JP2818604B2 - Temperature control method for injection molding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a temperature control method for an injection molding machine, and can be used for a temperature control device having a temperature shift function corresponding to an idle time or the like.

(Background technology)

2. Description of the Related Art Conventionally, in the production of synthetic resin molded products, an injection method is frequently used, and an injection molding machine for injecting a molten resin into a mold has been frequently used.

Injection molding machines have an injection nozzle or an electric belt heater at each part of the barrel for melting and kneading in order to heat and melt the raw resin, and the heating temperature is adjusted by a temperature control device connected to each heater. Have been done. The heating temperature greatly affects the moldability and molding result of the injected resin, and is set finely according to the type of resin, molding conditions, and the like.

Meanwhile, in a factory or the like where injection molding is performed, the molding operation is suspended due to a break time of an operator or the like. At this time, if the barrel is left to be heated, the molten resin inside may be deteriorated, and the molded product may be defective. On the other hand, if the heating of the barrel is stopped while the resin is filled, the resin may be cooled and solidified in the barrel, making recovery difficult. In order to avoid such inconveniences, the heating of the barrel is temporarily suppressed during the downtime, and the temperature is kept as low as possible within a range where the melting of the resin can be maintained.

In recent temperature control device for the injection molding, as shown in FIG. 5, with respect to a normal injection temperature Tn, it moves the barrel comes to the specified shift start time P ₀ to a predetermined shift temperature Ts, shift It reaches its end time P ₁ has been developed which has the original temperature shift function to return to the injection temperature Tn, in such a shift function with temperature control device can perform the response to downtime automatically.

[Problems to be solved by the invention]

Incidentally, the shift operation of the conventional temperature control device, and resumed heating from the shift end time P _1, to return to the actual injection temperature Tn since it takes time to raise the temperature becomes time P ₁ '.

Therefore, lowering Combining an end time of the pause time shift end time P _1, rest time has not reached a sufficient injection temperature Tn in the barrel molding operation upon completion, the efficiency caused unnecessary delays in the work Will be.

On the other hand, it has been attempted to specify the shift end time somewhat earlier than the end of the pause time. However, the temperature rise delay of the shift function varies depending on various conditions such as the shift temperature, the injection temperature, the resin and the thermal characteristics of the injection molding machine. For example, as shown by the dotted line in FIG. If set, the return to the injection temperature Tn will be at a later time P ₁ ″. For this reason, it is difficult even for a skilled operator to set an appropriate time for various conditions during injection molding. Was.

An object of the present invention is to provide a temperature control method for an injection molding machine that can perform a clear temperature shift operation with a simple operation.

[Means for solving the problem]

According to the present invention, the injection molding machine is usually maintained at the injection temperature, and the shift time is shifted to the shift temperature defined by the shift start time and the shift end time. The temperature rise time from the shift temperature to the injection temperature is determined based on the temperature rise characteristics of the injection molding machine, and the heating for the return is performed at a time earlier than the shift end time by the temperature rise time. By starting, a temperature control method for an injection molding machine is configured.

Here, as the temperature rise characteristics, the temperature rise gradient of the injection molding machine, that is, the temperature rise rate accompanying heating, and the temperature rise behavior itself during heating can be used.

When recording these temperature rise characteristics, a method of storing them as a function or data table can be adopted.In addition to those measured separately for each condition, the progress of the heat-up operation of the injection molding machine is measured each time operation starts. May be.

[Action]

In such an embodiment of the present invention, the shift operation according to the designated shift time, injection temperature and shift temperature is automatically executed, and it is possible to cope with the suspension time and the like. Also,
The heating of the barrel is started prior to the end time of the shed according to the temperature rise time based on the temperature rise characteristics of the injection molding machine, and the barrel temperature is reliably returned to the injection temperature at the shift end time by the preheating. Therefore, simplification of the designation of the shift time is realized by an accurate shift operation without a time delay,
Thereby, the above object is achieved.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, an injection molding machine 1 has an electric belt heater 3 wound around a cylindrical barrel 2 and a screw 4 coaxially arranged inside, and is supplied from a hopper 5 at a base end. The raw resin pellets are heated and melted by the heater 3 while being kneaded by the screw 4 while being kneaded under pressure, sent to the nozzle 6 at the tip, and the molten resin is injected into the mold 7 to which the nozzle 6 is connected to perform molding. is there.

A barrel temperature controller 10 is connected to the injection molding device 4 for adjusting the heater 3 for heating the barrel 2.

The temperature regulator 10 designates a temperature to the controller 11 according to the target temperature To designated externally. The controller 11 performs power control with reference to the detected temperature from the temperature sensor 12, and maintains the heater 3 at the designated temperature. The heater 3 and the controller 11 are arranged in three systems corresponding to the base end portion, the middle portion, and the front end portion of the barrel 2, and the distribution of the temperatures T ₁ , T ₂ , and T ₃ is adjusted by the temperature controller 10 for each system. By doing so, zone control for making each part of the barrel 2 an optimum state is performed.

The temperature adjuster 10 is connected to a temperature shift control means 20 for performing basic temperature setting and shift operation.

Temperature shift control means 20, the exit temperature setting unit 21 for setting the injection temperature Tn in the normal shift temperature setting unit 22 for setting a shift temperature Ts, the shift start time P ₀ and the shift end time
A shift time setting unit 23 for setting a P _1, the console 24 for an operator to perform setting operation for each of these settings 21 to 23 are connected. Further, the temperature shift control means 20
Is provided with a heating gradient recording means 25, a heating time calculating section 26, and a target temperature specifying means 27.

The temperature rise gradient recording means 25 is composed of a tracing device and a storage device connected to the temperature sensor 12 attached to the heater 3, and investigates a temperature change during a heat-up operation at the start of operation of the injection molding machine. The temperature rise gradient Gt for each temperature region is calculated based on the result, and is recorded as a function represented by a graph as shown in FIG.

The heating time calculating section 26 calculates the temperatures Tn and Ts from the setting sections 21 to 23.
And the shift end time P ₁ , read the temperature rise gradient Gts corresponding to the temperature Ts from the recording means 25, and read the temperature rise time from each value. Is calculated, and the heating restart time P ₂ = P ₁ −ΔP is also calculated.

The target temperature designation means 27 is configured using a sequence controller or the like that operates based on a built-in clock or the like, and based on the values from each of the setting units 21 to 23 and the heating time calculating unit 26, a target temperature To according to time. Is output to the barrel temperature controller 10. At this time, usually as the target temperature To specify the injection temperature Tn, specify the shift temperature Ts becomes the shift start time P _0, again injection temperature becomes a heating restart time P ₂
It is set to specify Tn.

In this embodiment configured as described above, the injection molding operation is performed in the following procedure.

Before starting the work, the injection temperature T
n, shift temperature Ts, shift start time P ₀ , shift end time P
₁ is set, and the injection molding machine 1 or the temperature shift control means 20 is set.
Start The started injection molding machine 1 sets the target temperature To =
The barrel 2 is heated at the injection temperature Tn, and a heat-up operation to the injection state is performed. During this time, the temperature change of the injection molding machine 1 is measured and recorded by the temperature gradient recording means 25.

Injection injection preparation of molding machine 1 starts the molding operation Once you have it, between the shift start time P ₀ of the shift end time P ₁ is to pause the work for the rest.

Temperature shift control unit 20 is to maintain the temperature between the barrel 2 of the normal work injection temperature Tn, performs a shift operation becomes a specified shift start time P _0.

As shown in Figure 4, the target temperature designation unit 27 changes the target temperature To shift temperature Ts with the detection of the shift start time P _0, proceeds to suppress the heating of the heater 3 barrel 2 to the shift state Let it.

At the same time, the heating gradient recording means 25 and the heating time calculating section 26
Heating restart time P ₂ is calculated by the target temperature designation unit 27
To maintain the shift state until this time P _2.

Then, with the detection of the heating restart time P _2, the target temperature designation unit 27 returns the target temperature To based on the injection temperature Tn prior to the shift end time P _1, barrel 2 to resume heating of the heater 3
Is returned to the injection state.

Here, the heating restart time P ₂ is earlier than the shift end time P ₁ temperature rising time [Delta] P, and heated time [Delta] P on the basis set temperature difference Tn shift operation, the temperature increase gradient Gts according to Ts and temperature Ts because they are computed, the temperature of the barrel 2 to the shift end time P ₁ to recover to an injection temperature Tn.

Although resting have a molding operation is resumed immediately after the shift end time P _1, the temperature of the barrel 2 have already been restored to the injection temperature Tn, injection of the injection molding machine 1 is carried out without problems.

According to this embodiment, the following effects can be obtained.

That is, in the injection molding operation, the shift start time P ₀ ,
By setting the shift end time P ₁ , the injection temperature Tn, and the shift temperature Ts, the temperature of the injection state can be automatically adjusted and the shift operation corresponding to the idle time can be automatically executed. In addition, the temperature of the injection molding machine 1 can be easily and reliably controlled.

In addition, the heating time Δ based on the heating gradient Gt of the injection molding machine 1
Determine the heating restart time P ₂ from P, by resuming the heating of the barrel 2 before the shift end time P _1, the injection temperature of the barrel 2 during the time P _1, that downtime end temperature Tn
Can be reliably restored.

Therefore, the molding operation can be restarted immediately after the pause time, and the efficiency can be improved.

Further, since an accurate shift operation without time delay can be performed with respect to the designated times P ₀ and P ₁ , the designation of the shift time can be performed very easily by anyone.

The present invention is not limited to the above embodiment, but includes the following modifications.

That is, the temperature rising characteristic for obtaining the temperature rising time ΔP is not limited to the temperature rising gradient Gt, and the temperature rising behavior itself during heating of the injection molding machine 1 as shown in FIG. 4 may be used. This temperature rise behavior is a record of the elapsed time from the start of the heat-up operation of the injection molding machine 1 and the temperature T as it is, and the temperature rise time is calculated from the horizontal axis coordinates corresponding to the shift temperature Ts and the injection temperature Tn on the vertical axis. It is possible to determine ΔP.

Further, as the temperature rising characteristics such as the temperature rising gradient Gt, in addition to the actual measurement from the heat-up operation of the injection molding machine every time the operation is started, a temperature measured separately for various conditions may be read and used.

Here, if the temperature rise characteristics are measured in advance, it may be measured at the time of temperature rise inspection at the time of product completion inspection or at the time of installation, etc. It is possible to obtain a corresponding accurate temperature rise characteristic.

Further, the recording of the temperature rise characteristics may be performed in an arbitrary format such as a function or a data table for each area, that is, any type that can be appropriately used in calculating the temperature rise time ΔP.

On the other hand, the calculation of the heating time ΔP is not performed every time the shift operation is performed based on the heating characteristics such as the heating gradient Gt, but may also be performed when the heating gradient Gt or the like is investigated by the heat-up operation. Good. However, when the shift temperature Ts is sometimes changed during the molding operation, it is desirable to perform the calculation again for each shift operation as in the above embodiment.

In addition, the apparatus to which the present invention is applied is not limited to the injection molding machine 1 of the above embodiment, and the temperature control device is not limited to the apparatus using the barrel temperature adjuster 10 and the temperature shift control means 20. An appropriate device configuration may be set according to the temperature rise characteristics and the like employed in the implementation.

〔The invention's effect〕

As described above, according to the temperature control method of the injection molding machine of the present invention, the heating is performed prior to the shift end by the temperature rising time based on the temperature rising characteristic, so that the accurate temperature shifting operation can be performed with a simple operation. It can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, FIG. 2 is a graph showing a temperature rising gradient adopted in the embodiment, FIG. 3 is a graph showing a temperature change of a shift operation in the embodiment, FIG. 4 is a graph showing a temperature raising behavior that can be adopted as the temperature raising characteristic of the present invention, and FIG. 5 is a graph showing a temperature change in a conventional shift operation. 1 ... injection molding machine, 2 ... barrel, 3 ... heater, 10 ...
... Barrel temperature controller, 20 ... Temperature shift control means, Tn ...
… Injection temperature, Ts… Shift temperature, P ₀ … Shift start time, P ₁ … Shift end time, P ₂ …… Heating restart time, Gt…
... temperature rise gradient, ΔP ... temperature rise time.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tsunobu Toya 2068-3 Ooka, Numazu-shi, Shizuoka Pref. Toshiba Machine Co., Ltd. Numazu Office (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 45 / 00-45/84

Claims (1)

(57) [Claims] An injection molding machine is usually maintained at an injection temperature, and is shifted to a shift temperature during a shift time defined by a shift start time and a shift end time. The temperature rise time from the shift temperature to the injection temperature is determined based on the recorded temperature rise characteristics of the injection molding machine, and the heating for the return is performed at a time earlier than the shift end time by the temperature rise time. A temperature control method for an injection molding machine.