JP2023153704A - Measuring device and measuring method for measuring heat transfer coefficient between resin and metal - Google Patents

Abstract

To press a punch 21 against molten resin 11 in a pot 6 to measure temperatures of the resin 11 and the punch 21 and obtain heat transfer coefficient between the resin 11 and the punch 21, and to prevent movement of a resin side temperature sensor 13 when the punch 21 is pressed against the molten resin 11.SOLUTION: A plurality of temperature probes for measuring temperature of each point of resin 11 having different separation distance from an interface of the resin 11 and a punch 21 are collectively held in one block 34, and the block 34 is supported on a pot 6 through a support member 35. Molten resin is stored in the pot 6, an upper surface of the block 34 is positioned near an upper surface of the molten resin 11, and in such a state, the punch 21 is fitted into the pot 6 and pressed against the molten resin 11.SELECTED DRAWING: Figure 4

Description

The present invention relates to a measuring device and method for measuring a heat transfer coefficient between a resin and a metal.

It is generally known that the heat transfer coefficient between two objects in contact with each other is calculated based on the temperature distribution of both objects.

For example, Patent Document 1 describes a method of measuring a heat transfer coefficient between a stator core and a case of a motor. In this method, a case block made of the same material as the case is brought into contact with a core block made of the same material as the stator core and pressurized, and in this state the core block is heated by a heater. After both blocks reach a steady state with no temperature change, the temperature distribution of both blocks is measured, and a heat transfer coefficient is calculated based on the temperature distribution.

Patent Document 2 describes a method of measuring a heat transfer coefficient between a material to be hot forged and a punch. In this method, the material is heated to a predetermined temperature in an atmospheric furnace and placed in a lower mold. A punch is pressed against the material, and the change in temperature of the punch before and after pressing is measured. This measured temperature change is compared with a temperature change based on a numerical simulation performed by setting the heat transfer coefficient to a predetermined value in advance. Then, the heat transfer coefficient is determined by resetting the heat transfer coefficient and repeating the numerical simulation until both temperature changes meet a predetermined condition.

JP2018-200226A JP 2018-8299 Publication

Patent Documents 1 and 2 calculate the heat transfer coefficient between solid metals, but the present invention measures the heat transfer coefficient between the molten resin and the metal (punch) when the resin solidifies. The heat transfer coefficient determines how much heat is transferred from the resin to the mold during injection molding, for example, so it is possible to understand the temperature distribution of the resin during molding and after demolding.

Even when the measurement target is molten resin, a punch is inserted into a pot storing the molten resin, pressed against the molten resin, and the temperature of the resin and punch is measured in that state to determine the heat transfer coefficient. It is possible to use the same method as for measuring the heat transfer coefficient between

However, unlike metals, resins have low thermal conductivity and large heat capacity. Therefore, as shown in Figure 7, the resin has a temperature distribution with a remarkable gradient only near the interface with the punch (temperature distribution in the punch insertion direction), and there is also a temperature difference at the interface between the resin and the punch. small. Note that Figure 7 shows the calculation results from a heat transfer analysis assuming that the heat transfer coefficient between the resin and the mold and the heat transfer coefficient between the Al and the mold are the same (2500 W/m ² K). It shows the temperature distribution of the punch, resin, and Al 20 seconds after they were pressed against the resin and Al at 200°C.

Therefore, in order to obtain a highly reliable heat transfer coefficient when the object to be measured is a resin, it is necessary to accurately capture the temperature distribution of the resin near the interface.

The problem then becomes how to maintain multiple temperature measuring probes such as thermocouples in order to obtain the above temperature distribution at a predetermined interval near the above interface without shifting their positions under pressure by the punch. That's true. If pressure is applied to the temperature probes through the resin when the punch is pressed against the resin, the positions of individual temperature probes may shift and the spacing between the temperature probes may change, or if all the temperature probes are connected to the resin. The problem is that it sinks deep into the interior of the world.

SUMMARY OF THE INVENTION An object of the present invention is to suppress the displacement of a temperature measuring element in the punch insertion direction when a punch is pressed against a resin, thereby making it possible to measure a heat transfer coefficient with high reliability.

In order to solve the above problems, the present invention holds a plurality of temperature measuring elements in one block, and supports this block in a pot.

The heat transfer coefficient measuring device disclosed herein is
A pot for storing molten resin,
a metal punch that is fitted into the pot and whose tip end is pressed against the resin;
a resin side temperature sensor that measures the temperature of the resin;
a punch-side temperature sensor that measures the temperature of the punch;
A heat transfer coefficient measuring device comprising: an arithmetic device that calculates a heat transfer coefficient between the resin and the punch from the measured temperatures of the resin and the punch;
The above resin side temperature sensor is
a plurality of temperature probes that electrically measure the temperature of each point of the resin at different distances from the interface between the resin and the punch; a block that holds the plurality of temperature probes; and a support member supported on the pot so that its upper surface is positioned near the upper surface of the resin.

In addition, the heat transfer coefficient measurement method disclosed herein is
A step of inserting a punch into a pot storing molten resin and pressing the tip of the punch against the resin;
Measuring the temperature of the resin and the punch;
determining a heat transfer coefficient between the resin and the punch from the measured temperatures of the resin and the punch,
A plurality of temperature probes that electrically measure the temperature of each point of the resin at different distances from the interface between the resin and the punch are held in one block, and the block is connected to the pot via a support member. Please support
The molten resin is stored in the pot, and the top surface of the block is positioned near the top surface of the resin, and in this state, the punch is inserted into the pot and its tip is pressed against the resin. It is characterized by guessing.

According to the above measuring device and measuring method, since a plurality of temperature measuring points are held together in one block, the distance between the temperature measuring points in the punch insertion direction changes as the punch is pressed against the molten resin. can be avoided. In other words, when the punch is pressed against the top surface of the molten resin, even if the punch contacts the block, the pressure from the punch is not directly transmitted to the temperature probe, so it is not possible to measure the temperature of multiple temperature probes. Changes in the spacing of the points are avoided.

Even if the pressure from the punch is transmitted to the support member through the block and the support member is deformed and the block moves in the insertion direction of the punch, the block will move in accordance with the punch. Therefore, there are large changes in the positional relationship between the plurality of temperature probes held in the block and the tip of the punch, and furthermore, in the positional relationship between the top surface of the resin against which the tip of the punch is pressed and the plurality of temperature probes. Does not occur.

In this way, when the punch is pressed against the resin, the multiple temperature probes are prevented from shifting in the punch insertion direction, making it possible to accurately capture the temperature distribution near the resin interface, increasing reliability. A high heat transfer coefficient can be obtained.

Although a thermistor or a resistance thermometer can be used as the temperature measuring element of the resin side temperature sensor, it is preferable to connect the tips of two types of metal wires to form a thermal junction (temperature measuring point). ) is a thermocouple. In the case of thermocouples, the wires can be made thinner and have lower rigidity, which prevents resistance to phase change and cooling shrinkage of the resin, and therefore avoids deterioration of temperature measurement accuracy due to distortion. It will be done.

In one embodiment of each of the measuring device and the measuring method, the metal wire of the thermocouple has a portion embedded in the resin other than the thermal junction made of a highly heat-resistant resin having a melting point higher than that of the resin. Insulated coated. Therefore, it is possible to avoid accidental short-circuiting of the two wires of each thermocouple other than the hot junctions due to the molten resin.

In one embodiment of each of the measuring device and method, the block is supported by the pot so that its upper surface is flush with the upper surface of the molten resin, and the tip of the punch is pressed against the resin. When the block is opened, a part of the tip surface is in contact with the top surface of the block. Since the relative positional relationship between the punch and the block is fixed due to the contact between the punch and the block, it is possible to reliably prevent the plurality of temperature measuring elements from sinking in the punch insertion direction.

In one embodiment of each of the above-mentioned measuring device and measuring method, the punch-side temperature sensor includes a plurality of temperature measuring elements each embedded in the punch and electrically measuring the temperature of the punch, and the plurality of temperature measuring elements extend from the top to the bottom of the punch, or from the outer periphery of the punch to the center, so that the temperature measurement point at each tip is on the same circumference centered on the axis of the punch. They are placed at intervals.

According to this, the temperature measuring element itself does not become an intervening body that absorbs heat between the punch tip surface and each temperature measuring point. Furthermore, since each measurement point is arranged on the same circumference, the conditions for heat transfer from the resin to each temperature measurement point are the same. Therefore, the reliability of the temperature measured by each temperature probe becomes high, and the reliability of the heat transfer coefficient obtained based on these measured temperatures becomes high.

In one embodiment of each of the above-mentioned measuring device and measuring method, the plurality of temperature measuring elements of the punch-side temperature sensor measure the temperature at each point of the punch having a different distance from the interface between the resin and the punch. Therefore, the positions of the respective temperature measurement points are shifted in the axial direction of the punch. Therefore, the temperature distribution in the punch insertion direction in the punch can be reliably captured, and the reliability of the obtained heat transfer coefficient becomes high.

In one embodiment of the measuring device, the pot includes a temperature adjusting device that adjusts the temperature of the resin contained therein. If the temperature of the resin is raised externally and then transferred to the pot, heat will be taken away by the pot etc. and the resin will have a complicated temperature distribution. On the other hand, according to this embodiment, since the resin can be adjusted to a predetermined temperature within the pot, the uniformity of the resin temperature can be improved before the punch is inserted into the pot, and the reliability is high. This is advantageous in obtaining the heat transfer coefficient. The temperature of the resin may be controlled by heating and melting the resin using a temperature control device within the pot, or the resin may be heated and melted outside, transferred to the pot, and the temperature may be controlled within the pot using a temperature control device.

In one embodiment of the measuring method, before inserting the punch into the pot, the resin is heated and melted inside the pot using a temperature control device to adjust the temperature to a predetermined temperature. According to this, since the resin can be adjusted to a predetermined temperature in the pot, it is possible to improve the uniformity of the resin temperature before inserting the punch into the pot, and to obtain a highly reliable heat transfer coefficient. It will be advantageous.

The resin may be thermoplastic or thermosetting.

In one embodiment of the measuring device, the resin storage portion of the pot that stores the resin and the insertion portion of the punch have a perfect circular cross-sectional shape perpendicular to the insertion direction of the punch. This facilitates positioning of the punch with respect to the pot when the punch is inserted into the pot.

In one embodiment of the measuring device, a portion of the metal wire of the thermocouple that protrudes from the block toward the inner circumferential surface of the pot is a curved portion that protrudes downward from the support member. has. According to this configuration, even if the block is largely displaced downward due to insertion of a punch during measurement under high pressure, for example, the bending of the curved portion can suppress shearing and damage to the metal wire. In this way, measurement reliability can be ensured.

According to the present invention, since the temperature measuring element is prevented from shifting in the punch insertion direction when the punch is pressed against the molten resin, the temperature near the interface of the resin can be reliably measured. It is possible to obtain a heat transfer coefficient with high properties.

1 is a perspective view of a heat transfer coefficient measuring device according to Embodiment 1. FIG. A cross-sectional view of the device. FIG. 3 is a cross-sectional view showing part of the device before and after pressing a punch against molten resin. FIG. 3 is a cross-sectional view showing the arrangement of a resin-side temperature sensor of the device. A perspective view of a resin side temperature sensor. FIG. 7 is a graph diagram showing changes in punch temperature over time in the embodiment and the comparative example when a punch is pressed against resin. FIG. 2 is a graph diagram showing the temperature distribution of the punch, resin, and Al after a predetermined period of time has elapsed since the punch was pressed against the resin and Al. FIG. 4 is a diagram corresponding to FIG. 4 of the heat transfer coefficient measuring device according to the second embodiment. FIG. 5 is a diagram corresponding to FIG. 5 of the heat transfer coefficient measuring device according to the second embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on drawing. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications, or its uses.

(Embodiment 1)
<Heat transfer coefficient measuring device>
A heat transfer coefficient measuring device 1 shown in FIG. 1 is a device that measures a heat transfer coefficient between a thermoplastic resin and a metal. This heat transfer coefficient measuring device 1 includes a pot device 2 for storing molten resin, a punch device 3, and a calculation device 4.

The pot device 2 includes a base 5, a pot 6 supported on the base 5, and a lid 7 that closes the upper end opening of the pot 6. As shown in FIG. 2, the pot 6 includes a metal base 8 and a metal cylindrical body 9 fixed to the base 8 and having a vertical axis. A resin storage section 12 that stores resin 11 is formed by the base 8 and the cylindrical body 9. The horizontal cross-sectional shape (the cross-sectional shape perpendicular to the punch insertion direction, which will be described later) of the resin storage portion 12 is a perfect circle. The resin reservoir 12 is provided with a resin-side temperature sensor 13 that measures the temperature of the resin 11 to measure the heat transfer coefficient. The resin side temperature sensor 13 will be explained in detail later.

The pot device 2 includes a temperature control device that heats and melts the resin 11 accommodated in the resin storage section 12 and adjusts the temperature to a predetermined temperature. The temperature control device includes a plurality of rod-shaped heaters 15 embedded in the base 8, a temperature sensor (thermocouple) 16 that measures the temperature of the base 8, and a rod-shaped heater 15 that measures the temperature of the base 8 so that the temperature measured by the temperature sensor 16 becomes a predetermined value. A control device (not shown) that controls the operation of the heater 15 is provided. Furthermore, the temperature adjustment device includes a band heater 17 wrapped around the cylindrical body 9, a temperature sensor (thermocouple) 18 that measures the temperature of the cylindrical body 9, and a band heater that adjusts the temperature measured by the temperature sensor 18 to a predetermined value. 17 is provided.

A nitrogen supply pipe 19 that supplies nitrogen to the surface of the resin 11 stored in the pot 6 to prevent oxidation of the resin 11 is connected to a lid 7 that closes the upper end opening of the pot 6 .

The punch device 3 includes a cylindrical metal punch 21 that is fitted into the pot 6, and a punch-side temperature sensor that includes a plurality of (three rod-shaped in this embodiment) temperature probes 23 embedded in the punch 21. 22, a heat insulating material 26, and an elastic seal 27. A rod attachment hole (threaded hole) 28 is opened in the top surface of the punch 21 to which a pressure rod of a pressure tester is coupled.

<About the punch side temperature sensor 22>
Each of the plurality of temperature measuring elements 23 is made of a thermocouple, and all of them extend forward in the punch insertion direction from the upper end of the punch 21, that is, downward. The plurality of temperature measuring probes 23 are arranged to measure the temperature of each point of the punch 21 at different distances from the contact interface between the resin 11 and the punch 21 (hereinafter simply referred to as "interface"). The position of the point 23a is shifted in the axial direction of the punch 21. As can be seen from FIG. 1, the temperature measuring points 23a at the tips of each of the plurality of temperature measuring elements 23 are arranged at intervals on the same circumference centered on the axis of the punch 21.

In this embodiment, the temperature measuring points 23a of each of the three temperature measuring elements 23 are arranged at a position 2 mm, 4 mm, and 6 mm away from the tip surface of the punch 21.

<About insulation between punch and pot and prevention of resin leakage>
The fitting portion 21a of the punch 21 that is fitted into the pot 6 has a perfect circular cross-sectional shape perpendicular to the fitting direction. The fitting part 21a is formed to be concentric with the base (upper part) 21b of the punch 21 and to have a smaller diameter than the base 21b. An annular heat insulating material 26 and an annular elastic seal 27 are fitted into the fitting portion 21a, with the latter disposed on the upper side and in vertical contact with each other. The upper surface of the elastic seal 27 is in contact with the lower surface of a portion of the base portion 21b that protrudes from the upper end of the fitting portion 21a to the periphery. This lower surface serves as a pressing portion 29, which will be described later.

As shown in FIG. 3, the heat insulating material 26 is a cylindrical body, and when the fitting part 21a is fitted into the pot 6, the outer circumferential surface of the fitting part 21a and the inner circumferential surface of the pot 6 (inner circumferential surface of the cylindrical body 9) It is provided so as to be interposed between the two surfaces. The heat insulating material 26 suppresses heat transfer between the pot 6 and the punch 21 while the punch 21 is being inserted into the pot 6 and in a state where the punch 21 is pressed against the resin 11 of the pot 6.

The elastic seal 27 is a so-called O-ring, and is provided so as to be interposed between the outer circumferential surface of the fitting portion 21a and the inner circumferential surface of the pot 6 above the heat insulating material 26 when the fitting portion 21a is fitted into the pot 6. It is being When the punch 21 is pressed against the resin 11 of the pot 6, the elastic seal 27 prevents the resin 11 from leaking from between the fitting portion 21a of the pot 6 and the punch 21.

This prevention of resin leakage will be explained. Between the outer circumferential surfaces of the heat insulating material 26 and the elastic seal 27 fitted in the fitting part 21a of the punch 21 and the inner circumferential surface of the pot 6, when the fitting part 21a is fitted into the pot 6, the inside of the pot 6 is A clearance is provided to allow gas (nitrogen gas) to escape to the outside. In other words, the outer circumferential surfaces of the heat insulating material 26 and the elastic seal 27 fitted into the fitting part 21a and the inner circumferential surface of the pot 6 are not in close contact with each other over the entire circumference without any gaps, but the aim is to make the fitting smooth. As such, a slight clearance is created between at least one portion of the outer circumferential surface and the inner circumferential surface at the time of fitting.

Then, as shown in FIG. 3(A), the tip surface of the punch 21 comes into contact with the resin 11 of the pot 6, and as shown in FIG. 3(B), when the tip surface is pressed against the resin 11, the punch 21 Pressure is applied to the elastic seal 27 from the pressing portion 29 of 21. Since the heat insulating material 26 is supported by the resin 11 and does not substantially move, the elastic seal 27 is pressed against the upper end surface of the heat insulating material 26 by the pressure from the pressing portion 29 . As a result, the elastic seal 27 is elastically deformed so that its inner and outer circumferential parts protrude to the inner and outer circumferential sides, respectively, and to put it simply, it is crushed and the insertion part 21a of the punch 21 is It is strongly pressed against the outer peripheral surface and the inner peripheral surface of the pot 6. Therefore, the resin 11 is prevented from leaking between the outer circumferential surface of the insertion portion 21a of the punch 21 and the inner circumferential surface of the pot 6.

<About the resin side temperature sensor 13>
As shown in FIG. 4, the resin side temperature sensor 13 includes a plurality of (three in this embodiment) temperature probes 31. The plurality of temperature measuring elements 31 are horizontally arranged at small intervals in the punch insertion direction (vertical direction) and held by one block 34. Preferably, the upper surface of the block 34 is positioned near the upper surface of the molten resin 11 stored in the pot 6, and the upper surface of the block 34 is preferably prevented from being immersed in the molten resin 11. A block 34 is supported by a support member 35 on the pot 6 so that the upper surface and the upper surface of the block are flush with each other.

As shown in FIG. 5, each of the plurality of temperature measuring elements 31 is a thermocouple that is formed by joining the tips of two types of metal wires 31a and 31b to each other to form a thermal junction (temperature measuring point) 31c. The portions of the metal wires 31a and 31b that are buried in the resin other than their thermal contacts 31c are insulated coated with a highly heat-resistant resin whose melting point is higher than that of the resin.

The plurality of temperature measuring elements 31 are held together in a block 34 made of an electrically insulating material, with the parts of the metal wires 31a and 31b near the thermal contact point 31c spaced apart vertically by a small distance. That is, the parts of each of the plurality of temperature probes 31 near the thermal contact point 31c are stacked vertically with minute intervals, and the electrical insulating material is hardened so that the parts are wrapped in a rectangular parallelepiped shape. Block 34 is used. Heat-resistant cement can be preferably used as the electrical insulating material. The upper surface of the block 34 is smooth. The block 34 is supported by the pot 6 by a support member 35 so that its smooth upper surface is horizontal.

The protruding ends of the metal wires 31a and 31b of each of the plurality of temperature measuring elements 31 are joined together so that the part protruding from the block 34 toward the center of the resin reservoir 12 of the pot 6 has a V-shape in plan view. and is used as a thermal junction 31c. The thermal contacts 31c of each of the plurality of temperature probes 31 are arranged in the center of the resin reservoir 12 at small intervals in the punch insertion direction.

In this embodiment, the thermal junctions (temperature measurement points) 31c of each of the three temperature probes 31 are located at positions 0.5 mm, 1.5 mm, and 2.5 mm away from the top surface of the block 34. It is located.

Note that the portion of each of the metal wires 31a and 31b of the plurality of temperature measuring elements 31 that protrudes from the block 34 toward the inner circumferential surface of the resin reservoir 12 of the pot 6 extends horizontally to the outside of the pot 6.

The support member 35 is made of highly heat-resistant fibers having electrical insulation properties, is fixed to the upper corner of the block 34, is provided horizontally, and has flexibility. The cylindrical body 9 constituting the pot 6 is composed of an upper cylindrical part 9a and a lower cylindrical part 9b which are vertically aligned. The supporting member 35 is sandwiched between the upper cylindrical part 9a and the lower cylindrical part 9b at both sides so as to straddle the central part of the resin storage part 12 of the pot 6 and extend from one side of the pot 6 to the other. is fixed.

As the molten resin 11 contracts as it cools, the position of the block 34 lowers. In order to cause the block 34 (that is, the temperature measuring element 31) to follow the contraction of the resin, the support member 35 is designed to break when a predetermined load is applied. For example, the support member 35 has a thickness (tex count) of 1.7 g/1000 m to 2500 g/1000 m, which is made up of multiple fibers with a fiber diameter of 4 μm to 13 μm and a breaking strain of 5.5% or less. Fiber bundles of can be suitably used.

<About the arithmetic unit 4>
The temperature of the resin 11 measured by the resin-side temperature sensor 13 and the temperature of the punch 21 measured by the punch-side temperature sensor 22 are converted into electrical signals and input to the calculation device 4 as temperature data. The calculation device 4 calculates the heat transfer coefficient h by calculating the temperature data.

Specifically, the temperature distribution in the punch insertion direction near the interface of the resin 11 is determined by fitting from temperature data of a plurality of points having different distances from the interface measured by the resin side temperature sensor 13. The temperature distribution in the punch insertion direction of the punch 21 is determined by fitting from the temperature data of a plurality of points having different distances from the interface measured by the punch-side temperature sensor 22. From the temperature distribution of each of the resin 11 and the punch 21, the temperature Tr on the resin 11 side and the temperature Tm on the punch 21 side at the interface are determined.

When the heat flux passing through the interface between the resin 11 and the punch 21 is q, the heat transfer coefficient h is given by "h=q/(Tr-Tm)". The calculation device 4 calculates the heat transfer coefficient h based on the temperature Tr on the resin 11 side, the temperature Tm on the punch 21 side, and the known heat flux q.

The heat flux q is given by q=a×(Tm-Te)/L, where Te is the temperature at a position a length L away from the surface of the punch 21 in the punch insertion direction, and a is the thermal conductivity of the punch 21. . Therefore, the heat flux q is determined from the Tm obtained by the above fitting, the above Te, the thermal conductivity a, and the length L. Note that the heat flux q measured in advance and stored electronically may be used to calculate the heat transfer coefficient h.

<Measurement method of heat transfer coefficient>
A method for measuring the heat transfer coefficient between resin and metal using the heat transfer coefficient measuring device 1 will be described.

<Preparation process>
A punch device 3 is attached to a pressure rod of a pressure testing machine, and a pot device 2 is installed below the punch 21. The resin 11 to be measured is placed in the resin reservoir 12 of the pot 6, and the upper opening of the pot 6 is closed with the lid 7. Nitrogen gas is supplied into the pot 6 from the nitrogen supply pipe 19. In this state, the resin 11 is heated and melted to a predetermined temperature (for example, 200° C.) using a rod-shaped heater 15 embedded in the base 8 and a hand heater 17 wrapped around the cylindrical body 9. The amount of resin 11 is determined so that when it is heated and melted to a predetermined temperature, the upper surface of block 34 of resin side temperature sensor 13 is positioned near the upper surface of resin 11. Preferably, the upper surface of the block 34 is not immersed in the molten resin 11, and furthermore, the upper surface of the resin 11 is flush with the upper surface of the block 34.

<Process of inserting and pressing a punch into the molten resin in the pot>
The heating of the resin 11 by the heaters 15 and 17 is stopped (even during heating), and the lid 7 is removed from the pot 6. The pressure testing machine is operated, the punch 21 is inserted into the pot 6, and the tip end surface of the punch 21 is pressed against the molten resin 11. When the punch 21 is inserted into the pot 6, the inner circumferential surface of the pot 6 is determined from the clearance between the outer peripheral surface of the heat insulating material 26 and the elastic seal 27 fitted into the insertion part 21a of the punch 21 and the inner peripheral surface of the pot 6. gas (nitrogen gas) escapes to the outside.

When the tip of the punch 21 contacts and is pressed against the molten resin 11 of the pot 6 as shown in FIG. 3(A), the heat insulating material 26 is supported by the molten resin 11 as shown in FIG. 3(B). The punch 21 is slightly pushed into the molten resin 11 without moving. As a result, pressure is applied to the elastic seal 27 from the pressing portion 29 of the punch 21, and the elastic seal 27 is pressed against the upper end surface of the heat insulating material 26. As a result, the elastic seal 27 is elastically deformed to be crushed, and its inner and outer circumferential sides are strongly pressed against the outer circumferential surface of the insertion portion 21a of the punch 21 and the inner circumferential surface of the pot 6.

Therefore, the heat insulating material 26 prevents heat transfer from the pot 6 to the punch 21, and the elastic seal 27 prevents the molten resin 11 from leaking between the outer peripheral surface of the insertion part 21a of the punch 21 and the inner peripheral surface of the pot 6. will definitely be prevented.

Further, even if the punch 21 contacts the block 34 when the punch 21 is pressed against the upper surface of the molten resin 11, the pressure from the punch 21 is not directly transmitted to the temperature probe 31, so that multiple temperatures can be measured. Changes in the interval between the temperature measurement points 31c of the probe 31 can be avoided.

Even if the top surface of the block 34 is in a state that slightly protrudes upward from the top surface of the molten resin 11, when the punch 21 hits the block 34, the support member 35 is bent, so that the block 34 has its top surface aligned with the top surface of the molten resin 11. It follows the punch 21 and is pushed down until it becomes flush with the punch 21. Therefore, the intervals between the temperature measurement points 31c of the plurality of temperature measurement elements 31 do not change, and since the top surface of the block 34 is flush with the top surface of the molten resin 11, the interface between the temperature measurement points 31c The separation distance becomes the desired separation distance.

<Process of measuring the temperature of resin and punch>
When the punch 21 is pressed against the resin 11, the position of the punch 21 is fixed, and the temperatures of the resin 11 and the punch 21 are measured by the resin side temperature sensor 13 and the punch side temperature sensor 22. Since the resin side temperature sensor 13 includes a plurality of temperature measuring elements 31, the resin temperature sensor 13 measures the resin temperature at a plurality of points having different distances from the interface. Since the punch-side temperature sensor 22 includes a plurality of temperature measuring elements 23, the punch-side temperature sensor 22 measures the punch temperatures at a plurality of points having different distances from the interface.

When the resin 11 cools and contracts, the support member 35 breaks and the block 34 follows the contraction of the resin 11, so that the top surface of the block 34 becomes substantially flush with the top surface of the resin 11. The condition is maintained. Therefore, even if a gap is created between the resin 11 and the punch 21 due to contraction of the resin 11, the temperature at each position of the resin 11 can be measured approximately as intended.

<Process of determining heat transfer coefficient from measured temperature>
The heat transfer coefficient between the resin 11 and the punch 21 is determined by the arithmetic unit 4 from the temperatures at a plurality of points on each of the resin 11 and the punch 21 measured by the resin side temperature sensor 13 and the punch side temperature sensor 22.

Specifically, the temperature distribution in the punch insertion direction near the interface of the resin 11 is determined by fitting from temperature data on the resin side at a plurality of points having different distances from the interface. From the temperature data on the punch side at a plurality of points having different distances from the interface, the temperature distribution in the punch insertion direction of the punch 21 is determined by fitting. From the temperature distribution of each of the resin 11 and the punch 21, the temperature Tr on the resin 11 side and the temperature Tm on the punch 21 side at the interface are determined. The heat transfer coefficient h=q/(Tr-Tm) is calculated based on the temperature difference (Tr-Tm) at this interface and the heat flux q stored electronically in advance.

The resin 11 is cooled and solidified from a molten state as heat is removed by the punch 21 pressed against its upper surface. That is, a phase change occurs from a liquid phase to a solid phase. In this embodiment, the temperature measurement of the resin 11 and the punch 21 is started from the time when the punch 21 is pressed against the resin 11, and the resin 11 changes from the liquid phase to the solid state based on the change over time of the temperature difference (Tr - Tm) at the interface. Find the change in heat transfer coefficient when changing to phase.

When a gap is created between the resin 11 and the punch 21 due to contraction of the resin 11, the heat transfer coefficient of heat transfer from the resin 11 to the punch 21 across the gap (air layer) is measured.

<Effects of the combination of insulation material and elastic seal>
Regarding the above embodiment and a comparative example (without heat insulating material) in which an O-ring groove is provided at the upper end of the insertion part 21 of the punch 21 and the elastic seal (O-ring) 27 is fitted into this groove, the punch 21 is attached to the resin 11. The change over time of the punch side temperature measured by the temperature measuring element 23 of the punch side temperature sensor 22 when pressed was investigated. The results are shown in FIG.

In the embodiment (a combination of a heat insulating material and an elastic seal), the temperature measured by the temperature probe 23 is lower than that in the comparative example (no heat insulating material), and the heat insulating material 26 prevents the flow from the pot 6 to the punch 21. It can be seen that it works effectively in suppressing heat transfer. Further, in the comparative example (without heat insulating material), there is a large temperature difference between a measurement point at a distance of 2 mm from the interface, and measurement points at a distance of 4 mm and 6 mm from the interface. It is recognized that this is because the resin enters the gap between the pot 6 and the punch 21, and resin leaks, resulting in uneven heat transfer from the pot 6 to the punch 21. In contrast, in the embodiment (combination of heat insulating material and elastic seal), the temperature difference between each measurement point is small. From this, it can be seen that resin intrusion and resin leakage between the pot 6 and the punch 21 are prevented by the heat insulating material 26 and the elastic seal, and therefore, uneven heat transfer from the pot 6 to the punch 21 is prevented. It can be seen that

<Effects of resin side temperature sensor>
Regarding the above embodiment and a comparative example (without a support member) in which three temperature probes (thermocouples) 31 are held in the block 34 and arranged in the center of the resin reservoir 12 of the pot 6 in a manner extending from the side, the punch 21 was pressed against the molten resin 11, and when the resin 11 was cooled and solidified, the position of the temperature measuring point 31c of each temperature measuring element 31 was examined.

In both the embodiment (with support member) and the comparison (without support member), the three temperature measurement elements 31 are located at a position where each temperature measurement point 31c is 0.5 mm away from the top surface of the block 34, at a position 1.5 mm away from the top surface of the block 34, and at a position 1.5 mm away from the top surface of the block 34. It was held on the block 34 at a distance of 2.5 mm. Then, with the block 34 positioned such that its upper surface was flush with the upper surface of the molten resin 11, the punch 21 was inserted into the pot 6 and pressed against the molten resin 11. The aim is to measure the temperature at positions separated from the interface by 0.5 mm, 1.5 mm, and 2.5 mm.

In the comparative example (without a support member), the temperature measurement point 31c, which aims to measure the temperature at a position 0.5 mm away from the interface, is set at a temperature measurement point 31c from the upper surface of the resin 11 by cooling and solidifying the resin 11 pressed by the punch 21. It was sunk at a distance of 238mm. The temperature measurement point 31c, which aims to measure the temperature at each position at a distance of 1.5 mm and 2.5 mm from the interface, was also deeply sunk, similar to the temperature measurement point 31c, which aimed to measure the temperature at a position 0.5 mm away. .

On the other hand, in the embodiment (with support member), each temperature measurement point 31c aiming at measuring the temperature at each position at a distance of 0.5 mm, 1.5 mm, and 2.5 mm from the interface is pressed by the punch 21. The separation distances from the upper surface of the resin 11 after cooling and solidifying the resin 11 were 0.502 mm, 1.557 mm, and 2.360 mm, respectively.

From this result, in the case of the embodiment, although the distance between the three temperature measurement points 31c changes somewhat due to the effect of cooling and solidification (shrinkage) of the resin 11, when the punch 21 is pressed against the resin 11, the distance between the three temperature measurement points 31c is The top surface of the block 34 is kept substantially flush with the top surface of the resin 11, and when the resin 11 cools and contracts, the support member 35 breaks, and the top surface of the block 34 becomes the top surface of the resin 11. It became clear that the resin temperature could be measured at approximately the targeted position, as the resin temperature remained approximately flush with the target position.

Although the above embodiment is a case where the resin is thermoplastic, it goes without saying that the present invention can also be applied to thermosetting resin.

(Embodiment 2)
Other embodiments according to the present disclosure will be described in detail below. In addition, in the description of these embodiments, the same parts as in Embodiment 1 are given the same reference numerals, and detailed description thereof will be omitted.

In the first embodiment, as shown in FIGS. 4 and 5, the portion of the metal wires 31a and 31b of each of the plurality of temperature measuring elements 31 that protrudes from the block 34 toward the inner circumferential surface of the resin reservoir 12 of the pot 6. had a configuration extending horizontally to the outside of the pot 6. Further, the number of supporting members 35 was one, and the structure was such that it was fixed to the upper corner of the block 34 and provided horizontally.

However, the shapes of the metal wires 31a and 31b, the arrangement and number of the supporting members 35, etc. are not limited to the above configuration.

For example, as shown in FIGS. 8 and 9, two or more supporting members 35 (two in FIG. 9) may be provided, or the supporting members 35 may be fixed to the lower corners of the blocks 34.

Further, the portions of the metal wires 31a and 31b of each of the plurality of temperature measuring elements 31 that protrude from the block 34 toward the inner peripheral surface of the resin reservoir 12 of the pot 6 have a curved shape, preferably a curved shape instead of extending horizontally. The shape may include a downwardly curved curved portion 31d. In addition, it is more preferable that the curved part 31d is curved so as to protrude below the support member 34.

By inserting the punch 21, the resin 11 at and near the interface between the resin 11 and the punch 21 is cooled and solidified. With the configuration of Embodiment 1, the temperature at the interface and the vicinity of the interface of the resin 11 can be reliably measured in measurements under low pressure, for example, about 8 MPa or less, and therefore a highly reliable heat transfer coefficient can be obtained. be able to.

However, when measuring under high pressure, for example over about 8 MPa, preferably over 10 MPa, the insertion of the punch 21 causes shearing and damage to the metal wires 31a and 31b embedded in the solidified resin 11, resulting in measurement failure. It may become difficult to ensure reliability.

In the configuration shown in FIGS. 8 and 9, the metal wires 31a and 31b have a curved portion 31d. Most of the curved portion 31d is located below the support member 35. When the punch 21 is inserted, the support member 35 is broken as described above, but the resin 11 around the curved portion 31d is located at a sufficient distance from the lower surface of the punch 21, and even when the punch 21 is inserted, the support member 35 is broken. , still in a molten state. Therefore, even if the block 34 is largely displaced downward due to the insertion of the punch 21 during, for example, measurement under high pressure, shearing and damage to the metal wires 31a and 31b can be suppressed due to the bending of the curved portion 31d. In this way, measurement reliability can be ensured.

In the configurations shown in FIGS. 8 and 9, the curved portion 31d has a bent shape, but is not limited to this configuration, and may have a smooth curved shape, for example.

1 Heat transfer coefficient measuring device 2 Pot device 3 Punch device 4 Arithmetic device 6 Pot 11 Resin 12 Resin reservoir 13 Resin side temperature sensor 15, 17 Heater 16, 18 forming the temperature adjusting device 21 Punch 21a Insertion part 21b Base 22 Punch side temperature sensor 23 Temperature measuring element 23a Temperature measuring point 31 Temperature measuring element 31a, 31b Metal wire 31c Thermal junction (temperature measuring point)
34 Block 35 Support member

Claims (18)

A pot for storing molten resin,
a metal punch that is fitted into the pot and whose tip end is pressed against the resin;
a resin side temperature sensor that measures the temperature of the resin;
a punch-side temperature sensor that measures the temperature of the punch;
A heat transfer coefficient measuring device comprising: an arithmetic device that calculates a heat transfer coefficient between the resin and the punch from the measured temperatures of the resin and the punch;
The above resin side temperature sensor is
a plurality of temperature probes that electrically measure the temperature of each point of the resin at different distances from the interface between the resin and the punch; a block that holds the plurality of temperature probes; A heat transfer coefficient measuring device comprising: a support member supported on the pot so that its top surface is positioned near the top surface of the resin. In claim 1,
A heat transfer coefficient measuring device characterized in that the temperature measuring element of the resin side temperature sensor is a thermocouple made by joining the tips of two types of metal wires together to form a thermal contact. In claim 2,
The heat transfer coefficient of the metal wire of the thermocouple is characterized in that the portion buried in the resin other than the thermal contact point is coated with an insulation coating with a high heat resistant resin whose melting point is higher than the melting point of the resin. Measuring device. In claim 1 or claim 2,
A heat transfer coefficient measuring device characterized in that the block is supported by the pot so that its upper surface is flush with the upper surface of the molten resin. In claim 1 or claim 2,
The punch-side temperature sensor includes a plurality of temperature probes that are each embedded in the punch and electrically measure the temperature of the punch,
The plurality of temperature measuring elements of the punch-side temperature sensor extend downward from above the punch, or extend from the outer periphery of the punch toward the center, and each temperature measuring point at the tip thereof is located at the center of the punch. A heat transfer coefficient measuring device characterized in that the devices are arranged at intervals on the same circumference centered on the axis of the device. In claim 5,
The plurality of temperature measuring elements of the punch-side temperature sensor are arranged so that the temperature measuring points of the respective temperature measuring points are arranged on the punch in order to measure the temperature of each point on the punch which has a different separation distance from the interface between the resin and the punch. A heat transfer coefficient measuring device characterized in that the heat transfer coefficient is shifted in the axial direction. In claim 1 or claim 2,
A heat transfer coefficient measuring device characterized in that the pot is equipped with a temperature adjustment device that adjusts the temperature of the resin housed inside the pot. In claim 1 or claim 2,
A heat transfer coefficient measuring device characterized in that the resin is thermoplastic. In claim 1 or claim 2,
The heat transfer coefficient measuring device is characterized in that the resin storage part for storing the resin of the pot and the insertion part of the punch have a perfect circular cross-sectional shape perpendicular to the insertion direction of the punch. In claim 1 or claim 2,
Heat transfer characterized in that a portion of the metal wire of the thermocouple that protrudes from the block toward the inner circumferential surface of the pot has a curved portion that protrudes downward from the support member. Coefficient measurement device. A step of inserting a punch into a pot storing molten resin and pressing the tip of the punch against the resin;
Measuring the temperature of the resin and the punch;
determining a heat transfer coefficient between the resin and the punch from the measured temperatures of the resin and the punch,
A plurality of temperature probes that electrically measure the temperature of each point of the resin at different distances from the interface between the resin and the punch are held in one block, and the block is connected to the pot via a support member. Please support
The molten resin is stored in the pot, and the top surface of the block is positioned near the top surface of the resin, and in this state, the punch is inserted into the pot and its tip is pressed against the resin. A heat transfer coefficient measurement method characterized by applying In claim 11,
A method for measuring a heat transfer coefficient, characterized in that the temperature measuring element of the resin side temperature sensor is a thermocouple made by joining the tips of two types of metal wires together to form a thermal contact. In claim 11 or claim 12,
The heat transfer coefficient of the metal wire of the thermocouple is characterized in that the portion buried in the resin other than the thermal contact point is coated with an insulation coating with a high heat resistant resin whose melting point is higher than the melting point of the resin. Measurement method. In claim 11 or claim 12,
The block is supported in the pot so that its upper surface is flush with the upper surface of the molten resin,
A method for measuring a heat transfer coefficient, characterized in that when the tip end surface of the punch is pressed against the resin, a part of the tip end surface is brought into contact with the upper surface of the block. In claim 11 or claim 12,
The punch-side temperature sensor includes a plurality of temperature probes that are each embedded in the punch and electrically measure the temperature of the punch,
The plurality of temperature measuring elements of the punch-side temperature sensor extend downward from above the punch, or extend from the outer periphery of the punch toward the center, and each temperature measuring point at the tip thereof is located at the center of the punch. A heat transfer coefficient measurement method characterized in that the heat transfer coefficients are arranged at intervals on the same circumference centered on the axis of the. In claim 15,
The plurality of temperature measuring elements of the punch-side temperature sensor are arranged so that the temperature measurement points are positioned on the punch in order to measure the temperature of each point on the punch that has a different distance from the interface between the resin and the punch. A heat transfer coefficient measurement method characterized by being shifted in the axial direction. In claim 11 or claim 12,
A method for measuring a heat transfer coefficient, characterized in that before inserting the punch into the pot, the resin is heated and melted inside the pot using a temperature control device to adjust the temperature to a predetermined temperature. In claim 11 or claim 12,
A heat transfer coefficient measuring method characterized in that the resin is thermoplastic.