JPH09225971A - Injection molding die having thermo-couple and injection molding die temperature-measuring device equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a manufacturing cost while fluctuation in surface temperature of a mold can be quickly accurately detected. SOLUTION: For a part wherein an influence of heat flux by heat medium flowing in a heat medium channel 22b in an outer wall surface of a stationary side mold 22 is not received, and fluctuation in outside air temperature has a direct influence, a thermo-couple 3 is fitted by sticking a pressure sensitive adhesive tape 21 under a state of putting its temperature detecting part 3a between an outer wall surface and the pressure sensitive adhesive tape 21. In the same way as this, for a part wherein an influence of heat flux by heat medium flowing through a heat medium passage 23b in an outer wall surface of a movable side mold 23 is not received, and fluctuation in outside air temperature has a direct influence, the thermo-couple is fitted by sticking the pressure sensitive adhesive 21 onto the outer wall surface under a state of putting the temperature detecting part 3a of the thermo-couple 3 between the outer wall surface and the pressure sensitive adhesive tape 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die having a thermocouple for measuring a mold temperature and an injection molding die temperature measuring device including the same.

[0002]

2. Description of the Related Art A conventional injection molding die having a thermocouple has a sprue 11 of a fixed side die 101, as shown in FIG.
3 and the insertion hole 105 at a portion that does not interfere with the cooling water pipe 111.
And a temperature detecting portion 103a of the thermocouple 103 held by a holder equipped with a fixing joint 107 and a fixing adapter 108 is inserted into the insertion hole 105, while
The temperature of the thermocouple 104 held by a holder provided with an insertion hole 106 in a portion of the movable mold 102 that does not interfere with the cooling water pipe 112 and having a fixing joint 109 and a fixing adapter 110 in the insertion hole 106. The detection unit 104a is inserted.

[0003]

In the injection molding machine, when the outside air temperature fluctuates, its influence appears immediately before the mold surface temperature. For example, when the outside air temperature decreases, the mold surface temperature, that is, the surface temperature of the cavity and the surface temperature of the core decrease. When the mold is clamped in this state and the molten resin is injected and filled in the cavity, the amount of temperature drop of the molten resin when the molten resin comes into contact with the surfaces of the cavity portion and the core portion is It becomes large in comparison, and the resin cannot be replenished to every corner of the cavity. As a result, there is a possibility that molding defects such as sink marks and distortions appearing in the molded product and the weight and size of the molded product are reduced as compared with good products. The surface temperature of the cavity portion and the core portion cannot be measured by directly attaching a temperature sensor to the cavity portion and the core portion. This is because if the surface of the cavity and the surface of the core are given the surface shape of the molded product as they are and a temperature sensor is attached, the appearance of the molded product will be hindered.

However, in the above-mentioned conventional technique, the temperature detecting portion of the thermocouple inserted into the insertion hole is easily affected by the heat flux due to the cooling water in the cooling water pipe and the resin in the cavity, and the above-mentioned fluctuation of the outside air temperature. Since it is not possible to quickly and accurately detect the change in the mold surface temperature due to the above, there is a possibility that molding defects may occur. In addition, it is necessary to perform a drilling process to form an insertion hole in the mold, and a fixing joint and a fixing adapter for mounting the thermocouple must be prepared, which increases the manufacturing cost. There is a problem.

The present invention has been made in view of the problems of the above-mentioned conventional techniques, and changes in temperature similar to the temperature changes on the surface of the mold cavity or the surface of the mold core due to changes in the outside air temperature. It is an object of the present invention to realize an injection mold having a thermocouple and a mold temperature measuring device for injection molding including the thermocouple, which can detect a change in the mold wall temperature shown quickly and accurately and can reduce the manufacturing cost. To do.

[0006]

In order to achieve the above object, an injection molding die having a thermocouple of the present invention is internally provided with a heat medium flow passage through which a heat medium for adjusting the temperature of the die flows. In the injection molding die, the temperature of the outer wall surface of the die is not affected by the heat flux due to the heat medium flowing through the heat medium passage, and the temperature of the outside air temperature is directly affected by the temperature detection. The adhesive tape is characterized in that a thermocouple is attached by fixing the parts to each other. Further, the adhesive tape in the state where the temperature detecting part of the thermocouple is sandwiched between the outer wall surface of the mold and the adhesive tape. It is effective to attach by attaching to the outer wall surface of the mold.

Further, the thermocouple may be mounted by embedding a temperature detecting portion of the thermocouple in a mounting plate with at least a part thereof exposed from the back surface and screwing the mounting plate to the outer wall surface of the mold, The thermocouple may be attached by screwing the pressing plate to the outer wall surface of the mold with the temperature detecting portion sandwiched between the outer wall surface of the mold and the pressing plate.

In addition, an injection molding die temperature measuring device according to the present invention provides an injection molding die having a thermocouple according to any one of claims 1 to 4 and a detection value detected by the thermocouple. An A / D converter for converting into a digital signal;
In order to sample the digital signal sent from the A / D converter based on the timing signal sent from the sequence control device and store it as a sampling value, and to convert the sampling value into a numerical value or a graph and display it on the display. And an arithmetic processing unit that outputs the display signal of.

[0009]

The mold side wall surface, which is the outer wall surface of the mold, is located at a position different from that of the cavity and core, but the surface temperature drops due to the decrease in outside air temperature, which is the same as the surface of the cavity and core. Therefore, it is expected that the temperature change on the surface of the cavity and the core part due to the change of the outside air temperature shows a tendency similar to the temperature change on the side wall surface of the mold. That is, if the surface temperature change of the side wall surface of the mold is detected, it is expected that the change tendency of the surface temperature of the cavity portion and the core portion can be predicted, and as a result, the change tendency of the quality of the molded product can be predicted.

Further, since it is not influenced by the heat flux due to the heat medium flowing through the heat medium passage provided inside the mold, the fluctuation of the mold surface temperature due to the fluctuation of the outside air temperature can be detected quickly and accurately. . As a result, it becomes possible to predict in advance the occurrence of defective molding of the molded product due to the fluctuation of the mold surface temperature and take appropriate countermeasures.

Further, since it is not necessary to provide an insertion hole for inserting the temperature detecting portion of the thermocouple in the mold, the manufacturing cost can be reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing an example of an injection molding machine using an injection molding die temperature measuring device equipped with an injection molding die having a thermocouple according to the present invention.

A mold M attached to a mold clamping device (not shown)
Is internally provided with a heat medium flow passage (not shown) through which the heat medium flows, and a mold temperature controller 8 connected to the heat medium flow passage through pipes 5 and 6 controls the temperature to a predetermined temperature. The mold temperature of the mold M can be adjusted by circulating and supplying the generated heat medium. The mold M may be either a fixed mold or a movable mold.

The temperature detecting portion of the thermocouple 3 is located at a portion of the outer wall surface of the mold M which is not affected by the heat flux from the heat medium flowing through the heat medium flow passage and is directly affected by the change in the outside air temperature. 3a is fixed, the detected value of the thermocouple 3 is amplified by the amplifier 7, then converted into a digital signal by the A / D converter 2 and sent to the arithmetic processing unit 1.

Here, the arithmetic processing section 1 includes an A / D converter 2
The digital signal sent from the sequence controller 9
In addition to having a function of sampling based on the timing signal sent from the device and storing it as a sampling value, and outputting a display signal for converting the sampling value into a numerical value or a graph and displaying it on the display unit 4. ,
It has a function of transferring the sampling value to the temperature control unit of the mold temperature controller 8 or the control unit 10 of the injection molding machine.

Next, an embodiment of the injection molding die having the thermocouple of the present invention will be described.

(First Embodiment) As shown in FIGS. 2 and 3, the mold M according to the present embodiment comprises a stationary mold 22 having a cavity portion 22a communicated with a sprue 22c and a core portion 23a. The movable mold 23 has.

The fixed-side die 22 is a heat medium flow passage 2 for flowing a heat medium for adjusting the die temperature to a predetermined temperature.
2b is provided internally, and a portion of the outer wall surface thereof which is not affected by the heat flux due to the heat medium flowing through the heat medium passage 22b, and which is directly affected by the change in the outside air temperature, has a thermocouple 3 Is attached by adhering the adhesive tape 21 to the outer wall surface with the temperature detecting portion 3a sandwiched between the outer wall surface and the adhesive tape 21. Similarly, the movable-side mold 23 is internally provided with a heat medium flow passage 23b for flowing the heat medium, and the influence of the heat flux due to the heat medium flowing through the heat medium flow passage 23b on the outer wall surface thereof. In a portion that is not affected by the change in the outside air temperature and has a direct influence on the outside wall temperature, the thermocouple 3 sandwiches the temperature detecting portion 3a between the outside wall surface and the adhesive tape 21 and attaches the adhesive tape 21 to the outside wall surface. It is attached by sticking to.

According to this embodiment, it is not necessary to perform a process for mounting the thermocouple 3 on the mold M, and the mounting position of the temperature detecting portion 3a of the thermocouple 3 is not restricted.

(Second Embodiment) As shown in FIG. 4, in the mold M of this embodiment, the thermocouple 3 has a temperature detecting portion 3a in which a part of the temperature detecting portion 3a is exposed from at least the back surface (lower surface in the drawing). Then, the screws 32 embedded in the mounting plate 31 and fitted into the plurality of mounting holes 31a provided in the mounting plate 31 from the front side are screwed into the screw holes 33 formed in the outer wall surface of the mold M. Installed by screwing. Since the other points are the same as those in the first embodiment, the description thereof will be omitted.

(Third Embodiment) As shown in FIG. 5, in the mold M of this embodiment, the thermocouple 3 has its temperature detecting portion 3a between the pressing plate 41 and the outer wall surface of the mold M. It is mounted by screwing screws 42, which are respectively inserted into a plurality of mounting holes 41a provided in the holding plate 41 in a sandwiched state, into screw holes 43 formed on the outer wall surface of the mold M and screwing them. ing.
Since the other points are the same as those in the first embodiment, the description thereof will be omitted.

In order to confirm the effect, a comparative experiment is performed between the case where the injection molding die having the thermocouple according to the present invention is used and the case where the injection molding die having the thermocouple according to the above-mentioned conventional technique is used. The results will be described below.

Polycarbonate is used as a molding material,
A molded product having a standard weight of 21.60 grams was injection-molded for 500 shots over about 12 hours, and the mold temperature was measured for each shot, and the weight of each molded product was measured. The outside air temperature at this time fluctuated within the range of 6.6 ° C.

FIG. 6 shows a graph plotting the measured values of the mold temperature and the weight of the molded product measured for each shot when the injection molding mold having the thermocouple according to the present invention is used, and FIG. Shows a graph plotting the measured value of the mold temperature and the weight of the molded product measured for each shot when an injection molding mold having a thermocouple according to the related art is used.

As is apparent from FIG. 6, in the injection molding die temperature measuring device according to the present invention, the measured value T of the die temperature from about 200 shots to 500 shots.
While the variation pattern of w and the variation pattern of the weight Pw of the molded product are almost the same, as is apparent from FIG. 7, in the conventional technique, the variation pattern of the measured value Tw of the mold temperature and the molded product The variation pattern of the weight Pw almost does not match in each shot.

[0027]

Since the present invention is configured as described above, the following effects can be obtained.

Since the temperature detecting portion of the thermocouple is fixed to the outer wall surface of the mold, a change in the mold surface temperature equivalent to a change in the surface temperature of the cavity portion and the core portion caused by a change in the outside air temperature at the time of injection molding can be performed quickly. Can be accurately detected. As a result, it is possible to promptly and accurately predict the change in the weight of the molded product due to the change in the outside air temperature, and effectively utilize it for quality control of the molded product and molding process control. In addition, unlike the conventional example, it is not necessary to insert the temperature detection part of the thermocouple into the insertion hole formed in the mold and then attach it through a separately prepared fixing joint or fixing adapter, which reduces the manufacturing cost. It can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of an injection molding machine equipped with a mold temperature measuring device according to the present invention.

FIG. 2 is a sectional view showing a first embodiment of an injection molding die having a thermocouple according to the present invention.

3 shows only a thermocouple and its vicinity in the injection molding die having the thermocouple shown in FIG. 2, (a) is a schematic partial plan view thereof, and (b) is an AA line of (a). It is a schematic partial sectional view which follows.

FIG. 4 shows a second embodiment of an injection molding die having a thermocouple according to the present invention, (a) is a schematic partial plan view thereof,
(B) is a schematic partial sectional view which follows the AA line of (a).

FIG. 5 shows a third embodiment of an injection molding die having a thermocouple according to the present invention, (a) is a schematic partial plan view thereof,
(B) is a schematic partial sectional view which follows the AA line of (a).

FIG. 6 is a graph showing the correlation between the variation in the measured value of the die temperature and the variation in the weight of the molded product when the injection molding die having the thermocouple according to the present invention is used.

FIG. 7 is a graph showing the correlation between the variation of the measured value of the die temperature and the variation of the weight of the molded product when the injection molding die having the thermocouple according to the conventional technique is used.

FIG. 8 is a schematic cross-sectional view showing a conventional injection molding die having a thermocouple.

[Explanation of symbols]

 1 arithmetic processing unit 2 A / D converter 3 thermocouple 3a temperature detection unit 4 indicator 5, 6 piping 7 amplifier 8 mold temperature controller 9 sequence control device 10 injection molding machine control unit 21 adhesive tape 31 mounting plate 31a , 41a Mounting holes 32, 42 Screws 33, 43 Screw holes 41 Holding plate

Claims (5)

[Claims] 1. An injection-molding die having a heat medium passage through which a heat medium for adjusting a die temperature is provided, wherein the heat medium passage on the outer wall surface of the die (M) is The thermocouple (3) is attached by fixing the temperature detecting portion (3a) to a portion that is not affected by the heat flux due to the flowing heat medium and is directly affected by the change in the outside air temperature. An injection molding die having a thermocouple. 2. A thermocouple (3) has a temperature detecting section (3).
The adhesive tape (21) was attached to the outer wall surface of the mold (M) with the adhesive tape (21) sandwiched between the outer wall surface of the mold (M) and the adhesive tape (21). An injection molding die having a thermocouple according to claim 1. 3. A thermocouple (3) has a temperature detecting section (3).
a) is embedded in a mounting plate (31) with a part thereof exposed from at least the back surface, and the mounting plate (31) is mounted on the outer wall surface of the mold (M) by screwing. A mold for injection molding having a thermocouple according to claim 1. 4. The thermocouple (3) has a temperature detecting section (3).
It was attached by screwing the holding plate (41) to the outer wall surface of the mold (M) while sandwiching a) between the outer wall surface of the mold (M) and the holding plate (41). An injection molding die having a thermocouple according to claim 1. 5. An injection molding die (M) having a thermocouple according to any one of claims 1 to 4, and an A / which converts a detection value detected by the thermocouple (3) into a digital signal.
The digital signal sent from the D converter (2) and the A / D converter (2) is sampled based on the timing signal sent from the sequence controller (9) and stored as a sampled value. An injection molding die temperature measuring device, comprising: an arithmetic processing unit (1) for converting a sampling value into a numerical value or a graph and outputting a display signal for displaying on a display (4).