JPH03159725A - Temperature-controlling method of injection molding machine - Google Patents

Abstract

PURPOSE:To enable the sure action of temperature-shift to be carried out by simple operation by a method in which the temperature of an injection molding machine is transferred to shifting temperature at shifting time, and heating is started from shift-finished time before at least temperature-raising time from shifting temperature to injecting temperature. CONSTITUTION:A temperature shift-controlling means 20 keeps the temperature of a barrel 2 at injecting temperature Tn during normal operation, but achieves shifting operation at designated shift-starting time P0. An aimed temperature-designating means 27 changes the aimed temperature T0 into shifting temperature Ts with the detection of shift-starting time P0, and transfers the barrel 2 into shifting condition by suppressing the heating of a heater 3. The aimed temperature-designating means 27 restores the aimed temperature T0 to original injecting temperature Tn before shift- finishing time P1 with the detection of heating-again starting time P2, and restores the barrel 2 to injecting condition by starting again the heating by the heater 3. The molding operation having been stopped starts again immediately after the shift-finishing time P1, but the temperature of the barrel 2 has been already restored to injection temperature Tn, whereby the injection of the injection molding machine 1 is carried out without any trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a temperature control method for an injection molding machine, and can be applied to a temperature control device having a temperature shift function corresponding to downtime, etc.

[Background technology]

BACKGROUND ART Conventionally, injection methods have been frequently used in the production of synthetic resin molded products, and injection molding machines for injecting molten resin into molds have been frequently used.

In an injection molding machine, each part of the injection nozzle or barrel for melting and kneading is equipped with an electric belt heater, etc. to heat and melt the raw resin, and the heating temperature is adjusted by a temperature control device connected to each heater. It is being said. This heating temperature has a great influence on the moldability and molding results of the injected resin, and is finely set depending on the type of resin, shaping conditions, etc.

By the way, in factories and the like that carry out injection molding, certain molding operations are suspended during breaks for workers.

At this time, if the barrel is left heated, there is a risk that the molten resin inside will deteriorate and the molded product will be defective. On the other hand, if heating of the barrel is stopped while it is filled with resin, the resin may cool and solidify within the barrel, making recovery difficult. In order to avoid such inconveniences, heating of the barrel is temporarily suppressed during downtime to keep the temperature as low as possible within a range that maintains the melting of the resin.

In recent temperature control devices for injection molding, as shown in FIG.
A temperature control device has been developed that has a temperature shift function that causes the injection temperature to shift to s and then returns to the original injection temperature Tn at the shift end time P1. It can be carried out.

[Problem to be solved by the invention]

By the way, in the shift operation of the conventional temperature control device, the shift end time P. Heating is resumed from
′.

Therefore, if the end time of the rest time is set to the shift end time P1, the barrel will not have reached the injection temperature Tn sufficient for the molding operation at the end of the rest time, causing an unnecessary delay in the work and reducing efficiency. I will let you do it.

On the other hand, attempts have been made to specify the shift end time somewhat earlier than the end of the downtime. However, the temperature rise delay of the shift function changes depending on various conditions such as the shift temperature, injection temperature, and thermal characteristics of the resin and injection molding machine. When the injection temperature is set, the return to the injection temperature Tn occurs at a later time P1''.For this reason, it is difficult even for experienced operators to set an appropriate time for the various conditions during injection molding. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature control method for an injection molding machine that allows accurate temperature shift operation with simple operations.

[Means to solve the problem]

The present invention normally maintains the injection molding machine at the injection temperature, shifts it to the shift temperature at the shift time determined by the shift start time and the shift end time, and records in advance when returning from the shift temperature to the injection temperature. The heating time from the shift temperature to the injection temperature is determined based on the heating characteristics of the injection molding machine, and the heating for the return is carried out at a time before the shift end time by the heating time. This is a method for controlling the temperature of an injection molding machine by starting the process.

Here, as the temperature increase characteristic, in addition to the temperature increase gradient of the injection molding machine, that is, the temperature increase rate accompanying heating, the temperature increase behavior itself during heating can be used.

When recording these temperature rise characteristics, a method of storing them as functions or data tables can be adopted, and in addition to measuring separately for each various conditions, the progress of the heat-up operation of the injection molding machine can be actually measured each time the injection molding machine starts operation. You may.

[Effect]

In the present invention, the specified shift time,
A shift operation according to the injection temperature and shift temperature is automatically executed, making it possible to cope with downtime and the like. In addition, heating of the barrel is started prior to the shift end time according to the temperature rise time based on the temperature rise characteristics of the injection molding machine, and this preliminary heating ensures that the barrel temperature returns to the injection temperature at the shift end time. Ru. Therefore, the shift time specification can be simplified by accurate shift operation without time delay, thereby achieving the above object.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, an injection molding machine I 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 the base end. Molding is performed by heating and melting the raw resin pellets with a heater 3, kneading them under pressure with a screw 4, and feeding them toward a nozzle 6 at the tip, and injecting the molten resin into a mold 7 to which the nozzle 6 is connected. be.

A barrel temperature regulator 10 is connected to the injection molding machine 4 in order to adjust the heater 3 that heats the barrel 2.

The temperature regulator 10 specifies a temperature to the controller 11 according to an externally specified target temperature To. controller l1
performs power control with reference to the detected temperature from the temperature sensor l2, and maintains the heater 3 at a specified temperature. Heater 3
Three systems of controllers 11 are arranged corresponding to the proximal end, middle part, and distal end of the barrel 2, and the temperature regulator 10
For each system, the temperature T l +Tl. Zone control is performed to bring each part of the barrel 2 into an optimal state by adjusting the distribution of T3.

A temperature shift control means 20 for performing basic temperature setting and shift operations is connected to the temperature regulator 10.

The temperature shift control means 20 includes an injection temperature setting section 2l that sets the normal injection temperature Tn, a shift temperature setting section 22 that sets the shift temperature Ts, and a shift start time P. and a shift time setting section 23 for setting a shift end time P1, and a console 24 for an operator to perform setting operations is connected to each of these setting sections 2I-23. Also,
The temperature shift control means 20 includes a temperature increase gradient recording means 25, a temperature increase time calculation section 26, and a target temperature designation means 27.

The temperature increase gradient recording means 25 is composed of a tracing device, a storage device, etc. connected to the temperature sensor l2 attached to the heater 3, and investigates the temperature change during the heat-up operation at the start of operation of the injection molding machine. Based on the results, the temperature increase gradient Gt for each temperature range is calculated and recorded as a function represented by a graph as shown in FIG.

The temperature increase time calculation unit 26 receives the temperature T from each setting unit 21 to 23.
n, Ts and shift end time P1, read the temperature increase gradient Gts corresponding to the temperature Ts from the recording means 25, and calculate the heating restart time P, =P, -ΔP.

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 determines the target temperature according to time based on the values from each of the setting sections 21 to 23 and the heating time calculation section 26. To is output to the barrel temperature regulator IO. At this time, the injection temperature Tn is normally specified as the target temperature To, but the shift start time P
When it reaches 0, the shift temperature Ts is specified and the heating restart time P2
The setting is such that when the injection temperature Tn is reached, the injection temperature Tn is specified again.

In this embodiment configured as described above, the injection or molding work is performed in the following steps.

Before starting work, check the injection temperature T from the console 24.
n, shift temperature Ts, shift start time P. , the shift end time P1 is set, and the injection molding machine 1 or the temperature shift control means 20 is started. In the started injection molding machine 1, the barrel 2 is heated to a target temperature To=injection temperature Tn, and a heat-up operation to an injection state is performed. During this time, the temperature change of the injection molding machine 1 is measured and recorded by the temperature increase gradient recording means 25.

When the injection molding machine 1 is ready for injection, the molding work starts, but the work is stopped for a break between shift start time P0 and shift end time P1.

The temperature shift control means 20 maintains the temperature of the barrel 2 at the injection temperature Tn during normal operation, but at a designated shift start time P. When this happens, a shift operation is performed.

As shown in FIG. 4, the target temperature specifying means 27 changes the target temperature To to the shift temperature T upon detection of the shift start time P0.
s, the heating of the heater 3 is suppressed, and the barrel 2 is shifted to the shift state.

At the same time, the temperature increase gradient recording means 25 and the temperature increase time calculation section 2
6, the heating restart time P2 is calculated, and the target temperature specifying means 27 maintains the shifted state until this time P2.

Thereafter, upon detection of the heating restart time P2, the target temperature designating means 27 sets the target temperature To in advance of the shift end time P1.
is returned to the original injection temperature Tn, heating of the heater 3 is restarted, and the barrel 2 is returned to the injection state.

Here, the heating restart time P2 is earlier than the shift end time P1 by the temperature increase time ΔP, and the temperature increase time ΔP is equal to the set temperature difference Tn of the shift operation. Since the calculation is based on Ts and the temperature increase gradient Gts corresponding to the temperature Ts, the temperature of the barrel 2 recovers to the injection temperature Tn at the shift end time P1.

The halted cutting operation is resumed immediately after the shift end time P1, but the temperature of the barrel 2 has already been returned to the injection temperature Tn, and the injection cutting machine 1 can perform injection without any problem.

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

In other words, for injection molding work, shift start time P0,
By setting the shift end time P, the injection temperature Tn, and the shift temperature Ts, the temperature of the injection state can be automatically adjusted, and a shift operation corresponding to the rest time etc. can be automatically executed. The temperature of the injection molding machine 1 can be easily and reliably controlled.

Also, the temperature increase time Δ based on the temperature increase gradient Ct of the injection molding machine 1
Determine heating restart time P from P, and shift end time P1
By restarting the heating of the barrel 2 prior to this, the temperature of the barrel 2 can be reliably returned to the injection temperature Tn at time P1, that is, at the end of the pause time.

Therefore, a certain type of work can be resumed immediately after the downtime, and efficiency can be improved.

Furthermore, the specified time P. + Since accurate shift operations can be performed with no time delay relative to the PI, anyone can specify shift times extremely easily.

Note that the present invention is not limited to the above embodiments,
It also includes the following modifications.

In other words, the temperature increase characteristic for determining the temperature increase time ΔP is not limited to the temperature increase gradient Ct, but the heating behavior itself during heating of the injection molding machine 1 as shown in FIG. 4 may be used. . This temperature increase behavior is a record of the elapsed time and temperature T from the start of the heat-up operation of the injection molding machine 1, and the temperature increase is based on the horizontal axis coordinates corresponding to the shift temperature Ts and injection temperature Tn on the vertical axis. It is possible to determine the time ΔP.

Further, the temperature increase characteristics such as the temperature increase gradient Gt may be measured from the heat-up operation of the injection molding machine each time the operation starts, or may be separately measured for each various conditions and then read in and used.

Here, if you want to measure the temperature rise characteristics in advance, you can measure them during a complete inspection of the product or during a temperature rise inspection at the time of installation. It is possible to obtain accurate temperature rise characteristics according to the

Furthermore, when recording the temperature increase characteristics, any format such as a function for each region or a data table may be used, as long as it can be used appropriately in calculating the temperature increase time ΔP.

On the other hand, the calculation of the temperature increase time ΔP is not performed every time a shift operation is performed based on the temperature increase characteristics such as the temperature increase gradient Gt, but can also be performed when the temperature increase gradient Gt etc. is investigated by the heat up operation. good. However, if the shift temperature Ts is sometimes changed during a certain operation, it is desirable to recalculate it 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 embodiment described above, and the temperature control device thereof is not limited to the one using the barrel temperature regulator 10 and the temperature shift control means 20. , an appropriate device configuration may be set depending on the temperature increase characteristics and the like employed in the implementation.

〔Effect of the invention〕

As described above, according to the temperature control method for an injection or molding machine of the present invention, heating is performed prior to the end of the shift using a heating time based on the heating characteristics, thereby achieving an accurate temperature shift with a simple operation. can perform actions.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a graph showing a temperature increase gradient employed in the same embodiment, and FIG. 3 is a graph showing temperature changes during shift operation in the same embodiment. FIG. 4 is a graph showing a temperature increase behavior that can be adopted as the temperature increase characteristic of the present invention, and FIG. 5 is a graph showing temperature changes in a conventional shift operation. l... Injection molding machine, 2... Barrel, 3... Heater, 10... Barrel temperature regulator, 20... Temperature shift control means, Tn... Injection temperature, Ts... Shift temperature, P1...Shift start time, P1...Shift end time, P2...Heating restart time, Ct...Temperature increase gradient, ΔP
...heating time.

Claims (1)

[Claims] (1) The injection molding machine is normally maintained at the injection temperature, and is brought to the shift temperature at the shift time determined by the shift start time and shift end time. The temperature increase time from the shift temperature to the injection temperature is determined based on the temperature increase characteristics of the injection molding machine, and the heating for the return is started at a time before the shift end time by the temperature increase time. A temperature control method for an injection molding machine, characterized in that: