JP2002254137A - Injection molding apparatus and mold for investment casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding apparatus and a rubber mold for investment casting capable of precisely reproducing processing conditions and a operating state of respective rubber molds in a short time, and also performing the setting of the processing conditions of the injection molding apparatus in a short time, and thereby improving production efficiency of products. SOLUTION: In the injection molding apparatus for investment casting having an injection molding device capable of injecting heat molten material and also injecting heat molten material into the inside of a mold, a reading means capable of reading electronic information which is written in a memory medium arranged in the mold is provided, and based on the electronic information which is read out by the reading means, the injection molding device then performs injection of the heat molten material into the inside of the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding apparatus for investment casting and a mold used for investment casting, and more particularly to an injection molding apparatus and investment casting for investment casting used in the production of jewelry. It relates to the rubber mold used.

[0002]

2. Description of the Related Art In the production of jewelry, the following investment casting is often used. That is, after embedding and curing the prototype in rubber, cut the rubber and take out the prototype, inject the low-melting wax into the cavity in the rubber mold after removing the prototype, and put the obtained wax into a tree shape. Assemble to form a plaster mold,
The wax is burned and evaporated by raising the temperature in a furnace, and the molten metal is injected into a gypsum-shaped cavity formed as a result of the burning and evaporation to produce an original casting.

[0003]

However, investment casting using a rubber mold has the following problems. First, wax injection conditions often differ depending on the type of rubber mold. On the other hand, in the conventional wax injection molding apparatus, it is too complicated to change the injection conditions frequently, so that the injection conditions of each rubber mold are selected and only the rubber molds having the same injection conditions are selected. Had to collect and perform injection work. Further, in selecting the rubber mold, it is necessary for an operator to memorize the processing conditions of each rubber mold, and set the processing conditions of the injection molding apparatus based on the storage.

Second, since the quality of the rubber mold is deteriorated due to aging, the quality as a mold for injecting wax is deteriorated, and defects such as an increased rejection rate of a cast product are liable to occur. For this, it is necessary to memorize the usage status and usage result of each rubber mold.
An operator memorizes the usage status and the like, and sets the processing conditions of the injection molding apparatus based on the memorized information.

[0005] As described above, in the conventional investment casting, since the processing conditions and usage conditions of the individual rubber molds are set based on the memory of the operator, it is difficult to accurately reproduce the rubber mold. Therefore, it takes a long time to set the processing conditions of the injection molding apparatus, which causes a reduction in product manufacturing efficiency.

On the other hand, it is also possible for an operator to record the processing conditions and usage conditions of each rubber mold in a notebook, but there are many types and numbers of rubber molds and one rubber mold. Since a small amount of products are produced by the method, the recording operation needs to be performed very frequently, which leads to a decrease in the production efficiency of the products. Such a situation is the same when the worker stores the processing conditions and the use status of each rubber mold in a storage medium (a hard disk, a floppy (registered trademark) disk, or the like) on the computer.

[0007] Also, German Patent Application No. 3837713.
No. 3,037,593, No. 3,024,197 and No. 3,742,427, a concave portion is provided on the surface of the rubber mold in accordance with the processing conditions.
The information stored in the rubber mold is read by contacting a stylus with the surface of the rubber mold to detect the presence or absence of the recess, the number of the recesses and their positions. However, in the above invention, the number of recesses, that is, the number of information, is limited by the surface area of the rubber mold, and information may be lost due to deformation or deterioration of the recess due to aging of the rubber mold or the like. Also, it is not possible to record the usage data of the rubber mold.

Accordingly, an object of the present invention is to be able to accurately reproduce the processing conditions and usage conditions of individual rubber molds in a short time and to set the processing conditions of an injection molding apparatus in a short time. Accordingly, it is an object of the present invention to provide an investment casting injection molding apparatus and a rubber mold capable of improving the production efficiency of a product.

Another object of the present invention is to provide an injection molding for investment casting which can improve the production efficiency of a product even when the operator and the injection molding device are different when casting a small number of products of various kinds. An object of the present invention is to provide a molding device and a rubber mold.

[0010] Still another object of the present invention is that the capacity for storing information such as processing conditions and usage conditions of each rubber mold is hardly limited by the surface area of the rubber mold.
To provide an investment casting injection molding device and a rubber mold capable of preventing the information from being lost due to aging of the rubber mold and the like, and further adding, correcting and deleting the information once the information is stored. It is in.

[0011]

In order to solve the above-mentioned problems, in an investment casting apparatus of the present invention, a writing means capable of storing electronic information in a storage medium provided in a mold, A reading unit capable of reading the written electronic information, wherein the reading unit reads the electronic information stored in the storage medium, and sets an ejection condition based on the read electronic information. Injection is to be performed.

Other objects and features of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing an outline of a wax injector and an input device constituting an injection molding apparatus for investment casting according to a first embodiment.
FIG. 2 is a perspective view showing the relation between the tank and the valve according to the first embodiment. FIG. 3 is a perspective view of the valve of the first embodiment shown in FIG.
FIG. 3 is a cross-sectional view when viewed from an I direction. FIG. 4 is a side view showing an outline of an auto clamp constituting a part of the investment casting apparatus for investment casting of the first embodiment. FIG.
FIG. 5A is a top view of the rubber mold of the first embodiment, and FIG. 5B is a cross-sectional view of the rubber mold.

The injection molding apparatus for investment casting of the first embodiment includes a wax injector (injection molding machine) 1,
Input device 20, auto clamp 30, reading /
It comprises a writing device 40 and the like. The details will be described below.

The wax injector 1 has a tank (wax tank) 2 for storing wax having a characteristic of melting at a temperature of about 75 degrees C.
A valve 3 having a temperature control function for keeping the molten state and the most suitable injection temperature is provided inside.

The tank 2 stores wax therein and is sealed by a lid 4 having a sealing member (not shown). The inside of the tank 2 can be pressurized by a compressed gas. Inside the tank 2, there is provided a vacuum tank 5 whose inside is maintained at a pressure sufficiently lower than the atmospheric pressure and which is prevented from wax. Therefore, the wax is stored inside the tank 2 and outside the vacuum tank 5.

The valve 3 comprises a vacuum valve 6 and an injection valve 7
Are independently provided on opposite sides. The vacuum valve 6 can be opened by energizing an electromagnetic coil 8 for driving the vacuum valve 6, and the injection valve 7 can be opened by energizing an electromagnetic coil 9 for driving the injection valve 7. The vacuum valve 6 communicates with the vacuum tank 5, and the injection valve 7 communicates with the tank 2 through a wax injection pipe 10. On another side of the valve 3, a heater 11 and an injection nozzle 12 are provided so as to face each other. The rubber nozzle 13 can be brought into close contact with the tip of the injection nozzle 12.

The input device 20 is connected to an injection molding machine, and has a liquid crystal screen 21 and push buttons 22 on its upper surface. The liquid crystal screen 21 can display information on the quality of the product and a list of the rubber molds 13 to which the quality information has not been input yet. The push button 22 includes a button for scrolling a pointer on the liquid crystal screen 21 in addition to a button for inputting quality information of the ejected product. When the user presses the pass / fail button of the rubber mold number indicated by the pointer, the signal is sent to the CPU unit (described later) built into the injection molding machine.
To be sent to

The auto clamp 30 is fixed to a work table (not shown) via a base 31 in front of the injection nozzle 12 of the wax injector 1. On the base 31,
A stage 32 for mounting the rubber mold 13 is disposed via a forward cylinder 33. Since the stage 32 is fixed to the forward cylinder 33, the horizontal movement of the forward cylinder allows the stage 32 to move in the horizontal direction. A clamp cylinder 34 is arranged above the stage 32. On the lower surface of the clamp cylinder 34, a plate 35 is provided.
The rubber mold 13 mounted on the stage 32 is sandwiched and held by the stage 32 and the plate 35 by the vertical operation of 4. In the auto clamp 30 configured as described above, the stage 32 advances toward the wax injector 1 while holding the rubber mold 13, and the spool 14 provided on one side of the rubber mold 13 and the injection nozzle 12 are brought into close contact with each other. It is possible to do.

In the wax injector 1 of the present embodiment configured as described above, the vacuum is applied to the injection nozzle 12 by the auto clamp 30 so that the interior of the rubber mold 13 is connected to the valve 3 through the spool. When the valve 6 is opened by energizing the electromagnetic coil for driving the vacuum valve 6, the valve 3 communicates with the vacuum tank 5, so that the inside of the injection valve 7 and the inside of the rubber mold 13 that communicates through the injection nozzle 12. Is evacuated. On the other hand, after closing the vacuum valve 6 and opening the injection valve 7 by energizing the electromagnetic coil for driving the valve, the injection valve 7, the wax injection pipe 10 and the tank 2 are opened.
The molten wax in the tank 2 passes through the injection nozzle 12 to obtain injection energy by the pressurized gas in the tank 2 and is injected into the void inside the rubber mold 13.

The reading / writing device 40 is provided below the stage 32 on the side of the wax injector 1 as shown in FIG. 4, and is capable of reading and writing electronic information. The stage 32 has a predetermined size (about 15 mm in diameter) above the reading / writing device 40.
Is provided.

On the other hand, an IC tag 41 as a storage medium is embedded in the bottom of the rubber mold 13. IC tag 41
Has an IC chip (not shown) having a storage capacity of 1 kilobyte inside, and can store electronic information. The IC tag 41 has a square shape with a side length of about 15 mm by sealing an IC chip and an antenna (not shown) with resin. The IC tag 41 and the read / write device 40 can communicate with each other by radio waves via the hole of the stage 32. That is, while the IC tag 41 and the reading / writing device 40 are not in contact with each other, the radio wave emitted from the IC tag 41 is read by the reading / writing device 40.
The IC tag 41 can receive and read electronic information, or the IC tag 41 can receive radio waves emitted by the read / write device 40 and write electronic information inside the IC tag 41. Therefore, it is not necessary to provide a terminal for electrically connecting the read / write device 40 to the IC tag 41, and the IC tag 41 is connected to the read / write device 40.
It is possible to communicate with the read / write device 40 even at a distance of several meters from.

The production of the rubber mold 13 is carried out by filling a mold with a vulcanizing agent into a mold frame into which a master is fitted, and vulcanizing the mold at an elevated temperature. After vulcanization, the rubber mold is cut with a knife, separated into upper and lower parts, and the prototype is taken out. This separation is
It also has the purpose of allowing the wax mold to be removed during the later formation of the wax mold. The IC tag 41 is embedded in a rubber mold after vulcanization, but a concave portion (not shown) for embedding the IC tag 41 needs to be formed in the rubber mold in advance.
The concave portion is formed by using a mold in which a portion corresponding to the concave portion is projected in the production of the rubber mold. The IC tag 41 is buried in the recess formed in this manner.
The C tag 41 and the rubber are bonded by an adhesive so as not to be easily separated.

When the solidified wax (wax mold) is taken out after the wax is injected into the rubber mold 13, it is necessary to significantly deform the rubber to separate it. Therefore, the IC tag 41 must be very small or resistant to deformation. However, in this embodiment, since the small IC tag 41 is used, the IC tag 41 is deformed and separated from the rubber mold 13. Is not destroyed or the recorded information is not lost. The removal of the wax is performed by peeling the upper part (upper mold) of the rubber mold 13 upward. Therefore, the lower part (lower mold) of the rubber mold 13 is less deformed. Therefore, in this embodiment, the IC tag 4
1 is embedded in the lower mold.

Next, the conditions for wax injection will be described. First, among the conditions for wax injection, conditions for controlling wax injection (injection control conditions) are as follows. A Wax temperature in tank 2 B Temperature of injection nozzle 12, C Evacuation time of injection nozzle (vacuum time) D Wax injection time E Pressure in tank 2 (injection pressure) Among these conditions, tank 2 related to the viscosity of wax The temperature of the wax in the tank, the temperature of the injection chamber, and the pressure in the tank 2 relating to the injection speed of the wax are particularly important parameters, and must have a decisive difference depending on the type of the rubber mold 13. This determines whether or not the injection speed into the rubber mold 13 prevents the gas in the mold from remaining in the wax. In other words, the presence or absence of gas defects on the wax surface is affected. If the injection speed is too high, the gas remaining in the mold is caught without being discharged, so that a defect due to the residual gas may occur.
On the other hand, if it is too late, the wax solidifies during the injection and causes so-called hot water wrinkles.

Next, the condition of the mold holding (clamp) will be described. The conditions of the mold holding are as follows. F Mold holding pressure (mold pressure) G Mold release time (mold holding time) The condition of the mold holding, that is, the condition for holding the rubber mold 13 so as not to be deformed even when subjected to the injection pressure, is the same as the injection control condition. This is a necessary condition for improving the quality of the mold. If the mold holding pressure is too strong,
The wax mold becomes deformed due to the deformation of No. 3 and becomes apart from the original mold. On the contrary, if the wax mold is too weak, a gap is formed in the mating surface of the rubber mold 13 to cause burrs. Further, the holding time after the injection, that is, the wax solidifies after the injection and the injection nozzle 12
The waiting time until the rubber mold 13 is separated from the mold determines the quality of the wax mold. In addition, the condition of the mold holding is realized by the auto clamp 30.

In the investment casting apparatus of this embodiment, the conditions A to G described above, that is, the temperature of the wax in the tank 2, the temperature of the injection chamber, the exhaust time of the injection chamber, the wax injection time, the pressure in the tank 2, the pressure in the tank 2 The optimum values of the pressure and the mold release time of each rubber mold are measured, and the measured values are stored as electronic information in each rubber mold IC chip.

Further, the rejection rate of the product changes for each injection molding machine or worker, or the rejection rate of the product increases due to aging of the rubber mold. It is preferable to memorize also the average value of the product acceptance rate of the product and the average value of the product acceptance rate in the injection molding using the rubber mold. With this information, it is possible to find out that a particular injection molding machine is defective, that a particular worker is unsuitable for the work, or that the rubber mold needs to be discarded due to aging. Because you can. That is, it is useful to store in the IC tag 14 of each rubber mold 13 the above-mentioned average value of the product acceptance rate of each rubber or each injection molding machine, each worker or / and the like. If such information is recorded in the IC tag 41 of the rubber mold 13 so that it can be electronically retrieved, it is not necessary for the operator to wake up from the memory and input it to the computer. In addition, injection molding machines
Injection conditions suitable for each rubber mold 13 or injection conditions according to the number of injections can be automatically set. Further, when the rejection rate of the product for each rubber mold 13 reaches a predetermined value, it is preferable that the rubber mold 13 is discarded. Therefore, it is necessary to store information on the rejection rate or the quality of the product in each IC tag 41.

As described above, in the present embodiment, the following electronic information is stored in each IC chip of the rubber mold 13. Here, "model number 6 digits 20 bits" means that the information of the model number is in the order of 6 digits in decimal system, so that 20 bits are prepared in the IC chip to store this information. It is. 1 Model No. 6 digits 20 bits 2 Types of use 3 digits 10 bits 3 Injection pressure 2 digits 7 bits 4 Vacuum time 2 digits 7 bits 5 Injection time 2 digits 7 bits 6 Type pressure 2 digits 7 bits 7 Type retention time 2 digits 7 Bit 8 Rejection rate of this rubber mold 2 digits 7 bits 9 Wax temperature 3 digits 10 bits 10 Nozzle temperature 3 digits 10 bits 11 Rejection rate for each injection molding machine Average rejection rate of injection molding machines 01 to 50 7 bits × 50 = 350 bits 12 Rejection rate for each worker Average rejection rate for workers 01 to 50 7 bits × 50 = 350 bits 13 Scheduled production number 12 bits 14 Remaining production number 12 bits 15 Reserved 36 bits Total 852 bits An input device 20 capable of inputting the above information is connected to the injection molding machine. Therefore, information management, which is a feature of the present invention, can be performed by using only a single injection molding machine without using a LAN system to be described later. In addition, it has a separate and independent electronic information writing and reading device for the administrator,
Necessary information such as the number of products to be produced, the number of products rejected, or the rejection rate can be stored in advance by an administrator in an information medium mounted on a mold.

It should be noted that these pieces of information are merely examples, and other information may be stored, and the necessary number of bits can be changed.

In the injection molding apparatus for investment casting according to the present embodiment, a CPU unit having digital signal processing software is built in, and the IC in the rubber mold 13 read by the read / write device 40 is provided.
According to the information stored in the tag 41, a necessary command signal is given to the injection molding machine. The command signal is a command relating to the conditions from A to G described above. The injection molding machine can change the operating parameters of the injection molding machine in accordance with this command, and can inject wax under the most appropriate conditions for each rubber mold 13.

Here, the relationship between the CPU unit and the read / write device 40 will be described with reference to FIG. FIG. 6 is a system configuration diagram of the investment casting apparatus of the present embodiment.

The read / write device 40 has an RS2
A 32C port 42 is provided, and a CPU unit 50 built in the injection molding apparatus is provided with an input unit 51, an output unit 52, a D / A converter 53 for converting a signal into an analog signal, and an RS232C port 54.
The D / A converter 53 includes a timer unit 55 for controlling a vacuum time, an injection time, and a mold holding time, and a temperature control unit 56 for controlling a wax temperature and a nozzle temperature.
And a pressure control unit 57 for controlling the injection pressure and the mold pressure. The electronic information of the IC tag 41 is
When read by the read / write device 40,
RS232C port 42 to RS232C port 54,
The data is sent to the CPU unit 50 via the input unit 51. The CPU unit sends command signals to the timer unit 55, the temperature control unit 56, and the pressure control unit 57 through the output unit 52 and the D / A converter 53 according to a predetermined program. Each control unit has a necessary channel and can control the above conditions A to G.

Next, a second embodiment will be described. FIG.
FIG. 3 is a configuration diagram of a LAN including an injection molding machine and a computer according to a second embodiment. In the first embodiment, the number of injection molding machines is one. In the second embodiment, a large number of injection molding machines are installed. By arranging the injection molding machines as shown in FIG. Exchange of information becomes possible. In FIG. 7, each injection molding machine 1
Are connected to a central computer 61 via a hub 60. The same number of monitors (displays) 63 as the wax injectors 1 and corresponding to the respective injection molding machines are connected to the central computer 61 via a hub 62. With such a configuration, the central computer 61 can sum up and organize the product information produced by each injection molding machine, and can match the production command input in advance with the results. The difference between the production instruction and the actual result is displayed on a monitor 63 corresponding to each injection molding machine. Further, the model number of the rubber mold 13 to be produced next is displayed on the monitor. When the production is continued and the difference between the production instruction and the actual result has disappeared, the operator sets the next rubber mold 13 already instructed by the computer 61,
Replace the rubber mold 13 whose production has been completed. Further, the production efficiency for each operator, the production efficiency for each machine, or the defect rate for each injection molding machine can be displayed. It should be noted that the hub 60 and the hub 62 may be the same, and whether they are separate or the same can be selected according to the restriction on the place where the injection molding machine, the computer, etc. are installed, or the capacity of the hub. . The configurations, operations, and effects other than those described above are the same as those of the first embodiment.

The following is a modification of the first and second embodiments.
In the above embodiment, the electronic information in the IC tag 41 is written or read by radio waves. However, the electronic information may be written or read by connecting an IC chip and a writing / reading device with a cable. The writing / reading device is located around the injection molding machine or the auto clamp 30.
It may be installed inside the device. Further, the reading / writing device 40 may be held by a worker and brought close to the rubber mold 13. The shape of the IC tag 41 may be a shape other than a square, and its size and thickness are not limited to those described in the above embodiment. The shape and size of the hole of the stage 32 are not limited to those described in the above embodiment. The CPU unit may be provided outside the injection molding machine. Although the present invention has been described with reference to the above embodiments, the present invention is not limited to the above embodiments, and can be improved or changed within the scope of the purpose of improvement or the concept of the present invention.

[0036]

As described above, according to the present invention,
The processing conditions and usage conditions of each rubber mold can be accurately reproduced in a short time, and the processing conditions of an injection molding machine can be set in a short time, thereby improving the production efficiency of products. An injection molding device for investment casting and a rubber mold that can be achieved can be provided. Also,
It is possible to provide an investment molding injection molding apparatus and a rubber mold that can improve the production efficiency of products even when different operators and injection molding machines are used when casting a small number of products of various types. Further, the capacity for storing information such as processing conditions and usage conditions of each rubber mold is hardly limited by the surface area of the rubber mold, and the information is not lost due to aging of the rubber mold and the like. It is possible to provide an injection molding apparatus for investment casting and a rubber mold capable of adding, correcting, and deleting information even after storing the information.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outline of a wax injector and an input device constituting an injection molding apparatus for investment casting according to a first embodiment.

FIG. 2 is a perspective view showing a relation between a tank and a valve according to the first embodiment.

FIG. 3 is a cross-sectional view of the valve according to the first embodiment when viewed from a direction III in FIG. 2;

FIG. 4 is a side view showing an outline of an auto clamp constituting a part of the investment casting apparatus for investment casting of the first embodiment.

FIG. 5A is a top view of the rubber mold of the first embodiment, and FIG.
Is a cross-sectional view of a rubber mold.

FIG. 6 is a system configuration diagram of the investment casting apparatus of the present embodiment.

FIG. 7 is a configuration diagram of a LAN including an injection molding machine and a computer according to a second embodiment.

[Explanation of symbols]

 Reference Signs List 1 wax injector (injection molding machine) 13 rubber mold 40 reading / writing device 41 IC tag

Claims (9)

[Claims] 1. An injection molding apparatus for investment casting, comprising an injection molding machine capable of injecting a hot-melt material, and injecting the hot-melt material into a mold, comprising a memory provided in the mold. A reading unit capable of reading electronic information written on a medium; and based on the electronic information read by the reading unit, the injection molding machine injects the heat-fusible material into the mold based on the electronic information. And an injection molding apparatus. 2. The injection molding apparatus for investment casting according to claim 1, further comprising a writing unit capable of storing the electronic information in the storage medium provided in the mold. 3. The injection molding apparatus for investment casting according to claim 1, wherein the storage medium has an IC chip. 4. The injection molding apparatus for investment casting according to claim 1, wherein the electronic information is an injection condition. 5. The injection molding apparatus for investment casting according to claim 1, wherein the electronic information is information on a use condition of the mold. 6. The electronic information according to claim 1, wherein the electronic information is information on the quality of a product formed by injection.
Or the injection molding apparatus for investment casting according to 2. 7. The injection molding apparatus for investment casting according to claim 4, wherein the injection condition is a condition relating to injection control. 8. The injection molding apparatus for investment casting according to claim 4, wherein the injection condition is a condition relating to a die press. 9. A mold used for investment casting, comprising a storage medium capable of storing electronic information.