Heating barrel insulation method and device for injection molding machines

Abstract

To ensure good responsiveness during temperature control while maintaining heating and cooling functions including good insulation to improve mass productivity by shortening a molding cycle and improve yield rate by reducing defective products.SOLUTION: A heating barrel insulation device includes: a heat insulating layer part 4 that is attached to an outer periphery 3f of a heating part 3 and has a vacuum controlled space 5 formed therein; vacuum means 6 for enabling the vacuum controlled space 5 to be evacuated; sealing means 7 for sealing the vacuum controlled space 5; and sealing release means 8 for releasing the sealing of the vacuum controlled space 5. During temperature control of a heating barrel 2, the sealing means 7 or the sealing release means 8 is switched and controlled in accordance with a state of the temperature control, and at least the vacuum controlled space 5 is switched to a vacuum insulation mode Mv or a vacuum insulation release mode Mr.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for insulating a heater barrel of an injection molding machine that is suitable for use in insulating the heater barrel of an injection molding machine, and a heater barrel insulating device used to implement the method. [Background technology]

[0002] Generally, the injection device that constitutes an injection molding machine is equipped with a heating barrel that plasticizes the resin material that is fed into it, and since its temperature control requires accuracy and responsiveness, it is equipped with a heating section equipped with a band heater or the like on the outer periphery of the heating barrel, and a cooling section equipped with a jacket or the like that has an air-cooling function.Known examples of injection molding machines equipped with such heating and cooling means include the temperature control device for an injection molding machine described in Patent Document 1 and the injection device described in Patent Document 2.

[0003] The temperature control device for an injection molding machine in Patent Document 1 controls the cooling function and heating function in a coordinated manner, performing highly stable control that avoids hunting and the like, and aims to achieve a temperature control device that is excellent in energy conservation while ensuring high control accuracy. It is equipped with a molding machine controller that detects the heating temperature of a specified part in the heating barrel using a temperature sensor and controls the heating part that heats the specified part and the cooling part that cools the specified part so that the detected temperature becomes a preset temperature, calculates the deviation value between the detected temperature and the set temperature, and performs PID control so that this deviation value becomes zero, and is configured with a PID control system that outputs only one of the relatively larger operation amounts to the corresponding heating part or cooling part: a heating operation amount that is generated using the I operation output, D operation output, deviation value, and heating-side proportional band and controls the heating part, and a cooling operation amount that is generated using the I operation output, D operation output, deviation value, and cooling-side proportional band and controls the cooling part.

[0004] In addition, the injection device in Patent Document 2 has a heating cylinder divided into a plurality of zones in the axial direction, and each zone has a plurality of band heaters wrapped around the outer surface of the heating cylinder, a plurality of heat insulating covers provided on the outside of the band heaters, and cooling means that supplies air independently from the outside to each heat insulating cover, so that each zone is independently temperature controlled.The injection device also has a predetermined suction means and a Stirling engine, and the suction means sucks air from each heat insulating cover, and the Stirling engine is configured to be driven using the sucked air as a heat source to generate electricity. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2016-083867 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-112775 Summary of the Invention [Problem to be solved by the invention]

[0006] However, conventional injection molding machines equipped with the above-mentioned heating and cooling means have the following problems to be solved.

[0007] That is, in this type of injection molding machine, temperature control is performed by switching between heating means and cooling means, so basically, it is necessary to switch between the heating means and cooling means and to directly transmit the heating temperature from the heating means and the cooling temperature from the cooling means to the heating barrel to perform temperature control on the heating side and temperature control on the cooling side.

[0008] On the other hand, since the target temperature for the heating barrel must usually be maintained at a high temperature of several hundred degrees Celsius, not only the capacity of the heating means but also the heat insulation capacity of the heat retention means, i.e., the insulation means, is important. Usually, an insulating cover or the like is used as the insulation means. While the addition of an insulating cover to improve insulation is advantageous during heating (when the temperature rises), a side effect is that it significantly reduces the responsiveness when switching from heating to cooling. In particular, if the temperature remains high for a long period of time, this can lead to molding defects such as resin burning.

[0009] As described above, in an injection molding machine equipped with a conventional heating / cooling means, it is not easy to improve responsiveness during temperature control while maintaining good heating and cooling functions, and there has been a demand for an improved heating / cooling means that can improve both of these capabilities, i.e., heat insulation capability and high responsiveness in temperature control.

[0010] SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for insulating the heater barrel of an injection molding machine which solves the problems present in the background art. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, the heating barrel insulating method for an injection molding machine 1 according to the present invention is characterized in that, when insulating at least a heating barrel 2 equipped with a heating section 3, an insulating layer section 4 is attached to the outer periphery 3f of the heating section 3 and has a vacuum-controlled space 5 formed therein, a vacuum means 6 that enables the vacuum-controlled space 5 to be evacuated, a sealing means 7 that enables the vacuum-controlled space 5 to be sealed, and a sealing release means 8 that releases the sealing of the vacuum-controlled space 5, and during temperature control of the heating barrel 2, the sealing means 7 or the sealing release means 8 is switched and controlled according to the temperature control state, so that during heating control in which the heating section 3 is turned ON to heat the heating barrel 2, the vacuum-controlled space 5 is switched and controlled to a vacuum insulation mode Mv, and during cooling control in which the heating section 3 is turned OFF to release the heating of the heating barrel 2, the vacuum-controlled space 5 is switched and controlled to a vacuum insulation release mode Mr.

[0012] In addition, in order to solve the above-mentioned problems, the heating barrel insulation device 10 of the injection molding machine 1 according to the present invention is characterized in that, when configuring a heating barrel insulation device that insulates at least a heating section 3 mounted thereon, it comprises an insulation layer section 4 that is attached to the outer periphery 3f of the heating section 3 using band heaters 3b..., covers all or part of the outer periphery 3bf... of the band heaters 3b..., and is configured in a band shape with a ring-shaped vacuum-controlled space 5 inside, a vacuum means 6 that makes the vacuum-controlled space 5 evacuable, a sealing means 7 that makes the vacuum-controlled space 5 sealable, a sealing release means 8 that releases the sealing of the vacuum-controlled space 5, and a molding machine controller 11 that switches and controls the sealing means 7 or the sealing release means 8 in accordance with the state of the temperature control when controlling the temperature of the heating barrel 2, and switches at least the vacuum-controlled space 5 to vacuum insulation mode Mv or vacuum insulation release mode Mr.

[0013] In this case, according to a preferred embodiment of the invention, during cooling control, the inside of the vacuum-controlled space 5 can be suctioned by the vacuum means 6, and outside air Ao can be circulated through the vacuum-controlled space 5. Meanwhile, when configuring the heating barrel insulation device 10, the vacuum means 6 can be a vacuum pump 6p that suctions the inside of the vacuum-controlled space 5. Furthermore, the sealing means 7 can be a check valve 7v connected between the vacuum-controlled space 5 and the vacuum means 6, and the sealing release means 8 can be an on-off valve 8v connected between the vacuum-controlled space 5 and the atmosphere Ao. [Effects of the Invention]

[0014] The heating barrel insulating method and heating barrel insulating device 10 for the injection molding machine M according to the present invention have the following significant effects.

[0015] (1) The heat insulating layer 4 is attached to the outer periphery 3f of the heating section 3 and has a vacuum-controlled space 5 formed therein, a vacuum means 6 that allows the vacuum-controlled space 5 to be evacuated, a sealing means 7 that allows the vacuum-controlled space 5 to be sealed, and a sealing release means 8 that releases the sealing of the vacuum-controlled space 5. The sealing means 7 or the sealing release means 8 are switched depending on the temperature control state, and at least the vacuum-controlled space 5 is switched to vacuum insulation mode Mv or vacuum insulation release mode Mr. This ensures good responsiveness during temperature control while maintaining heating and cooling functions, including good heat insulation. This improves mass productivity by shortening the molding cycle and improves yield by reducing defective products.

[0016] (2) During heating control, in which the heating unit 3 is turned on to heat the heating barrel 2, the mode is switched to the vacuum insulation mode Mv, and during cooling control, in which the heating unit 3 is turned off to cancel heating of the heating barrel 2, the mode is switched to the vacuum insulation cancellation mode Mr. This can be used for the normal temperature control sequence related to the temperature control of the heating barrel 2. This makes it possible to achieve optimal temperature control for the heating barrel 2.

[0017] (3) Since the band heater 3b is used for the heating unit 3, it is possible to configure the heating unit 3 in the same manner as a conventional heating unit 3 that uses a band heater 3b. This allows for easy implementation without any particular changes to the configuration or layout of the heating unit 3.

[0018] (4) The band heater 3b is configured to cover all or part of the outer peripheral surface 3bf and has a band-like shape with a ring-shaped vacuum control space 5 inside, so this can be implemented without significantly changing the overall radial size of the heating barrel 2. This makes it possible to avoid unnecessary complication and an increase in size of the injection molding machine 1.

[0019] (5) In a preferred embodiment, during cooling control, the inside of the vacuum-controlled space 5 is suctioned by the vacuum means 6, and outside air Ao is circulated through the vacuum-controlled space 5, thereby realizing a cooling function by air-cooling action.

[0020] (6) In a preferred embodiment, when constructing the heating barrel insulation device 10, if a vacuum pump 6p that sucks the inside of the vacuum control space 5 is used as the vacuum means 6, the suction action on the vacuum control space 5 can be reliably achieved, so that the mode can be easily switched to the vacuum insulation mode Mv. Furthermore, when switched to the vacuum insulation cancellation mode Mr, the mode can also be used as a blower function to circulate outside air Ao, so that the air cooling function can be easily achieved.

[0021] (7) In a preferred embodiment, if a check valve 7v connected between the vacuum control space 5 and the vacuum means 6 is used in the sealing means 7, the sealing means 7 can be constructed simply by adding the check valve 7v, which contributes to facilitating implementation of the sealing means 7 and reducing costs.

[0022] (8) In a preferred embodiment, if the sealing release means 8 uses an on-off valve 8v connected between the vacuum-controlled space 5 and the atmosphere Ao, the sealing release means 8 can be configured simply by adding the on-off valve 8v, which contributes to facilitating the implementation of the sealing release means 8 and reducing costs. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of an entire control system including a cross-sectional side view of an injection unit in an injection molding machine equipped with a heater barrel heat insulating device according to a preferred embodiment of the present invention; [Figure 2] Overall system diagram of the heating barrel insulation device, [Figure 3] FIG. 2 is a cross-sectional front view showing an outline of the state in which the heating barrel insulation device is attached to the heating barrel; [Figure 4] FIG. 2 is a cross-sectional side view showing an outline of the state in which the heating barrel insulation device is attached to the heating barrel; [Figure 5] FIG. 2 is an external perspective view showing each component of the heating barrel insulation device; [Figure 6] 1 is a flowchart for sequentially explaining a heating barrel insulation method according to a preferred embodiment of the present invention; [Figure 7] FIG. 10 is an explanatory diagram of the operation of the vacuum insulation mode when the heating barrel insulation method is implemented; [Figure 8]FIG. 10 is an explanatory diagram of the operation of the vacuum insulation cancellation mode when the heating barrel insulation method is implemented; DETAILED DESCRIPTION OF THE INVENTION

[0024] Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0025] First, an outline of an injection molding machine 1 equipped with a heating barrel insulation device 10 according to this embodiment will be described with reference to FIG.

[0026] 1, 1i denotes an injection unit, and this injection unit 1i and a mold clamping unit (not shown) constitute an injection molding machine 1. The injection unit 1i includes a heating barrel 2, which has an injection nozzle 2n at its front end and is connected at its rear end to a material supply unit 21 that has a hopper 21h for feeding a resin material into the heating barrel 2. A screw 22 is inserted into the heating barrel 2, and the rear end of the screw 22 extends rearward from the material supply unit 21 to connect to a screw drive unit 23 (not shown in detail) that drives the screw 22 to rotate and move back and forth.

[0027] The outer peripheral surface 2f of the heating barrel 2 and the outer peripheral surface 2nf of the injection nozzle 2n are provided with multiple heating sections 3... arranged sequentially along the axial direction Fs. That is, five heating sections 3... are provided, respectively attached to the injection nozzle 2n, the front portion of the heating barrel 2, the middle portion of the heating barrel 2, the rear portion of the heating barrel 2, and the rearmost portion of the heating barrel 2. Each heating section 3... incorporates a heating element and uses a band heater 3b... wrapped around the outer peripheral surface 2f... and 2nf.... By using band heaters 3b... as the heating sections 3, a heating section 3 similar to a conventional heating section 3 using band heaters 3b... can be constructed, which can be easily implemented without any particular changes to the configuration or layout of the heating section 3. Meanwhile, a heat insulating layer 4... is attached to the outer peripheral surface 3f... of each heating section 3.... Each heat insulating layer 4... constitutes the heating barrel insulation device 10 according to this embodiment, which is a key part of the present invention.

[0028] Next, the configuration of the heating barrel insulation device 10 according to this embodiment will be specifically described with reference to FIGS. 1 to 5. FIG.

[0029] As shown in Figures 1 to 3, the above-mentioned heating barrel insulation device 10 includes a total of five heat insulating layers 4... attached to the outer circumferential surface 3f... of each heating section 3.... The heat insulating layer 4 (the same applies to the other heat insulating layers 4...) covers all or part of the outer circumferential surface 3bf of the band heater 3b and is configured in a band shape with a ring-shaped vacuum control space 5 inside. By configuring the heat insulating layer 4 in this way, it can be implemented without significantly changing the overall radial size of the heating barrel 2, thereby avoiding unnecessary complication and an increase in size of the injection molding machine 1.

[0030] 5(a)-(c) show external perspective views of the components that make up the heat insulating layer 4. Note that (d) shows the band heater 3b. (a) shows the outer panel 25 that makes up the outermost part of the heat insulating layer 4, (b) shows the vacuum-controlled space-forming panel 26 that is arranged inside the outer panel 25, and (c) shows the inner panel 27 that is arranged inside the vacuum-controlled space-forming panel 26 and abuts against the outer peripheral surface 3bf of the band heater 3b.

[0031] In this case, the outer panel 25, the vacuum-controlled space-forming panel 26, and the inner panel 27 can each be formed from a single stainless steel panel approximately 1-2 mm thick. The outer panel 25 is formed as a single rectangular panel, with a pair of round-bar-shaped bolt insertion rods 25s and 25t fixed to both ends of the panel by welding or the like. A first connecting pipe 25i and a second connecting pipe 25o, which protrude outward from the outer peripheral surface and communicate with the inner peripheral surface, are fixed near the bolt insertion rods 25s and 25t. The vacuum-controlled space-forming panel 26 is formed as a rectangular frame, with outlet holes 26x formed near one end of the panel in the longitudinal direction (circumferential direction) through which multiple cable outlet pipes 3bx (see (d)) for guiding the cables of the band heater 3b are inserted. The inner panel 27 is also formed as a single rectangular panel.

[0032] The outer panel portion 25, the vacuum-controlled space forming panel 26, and the inner panel portion 27 are then stacked as shown in Figures 3 and 4. This forms a single panel-shaped heat insulating layer portion 4, and inside it is formed a ring-shaped hollow air jacket that is sealed except for the first connecting pipe portion 25i and the second connecting pipe portion 25o, i.e., the vacuum-controlled space 5.

[0033] The heat insulating layer 4 has a vacuum-controlled space 5 therein, and therefore can be implemented in various forms. For example, the inner surface of the heat insulating layer 4 (the inner panel 27 side) is attached to the outer periphery 3f of the heating unit 3 mounted on the heating cylinder 2. Therefore, if the inner diameter of the inner surface of the heat insulating layer 4 is formed to fit the outer periphery 3f, the heat insulating layer 4 may be integrally assembled in advance by welding or the like. Alternatively, the outer panel 25 and the vacuum-controlled space-forming panel 26, or the vacuum-controlled space-forming panel 26 and the inner panel 27 may be integrally formed. Furthermore, when attaching the heat insulating layer 4 to the outer periphery 3f of the heating unit 3, the inner panel 27, the vacuum-controlled space-forming panel 26, and the outer panel 25 may be stacked in this order, and the bolt insertion rods 25s and 25t of the outer panel 25 may be fastened and fixed with bolts and nuts B. To prevent air leakage, packing or the like may be inserted between the outer panel 25 and the outer panel 25, as needed.

[0034] Next, the configuration of the heating barrel insulation device 10 other than the heat insulating layer portions 4 will be described mainly with reference to FIGS.

[0035] 2, one end of check valves 7v constituting the sealing means 7 is connected to the second connecting pipes 25o of each heat insulating layer 4, and the other ends of the check valves 7v are joined together to connect to the suction port of the vacuum pump 6p constituting the vacuum means 6. Reference numeral 31 denotes a motor that drives the vacuum pump 6p.

[0036] In this way, if the sealing means 7 uses a check valve 7v connected between the vacuum-controlled space 5 and the vacuum means 6, the sealing means 7 can be constructed simply by adding the check valve 7v, which contributes to easier implementation and lower costs related to the sealing means 7.In addition, if the vacuum means 6 uses a vacuum pump 6p that sucks the inside of the vacuum-controlled space 5, the suction action on the vacuum-controlled space 5 can be reliably achieved, so that it is possible to easily switch to the vacuum insulation mode Mv.In addition, when switched to the vacuum insulation release mode Mr, it can also be used as a blower function to circulate outside air Ao, so that the air-cooling function can be easily achieved.

[0037] 2, one end of an on-off valve 8v using a solenoid valve constituting the seal releasing means 8 is connected to the first connecting pipe portion 25i of the heat insulating layer 4 (the same is true for the other heat insulating layer portions 4, etc.), and the other end of the on-off valve 8v is open to the atmosphere Ao. As a result, the on-off valve 8v is connected between the vacuum-controlled space 5 and the atmosphere Ao. In this way, if the on-off valve 8v is used as the seal releasing means 8, the seal releasing means 8 can be constructed simply by adding the on-off valve 8v, which contributes to easier implementation and lower costs.

[0038] The cable of the band heater 3b that constitutes the heating unit 3 is led out through cable lead-out pipes 3bx... and connected to the output side of the power supply unit 32. 33... indicate temperature sensors (thermocouples) that measure the temperatures of each part of the heating barrel 2 including the injection nozzle 2n, i.e., the injection nozzle and the front, middle, rear and rearmost parts of the heating barrel.

[0039] The power supply unit 32, the vacuum pump 6p, and each on-off valve 8v... are connected to an output port of the molding machine controller 11, and each temperature sensor 33... is connected to a sensor input port of the molding machine controller 11. The molding machine controller 11 basically includes a controller main body with built-in hardware such as a CPU, and also includes an internal memory such as a hard disk managed by this controller main body. Therefore, the molding machine controller 11 is configured as a computer system and has the function of managing the overall control of the injection molding machine 1. Furthermore, the molding machine controller 11 includes a sequence control program for executing the heating barrel insulation method according to this embodiment, and also includes peripheral devices such as a display (not shown).

[0040] Next, the heating barrel insulating method according to this embodiment will be described mainly according to the formula chart shown in FIG. 6 with reference to FIGS.

[0041] Assume that the injection molding machine 1 is currently in a stopped state (step S1). In this state, the vacuum pump 6p and the band heaters 3b are in the OFF position, and the on-off valve 8v is in the closed position Sc. In this state, it is assumed that a heating command is output from the molding machine controller 11 (step S2).

[0042] As a result, the vacuum pump 6p is turned ON and the band heaters 3b are turned ON (steps S3 and S4). As a result, as shown in FIG. 7, the air A inside the vacuum-controlled space 5 is sucked in by the vacuum pump 6p, and the vacuum-controlled space 5 is switched to the vacuum insulation mode Mv, in which a vacuum is created inside the vacuum-controlled space 5. At this time, once a predetermined vacuum state is achieved, the vacuum pump 6p may be turned OFF if necessary. Even in this case, the check valves 7v are connected to the second connecting pipe portions 25o, so the vacuum-controlled space 5 remains sealed. In other words, the first connecting pipe portions 25i are kept closed by the on-off valves 8v, so the vacuum state of the vacuum-controlled space 5 is maintained.

[0043] Furthermore, the heating barrel 2 is heated by the ON position of the band heaters 3b, and the temperatures detected by the temperature sensors 33 are transmitted to the molding machine controller 11, so that the molding machine controller 11 monitors the temperature rise state of the heating barrel 2 (step S5). When the detected temperature reaches a predetermined temperature target value set in advance, the molding machine controller 11 executes a temperature control process using PID control (feedback control) for the temperature to maintain the temperature target value (steps S6 and S7).

[0044] On the other hand, once the temperature has stabilized, the predetermined molding process, i.e., the production process, can be carried out. When the production process is completed, necessary termination processes such as stopping the operation of the injection molding machine 1 are carried out (steps S8 and S9).

[0045] On the other hand, suppose that during production processing, the temperature of the heating barrel 2 rises excessively, and a cooling command is output from the molding machine controller 11 (steps S8, S10). As a result, the on-off valve 8v is controlled to switch to the open position So, and the band heaters 3b... are controlled to switch to the OFF position (steps S11, S12). Also, if the vacuum pump 6p is OFF, it is switched ON (step S13).

[0046] As a result, as shown in Fig. 8, outside air Ao flows into the vacuum-controlled space 5 through the on-off valve 8v, and the vacuum-controlled space 5 is switched to the vacuum insulation cancellation mode Mr. Moreover, the inside of the vacuum-controlled space 5 is suctioned by the vacuum pump 6p, so that outside air Ao flows inside the vacuum-controlled space 5. In other words, a cooling function by air cooling can be achieved.

[0047] In this way, when implementing the heating barrel insulation method, during heating control, the heating unit 3 is turned ON to heat the heating barrel 2, and during heating control, the mode is switched to the vacuum insulation mode Mv, and during cooling control, the heating unit 3 is turned OFF to release the heating of the heating barrel 2, and the mode is switched to the vacuum insulation release mode Mr. This can be used for the normal temperature control sequence related to the temperature control of the heating barrel 2, and optimal temperature control for the heating barrel 2 can be achieved.

[0048] The heating barrel insulation method (heating barrel insulation device 10) for the injection molding machine 1 according to this embodiment includes an insulation layer 4 attached to the outer periphery 3f of the heating section 3 and having a vacuum-controlled space 5 formed therein, a vacuum means 6 for evacuating the vacuum-controlled space 5, a sealing means 7 for sealing the vacuum-controlled space 5, and a sealing release means 8 for releasing the sealing of the vacuum-controlled space 5. The sealing means 7 or the sealing release means 8 are switched depending on the temperature control state, switching at least the vacuum-controlled space 5 between vacuum insulation mode Mv or vacuum insulation release mode Mr. This ensures good responsiveness during temperature control while maintaining good heating and cooling functions, including good insulation. This improves mass productivity by shortening the molding cycle and improves yield by reducing defective products.

[0049] Although the preferred embodiment has been described in detail above, the present invention is not limited to such an embodiment, and the detailed configuration, shape, material, quantity, numerical values, etc. can be changed, added, or deleted as desired within the scope that does not deviate from the gist of the present invention.

[0050] For example, while the embodiment illustrates an application to a heating barrel 2 equipped with a heating unit 3, the present invention can be applied similarly to a heating barrel 2 equipped with both a heating unit 3 and a cooling unit. In this case, during cooling control, the vacuum means 6 may be stopped and only the vacuum state may be released. That is, only the vacuum state of the vacuum-controlled space 5 may be released, and it is not necessary to circulate outside air Ao through the vacuum-controlled space 5. Furthermore, during cooling control, the vacuum pump 6p may be switched to a blower means using a fan or the like, without using the vacuum pump 6p. Furthermore, various vacuum pumps 6p can be used as the vacuum means 6, and they can be replaced with means having similar functions. Furthermore, although a check valve 7v is used as the sealing means 7 and an on-off valve 8v is used as the sealing release means 8, a control valve may be connected as needed to appropriately adjust the vacuum level. [Industrial Applicability]

[0051] The heater barrel insulating method and heater barrel insulating device according to the present invention can be used to insulate heater barrels provided in various injection molding machines. [Explanation of symbols]

[0052] 1: injection molding machine, 2: heating barrel, 3: heating section, 3f: outer periphery of heating section, 3b: band heater, 3bf: outer periphery of band heater, 4: heat insulating layer, 5: vacuum control space, 6: vacuum means, 6p: vacuum pump, 7: sealing means, 7v: check valve, 8: sealing release means, 8v: on-off valve, 10: heating barrel heat insulating device, 11: molding machine controller, Mv: vacuum insulation mode, Mr: vacuum insulation release mode, Ao: outside air

Claims

1. a heat insulating layer attached to the outer periphery of the heating unit and defining a vacuum-controlled space therein; a vacuum means for creating a vacuum in the vacuum-controlled space; a sealing means for sealing the vacuum-controlled space; and a sealing release means for releasing the sealing of the vacuum-controlled space. The method for insulating a heating barrel of an injection molding machine includes: a heat insulating layer attached to the outer periphery of the heating unit and defining a vacuum-controlled space therein; a vacuum means for creating a vacuum in the vacuum-controlled space; a sealing means for sealing the vacuum-controlled space; and a sealing release means for releasing the sealing of the vacuum-controlled space. The method switches between the sealing means and the sealing release means depending on the temperature control state during temperature control of the heating barrel; and switches between the vacuum-controlled space and the vacuum insulation mode during heating control, in which the heating unit is turned on to heat the heating barrel; and switches between the vacuum-controlled space and the vacuum insulation release mode during cooling control, in which the heating unit is turned off to release the heating of the heating barrel.

2. 2. The method for insulating a heater barrel of an injection molding machine according to claim 1, wherein, during the cooling control, the inside of the vacuum controlled space is suctioned by the vacuum means, and outside air is circulated through the vacuum controlled space.

3. a molding machine controller that controls the switching of the sealing means or the sealing release means in accordance with the state of the temperature control during temperature control of the heating barrel, and switches at least the vacuum-controlled space between a vacuum insulation mode and a vacuum insulation release mode; and a molding machine controller that controls the switching of the sealing means or the sealing release means in accordance with the state of the temperature control during temperature control of the heating barrel, and switches at least the vacuum-controlled space between a vacuum insulation mode and a vacuum insulation release mode.

4. 4. The heating barrel heat insulating device for an injection molding machine according to claim 3, wherein said vacuum means uses a vacuum pump for sucking the inside of said vacuum control space.

5. 4. The heater barrel heat insulating device for an injection molding machine according to claim 3, wherein said sealing means is a check valve connected between said vacuum control space and said vacuum means.

6. 4. The heater barrel heat insulating device for an injection molding machine according to claim 3, wherein said sealing release means is an on-off valve connected between said vacuum controlled space and the atmosphere.

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