JPH0314338Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method in which a temperature sensor is provided in an injection mold to control the cooling time and other factors of a synthetic resin injected into the mold.

[Prior art and its problems]

Conventionally, in most cases, the pressure holding time and cooling time of the resin filled in the cavity of the mold were preset by a timer. Although not in the technical field of injection molding, the invention described in Japanese Utility Model Publication No. 53-2609 provides a temperature detection element close to the mold surface as a control device for casting cooling time in mold casting.
A proposal has been made to determine the timing of mold opening based on the detection signal. The aim was to shorten casting cycle time and improve productivity.

[Problem to be solved]

In the former mold opening control using a timer, the resin cooling time within the cavity tends to be set longer than the minimum necessary time for safety. As a result, the injection cycle became longer, and productivity tended to deteriorate accordingly.

In addition, in mold casting, the method of embedding the temperature detection element 3 close to the mold surface requires opening a new hole in the mold and arranging the tip of the hole extremely close to the mold surface. Drilling holes requires extreme care. Otherwise, the mold may be wasted due to failure in drilling.

Furthermore, it is a very tedious and difficult process to accurately attach the small sensor to the bottom of the hole in the mold. Moreover, since the sensor is provided with a lead wire, it is extremely difficult to connect the sensor with the lead wire to the bottom of the hole and to accurately detect the temperature.

[Means to solve the problem]

Therefore, the purpose of the present invention is to provide a temperature sensor that can accurately detect the resin temperature in the mold cavity, and to provide a control device that allows the temperature sensor to be installed accurately and easily. has the following configuration.

That is, in a resin filling space of a molding die, an ejector pin 12 that forms part of the constituent surface of the space, is manufactured as a separate member from the mold body, and is necessary for the mold. Alternatively, the temperature sensor 1 is inserted into the tip of a pin such as the sukkah pin 10, and the lead wire 3 that connects the sensor 1 and a control section arranged outside the mold is inserted so that the inside of the pin is oriented in the axial direction. A control device for an injection molding machine, in which the pin is guided into a formed hole and led out from the rear end of the pin, and controls at least the cooling time of the resin in the mold according to the temperature detected by the sensor 1 or the temperature change thereof. It is.

[Effect]

According to this device, as an example, the ejector pin 1
2 is removed from the mold, the temperature sensor 1 is attached to the tip thereof, and the lead wire 3 is placed in the hole provided inside the ejector pin 12, and then the ejector pin 12 is inserted into the mold. Just do it. Then, since the tip end surface of the ejector pin 12 constitutes a part of the cavity, the temperature of the injected resin can be accurately detected.

[Example of idea]

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of a mold showing the main parts of this device. This mold is a three-plate mold with a so-called pinpoint gate.

That is, the movable side mounting plate 5 and the fixed side mounting plate 15
has an intermediate plate 6 between the intermediate plate 6 and the intermediate plate 6;
A runner groove 7 is formed in. Further, a runner kick plate 16 and a soccer pin 10 are provided on the dividing surface 9 of the runner mold attached to the fixed side attachment plate 15. This satsuka pin 1
0 has a pin with an enlarged head at its tip. Further, an ejector pin 12 is provided within the movable side mounting plate 5, and is configured to be freely removable and removable by a cylinder 17.

In the embodiments shown in FIGS. 1 and 3, the temperature sensor 1 is attached to the tip of the ejector pin 12. That is, the ejector pin 12, which is a member separate from the mold, is formed hollow, the temperature sensor 1 is provided at its tip, and its tip surface is closed. Then, the lead wire 3 is inserted into the pin. In this state, insert the ejector pin 12 into the mold, and attach its end to the mold component.
Fix by screwing or other means. The lead wire 3 is then taken out of the mold.

As the temperature sensor 1, various conventionally known sensors such as a resistance temperature sensor, a thermistor sensor, or a thermocouple sensor can be used. The output signal of this temperature sensor 1 (indicating the temperature inside the cavity) is compared with the comparison signal from the temperature setting device for pressure holding, and when the temperature inside the cavity becomes lower than the comparison temperature, the pressure holding valve is operated to complete the pressure holding process.

Furthermore, the output signal of the temperature sensor inside the cavity is compared with the comparison signal of the mold opening/closing temperature setting device by a second comparator. Then, the mold is opened by a product signal of an output signal output when the cavity internal temperature becomes lower than the comparison temperature and a completion signal when the above-described pressure holding valve operation is completed.

Next, how to use the present invention will be explained.

First, the mold is closed, then the mold is clamped under high pressure, and the nozzle 18 of the injection cylinder is touched to the mold as shown in FIG. The nozzle 18 injects the molten resin material from the runner groove 7 into the cavity. Then, the molding machine enters the pressure holding process with the cavity and runner filled with resin. After injection, the resin in the cavity is gradually cooled and hardened. When the temperature sensor 1 detects that the temperature inside the cavity has fallen to the preset temperature of the pressure-holding temperature setting device, a pressure-holding valve operation signal is output from the first comparator in FIG. Finish the pressure holding process.

When the temperature inside the cavity further decreases and the temperature sensor 1 detects that it has become below the set temperature of the mold opening/closing temperature setting device, the mold is opened by the output signal from the second comparator. Then, the molded product 4 is ejected by the ejector pin 12, and as it falls, the runner 8 separates from the molded product 4 and falls. The next injection cycle then begins again.

[Modified example]

It should be noted that the present invention is not limited to the above-mentioned embodiment; for example, a temperature sensor 1 may be provided at the tip of the suction pin 10 as shown in FIG.

Furthermore, the tip end surface of the guide pin 19 in FIG. 1 may be extended to the boundary surface of the cavity, and the temperature sensor 1 may be inserted therein.

Furthermore, the control block diagram of the molding machine based on the output signal of the temperature sensor 1 is of course not limited to that shown in FIG. Furthermore, the pressing step may be controlled by a timer.

[Effect of idea]

According to this device, while guiding the lead wire inside the pins such as the ejector pin 12 necessary for the mold,
Since the sensor only needs to be attached to the tip, the attachment is extremely easy and the mold will never be damaged.

This is because the sensor 1 is provided on a pin that is manufactured separately from the mold, so that the sensor can be reliably mounted at an accurate position and the lead wires can be wired accurately with the pin removed. Therefore, the reliability of the detected temperature is high.

Moreover, since the pin itself uses what is necessary for the mold, the mold itself will not be damaged, and no new machining will be required for the mold.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a mold showing the main parts of this control device, FIG. 2 is a vertical cross-sectional view showing the main parts of this device in the suction pin 10, and FIG. 3 is the temperature of the device in the ejector pin 12. FIG. 4 is an enlarged view showing an embodiment of the sensor 1, and FIG. 4 is a block diagram showing an example of the control device. 1... Temperature sensor, 2... Space, 3... Lead wire, 4... Molded product, 5... Movable side mounting plate,
6... Intermediate plate, 7... Runner groove, 8...
Runner, 9...Divided surface, 10...Satsuka pin, 11...Tie bar, 12...Ejector pin, 13...Small hole, 14...Core, 15...Fixed side mounting plate, 16...Runner kick plate , 17...
Cylinder, 18... nozzle, 19... guide pin.

Claims (1)

[Scope of utility model registration request] In the resin filling space of a molding die, an ejector pin 12 or a suction pin that forms part of the constitutive surface of the space, is manufactured as a separate member from the mold body, and is necessary for the mold. A temperature sensor 1 is inserted into the tip of a pin such as No. 10, and a lead wire 3 connecting the sensor 1 and a control section arranged outside the mold is formed in the axial direction inside the pin. The control device for an injection molding machine is configured to control at least the cooling time of the resin in the mold according to the temperature detected by the sensor 1 or the temperature change thereof.