JP2000141374A - Equipment for dynamically measuring pressure, specific volume and temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to realize the dynamical measurements of a pressure, a specific volume and a temperature close to actual phenomena by a method wherein a heating device, a cooling device, which can control a cooling rate, sensors respectively measuring the temperature and pressure of a resin and the displacement measuring sensor of the thickness of a cavity part are equipped in molds, the form part of a top mold between which fits in the form part of the bottom mold. SOLUTION: After desired measuring data set is set, the weight of a sample, which is desired to be metered, is imputted and a metered sample is put in a bottom mold, a top mold and the bottom mold are closed together with a pressing device 2 and then the sample is melted by being heated up to a set temperature with a heating panel. The melted resin in a cavity part is pressed with a hydraulic unit 41 up to a set pressure so as to deaerate the top and bottom molds by pumping in order to remove bubbles in the melted resin and air layer between resins. After that, the resin in re-pressed up to a set pressure and held for several seconds in order to reset a displacement sensor to zero at the stage that a temperature T and a pressure P become constant values. The resin is cooled down at a set cooling rate under the condition that P is kept constant so as to measure the change of the state of the resin during the period until the resin reaches the normal temperature with respective T-, P- and displacement-sensors. Thus, the dynamical measurement of a P-specific volume-T close to actual phenomena can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PvT dynamic measurement device.

[0002]

2. Description of the Related Art In molding a resin molded product, it is necessary to grasp molding characteristics of each resin used. Therefore, as a method for grasping the molding characteristics of the resin, there is a method of measuring in advance the temporal behavior of P (pressure), v (specific volume), and T (temperature) inside the resin.

As an apparatus for measuring such PvT, a PvT measuring apparatus 100 as shown in FIG. 14 has already been proposed (see Japanese Patent Application Laid-Open No. Hei 5-164594).
That is, the measuring device 100 is
The liquid 300 is filled around the resin 200 in the
02 is shut off, the volume of the cavity 101 is kept constant, the temperature of the resin 200 is changed, and the pressure of the resin 200 is measured via the liquid 300.

However, in the case of this measuring device 100, since it is an air-cooled cooling system, even in MAX, it is 30 ° C. /
Since cooling can be performed only at a cooling rate of about min and the cooling rate cannot be changed during the measurement, there are the following problems. That is, in ordinary resin molding, since the mold is cooled with water, the cooling rate is 200 ° C.
/ Min in some cases. When the cooling rate is different, particularly in the case of crystalline resin, the crystallization behavior is different depending on the cooling rate, so that the amount of shrinkage is different and the PvT curve is also shifted in the horizontal direction. For this reason, in data measured in a state different from the actual change in specific volume, unlike an actual phenomenon, a large error occurs in a calculation for estimating a contraction amount.

In actual molding, the cooling rates are different (the cooling rate is high in the temperature-lowering area, but low in the low-temperature area), but the cooling rate cannot be changed by the conventional measuring method, so that the cooling rate changes. PvT in such a process
Can not measure changes.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a PvT dynamic measurement device capable of realizing a PvT dynamic measurement close to an actual phenomenon in view of such circumstances.

[0007]

In order to achieve such an object, a dynamic PvT measuring apparatus according to the present invention is capable of simultaneously measuring the pressure, specific volume and temperature inside a resin during molding. Mechanical measuring device, a press device having a mold in which the upper mold part fits into the lower mold part, a heating device for the mold, a cooling device for the mold that can control the cooling rate, The temperature sensor measures the temperature of the resin in the mold, the pressure sensor measures the pressure of the resin in the mold, and the displacement sensor measures the displacement of the thickness of the cavity.

[0008] Further, the dynamic PvT measuring apparatus of the present invention comprises:
The cooling device is capable of cooling at a cooling rate of 100 ° C./min or more, and the cooling device is optional in a range of 0.01 ° C./min to 200 ° C./min. It is preferable that the cooling device be capable of cooling at a cooling rate according to a cooling profile along an assumed pattern of resin molding.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 and FIG.
1 shows an embodiment of a PvT dynamic measurement device (hereinafter, simply referred to as “measurement device”) according to the present invention.

As shown in FIGS. 1 and 2, the measuring device 1 includes a pressing device 2, a cooling device 3, and a control device 6. As shown in FIGS. 1 to 3, the press device 2 includes a device main body 4 and a mold 5.

The apparatus main body 4 includes a hydraulic unit 41, an upper press unit 42, and a lower press unit 43. The upper press unit 42 includes the upper press plate 4
2a, a press plate cooling plate 42b, a heating plate 42c, and a mold cooling plate 42d are integrally provided, and four columnar columns (only two are shown in the figure) 42e on the base 44. Is fixed at a predetermined height.

The lower press unit 43 integrally includes a lower press plate 43a, a press plate cooling plate 43b, a heating plate 43c, and a die cooling plate 43d, and is moved up and down by the hydraulic unit 41 toward the upper press unit 42. It has become. The hydraulic unit 41 includes a hydraulic pump 41a and a cylinder 41b.
1a moves the lower press unit 43 up and down by moving the cylinder 41b up and down under the control of the control device 6, and applies a pressure of 2000 kg / cm ² or more between the upper and lower dies 51 and 52 of the mold 4 described later. Is available.

The mold 5 includes an upper mold 51 and a lower mold 52,
The upper mold 51 is fixed to the upper press unit 42 along the mold cooling board 42d, and the lower mold 52 is fixed to the lower press unit 43 along the mold cooling board 43d.
As shown in FIG. 3, the upper die 51 has a convex portion 51a, which fits into the concave portion 52a of the lower die 52, and has a flat cavity portion 7 having a predetermined thickness. Is formed.

As shown in FIG. 4, the lower mold 52 is
A cooling flow channel 52b for a cooling liquid is provided inside so as to surround 2a. Further, the mold 5 is not shown,
A pressure sensor for the resin in the cavity 7, a temperature sensor for the resin in the cavity 7, and a displacement sensor for the thickness of the cavity 7 (a gap between the bottom surface of the concave portion 52 a and the convex portion 51 a) are provided therein. I have.

The press plate cooling plates 42b and 43b are
Although not shown, a flow path is provided inside, and a cooling liquid sent from a cooling device 3 described later is always passed through the flow path, so that heat from the heating plates 42 c and 43 c is transferred to the upper press plate 42.
a or the lower press plate 43a. The heating plates 42c and 43c are provided with a heating wire 45 and a temperature sensor therein. When the heating plates 42c and 43c are energized, the heating wire 45 generates heat, so that the upper mold 51 or the lower mold 52 can be heated.

The mold cooling boards 42d and 43d are controlled by a cooling liquid sent from a cooling device 3 which will be described later.
The upper mold 51 or the lower mold 52 can be cooled. Further, the press device 2 includes a position sensor 47 for measuring a distance between the upper press plate 42a and the lower press plate 43a.

The cooling device 3 includes a cooling water tank 31, a cooling water pumping device 32, and a piping device 33. Although not shown, the cooling water tank 31 includes a supply pipe for tap water, a drain pipe, and a cooler.
And is connected to the cooling water pumping device 32 via.

The cooling water pumping device 32 can send the cooling water supplied from the cooling water tank 31 to the piping device 33 at a flow rate of 20 liter / min or more so that a cooling rate of 200 ° C./min can be achieved. It has become. The piping device 33 can branch the pressurized cooling water by the branch pipe 35 and supply it to the upper mold 51, the lower mold 52, and both the mold cooling boards 42d and 43d, and also cool the upper mold 51, the lower mold 52, and the both molds. Board 4
After the return water passing through 2d and 43d is merged, it is returned to the cooling water tank 31.

Each branch pipe 35 is provided with an electromagnetic valve 36 whose ON / OFF control is performed by the control device 6 described later. That is, the cooling rate can be controlled in the range of 0.01 ° C./min to 200 ° C./min by opening and closing the solenoid valve 36 and adjusting the flow rate.

Although not shown, each branch pipe 35 is provided between the upper mold 51, the lower mold 52, and both the mold cooling boards 42d and 43d above the solenoid valve 36 via the branch pipe 35. Type 5
1, a lower die 52, and a pumping air supply pipe for sending pumping air to cooling water passages of both mold cooling boards 42d and 43d. That is, if water remains in the mold cooling boards 42d and 43d and the cooling water passage 52b of the lower mold 52, the heating boards 42c and 43
At the time of heating by (c), the water may evaporate and heating may not be performed as set. Therefore, the water in the cooling water passage can be removed in advance by the compressed air before heating.

The control device 6 is capable of setting the temperature and pressure at the time of pressing. The control device 6 has various information measured by the temperature, pressure and position sensors installed in the pressing device 2 and the mold 5. Each information of the temperature / pressure / displacement sensor provided in the control unit is calculated by the measurement data calculation unit 62 to control the temperature and pressure as set. That is, when the temperature is not as set, the solenoid valve 36 of the piping device 33 is ON-OFF controlled to supply cooling water to the upper mold 51, the lower mold 52, and both mold cooling boards 42d and 43d for cooling. In addition, the heating wire 42 of the heating panels 42c and 43c is energized to heat the heating panels 42c and 43c to heat the mold 5 so that the temperature is set as set. Also,
On the way, the cooling rate can be freely changed.

On the other hand, if the pressure is not as set, the hydraulic pump 41a is operated to push up the cylinder 41b upward so that the pressure is set as set. Also,
The control device 6 calculates the specific volume at each temperature and pressure from the thickness of the cavity 7 measured by the position sensor 47 and the displacement sensor.

The temperature and specific volume changes at each pressure are as follows:
It can be displayed on a display of a personal computer 63 as a display device. Next, the operation of measuring PvT using the measuring device 1 will be described in detail with reference to FIG.

(1) Set a data set to be measured,
Input the weight of the sample (pellet or powder resin material) to be measured. (2) Place the weighed sample in the lower mold 52. (3) Activate the press device 2 to move the upper die 51 and the lower die 52
And close. (4) The heating wires 45 of the heating panels 42c and 43c are energized to heat to the set heating temperature, thereby melting the sample. (5) Activate the hydraulic unit 41 and move the cavity 7
The molten resin inside is pressurized to the set pressure. (6) The upper and lower molds 51 and 52 are pumped and degassed to remove bubbles existing in the molten resin and an air layer between the resins. (7) Re-pressurize to the set pressure, hold it for several seconds, and reset the displacement sensor to zero when the temperature and pressure become constant. (8) From this state, the temperature is cooled with cooling water while keeping the pressure constant, and the temperature is controlled so that the cooling rate at that time is as set. (9) A change in the state of the resin until the resin is cooled to room temperature by this operation is monitored by a temperature sensor, a pressure sensor, and a displacement sensor. When the pressure measured by the pressure sensor is not as set, the control device 6 operates the hydraulic unit 41 to repressurize the pressure to the set pressure. If the temperature measured by the temperature sensor is not as set, the control device 6 turns the solenoid valve 36 ON-OF.
F control is performed to correct the cooling rate as set. (10) The measured values detected by each sensor are processed by the arithmetic processing unit and then displayed on the display of the personal computer 63.

The specific volume v (unit: g / cm^Three) The tree
The volume (area x height) of the area filled with fat,
That is, the concave portion 52a of the lower die 52 measured by the displacement sensor
Clearance L (cm) between bottom surface and convex portion 51a of upper mold 51, concave mold
The area A (cm) of the bottom surface of the portion 52a ^Two), Filled resin weight
When the amount is M (g), it is calculated by v = M / (LA)
Value.

Since the measuring apparatus 1 is configured as described above, it can measure PvT at a cooling rate (200 ° C./min) close to an actual phenomenon. Therefore, the accuracy of estimating the amount of shrinkage of the resin is increased, which helps to process a molded article with high dimensional accuracy. Also, as shown in FIG. 6, even at a low cooling rate of 30 ° C./min, as shown in FIG. 7, even at a medium cooling rate of 70 ° C./min, as shown in FIG. PvT can be measured at a cooling rate such as speed, and CAE
(Computer aided engineering) and the like, and the accuracy of the prediction formula used in computer aided engineering and the like, and the prediction accuracy of deformation analysis and the like increase.

Further, as shown in FIGS. 9 to 11, PvT can be measured by changing the cooling rate in multiple stages, an ideal cooling rate change can be set, and a molded product with higher dimensional accuracy can be obtained. it can. In addition, as shown in FIG. 12, it is possible to measure PvT, which is held for a long time in a specific temperature range and in which crystallization characteristics are sufficiently considered. In addition, since the measuring device 1 not only measures the displacement by providing the position sensor 47 in the press device 2 itself, but also provides the displacement sensor in the mold 5, the expansion and contraction of the mold 5 is cut. In addition, the displacement can be measured with higher accuracy.

The dynamic measurement device for PvT according to the present invention comprises:
It is not limited to the above embodiment. For example, in the above embodiment, tap water is used as the refrigerant of the cooling device.However, instead of cooling water using tap water, low-temperature cooling water or lubricating oil using a chiller may be used. It is possible.

Conversely, in order to achieve a low cooling rate such as 0.01 ° C./min or an arbitrary cooling rate, the medium of the cooling water is changed or the flow rate is adjusted in advance, and the cooling at that time is performed. The cooling speed can be controlled at the time of measurement by measuring the speed in advance and setting it in a state suitable for an arbitrary cooling speed. For example, for slow cooling rates, lubricating oil may be used. Furthermore, when changing the cooling rate in multiple stages,
A plurality of cooling pumps or temperature controllers may be provided and switched by a piping device.

In the above embodiment, the cavity 7 has a flat plate shape. However, the cavity portion 7 may have a columnar shape or a cylindrical shape. The molded articles 8 and 9 to be obtained as shown in FIGS. 13A and 13B may be formed.

[0031]

Embodiments of the present invention will be described below in more detail.

(Example 1) PvT measurement was performed using the measuring apparatus 1 shown in FIG. 4 under the following conditions, and the results are shown in Table 1. -Type of resin: high-density polyethylene (HDPE)-Sample weight: 10 g-Shape of concave portion 52a: 50 mm x 50 mm flat plate-Set pressure: 20, 40, 60, 100, 160 MPa-Set temperature: 270 to 70 ° C Cooling rate: 10, 100, 200 ° C / min ・ Refrigerant: Water ・ Refrigerant temperature: 25 ° C ・ Refrigerant flow rate: 20 L / min ・ Cooling pipe diameter: 8mm

[Table 1] As shown in Table 1, from the measurement results, it was found that when the pressure was increased, the specific volume was decreased, and the crystallization temperature was shifted to a higher temperature side.

As described above, the dynamic PvT measuring apparatus according to the present invention is constructed as described above.
Dynamic measurement of vT can be enabled. Therefore, the accuracy of estimating the amount of shrinkage of the resin is increased, which helps to process a molded article with high dimensional accuracy. In addition, PvT under different cooling rates
Can be measured, the accuracy of the prediction formula used in CAE (computer aided engineering) or the like increases, and the prediction accuracy of deformation analysis or the like increases.

[Brief description of the drawings]

FIG. 1 is a schematic diagram schematically showing one embodiment of a dynamic PvT measuring apparatus according to the present invention.

FIG. 2 is a block diagram of the measuring device of FIG.

FIG. 3 is an enlarged sectional view of a press device portion of the measuring device of FIG.

FIG. 4 is a plan view showing a lower mold of the measuring device of FIG. 1;

FIG. 5 is a measurement flowchart of the measurement device of FIG. 1;

FIG. 6 shows a PvT at a low cooling rate using the measuring apparatus of FIG.
Is a graph representing.

FIG. 7 shows a PvT at a medium cooling rate using the measuring apparatus of FIG.
Is a graph representing.

FIG. 8 shows a PvT at a high cooling rate using the measuring apparatus of FIG.
Is a graph representing.

FIG. 9 shows Pv at the three-stage cooling rate using the measuring apparatus of FIG.
6 is a graph showing one example of T.

FIG. 10 shows P at a 5-stage cooling rate using the measuring apparatus of FIG.
It is a graph showing an example of vT.

FIG. 11 is a graph showing P at a five-stage cooling rate using the measuring apparatus of FIG. 1;
It is a graph showing another example of vT.

FIG. 12 shows P during long-term cooling measurement using the measurement apparatus of FIG.
It is a graph showing another example of vT.

FIG. 13 is a perspective view showing an example of the shape of a molded product.

FIG. 14 is a sectional view of a conventional PvT measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measuring device 3 Cooling device 5 Die 51 Upper mold 51a Convex part 52 Lower mold 52a Concave part 7 Cavity part 8, 9 Molded product

Continued on front page F term (reference) 2F051 AA12 AB02 AB06 AC04 AC09 4F202 AA05 AP03 AP05 AP11 AR08 CA09 CB01 CK90 CN01 CN05 4F204 AP03 AP05 AP11 AR08 FA01 FB01 FQ01 FQ15

Claims (4)

[Claims] 1. A PvT dynamic measuring device for simultaneously measuring the pressure, specific volume and temperature inside a resin during molding, wherein the upper mold has a mold fitted into the lower mold. A press device, a heating device for the mold, a cooling device for the mold with a controllable cooling rate, a temperature sensor for measuring the temperature of the resin in the mold, and a pressure sensor for measuring the pressure of the resin in the mold. And a displacement sensor for measuring a displacement of the thickness of the cavity portion. 2. The dynamic PvT measuring device according to claim 1, wherein the cooling device is capable of cooling at a cooling rate of 100 ° C./min or more. 3. The cooling device according to claim 1, wherein the cooling unit is 0.01 ° C./min to 200 ° C.
3. The dynamic PvT measuring apparatus according to claim 1, wherein the apparatus can be cooled at an arbitrary cooling rate in a range of min. 4. The dynamic PvT measuring apparatus according to claim 1, wherein the cooling device is capable of cooling with a cooling profile along an assumed pattern of resin molding.