JPH0471811A - Method for setting curing time of thermosetting resin molding - Google Patents

Abstract

PURPOSE:To easily and surely set the practically curing time in actual molding of thermosetting resin by a method wherein the setting time is set on the basis of the time, until which the change of the propagation velocity of supersonic wave in the thermosetting resin in a mold becomes constant. CONSTITUTION:A supersonic testing device 3 is provided in the mold 2 of a molding equipment 1 so as to emit supersonic wave in the mold 2 at the molding of thermosetting resin and, at the same time, measure the change of the propagation velocity of supersonic wave in the thermosetting resin in the mold 2. The setting time is set on the basis of the time until the change of said propagation velocity becomes constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for setting the curing time of a thermosetting resin in thermosetting resin molding.

(Prior Art) Generally, in thermosetting resin molding, the curing time of the thermosetting resin is examined based on the gelation time. That is, in actual molding, the curing time is set in advance to be longer than the gelling time, and after the thermosetting resin has reliably hardened, the molded product is taken out from the mold. Then, when aiming to improve productivity, this curing time is gradually shortened for each molding, and finally the curing time is shortened to a point where there is no problem with molding.In this way, conventional methods Based on the gelation time, the curing time was shortened based on experience in actual molding, and the curing time was set to avoid waste.

(Problem to be Solved by the Invention) However, since the gelation time is a table test, there is a large difference from actual molding conditions (temperature, pressure, etc.). Furthermore, in actual molding, depending on the wall thickness and shape of the molded product, it may not harden during the gelation time. Furthermore, since fillers, reinforcing materials, and the like are added to the thermosetting resin, it is difficult to express the curing time based on the gelation time of the thermosetting resin alone. In addition, the curing time of thermosetting resins changes depending on the molding temperature. Due to these problems, it is difficult to determine an efficient curing time based on the gelation time, and there is a problem that molding defects are likely to occur.

The present invention has been made in view of the above circumstances, and is capable of easily and reliably setting an efficient curing time in actual molding of a thermosetting resin. The purpose is to provide a configuration method.

(Means for Solving the Problems) The method for setting the curing time in thermosetting resin molding of the present invention includes heating and compressing the thermosetting resin in a mold.
A method of setting the curing time of the thermosetting resin in a molding method for curing the thermosetting resin into a desired shape, the method includes transmitting ultrasonic waves into a mold and curing the thermosetting resin within the mold. The curing time is set by measuring the change in the propagation speed of the ultrasonic waves propagating through the plastic resin, and setting the curing time based on the time it takes for the change in the propagation speed to become constant.

(Function) By heating and compressing the thermosetting resin within a mold, the thermosetting resin is cured into a desired shape.

Then, while transmitting ultrasonic waves into the mold, changes in the propagation speed of the ultrasonic waves propagating through the thermosetting resin within the mold are measured. At this time, the propagation speed of the ultrasonic wave changes as the resin hardens, and becomes constant after hardening. Therefore, by setting the curing time based on the time it takes for this propagation speed to become constant, that is, the time it takes for the resin to reach a hardened state, we can ensure that the thermosetting resin is cured without waste. A time will be set.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows the overall configuration of a molding apparatus 1 used in the present invention.

That is, this molding apparatus 1 includes a mold 2 and an ultrasonic inspection device 3, which transmits ultrasonic waves into the mold 2 and inspects the cough mold 2 during molding of thermosetting resin. The change in the propagation velocity of the ultrasonic waves propagating through the thermosetting resin inside the thermosetting resin is measured, and the curing time of the thermosetting resin is set based on this.

The mold 2 is closed with an ejector plate 23 interposed between a lower mold 21 and an upper mold 22, so that a cavity 24 is formed inside thereof. This mold 2 is
It is used by heating and compressing a thermoplastic resin molding material in the cavity 24 between surface plates 4 of a compression molding machine (not shown).

The ultrasonic inspection device 3 includes an ultrasonic probe 31, an ultrasonic flaw detector 32, and a differentiator 33.

The ultrasonic probe 31 is a sensor that transmits and receives ultrasonic waves, and is provided at the bottom of the lower mold 21 with its ultrasonic wave transmitting and receiving surface facing toward the cavity 24 .

The ultrasonic flaw detector 32 is configured to transmit ultrasonic waves via the ultrasonic probe 31 and receive the reflected waves.

The differentiator 33 is configured to differentiate the propagation velocity of the reflected wave obtained by the ultrasonic flaw detector 32 and detect the time when the differential value becomes 04.

The molding apparatus 1 configured as described above is configured to set the curing time based on the time required until the differential value of the differentiator 33 becomes 0.

Next, a molding method using this molding apparatus 1 will be explained.

First, a thermoplastic resin molding material is placed in the cavity 24 and is heated and compressed between the surface plates 4 and 4 of a compression molding machine (not shown). Then, the molding material stripes are heated in the mold 2 and become fluid, and spread throughout the cavity 24, causing a chemical reaction and beginning to harden.

At the same time, the ultrasonic probe 3 is sent from the ultrasonic flaw detector 32.
1, an ultrasonic wave of 5 M)lz is transmitted at a frequency of 2 KHz, and its reflected wave is detected. Then, the propagation speed of the ultrasonic waves propagating through the molding material inside the cavity 24 is measured.

At this time, as shown in FIG. 2, the emitted wave 10 from the clam sonic probe 31 is received as reflected waves 11 and 12 if no molding material has entered the cavity 24. Further, when the molding material is contained in the cavity 24, a reflected wave 13 passing through the molding material appears between the reflected waves 11 and 12, as shown in FIG.

This reflected wave 13 appears at a certain delay time 14 from the reflected wave 11, and this delay time 14 changes with curing. That is, the propagation speed of the reflected wave 13 at this time changes as the molding material hardens, and remains constant in the hardened state, as shown in FIG.

Then, a differentiator 33 differentiates this change in propagation velocity. Then, as shown in FIG. 5, the time required for the differential value to reach O, that is, the time required for the molding material to reach a hardened state, can be determined. Then, a curing time is set based on the time it takes to reach this hardened state, and when this hardening time is reached, the mold 2 is opened and the molded product is taken out.

As a result, a molded article that is reliably cured can be obtained without wasting curing time.

Note that the frequency of the transmitted ultrasonic waves is not particularly limited as long as reflected waves can be received. Further, in this embodiment, the change in the propagation velocity of the reflected wave 13 is differentiated, but when the change in the delay time 14 is differentiated, the differential value is O
You may also calculate the time required until .

(Effects of the Invention) As described above, according to the present invention, an efficient curing time is set in which the thermosetting resin is reliably cured, so molded products can be efficiently manufactured in actual molding. be able to. Furthermore, since the cured state of the molded article can be determined by the propagation velocity of the ultrasonic waves, the molded article can be obtained in a reliable cured state without causing molding defects.

[Brief explanation of drawings]

Figures 1 to 5 are drawings according to the present invention, in which Figure 1 is an overall configuration diagram showing an outline of the overall configuration of the molding device, and Figure 2 is a case in which there is no molding material in the mold. Figure 3 is a waveform diagram of ultrasonic waves obtained when there is molding material in the mold, Figure 4 is a graph showing changes in delay time as molding time elapses, FIG. 5 is a graph obtained by differentiating FIG. 4. 1 A 2... Mold patent distributor Sekisui Chemical Co., Ltd. Representative Hiroshi 1) Kaoru Figure 2 Figure 3! Figure 4

Claims (1)

[Claims] 1) In a molding method in which the thermosetting resin is cured into a desired shape by heating and compressing the thermosetting resin in a mold, the curing time of the thermosetting resin is set. The method includes transmitting ultrasonic waves into a mold, measuring changes in the propagation speed of the ultrasonic waves propagating through a thermosetting resin in the mold, and measuring the change in the propagation speed until the change in propagation speed becomes constant. A method for setting a curing time in thermosetting resin molding, the method comprising setting the curing time based on the time of .