JP2009226597A - Resin molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin molding machine allowing accurate confirmation of a molten state and a kneading state of resin. <P>SOLUTION: The resin molding machine 1 includes a cylinder 3, a tubular die 54 successively provided to the cylinder 3, a screw 2 provided inside the cylinder 3, and a window 8 provided on the outer surface of the cylinder 3 or die 54 for visual recognition of the molten resin inside the cylinder 3 or die 54. The window 8 is composed of single crystal of CaF<SB>2</SB>, single crystal of CeF<SB>3</SB>, single crystal of Gd<SB>2</SB>SiO<SB>5</SB>, or single crystal of Y<SB>3</SB>Al<SB>5</SB>O<SB>12</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resin molding machine that extrudes or injection-molds a resin material melted and kneaded in a cylinder, and more particularly to a resin molding machine that can observe a resin state inside the resin material.

  Resin materials such as plastic have different melting speeds in the above-mentioned resin molding machine for each type and additive type, so the shape and rotation of the screw provided in the resin molding machine can be adjusted according to the type of resin material. Change the number, adjust the heating temperature of the resin by the heater, change the shape of the discharge port of the die (die) and the flow path, that is, screw shape, screw rotation speed, heater heating temperature, die It is necessary to select the production conditions for the shape and the like and adjust the resin material in the resin molding machine so as to be in a molten state optimum for production.

  Conventionally, these production conditions are selected by estimating the melting state of the resin material in the resin molding machine from the state of the resin molded product molded by the resin molding machine, or by using the computer to determine the melting state in the resin molding machine. A simulation method was used. However, in the former method, it is necessary to repeatedly perform the operation of changing the production conditions and molding the resin molded product many times. Therefore, the selection of the production conditions is inefficient. In the latter method, the input data Since simulation errors due to errors and modeling errors occur, it has been difficult to obtain optimum production conditions with high accuracy.

And as a thing which solves these subjects, the plastic molding machine shown in patent documents 1 is proposed. This plastic molding machine is equipped with a radiation thermometer for resin temperature measurement in a barrel (cylinder) in which the resin is melted, and the resin temperature inside the barrel is measured by this radiation thermometer, and the measured temperature is adjusted to the measured temperature. Based on this, the molten state of the resin could be estimated.
JP-A-6-31795

  However, in this plastic molding machine, although the molten state can be estimated from the resin temperature in the barrel, the kneaded state (mixing condition) of the resin material cannot be estimated. Therefore, there has been a problem that it is difficult to select optimum production conditions including the screw shape in the resin molding machine and the rotational speed thereof (that is, related to the kneading state). In addition, as a solution to this problem, a configuration in which a transparent window using a normal glass material is provided in a predetermined part of the barrel and the internal state of the barrel is directly observed during operation can be considered. Since high pressure and high heat are applied by the molten resin, only a small window can be provided to avoid damage to the transparent window, and the glass material may be discolored by the high heat. There was a problem that it was difficult to confirm the state accurately.

  The present invention aims to solve the above problems. That is, an object of the present invention is to provide a resin molding machine capable of accurately confirming a molten state and a kneaded state of a resin.

In order to achieve the above object, the invention described in claim 1 includes a cylinder, a tubular die connected to the cylinder, a screw provided inside the cylinder, the cylinder or the die. In the resin molding machine having a window provided on the outer surface of the cylinder or the die so that the molten resin inside can be visually recognized, the window is a single crystal of CaF _2, a single crystal of CeF ₃ , Gd ₂ A resin molding machine comprising a single crystal of SiO ₅ or a single crystal of Y ₃ Al ₅ O ₁₂ .

The invention described in claim 2 is characterized in that, in the invention described in claim 1, the crystal orientation of the single crystal of CaF ₂ is <111> or <100>.

The invention described in claim 3 is the invention described in claim 1, characterized in that the crystal structure of the CeF ₃ single crystal is a trigonal LaF ₃ type.

The invention described in claim 4 is the invention described in claim 1, wherein the crystal orientation of the single crystal of Y ₃ Al ₅ O ₁₂ is <111>, <110>, or <100>. It is characterized by this.

According to the first aspect of the present invention, the window provided in the cylinder or the die is a single crystal of CaF _2, a single crystal of CeF _3, a single crystal of Gd ₂ SiO ₅ , or Y ₃ Al ₅ O _12. These have a high melting point, high strength, and high transparency, and are not damaged or discolored even when high pressure and high temperature are applied by the molten resin. A transparent and large window that allows easy visual recognition of the inside of the cylinder or die can be provided, and the molten state and kneaded state of the resin material can be accurately grasped and confirmed. Moreover, since the molten resin material can be directly visually confirmed, the foreign material contained in the resin material can be confirmed. Therefore, the quality of the resin molded product molded from the resin material can be improved.

According to the invention described in claim 2, since the crystal orientation of the single crystal of CaF ₂ constituting the window provided in the cylinder or die is <111> or <100>, the transparency and strength of this window Therefore, it is possible to provide a larger window that is easier to visually recognize and to more accurately grasp and confirm the molten state and kneaded state of the resin material.

According to the invention described in claim 3, since the crystal structure of the single crystal of CeF ₃ constituting the window provided in the cylinder or die is a trigonal LaF ₃ type, the transparency and strength of this window are reduced. Therefore, it is possible to provide a larger window that is easier to visually recognize, and can grasp and confirm the molten state and kneaded state of the resin material more accurately.

According to the invention described in claim 4, the crystal orientation of the single crystal of Y ₃ Al ₅ O ₁₂ constituting the window provided in the cylinder or die is <111>, <110>, or <100>. Therefore, the transparency and strength of this window can be further improved, so that a larger window can be provided that is easier to visually recognize, and the molten state and kneaded state of the resin material can be grasped more accurately and Can be confirmed.

(First embodiment)
Hereinafter, the resin molding machine which shows the 1st Embodiment of this invention is demonstrated with reference to FIGS. 1-3.

  As shown in FIG. 1, the resin molding machine 1 includes a screw 2, a cylinder 3, an observation window 8, a heater 7, a hopper 41, a die 54, and a screw driving unit (not shown). The resin molding machine 1 extrudes the resin material in the cylinder 3 melted by the heater 7 from the die 54 by rotating the screw 2 and, for example, a long resin molded product having the same cross section, such as a resin tube Is an extrusion molding machine.

  The screw 2 is made of a metal material having high wear resistance, and is formed in a long and substantially cylindrical shape as a whole. The outer diameter of the screw 2 (that is, the diameter of the projected area in the axial direction of the screw 2) is formed substantially constant. The L / D of the screw 2 (the ratio between the effective length (L) of the screw 2 and the diameter (D) of the screw 2 from JISB 8650) is normally set to about 24 to 28. The screw 2 includes a shaft portion 21, a flight 22, and a groove 23.

  The shaft portion 21 is formed in a long cylindrical shape. The flight 22 is erected from the outer peripheral surface of the shaft portion 21. The flight 22 is provided over substantially the entire length of the shaft portion 21 in the longitudinal direction, and is formed in a spiral shape. The groove 23 includes an outer peripheral surface of the shaft portion 21 and an outer surface of the flight 22 that is substantially orthogonal to the outer peripheral surface of the shaft portion 21 and is opposed to each other with a space therebetween, and has a substantially U-shaped cross section. ing. The grooves 23 are formed between the flights 22 formed in a spiral shape, and are formed in a spiral shape on the outer peripheral surface of the screw 2 in the same manner as the flights 22. The resin material is conveyed from the hopper port 4 toward the discharge port 5 through the groove 23.

  The screw 2 includes a supply unit 24 arranged on the hopper port 4 side, a compression unit 25 connected to the supply unit 24, and a measuring unit 26 connected to the compression unit 25 and arranged on the discharge port 5 side. . The supply unit 24, the compression unit 25, and the measuring unit 26 are names of parts along the longitudinal direction of the screw 2, respectively. The supply unit 24, the compression unit 25, and the measuring unit 26 are provided side by side along the longitudinal direction of the screw 2. Generally, the lengths of the supply unit 24, the compression unit 25, and the measuring unit 26 are formed to be substantially equal to each other.

  The supply unit 24 conveys the resin material supplied into the cylinder 3 from the hopper port 4 toward the compression unit 25, and preheats the resin material by the heater 7 and supplies the resin material to the compression unit 25 during the conveyance. The outer diameter of the shaft portion 21 of the supply portion 24 is formed constant in the longitudinal direction.

  The compression unit 25 is a resin material produced by heat supplied from a heater 7 described later and a shearing force generated between the inner surface of the cylinder 3 while the resin material conveyed from the supply unit 24 is conveyed toward the measuring unit 26. Melt. The outer diameter of the shaft portion 21 of the compression portion 25 is formed to gradually increase as it moves away from the supply portion 24 toward the measuring portion 26.

  The weighing unit 26 conveys the resin material melted by the compression unit 25 toward the discharge port 5 by a certain amount at a certain time. The outer diameter of the shaft portion 21 of the measuring unit 26 is formed to be constant in the longitudinal direction, and is larger than the outer diameter of the shaft portion 21 of the supply unit 24. The compression ratio of the screw 2 (according to JISB 8650, the ratio of the space volume formed by the one lead groove 23 of the supply unit 24 and the space volume formed by the one lead groove 23 of the measuring unit 26 in the screw 2) is usually 2.5 to. It is set to about 4.4.

  The screw 2 is the L / D of the screw 2 described above, the compression ratio of the screw 2, the ratio of the length of the supply unit 24, the compression unit 25 and the measuring unit 26, the shape of the flight 22 and the groove 23, and the rotational speed of the screw 2. Must be appropriately changed (adjusted) so as to obtain an optimal molten state for each type of resin material, etc. (that is, selection of production conditions).

  As shown in FIG. 1, the cylinder 3 is provided in a cylindrical shape and accommodates the screw 2 therein. The cylinder 3 is formed of a metal member having high wear resistance in order to reduce wear due to a resin material or the like. The inner diameter of the cylinder 3 is formed substantially constant and is slightly larger than the outer diameter of the screw 2. The cylinder 3 includes a hopper port 4 and a discharge port 5.

  The hopper port 4 is an opening continuous in the cylinder 3. The hopper port 4 is provided at the base end portion 3 a of the cylinder 3. A resin material is supplied into the cylinder 3 through the hopper port 4. A hopper 41 arranged in the vertical direction is attached to the hopper port 4. The entire shape of the hopper 41 is formed in a substantially funnel shape. In the hopper 41, for example, a solid resin material in the form of powder or pellets is stored, and this solid resin material is supplied to the hopper port 4.

  The discharge port 5 is an opening continuous in the cylinder 3. The discharge port 5 is provided at the tip 3 b of the cylinder 3. The resin material melted and kneaded in the cylinder 3 is discharged out of the cylinder 3 through the discharge port 5. A breaker plate 51 and a die 54 are attached to the discharge port 5.

  The breaker plate 51 is formed of a metal member or the like and is formed in a flat plate shape. The breaker plate 51 is provided with a plurality of holes penetrating the plate along the thickness direction of the plate. A wire mesh screen pack 53 is attached to the breaker plate 51. The resin material discharged from the discharge port 5 of the cylinder 3 passes through the hole of the breaker plate 51, is filtered through the screen pack 53, and is pushed out toward the die 54. The breaker plate 51 and the screen pack 53 have a function as a filter for removing foreign substances contained in the resin material, and the resin material is controlled by increasing the back pressure in the cylinder 3 and controlling the flow of the resin material. It also has a function of reliably melting.

  The die 54 is formed of a metal member or the like, and is formed in a cylindrical shape, for example. The molten resin material that has passed through the breaker plate 51 and the screen pack 53 is discharged from the discharge port 56 through the flow path 55 that penetrates the inside of the die 54, and is formed into a desired shape.

  The screw drive unit is composed of a motor or the like. The screw driving unit pivotally supports the screw 2 accommodated in the cylinder 3 so as to be rotatable about its axis, and rotationally drives the screw 2 about the axis.

  As shown in FIG. 1, the heater 7 is embedded in the outer peripheral surface 3 c of the cylinder 3. The heater 7 is a belt-like plate heater. Of course, the heater 7 may be a band-shaped band heater. The heater 7 supplies heat into the cylinder 3, and the resin material in the cylinder 3 is melted (heated and fluidized) by this heat. A plurality of heaters 7 are provided along the longitudinal direction of the cylinder 3.

  The heater 7 includes a heater 71 that supplies heat to a portion where the supply unit 24 of the screw 2 in the cylinder 3 is disposed, a heater 72 that supplies heat to a portion where the compression unit 25 is disposed, and a measuring unit 26. The heater 73 that supplies heat to the portion to be heated and the heater 74 that supplies heat to the breaker plate 51 and the die 54 can supply heat at different temperatures to each portion.

  The heater 7 needs to appropriately change (adjust) the temperature of each of the above parts so as to obtain an optimal molten state for each type of resin material (ie, selection of production conditions).

  The observation window 8 corresponds to the window described in the claims, and is arranged on the outer peripheral surface 3c of the cylinder 3 so that the inside of the cylinder 3 can be observed (that is, visually recognized) as shown in FIG. Specifically, an observation window 81 for visually recognizing a portion where the supply unit 24 of the screw 2 in the cylinder 3 is disposed, an observation window 82 for visually recognizing a portion where the compression unit 25 is disposed, And an observation window 83 for visually recognizing a portion where the measuring unit 26 is arranged.

  The width of the observation window 8 (that is, the length in the direction perpendicular to the longitudinal direction of the cylinder 3) is formed substantially the same as the inner diameter of the cylinder 3, and the length of the observation window 8 (that is, the length in the longitudinal direction of the cylinder 3). ) Is formed to be about 1 to 2 times the width of the observation window 8, and the thickness of the observation window 8 is formed to be equal to the thickness of the cylinder 3 where it is disposed. The surface located on the outer peripheral surface 3c side of the cylinder 3 in the observation window 8 is arranged without a step difference from the outer peripheral surface 3c of the cylinder 3, and the surface located on the inner peripheral surface 3d side of the cylinder 3 in the observation window 8 is similarly The inner circumferential surface 3d of the cylinder 3 is arranged without a step. From the viewpoint of the heating efficiency of the cylinder 3 by the heater 7, the width of the observation window 8 may be about half of the diameter of the cylinder 3.

  As shown in FIG. 2, the observation window 8 is arranged so that the inside of the cylinder 3 can be observed from one direction. In addition, as shown in FIG. 3, two observation windows 8 may be disposed relative to the diameter direction of the cylinder 3 so that the inside of the cylinder 3 can be observed from the opposite direction. By doing so, for example, when a transparent resin material is used, the inside of the cylinder can be visually recognized more clearly, and the state of the resin material can be confirmed more accurately. Furthermore, the two observation windows 8 may be arranged so as to form an angle of approximately 90 degrees with respect to the circumferential direction of the cylinder 3 so that the inside of the cylinder 3 can be observed from directions orthogonal to each other. By doing so, for example, when an opaque resin material is used, or when the screw configuration is biaxial, the inside of the cylinder, in particular, between the shaft and the shaft can be more clearly visually recognized. The state of the material can be confirmed more accurately.

  The observation window 8 is formed in a substantially square frustum shape in which the surface (namely, the lower surface) on the inner peripheral surface 3 d side of the cylinder 3 is larger than the surface (namely, the upper surface) of the outer peripheral surface 3 c of the cylinder 3. In addition, this substantially square frustum shape includes those in which the lower surface or the upper surface is curved along the circumferential direction of the cylinder 3, that is, if the projected area of the lower surface is larger than that of the upper surface, the substantially square frustum shape. Included in the shape. As a result, the observation window 8 is pressed against the cylinder 3 by the pressure of the resin material and is more firmly joined, and the observation window 8 can be prevented from falling off the cylinder 3. In addition, as long as it is not contrary to the objective of this invention, what kind of thing may be sufficient as the number of the observation windows 8, arrangement | positioning, a shape, and the attachment structure to the cylinder 3. FIG.

The observation window 8 is formed using a single crystal of calcium fluoride (CaF ₂ ). Conventionally, it has been difficult to produce a calcium fluoride single crystal large enough to be used as the observation window 8, but mass production is becoming realistic due to recent progress in crystal growth technology. Since the melting temperature (melting point) of the CaF ₂ single crystal is 1300 ° C. or higher, it is very high with respect to the melting temperature of the resin material (500 ° C. or lower), so that it is not altered by the heat of the resin material. Further, its strength is high and it is not destroyed by the pressure of the resin material. In particular, a CaF ₂ single crystal having a crystal orientation of <111> or <100> has high transparency, low attenuation of transmitted light (visible light and infrared light), refraction hardly occurs, and high strength. It is very suitable as a material for the observation window 8 in the present invention.

The observation window 8 may be formed using a single crystal of cerium fluoride (CeF ₃ ). Since the melting temperature (melting point) of CeF ₃ single crystal is 1300 ° C. or higher, it is very high with respect to the melting temperature (500 ° C. or lower) of the resin material, and therefore it is not altered by the heat of the resin material. Further, a CeF ₃ single crystal having a trigonal LaF ₃ type crystal structure is particularly suitable as a material for the observation window 8 in the present invention because of its high transparency and high strength.

The observation window 8 may be formed using a single crystal of gadolinium silicate (Gd ₂ SiO ₅ ). Since the melting temperature (melting point) of the single crystal of Gd ₂ SiO ₅ is 1950 ° C. or higher, it is very high with respect to the melting temperature (500 ° C. or lower) of the resin material, and therefore it is not altered by the heat of the resin material. . Further, the single crystal of Gd ₂ SiO ₅ is suitable as a material for the observation window 8 in the present invention because it has no deliquescence and is stable.

The observation window 8 may be formed using a single crystal of yttrium aluminate (Y ₃ Al ₅ O ₁₂ ). Since the melting temperature (melting point) of the Y ₃ Al ₅ O ₁₂ single crystal is 1900 ° C. or higher, it is very high with respect to the melting temperature required for the resin agent (500 ° C. or lower), and is therefore altered by the heat of the resin material. There is nothing. Y ₃ Al ₅ O ₁₂ single crystals are stable without deliquescence, and those with crystal orientation <100>, <110>, or <111> have high transparency and high strength. Therefore, it is suitable as a material for the observation window 8 in the present invention.

  The resin material is suitable for extrusion molding, such as polyethylene, polypropylene, vinyl chloride resin, or fluororesin.

  In the resin molding machine 1 having the above-described configuration, in order to select production conditions, first, a solid resin material is introduced into the hopper 41 and this solid resin material is supplied into the cylinder 3 from the hopper port 4. The inside of the cylinder 3 is heated by the heater 7, and the solid resin material supplied into the cylinder 3 is supplied into the groove 23 of the supply unit 24 of the screw 2, and the supply unit is rotated by the rotation of the screw 2. The material is sequentially transported while being melted and kneaded from within the groove 23 of 24 to the groove 23 of the compression unit 25 and into the groove 23 of the measuring unit 26.

  At this time, observation (observation and temperature measurement with an infrared radiation thermometer, etc.) from the observation windows 81, 82, 83, the molten state of the resin material in the supply unit 24, the compression unit 25, and the measurement unit 26 and The kneading state is confirmed, and production conditions such as the shape and rotation speed of the screw 2 and the temperature of the heater 7 are selected. In addition, more optimal production conditions can be obtained by changing the production conditions and performing this observation several times. Moreover, you may confirm the foreign material etc. which are contained in the resin material by this observation.

As described above, according to the present invention, since the observation window 8 provided in the cylinder 3 is made of a single crystal of CaF ₂ , the single crystal of CaF ₂ has a high melting point, high strength, and high transparency. Even if high pressure and high temperature are applied by the molten resin, it is not damaged or discolored. Therefore, it is possible to provide a transparent and large observation window 8 in which the inside of the cylinder 3 is easily visible, and the molten state of the resin material. In addition, the kneading state can be accurately grasped. In addition, since the molten resin material can be directly visually confirmed, the presence or absence of impurities contained in the resin material can be confirmed. Therefore, the quality of the resin molded product molded from the resin material can be improved. Even when the observation window 8 is composed of a single crystal of CeF _3, a single crystal of Gd ₂ SiO ₃ , or a single crystal of Y ₃ Al ₅ O ₁₂ , the above-described observation window 8 is a single crystal of CaF ₂ . An effect similar to that of the case of being composed of crystals can be obtained.

Further, by configuring the observation window 8 with a CaF ₂ single crystal having a crystal orientation of <111> or <100>, the transparency and strength of the observation window 8 can be further improved. In addition, a larger window can be provided, and the molten state and kneaded state of the resin material can be grasped and confirmed more accurately.

Further, by configuring the observation window 8 with a single crystal of the crystal structure of the trigonal LaF ₃ type CeF ₃ , the transparency and strength of the observation window 8 can be further improved. In addition, a larger window can be provided, and the molten state and kneaded state of the resin material can be grasped and confirmed more accurately.

Further, an observation window 8, crystal orientation <111>, <110>, or, by configuring a single crystal of Y ₃ Al ₅ O ₁₂ of <100>, further improving the transparency and strength of the observation window 8 For this reason, it is possible to provide a larger window that is easier to visually recognize and that can more accurately grasp and confirm the molten state and kneaded state of the resin material.

(Second Embodiment)
A resin molding machine showing a second embodiment of the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, the resin molding machine 1 </ b> A includes a screw 2, a cylinder 3, an observation window 8, a heater 7, a hopper 41, and a screw driving unit (not shown). Further, the resin molding machine 1A includes a die 54A shown in FIG. 4 instead of the die 54 shown in FIG. The resin molding machine 1 </ b> A pushes the resin material in the cylinder 3 melted by the heater 7 from the die 54 </ b> A in synchronization with the electric wire 92 by rotating the screw 2, thereby forming the coating 91 of the electric wire 92. It is a coating molding machine. Note that the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  The die 54A is a crosshead die in which a flow path 55 through which a resin material flows is bent 90 degrees therein, and includes a housing 541 and a rectifying member 542 as shown in FIG. ing.

  The housing 541 is formed in a substantially cylindrical shape using a metal material having high wear resistance, and includes a flow path 55 and an observation window 8A.

  The flow path 55 includes a rectification path 55a having a circular cross section provided through the housing 541 in the axial direction, and an introduction path 55b connected perpendicularly to one end of the rectification path 55a. Consists of. The introduction path 55b is a small-diameter pipe through which the resin material that has passed through the breaker plate 51 is introduced. A circular discharge port 56 through which the resin material introduced into the introduction path 55b is discharged is provided at the other end of the rectification path 55a, and a portion near the other end of the rectification path 55a is a discharge port. It is formed so that the diameter gradually decreases as it approaches 56.

  The observation window 8A corresponds to the window described in the claims, and as shown in FIG. 4, is arranged on the outer peripheral surface of the die 54A so that the inside of the die 54A can be observed (that is, visually recognized). Specifically, an observation window 84 for viewing the rectification path 55a from one side, and an observation window disposed relative to the diameter direction of the observation window 84 and the rectification path 55a and for viewing the rectification path 55a from the other side 85.

  The width of the observation window 8A (that is, the length in the direction orthogonal to the longitudinal direction of the rectification path 55a) is formed substantially the same as the inner diameter of the rectification path 55a, and the length of the observation window 8A (that is, the longitudinal direction of the rectification path 55a). The length of the observation window 8A is approximately equal to the width of the observation window 8A, and the thickness of the observation window 8A is equal to the thickness of the housing 541 where the observation window 8A is disposed. The surface located on the outer peripheral surface side of the housing 541 in the observation window 8A is arranged without a step difference from the outer peripheral surface of the housing 541, and the surface located on the wall surface side of the rectifying channel 55a in the observation window 8A is also the same as that of the rectifying channel 55a. It is arranged without a step from the wall.

  The observation window 8 </ b> A is formed in a substantially quadrangular pyramid shape in which the surface (that is, the lower surface) located on the wall surface side of the rectifying channel 55 a is larger than the surface (that is, the upper surface) located on the outer peripheral surface side of the housing 541. Note that the substantially square frustum shape includes a shape in which the lower surface or the upper surface is curved along the circumferential direction of the housing 541. That is, if the projected area of the lower surface is larger than that of the upper surface, the substantially square frustum shape. Included in the shape. As a result, the observation window 8A is pressed against the housing 541 by the pressure of the resin material and is more firmly joined, and the observation window 8A can be prevented from falling off the housing 541. As long as the object of the present invention is not violated, any number, arrangement, and shape of the observation window 8A and a mounting structure to the housing 541 may be used.

The observation window 8A is made of a single crystal of calcium fluoride (CaF ₂ ), as in the first embodiment. The observation window 8A is composed of a single crystal of cerium fluoride (CeF ₃ ), a single crystal of gadolinium silicate (Gd ₂ SiO ₅ ), or a single crystal of yttrium aluminate (Y ₃ Al ₅ O ₁₂ ). It may be.

  The rectifying member 542 is formed in a substantially bullet shape using a metal material having high wear resistance so that the flow of the resin material flowing in the rectifying passage 55 a is adjusted and the electric wire 92 is drawn from the discharge port 56. It is a member for guiding. The rectifying member 542 is disposed coaxially with the rectifying path 55a. The rectifying member 542 closes one end portion of the rectifying path 55a, and between the wall portion of the rectifying path 55a from the location where the introduction path 55b in the rectifying path 55a is connected to the vicinity of the discharge port 56. Are arranged with a slight gap evenly. Therefore, the resin material that has flowed into the rectifying passage 55a from the introduction passage 55b spreads evenly in the gap between the rectifying member 542 and the wall portion of the rectifying passage 55a and flows toward the discharge port 56. The rectifying member 542 is provided with an insertion hole 542a through which the electric wire 92 is inserted along the axis.

  The die 54A needs to appropriately change (adjust) the shape of the rectifying passage 55a, the shape of the rectifying member 542, etc. so that an optimum molten state can be obtained for each type of resin material (ie, selection of production conditions). ).

  In the resin molding machine 1 having the above-described configuration, in order to select production conditions, first, a solid resin material is introduced into the hopper 41, and this solid resin material is supplied into the cylinder 3 from the hopper port 4 of the cylinder 3. The inside of the cylinder 3 is heated by the heater 7, and the solid resin material supplied into the cylinder 3 is supplied into the groove 23 of the supply unit 24 of the screw 2, and the supply unit 24 is rotated by the rotation of the screw 2. From the groove 23 to the groove 23 of the compression section 25 and into the groove 23 of the measuring section 26 while being melted and kneaded.

  Then, after the molten resin material passes through the measuring unit 26, it is conveyed to the breaker plate 51, the screen pack 53, and the die 54A. The resin material conveyed to the die 54A is discharged in synchronism with the electric wire 92 drawn out from the discharge port 56 by a winder (not shown) to form a covering 91 that covers the periphery of the electric wire 92, and the covered electric wire 90 is formed. The

  At this time, observation (observation and temperature measurement using an infrared radiation thermometer, etc.) is performed from the observation windows 84 and 85, and the resin material in the rectifying passage 55a of the die 54A is melted, kneaded, and in the vicinity of the discharge port 56. The production conditions such as the shape and rotation speed of the screw 2, the temperature of the heater 7, the shape of the rectifying passage 55a, the shape of the rectifying member 542, and the like are selected. Moreover, more optimal production conditions can be obtained by performing this observation several times. Moreover, you may confirm the foreign material etc. which are contained in the resin material by this observation.

As described above, according to the present invention, since the observation window 8 provided in the die 54A is composed of a single crystal of CaF ₂ , the single crystal of CaF ₂ has a high melting point, high strength, and high transparency. Even if high pressure and high temperature are applied by the molten resin, it does not break or change color. Therefore, it is possible to provide a transparent and large observation window 8 in which the inside of the rectifying path 55a of the die 54A is easily visible, and the resin It is possible to accurately grasp the molten state, the kneaded state, the flow velocity in the vicinity of the discharge port 56, and the like. In addition, since the molten resin material can be directly visually confirmed, the presence or absence of impurities contained in the resin material can be confirmed. Therefore, it is possible to prevent the withstand voltage performance from being lowered due to the eccentricity and foreign matter mixing in the covered electric wire 90, and the quality of the resin molded product molded from the resin material can be improved. Even when the observation window 8 is composed of a single crystal of CeF _3, a single crystal of Gd ₂ SiO ₃ , or a single crystal of Y ₃ Al ₅ O ₁₂ , the above-described observation window 8 is a single crystal of CaF ₂ . An effect similar to that of the case of being composed of crystals can be obtained.

Further, by configuring the observation window 8 with a CaF ₂ single crystal having a crystal orientation of <111> or <100>, the transparency and strength of the observation window 8 can be further improved. In addition, a larger window can be provided, and the molten state and kneaded state of the resin material can be grasped and confirmed more accurately.

Further, by configuring the observation window 8 with a single crystal of the crystal structure of the trigonal LaF ₃ type CeF ₃ , the transparency and strength of the observation window 8 can be further improved. In addition, a larger window can be provided, and the molten state and kneaded state of the resin material can be grasped and confirmed more accurately.

Further, an observation window 8, crystal orientation <111>, <110>, or, by configuring a single crystal of Y ₃ Al ₅ O ₁₂ of <100>, further improving the transparency and strength of the observation window 8 For this reason, it is possible to provide a larger window that is easier to visually recognize and that can more accurately grasp and confirm the molten state and kneaded state of the resin material.

  In the present embodiment, the two observation windows 84 and 85 are disposed so as to face each other. However, the present invention is not limited to this. For example, the four observation windows are arranged in the circumferential direction of the housing 541. You may arrange | position so that it may make about 90 degree | times and can observe from four directions. By doing in this way, the eccentricity of the covered electric wire 90 can be observed more reliably.

  In addition, although each embodiment mentioned above was description regarding an extrusion molding machine, it is not limited to this, You may apply this invention to an injection molding machine.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

It is a block diagram which shows the outline of the resin molding machine which shows the 1st Embodiment of this invention. It is sectional drawing which follows the XX line of FIG. It is a figure which shows the other structural example of the resin molding machine shown by FIG. It is a block diagram which shows the outline of the die | dye of the resin molding machine which shows the 2nd Embodiment of this invention.

Explanation of symbols

1, 1A resin molding machine 2 screw 3 cylinder 7 heater 8, 8A observation window (window)
54, 54A Die 55a Rectifier

Claims (4)

A cylinder, a tubular die connected to the cylinder, a screw provided inside the cylinder, and an outer surface of the cylinder or the die so that a molten resin inside the cylinder or the die can be seen A resin molding machine having a window provided in
The resin molding machine, wherein the window is made of a single crystal of CaF _2, a single crystal of CeF _3, a single crystal of Gd ₂ SiO ₅ , or a single crystal of Y ₃ Al ₅ O ₁₂ . The resin molding machine according to claim 1, wherein the crystal orientation of the CaF ₂ single crystal is <111> or <100>. 2. The resin molding machine according to claim 1, wherein the crystal structure of the single crystal of CeF ₃ is a trigonal LaF ₃ type. 2. The resin molding machine according to claim 1, wherein the crystal orientation of the single crystal of Y ₃ Al ₅ O ₁₂ is <111>, <110>, or <100>.

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