the present embodiment, known or known equivalent devices can be used.

[0018]

According to the present invention, since the thickness can be measured from the electrostatic capacity of the tubular member in the deformable state that has come out of the die, each of them can be accurately measured. Can be corrected. According to the present invention, since the thickness can be accurately formed, it is possible to obtain a tubular member having high dimensional accuracy. According to the present invention, since a tubular member having a desired thickness and high dimensional accuracy can be obtained, the material of the tubular member can be saved.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a manufacturing process of a tubular member in an example of the present invention.

2A is an embodiment of the present invention, a perspective view for explaining a die and an electrode assembly of a capacitance meter and a counter electrode assembly provided on the die, and FIG. FIG.

FIG. 3 is a view for explaining an electrode assembly for measuring thickness using a capacitance meter used in an example of the present invention.

FIG. 4 is a schematic block configuration diagram for explaining a step of forming a tubular member in a conventional example.

[Explanation of symbols]

 1 ... Main electrode 2 ... Guard electrode 3 ... Insulation member 4 ... Connector 5 ... Lead wire 6 ... Internal holder 7 ... Insulation plate 8 ... Earth electrode 9 ... Insulation holder 10 ... External holder 131 ... Extrusion process 132 ... Molding process 133 ... Measuring process 134 ... Correction process 135 ... Cooling process 136 ... Size regulation process 137 ... Cutting process 138 ... Accumulation process 139 ... Computing device 140 ... Control means

Claims (2)

[Claims] 1. A die for extruding a melted plastic member to form a tubular member, at least one counter electrode assembly attached to the tip of a mandrel of the die and at ground potential, and the counter electrode assembly. An electrode assembly of a capacitance meter composed of a main electrode, a flat plate-shaped guard electrode, and a plate-shaped ground electrode, which are provided so as to face the electrode assembly, and a capacitance measured by the capacitance meter. A tubular member forming apparatus, comprising: a calculating means for converting into a thickness and a correcting means for correcting the thickness to a desired thickness based on the thickness calculated by the calculating means. 2. A step of extruding a melted plastic member from a die to form a tubular member, a step of measuring an electrostatic capacitance of the tubular member by a capacitance meter, and a static step measured in the step. Calculating the thickness based on the capacitance and determining whether it is the desired thickness; if it is not the predetermined thickness, correcting it to the predetermined thickness; A method for forming a tubular member, comprising the step of cooling the tubular member after being corrected to 1.