JP3050014B2 - Injection molding machine mold changing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for exchanging dies of an injection molding machine.

[0002]

2. Description of the Related Art Heretofore, a hot-runner type mold exchanging operation in an injection molding machine has been performed in the following procedure. (1) Preliminary temperature control of the mold hot runner: Specifically, the hot runner 3 of the mold (upper mold 1, lower mold 2) shown in FIG. Preliminary temperature control is performed by a heater for heating, and the temperature is raised.

(2) Mold change: This is performed automatically,
Attach the mold to the injection molding machine. (3) Mold operation confirmation: Specifically, an ejector device,
Check the operation of the core. (4) Wipe in the mold: Specifically, the Teflon-based rust preventive oil applied before storing the mold is wiped off.

(5) Molding confirmation (quality confirmation): This is performed about three shots in order to actually operate the injection molding machine and confirm the presence or absence of short shots, oil spots and the like. (6) Start continuous operation

[0005]

However, in the conventional method of exchanging the mold of an injection molding machine, a defective product is produced in the molding at the time of the molding confirmation in the above (5). There was a problem that it was wasted without using it. As shown in FIG. 4, the content of the defective product is short shot A caused by a decrease in the resin fluidity due to a low mold temperature, and deteriorated resin in the mold hot runner (residual resin from previous production). Material deterioration B due to inflow, oil stain C due to residual adhesion of rust preventive oil, and the like.

The present invention has been made in view of the above-mentioned conventional problems, and makes it possible to perform good molding from the first shot after the mold is mounted (at the time of confirming the molding), and to eliminate defective products due to mold replacement. It is an object of the present invention to provide a method of exchanging a mold of an injection molding machine which can be performed.

[0007]

SUMMARY OF THE INVENTION Therefore, a method of exchanging a mold of an injection molding machine according to the present invention provides a method for exchanging a mold of an injection molding machine by controlling a temperature of a mold hot runner in advance and at the same time. After adjusting the temperature of the whole, the mold is mounted on the injection molding machine, the residual resin from the previous production in the mold hot runner is discharged to the cavity mold side and removed, and the rust-preventive oil in the mold is removed. After wiping, the molding is confirmed by operating the injection molding machine, and the molding conditions for the first shot at the time of confirming the molding are partially changed.

It is more preferable to use a wax-based rust-preventive oil as the rust-preventive oil for storing the mold.

[0009]

In the above method, before the mold is replaced, the temperature of the mold is raised by preliminarily controlling the temperature of the entire mold, so that a decrease in resin fluidity at the time of molding confirmation can be prevented. Further, after the mold is mounted, the residual resin from the previous production in the mold hot runner is discharged to the cavity mold surface side and removed, thereby preventing the inflow of the deteriorated resin at the time of confirming the molding.
In addition, by partially changing the molding conditions of the first shot at the time of confirming the molding, the first shot can be optimized by increasing the injection pressure or the like. As a result, it is possible to perform favorable molding from the first shot at the time of confirming the molding, and it is possible to eliminate defective products due to mold replacement.

[0010] If a wax-based rust-preventive oil is used instead of the conventional Teflon-based rust-preventive oil as the rust-preventive oil for storing the mold, it is easy to confirm the application, and it is possible to prevent excessive application. In addition, wiping (washing) can be performed easily, and oil stains due to the remaining adhesion of rust preventive oil can be reduced.

[0011]

An embodiment of the present invention will be described below. In the present embodiment, the operation of exchanging the hot runner type mold in the injection molding machine is performed in the following procedure. (1) Preliminary temperature control of the mold hot runner: More specifically, for example, the mold (upper mold 1, lower mold 2) shown in FIG. The hot runner 3 is preliminarily temperature-controlled by the heating heater, and is heated.

(2) Preliminary temperature control of the entire mold: Specifically,
Simultaneously with the preliminary temperature control of the mold hot runner, as shown in FIG. 1, hot water of about 60 ° C. is supplied by the hot water supply device 5 using the cooling water circulation pipe 4 in the mold (upper die 1 and lower die 2). To regulate the temperature of the entire mold. In addition, assuming that the point P in FIG. 1 is a mold temperature measurement point, the temperature is controlled at 22 ° C. to 30 ° C. at this point.

(3) Mold change: This is performed automatically,
Attach the mold to the injection molding machine. (4) Mold operation confirmation: Specifically, an ejector device,
Check the operation of the core. (5) Residual resin purge in the mold hot runner: Specifically, as shown in FIG. 2, the molten resin is supplied by the injection screw 6 on the injection molding machine side by manual operation, and the molten resin is supplied to the injection molding machine side. The resin is sent from the hot runner 7 into the mold hot runner 3 to discharge the residual resin R in the mold hot runner 3 from the previous production to the cavity mold surface side and remove it.

(6) Wiping in the mold: Specifically, the rust preventive oil applied before storing the mold is wiped off. By changing the rust-preventive oil for storing the mold from the conventional Teflon-based oil to the wax-based oil, it is easy to check the application, prevent over-application, and also facilitate wiping (washing). Rust oil residue can be significantly reduced.

(7) Molding Confirmation (Quality Confirmation): This is performed about three shots in order to actually operate the injection molding machine and confirm the presence or absence of short shots, oil spots and the like. At this time, some of the molding conditions for the first shot are changed. Specifically, the injection pressure is increased by about 5%, the injection speed is increased by about 20%, and the measurement is corrected for the melt depressurized amount. These make it possible to obtain a non-defective product from the first shot at the time of molding confirmation. In addition, after the second shot, the molding condition is returned to the normal molding condition, and the quality is checked under the condition.

(8) Start of continuous operation: After confirmation of molding, continuous operation is started.

[0017]

As described above, according to the present invention, it is possible to perform good molding without short shots and material deterioration from the first shot at the time of molding confirmation after attaching a mold, and to perform defective molding due to mold replacement. Can be set to zero. Also, if wax-based rust-preventive oil is used as the rust-preventive oil for storing molds, wiping (washing) can be performed easily, and oil spots due to residual rust-preventive oil can be reduced. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing a specific example of preliminary temperature control of an entire mold in the method of the present invention.

FIG. 2 is a diagram showing a specific example of resin purge in a hot runner of a mold in the method of the present invention.

FIG. 3 is a diagram showing a mold hot runner preliminary temperature control.

FIG. 4 is a diagram showing an example of a defective product.

[Explanation of symbols]

 Reference Signs List 1 mold (upper mold) 2 mold (lower mold) 3 mold hot runner 4 cooling water circulation pipe 5 hot water supply device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 33/00-33/76

Claims (2)

(57) [Claims] When the mold of the injection molding machine is replaced, the temperature of the mold hot runner is preliminarily controlled, and after the entire temperature of the mold is preliminarily controlled, the mold is mounted on the injection molding machine. Residual resin from the previous production in the mold hot runner is discharged to the cavity mold surface side to remove it, wipe off the rust-preventive oil in the mold, and then operate the injection molding machine to confirm the molding. A mold changing method for an injection molding machine, wherein a part of a molding condition of a first shot at the time is changed. 2. The method according to claim 1, wherein a wax-based rust preventive oil is used as the rust preventive oil for storing the mold.