JPH07112447A - Forming of heat-setting resin - Google Patents

Abstract

PURPOSE:To prevent the variation of dimensional precision or mechanical strength, and flash from being produced by a method wherein a heat-setting resin material is fed in a mold, and the mold is closed to a first position, and after the mold is claamped to a second position while heating the mold, and then, the mold is opened to a third position, and the mold is cooled, and a molded article is taken out. CONSTITUTION:First, the powder of a heat-setting resin material 10 is fed in a cavity 20 of a mold, and an upper force member 22 of the mold is closed to a first specified position to compress the powder, and thus, a compressed body with a uniform density is obtained. By heating the mold under this condition, the powder is molten, and following the volume decrease resulting from the melting, the upper force member 22 is closed to a second specified position. Then, when the heat-setting resin material 10 is further heated, volume expansion generates compared to the condition right after the melting, and at the same time, the viscosity temporarily decreases. For these reasons, the mold is opened to a third specified position so that the resin which overflow from the cavity 20 may be prevented from entering a joined part of the mold. Under this condition, the resin is heat-set, and then, the mold is cooled and opened, and a molded article is taken out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a thermosetting resin.

[0002]

2. Description of the Related Art Conventionally, a thermosetting resin material such as phenol is molded by heating a mold to a resin curing temperature with a rod-shaped heater provided in the mold in advance and then molding the resin in the heated mold. A method has been adopted in which the material is supplied, the mold is completely closed, and after holding for a predetermined curing time, the mold is opened and taken out.
This method is generally called a compression molding method.

In general, thermosetting resins change from solid to liquid as the temperature changes from low temperature to high temperature.
And after becoming a liquid, the viscosity once goes from a high state to a low state, and it shows the characteristic that it cures when the temperature further rises. It is a method in which a mold is completely clamped by a predetermined force, is injected into a mold heated to a curing temperature by a rod-shaped heater in advance, is held for a certain curing time, and then the mold is opened to take out a molded product. This method is generally called an injection molding method.

[0004]

However, in the above-mentioned conventional compression molding method, since the resin material is supplied into the mold already heated to the curing temperature of the resin, the mold is contacted at the time of supplying the material. The curing of the resin has already started from the part, and the resin is compressed by the mold in the state where the curing is partially progressing in this way, so the curing reaction unevenness occurs in the molded product, and the dimensional accuracy and mechanical strength vary. There was a problem.

Further, in the conventional injection molding method, pressure is applied while the mold is completely closed while the viscosity of the resin material is low, so that the mold fitting part and the mold degassing part have a low viscosity. Resin material enters. Then, there is a problem that the resin that has entered causes a curing reaction and is molded as a burr.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a method for molding a thermosetting resin which has high dimensional accuracy and mechanical strength and is less likely to form burrs. To do.

[0007]

In order to solve the above-mentioned problems and to achieve the object, a method of molding a thermosetting resin of the present invention is a mold having a cavity processed into a desired shape. A first step of supplying a thermosetting resin material powder,
A second step of closing the mold to a first predetermined position, and a third step of closing the mold further to a second predetermined position while heating the mold by a heating means provided in the mold. Process, a fourth process of heating the mold to open the mold to a third predetermined position, a fifth process of cooling the mold, and a sixth process of opening the mold. And a seventh step of taking out the molded product from the mold.

Further, in the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are P (pressure) -V of the thermosetting resin material measured in advance.
It is characterized in that it is set based on the (volume) -T (temperature) characteristic.

Further, in the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are based on an output of a resin viscosity measuring sensor provided in the mold. It is characterized by being set.

Further, in the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are based on the output of the resin pressure measuring sensor provided in the mold. It is characterized by being set.

Further, the thermosetting resin molding method according to the present invention is characterized in that the heating means is a high-frequency circuit provided in a mold.

Further, in the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are preliminarily measured T (temperature) -ν (viscosity) of the thermosetting resin. It is characterized by being set based on the characteristics.

Further, the thermosetting resin molding method according to the present invention is characterized in that the opening / closing operation of the mold is speed-controlled.

Further, the thermosetting resin molding method of the present invention comprises a first step of supplying powder of the thermosetting resin material into a mold having a cavity processed into a desired shape,
While heating the mold by a second step of closing the mold to a first predetermined position, a third step of decompressing the inside of the mold, and a heating means provided in the mold, A fourth step of further closing the mold to a second predetermined position, a fifth step of heating the mold to a third predetermined position while heating the mold, and a sixth step of cooling the mold. Step, seventh step of opening the mold, and eighth step of removing a molded product from the mold
And the steps of.

Further, in the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are P (pressure) -V of the thermosetting resin material measured in advance.
It is characterized in that it is set based on the (volume) -T (temperature) characteristic.

Further, in the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are based on an output of a resin viscosity measuring sensor provided in the mold. It is characterized by being set.

Further, in the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are based on the output of the resin pressure measuring sensor provided in the mold. It is characterized by being set.

Further, in the method for molding a thermosetting resin according to the present invention, the heating means is a high frequency circuit provided in a mold.

In the thermosetting resin molding method according to the present invention, the first, second and third predetermined positions are T (temperature) -ν (viscosity) of the thermosetting resin measured in advance. It is characterized by being set based on the characteristics.

Further, the thermosetting resin molding method according to the present invention is characterized in that the opening / closing operation of the mold is speed-controlled.

[0021]

As described above, since the thermosetting resin molding method according to the present invention is configured, it functions as follows.
That is, first, the powder of the heat-effective resin is supplied into the cavity of the mold, the mold is closed to the first predetermined position, and the powder is compressed to form a compressed body of powder having a uniform density. obtain.
By heating the mold in this state, the powder is melted, and the mold is further closed to the second position in accordance with the volume decrease accompanying the melting. When the thermosetting resin is further heated, volume expansion occurs compared to the state immediately after melting, and the viscosity temporarily decreases, so the resin that expands and overflows from the cavity enters the mold matching part. Open the mold to a third position to prevent this. In this state, the resin is heated and cured, and then the mold is cooled. Then, the mold is opened and the molded product is taken out from the mold.

By carrying out the molding step of heating the mold after supplying the material to the mold in this way, the curing reaction at the time of supplying the material as in the conventional case does not occur, and the partial curing reaction unevenness of the thermosetting resin It is possible to prevent variations in dimensional accuracy and mechanical strength due to. Further, since the mold is opened to the third position as the resin material expands, the resin is prevented from entering the mold matching portion, and burr is prevented from occurring.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the structure of a molding apparatus 8 to which a molding method according to an embodiment of the present invention is applied. Further, FIG. 1 shows a state in which a resin material 10 is filled in a cavity 20 between an upper mold member 22 and a lower mold member 16, which will be described later.

In FIG. 1, a lower die member 16 is arranged on a base 12 via a hydraulic cylinder 14. The lower mold member 16 is formed in a cylindrical shape whose bottom is closed by a bottom plate portion 18, and the inside of the cylinder is defined as a cavity 20 for molding the thermosetting resin material 10. Above the lower mold member 16, an upper mold member 22a having a fitting portion 22a fitted to the inner peripheral surface of the cavity 20 is arranged. The upper mold member 22 is the lower mold member 1
By moving up and down with respect to 6, the volume of the cavity 20 defined by the lower surface of the fitting portion 22a and the upper surface of the bottom plate portion 18 can be changed. The drive device 24 for moving the upper mold member 22 up and down is provided with the flange portion 2 of the upper mold member 22.
It is connected to the upper part of 2b.

Inside the upper mold member 22 and the lower mold member 16, heaters 26 and 28 (for example, nichrome wire heater or high frequency heating coil) for heating these molds are provided. A mold temperature sensor 30 for detecting the temperature of the mold is provided inside the upper mold member 22. Further, a resin pressure detection sensor 32 for detecting the pressure of the resin material 10 in the cavity 20 and a resin viscosity detection sensor 34 for detecting the viscosity of the resin material 10 are arranged on the bottom plate portion 18 of the lower mold member 16. ing.

A plurality of through holes are formed in the bottom plate portion 18 of the lower mold member 16, and a push-up rod 36 for pushing up the completed molded product (10) is slidably fitted in the through holes. I am fit. The push-up rod 36 is fixed to the piston 14a of the hydraulic cylinder 14 in a vertically directed state, and pushes up the molded product (10) as the piston 14a moves up and down by the operation of the hydraulic cylinder 14.

The drive device 24 for the upper mold member 22 is connected to a control device 38 for controlling the drive distance and drive speed of the drive device. Further, the heaters 26, 28 and the mold temperature sensor 30 are connected to a control device 40 for controlling the overall operation of the molding device 8. The resin pressure detection sensor 32 and the resin viscosity detection sensor 34 are connected to the control device 40 via amplifiers 42 and 44 for amplifying the outputs thereof, respectively. The control device 40 is also connected to the control device 38 of the drive device 24 described above. Further, the control device 40 has a physical property value of the thermosetting resin material 10 to be molded, specifically, P (pressure) -V of the material.
(Volume) -T (temperature) characteristics and T (temperature) -ν of material
A storage device 46 that stores (viscosity) characteristics and the like is connected.

With such a configuration, the control device 40 controls the entire molding device 8 based on the outputs of the respective sensors, the physical properties of the resin material, and the preset mold opening / closing position data and mold moving speed data. Control movements.

Next, FIG. 2 is a diagram showing the procedure of the molding method of one embodiment, and FIG. 3 is a flowchart thereof. The procedure of the molding method will be described with reference to FIGS. 2 and 3.

First, in step S2, as shown in FIG. 2 (a), the upper mold member 22 is retracted upward from the lower mold member 16, and the thermosetting resin material 10,
Specifically, a supply device 4 for powder such as phenol resin material
Supply by 8. When the supply of the resin material into the cavity 20 is completed, a material supply completion signal is sent to the control device 40. When the controller 40 receives the material supply completion signal, the controller 40 reads the first mold clamping position data input in advance in the storage device 46 and sends it to the controller 38. First
The mold clamping position data of is obtained by searching the best position data by trial and error in advance. The reason why the upper mold member 22 is lowered to the first mold clamping position is to compress the powder of the resin material 10 supplied into the cavity 20 into a green compact having a constant density.

Next, in step S4, as shown in FIG. 2B, the upper mold member 22 is lowered to the first mold clamping position to compress the resin material 10 in the cavity 20. In this state, the flange portion 22b of the upper mold member 22 and the lower mold member 16 are not completely in close contact with each other, and a gap indicated by a in the drawing is left. When the upper mold member 22 descends to the first mold clamping position,
A signal from the control device 38 is sent to the control device 40 informing that the movement of the upper mold member 22 is completed.

When the control device 40 receives the movement end signal of the upper mold member 22, the heater 26,
28 is energized to start heating the upper mold member 22 and the lower mold member 16. When this heating is started, a timer in the control device 40 is activated and waits until a preset time T1 elapses. This time T1 is the time until the mold temperature is evenly transmitted to the resin material 10 and the resin material begins to melt. Further, the heaters 26 and 28 are controlled by the control device 40 based on the output value of the mold temperature sensor 30 so that the mold temperature is maintained at the temperature set by the control device 40. When the time T1 has elapsed, the control device 40 controls the drive device 24 to lower the upper mold member 22 to a preset second mold clamping position, as shown in FIG. 2 (c). Second
When the upper mold member 22 is lowered to the mold clamping position of
The flange portion 22b and the lower mold member 16 are in close contact with each other, and the distance indicated by b in the figure is substantially zero. The reason why the upper mold member 22 is lowered to the second mold clamping position in this way is to follow the volume decrease of the resin material due to the melting of the resin material 10 and the change from powder to liquid. At the second mold clamping position, the output of the resin pressure detection sensor 32, the output of the mold temperature sensor 30, and the P (pressure) -V (volume) -T (of the resin material stored in the storage device 46 are stored. The volume V of the resin material is obtained from the (temperature) characteristic and is calculated by the control device 40 so as to correspond to the volume. At this time, the molten resin material is prevented from entering the mold-matching portions of the upper mold member 22 and the lower mold member 16 to form burrs, and the pressure P of the resin material is not excessively increased (preferably the pressure is low). like)
Set the second mold clamping position. When the viscosity of the resin material is low, the resin material is more likely to enter the mold matching portion, so the pressure P of the resin material is T (temperature) of the resin material.
It is also set with reference to the value of the viscosity ν of the resin material, which is obtained from the −ν (viscosity) characteristic. That is, the pressure P is set to be small when the viscosity ν is low. The control of the pressure P is performed by controlling the descending speed of the upper mold member 22 by the control device 38. The viscosity ν may be directly measured by the resin viscosity sensor 34.

Next, after a preset time elapses after the resin material starts to melt, or after the output value of the resin viscosity detecting sensor 34 reaches the set viscosity, step S8.
Then, the first mold opening position data of the upper mold member 22, which is input in advance from the control device 40, is sent to the control device 38. Then, as shown in FIG.
Controls the drive unit 24 to raise the upper mold member 22 to the first mold open position. When the upper mold member 22 is raised to the first mold opening position, the flange portion 22b and the lower mold member 16 are spaced apart by the distance indicated by c in the drawing. Here, the reason why the upper mold member 22 is raised to the first mold opening position is to follow the volume expansion accompanying the heat curing of the resin material 10. If this step, the upper mold member 2
If 2 is not raised, a part of the expanded resin material 10 will enter the mold matching portion of the upper mold member 22 and the lower mold member 16 and generate burrs. Therefore, in this step, the mold can be opened to the first mold opening position to prevent the occurrence of burrs. The first mold opening position is the output of the resin pressure detection sensor 32, the output of the mold temperature sensor 30, and the P (pressure) -V (volume) of the resin material stored in the storage device 46. The volume V of the resin material is obtained from the T (temperature) characteristic and calculated by the control device 40 so as to correspond to the volume. Also, the upper mold member 2
The rising speed of 2 is controlled by the control device 38 so that the pressure P of the resin material does not exceed a predetermined pressure value.

When the movement to the first mold opening position is completed, a signal is sent from the control device 38 to the control device 40. When the signal is sent, the control device 40 holds it for a preset time, and then outputs a heater OFF signal at step S10 to turn off heating of the mold (upper mold member 22 and lower mold member 16).
F

After the heating of the mold is turned off, a signal is sent from the control device 40 to a mold cooling device (not shown), and a cooling medium (water or oil) is supplied to the mold in step S12 to cool the mold. To be done.

When the mold temperature sensor 30 detects that the mold has been cooled to a predetermined temperature, step S1
At 4, the controller 40 sends a signal to the controller 38 to raise the upper mold member 22 to the preset second mold opening position. When the signal is sent, the control device 38 controls the drive device 24 to raise the upper mold member 22 to the second mold open position as shown in FIG. The second mold opening position is a position where the molded product formed by curing the resin material 10 can be taken out.

When the upper die member 22 is raised to the second die opening position, the hydraulic cylinder 14 is operated in step S16, the push-up rod 36 is raised, and the product is taken out.

The molding of the thermosetting resin material is completed as described above.

As described above, in the molding method of the embodiment, since the resin material is heated after being supplied into the mold, the curing reaction does not occur at the time of supplying the material, Good molded products with little dimensional accuracy and mechanical strength variations can be obtained.

Further, since the mold is opened so as to follow the expansion of the resin when the resin is heated and cured, it is possible to prevent burrs caused by the resin expanding and protruding from the cavity.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus. Further, the present invention can be applied to a modified or modified version of the above embodiment without departing from the spirit of the invention.

[0043]

As described above, according to the method for molding a thermosetting resin material of the present invention, the following curing can be obtained. That is, first, the powder of the heat-effective resin is supplied into the cavity of the mold, the mold is closed to the first predetermined position, and the powder is compressed to form a compressed body of powder having a uniform density. obtain. By heating the mold in this state, the powder is melted, and the mold is further closed to the second position in accordance with the volume decrease accompanying the melting. When the thermosetting resin is further heated, volume expansion occurs compared to the state immediately after melting, and the viscosity temporarily decreases, so the resin that expands and overflows from the cavity enters the mold matching part. Open the mold to a third position to prevent this. In this state,
After the resin is heated and cured, the mold is cooled. Then, the mold is opened and the molded product is taken out from the mold.

By performing the molding step of heating the mold after supplying the material to the mold in this way, the curing reaction at the time of supplying the material unlike the conventional case does not occur, and the partial curing reaction unevenness of the thermosetting resin is caused. It is possible to prevent variations in dimensional accuracy and mechanical strength due to. Further, since the mold is opened to the third position as the resin material expands, the resin is prevented from entering the mold matching portion, and burr is prevented from occurring.

[Brief description of drawings]

FIG. 1 is a block diagram showing the structure of a molding apparatus to which a molding method according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a procedure of a molding method according to an embodiment.

FIG. 3 is a flowchart showing a procedure of a molding method according to an embodiment.

[Explanation of symbols]

 8 Molding Equipment 10 Resin Material 12 Base 14 Hydraulic Cylinder 16 Lower Mold Member 18 Bottom Plate Part 20 Cavity 22 Upper Mold Member 24 Drive Device 26, 28 Heater 30 Mold Temperature Sensor 32 Resin Pressure Sensing Sensor 34 Resin Viscosity Sensing Sensor 36 Push-up Rod 38,40 Control device 42,44 Amplifier 46 Storage device 48 Supply device

Claims (14)

[Claims] 1. A first mold for supplying powder of a thermosetting resin material into a mold having a cavity processed into a desired shape.
And a second step of closing the mold to a first predetermined position, while heating the mold by a heating means provided in the mold, the mold is further moved to a second predetermined position. Close until 3rd
And a fourth step of opening the mold to a third predetermined position while heating the mold, a fifth step of cooling the mold, and a sixth step of opening the mold. And a seventh step of taking out a molded product from the mold, the method of molding a thermosetting resin. 2. The first, second and third predetermined positions are P (pressure) -V of the thermosetting resin material measured in advance.
The method for molding a thermosetting resin according to claim 1, wherein the method is set based on the (volume) -T (temperature) characteristic. 3. The first, second and third predetermined positions are set based on an output of a resin viscosity measuring sensor provided in the mold. Molding method of thermosetting resin. 4. The first, second and third predetermined positions are set based on an output of a resin pressure measuring sensor provided in the mold. Molding method of thermosetting resin. 5. The method for molding a thermosetting resin according to claim 1, wherein the heating means is a high frequency circuit provided in a mold. 6. The first, second and third predetermined positions are set on the basis of a previously measured T (temperature) -ν (viscosity) characteristic of the thermosetting resin. Item 2. A method for molding a thermosetting resin according to Item 1. 7. The method of molding a thermosetting resin according to claim 1, wherein the opening / closing operation of the mold is controlled in speed. 8. A first supply of powder of thermosetting resin material into a mold having a cavity processed into a desired shape.
Step, a second step of closing the mold to a first predetermined position, a third step of depressurizing the mold, and a heating means provided in the mold to heat the mold. While closing the mold to a second predetermined position while
And a fifth step of opening the mold to a third predetermined position while heating the mold, a sixth step of cooling the mold, and a seventh step of opening the mold. And an eighth step of taking out a molded product from the mold, the method for molding a thermosetting resin. 9. The first, second and third predetermined positions are P (pressure) -V of the thermosetting resin material measured in advance.
The thermosetting resin molding method according to claim 8, wherein the thermosetting resin is set based on a (volume) -T (temperature) characteristic. 10. The first, second and third predetermined positions are set based on the output of a resin viscosity measuring sensor provided in the mold. Molding method of thermosetting resin. 11. The first, second and third predetermined positions are set based on an output of a resin pressure measuring sensor provided in the mold. Molding method of thermosetting resin. 12. The method of molding a thermosetting resin according to claim 8, wherein the heating means is a high frequency circuit provided in a mold. 13. The first, second and third predetermined positions are set on the basis of a previously measured T (temperature) -ν (viscosity) characteristic of the thermosetting resin. Item 9. A method for molding a thermosetting resin according to Item 8. 14. The method of molding a thermosetting resin according to claim 8, wherein the opening / closing operation of the mold is controlled in speed.