JP2018008423A - Injection molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding apparatus by which, when screws are exchanged, a zone of a heating cylinder is divided automatically and appropriately according to the kind of screw to control temperature, and other control is switched automatically.SOLUTION: An injection molding apparatus (1) is configured such that a wireless IC tag (11) is provided for each screw (3), the tag storing unique data, namely, specification data, wherein the data is read by the injection molding apparatus when the screw is mounted. The injection molding machine (1) is controlled based on the read specification data. For example, when information on the switching of the zones, namely, zone information, is used as specification data, and if the screw (3) is mounted, the zones (H1, H2, ...) are switched automatically based on the zone information on identification ID (11).SELECTED DRAWING: Figure 1

Description

  The present invention relates to an injection molding machine including a heating cylinder and a screw, and relates to an injection molding machine capable of replacing a screw or a heating cylinder.

  The injection molding machine is conventionally known and includes a mold clamping device that clamps a mold, an injection device that injects resin into the clamped mold, and the like. The injection device is composed of a heating cylinder and a screw that can be driven in the axial direction and the rotation direction in the heating cylinder, the heating cylinder is provided with a hopper at the rear and an injection nozzle at the front, A plurality of band heaters are provided on the outer peripheral surface. When the heating cylinder is heated by the band heater and the pellet-shaped resin is supplied from the hopper and the screw is rotated, the pellet-shaped resin is melted in the heating cylinder, kneaded by the screw, and sent to the front of the screw. When the screw is retracted by the molten resin and an appropriate amount is measured in front of the screw, the screw stops rotating. When the screw is driven forward in the axial direction, the molten resin is injected from the injection nozzle.

  By the way, a flight is formed on the screw, but its shape is not uniform in the axial direction but changes depending on the place. For example, in a general screw, a groove between flights changes in three sections of a rear section, an intermediate section, and a front section in the axial direction. Specifically, in the rear section close to the hopper, the grooves between the flights are formed deeply so that the pellet-shaped resin can be smoothly fed forward, and in the intermediate section, gradually toward the front in the axial direction. The resin formed and melted so as to become shallow is compressed and kneaded, and the front section is made shallow and the melted and kneaded resin is sent forward at a predetermined pressure. The rear section can be called a feed section, the intermediate section can be called a compression section, and the front section can be called a measuring section.

  Corresponding to such a screw, the heating cylinder can be independently temperature controlled in a plurality of zones divided in the axial direction. That is, a temperature sensor is embedded in each zone, and a band heater provided on the outer peripheral surface is PWM controlled to be managed at a desired temperature. The number of zones that are independently temperature controlled differs depending on the injection molding machine. For example, in an injection molding machine in which a heating cylinder is divided into first to fifth zones, the temperature is controlled as follows. The first zone close to the hopper and supplied with the pellet-shaped resin is controlled to a temperature at which the resin does not form a bridge in the hopper and a temperature at which the resin is preheated and easily melted. The second zone following the first zone is controlled at a relatively high temperature so as to efficiently melt the resin and substantially eliminate the ungelled resin. The third zone corresponding to the compression portion of the screw is controlled so that the temperature does not become too high because the resin is compressed and generates heat. A fourth zone following the third zone is controlled to a transition temperature from heat adjustment for compression to heat retention. The fifth zone, which is the foremost zone of the heating cylinder, is controlled to a temperature suitable for keeping the measured resin warm. When the resin is heated to a high temperature, the fluidity becomes high and a molded product having excellent transferability can be obtained. However, if the resin is too high, it may cause burning or discoloration. Accordingly, it is necessary to appropriately manage the temperature, but since the heating cylinder is controlled in temperature independently in a plurality of zones, it is possible to appropriately manage the temperature.

JP-A-11-300805 JP-A-6-71715

  The position of each zone whose temperature is controlled independently in the heating cylinder is generally fixed in the injection molding machine. However, Patent Document 1 discloses an injection molding machine that can change the position of such a zone. Has been. The injection molding machine described in this document is provided with more band heaters than the number of zones in the heating cylinder. Each band heater can be manually switched to a desired zone. Accordingly, in the heating cylinder having five zones as described above, the third zone for compressing the molten resin is lengthened, the fifth zone for weighing is shortened, and the length of each zone is set. Can be adjusted. Thus, since the length of each zone can be adjusted, even if the kind of resin changes or the injection capacity changes, it is possible to appropriately manage the temperature of the heating cylinder.

  Patent Document 2 describes an injection molding machine in which a screw and a heating cylinder that can be selected and attached from a plurality of screws having different diameters and flight shapes can be attached. In this injection molding machine, the screw condition data for all the attachable screws is stored in the storage area in the controller. Specifically, screw diameter, flight shape, maximum injection pressure, maximum holding pressure, injection motor torque limit, injection stroke, maximum injection speed, maximum rotation speed, metering motor torque limit, and the like. In this injection molding machine, when the operator replaces the screw, the operator inputs the diameter of the screw and the shape of the flight from the screen provided in the controller of the injection molding machine. Then, the injection molding machine reads out the screw condition data that matches the input screw diameter and flight shape from the storage area. As a result, screw condition data such as the maximum injection pressure and maximum holding pressure of the screw can be obtained. The molding conditions for appropriately molding the molded product change when the screw is replaced, but this injection molding machine automatically converts the molding conditions based on the obtained screw condition data. Accordingly, even if the screw is replaced, the molded product can be formed in substantially the same manner. In this injection molding machine, when there is a molding condition that does not match the screw condition data, for example, when there is a molding condition such that the injection pressure exceeds the maximum injection pressure of the screw, a warning is output. Therefore, safety is ensured to prevent accidents caused by screw replacement.

  In the injection molding machine, as described above, the heating cylinder is divided into a plurality of zones in the axial direction and independently controlled in temperature, so that the pellet-shaped resin is appropriately melted and compressed and kneaded. It can be weighed and is excellent. Moreover, it can be said that the injection molding machine described in Patent Document 1 is excellent because the length of each zone can be adjusted according to the type of resin and the injection capacity. However, there are also problems to be solved. Specifically, there is no guarantee that the number of divided zones of the heating cylinder or the length of each zone is optimal. The injection molding machine can replace the screw according to the purpose. The shape of the flight varies depending on the type of screw, and the position and length of the feed unit, compression unit, and weighing unit are different. The position of each zone of the heating cylinder is adjusted to an average position so that it can be generally handled even when such different types of screws are replaced. Therefore, a certain level of temperature control is possible. However, it is not necessarily adjusted to the optimum number of zones and zone positions for the screw. Then, for a predetermined type of screw, the third zone that assumes compression in the heating cylinder may be displaced with respect to the compression portion of the screw, and the temperature may not be appropriately controlled.

  By the way, in the injection molding machine described in Patent Document 2, screw condition data relating to replaceable screws is stored for all the screws, and if the screw diameter of the replaced screw and the shape of the flight are input, the corresponding screw is obtained. Condition data is read. This injection molding machine is excellent because it automatically converts molding conditions so as to conform to the screw condition data. It is also conceivable to change the zone of the heating cylinder in accordance with the screw to be replaced by applying the method described in Patent Document 2. However, the injection molding machine described in Patent Document 2 requires data input by an operator to specify the replaced screw. That is, it is necessary to input the screw diameter and the flight shape. However, such an input operation is complicated and may cause mistakes. If there is a mistake in the input, different screw condition data will be read, which is dangerous. Furthermore, there is a problem that the screw condition data must be stored in advance. It is cumbersome to memorize all replaceable screws. In addition, there is a problem that it is not possible to install a new screw that does not store the screw condition data.

  An object of the present invention is to solve the above-described problems. Specifically, when a screw is replaced, a zone of a heating cylinder is appropriately divided according to the type of screw, and each zone is appropriately heated. It is an object of the present invention to provide an injection molding machine which is controlled or automatically set and controlled on the basis of data inherent to the screw when the screw is replaced. .

  In order to achieve the above object, the present invention is directed to an injection molding machine in which a screw can be replaced. A wireless IC tag is provided on the screw, and specification data that is data unique to the screw is stored. Once the screw is installed, the specification data is read by the injection molding machine. This specification data is read into the controller, and the injection molding machine is controlled based on the specification data. The heating cylinder is provided with a plurality of band heaters larger than the number of zones, and the zone to which each band heater belongs is automatically switched corresponding to the attached screw. The band heater is provided in the heating cylinder at equal intervals, and the same number of temperature sensors as the band heater are provided in the heating cylinder so as to correspond to the band heater.

Thus, the invention according to claim 1 is an injection molding comprising a heating cylinder and a screw that is rotationally driven in the axial direction and the rotational direction in the heating cylinder, and the screw is replaceable. In the machine, the screw is provided with a wireless IC tag in which specification data relating to the screw is stored. When the screw is attached to the injection molding machine, the specification data is read, and based on the specification data. The injection molding machine is configured to be controlled, and is configured as an injection molding machine.
According to a second aspect of the present invention, in the injection molding machine according to the first aspect, the heating cylinder is divided into a plurality of zones in the axial direction so that the temperature of each zone is independently controlled. An injection molding machine characterized in that a plurality of band heaters greater than the number of zones are provided, and the zones to which each band heater belongs are automatically switched based on the read specification data. Configured as
According to a third aspect of the present invention, there is provided the injection molding machine according to the second aspect, wherein the band heater is provided in the heating cylinder at equal intervals in the axial direction. .
According to a fourth aspect of the present invention, in the injection molding machine according to the second or third aspect, in the heating cylinder, the same number of temperature sensors as the plurality of band heaters correspond to each of the band heaters. It is comprised as an injection molding machine characterized by being provided.

  As described above, according to the present invention, an injection molding machine that includes a heating cylinder and a screw that is rotationally driven in the axial direction and the rotation direction in the heating cylinder and in which the screw is replaceable is an object. It is said. The screw is provided with a wireless IC tag storing specification data relating to the screw. When the screw is attached to the injection molding machine, the specification data is read, and the injection molding machine is controlled based on the specification data. It is comprised so that. In other words, when the screw is replaced, the specification data for the screw is automatically read into the controller. The specification data includes, for example, an injection pressure limit value, a maximum plasticizing capacity, and the like. However, the molding conditions can be automatically changed based on such specification data, and the injection molding machine can be controlled. And since it is only necessary to read the specification data stored in the wireless IC tag, even if a new screw is attached, it can be controlled appropriately. Moreover, there is no room for operator error regarding the reading of the specification data. According to another invention, the heating cylinder is divided into a plurality of zones in the axial direction so that the temperature of each zone is independently controlled, and a plurality of band heaters more than the number of zones are provided and read. Based on the specification data, the zone to which each band heater belongs is automatically switched. Depending on the type of screw, the lengths of the feed unit, compression unit, and metering unit differ, but each zone of the heating cylinder is adjusted to an appropriate length according to the type of screw. The zone temperature is guaranteed to be properly managed. According to another invention, the band heaters are provided in the heating cylinder at equal intervals in the axial direction. Therefore, the adjustment of the zone length has a high degree of freedom. As a result, a zone suitable for the screw is set. According to another invention, the heating cylinder is provided with the same number of temperature sensors as the plurality of band heaters corresponding to each band heater. Since the same number of temperature sensors as the band heater is provided, each band heater can be individually controlled based on the temperature detected from the temperature sensor, and the temperature set in the zone to which it belongs can be controlled with high accuracy. It becomes possible to do.

It is a front view which shows the injection molding machine which concerns on embodiment of this invention in a partial cross section. It is a front view which shows the injection molding machine which concerns on the 2nd Embodiment of this invention in a partial cross section.

  Hereinafter, an injection molding machine according to an embodiment of the present invention will be described. The injection molding machine according to the present embodiment is composed of a mold clamping device for clamping a mold, an injection device 1 for injecting resin into the mold, and the like, as in a conventional injection molding machine. As shown in FIG. 1, the injection device 1 includes a heating cylinder 2 and a screw 3 provided in the heating cylinder 2 so as to be driven in the rotational direction and the axial direction. An injection nozzle 5 is provided at the front end of the heating cylinder 2, and a hopper 6 is provided near the rear end.

  In the injection device 2 according to the present embodiment, a large number of band heaters 7a, 7b,... Are provided on the outer peripheral surface of the heating cylinder 2, and the same number of temperature sensors 8a, 8b,. There is a great feature in that it is embedded in the heating cylinder 2. In the present embodiment, 16 band heaters and temperature sensors are provided. That is, the first to sixteenth band heaters 7a, 7b,... And the first to sixteenth temperature sensors 8a, 8b,. In the present embodiment, the first to sixteenth band heaters 7a, 7b,... Have the same width and are provided at equal intervals in the axial direction. As will be described below, the heating cylinder 2 can be controlled in temperature for each zone divided in the axial direction, but the number 16 of band heaters 7a, 7b,. The first to sixteenth temperature sensors 8a, 8b,... Made of thermocouples are embedded in the heating cylinder 2 at positions corresponding to the first to sixteenth band heaters 7a, 7b,.

  Similarly to the conventional injection molding machine, the injection molding machine according to the present embodiment is also provided with a controller 14 for controlling a mold clamping device, an injection device, and the like. In the controller 14, first to sixteenth PWM controllers 15a, 15b,... Corresponding to the first to sixteen band heaters 7a, 7b,. The first to sixteenth PWM controllers 15a, 15b,... Are inputted with the temperature of the heating cylinder 2 from the first to sixteenth temperature sensors 8a, 8b,. The first to sixteenth band heaters 7a, 7b,. By the way, the heating cylinder 2 has a target temperature set for each zone divided in the axial direction. In this embodiment, the heating cylinder 2 is divided into five, that is, the first to fifth zones H1, H2,..., And the target temperature in the first to fifth zones H1, H2,. It is stored in the setter, the H2 temperature setter,. These target temperatures are given to the first to sixteenth PWM controllers 15a, 15b,... Via the switcher 17, and the first to sixteenth band heaters 7a, 7b,. , H2,... Is controlled based on any target temperature. That is, the first to sixteenth band heaters 7a, 7b,... Belong to one of the first to fifth zones H1, H2,.

  As is well known, the shape of the flight of the screw 3 changes in the axial direction, and can be divided into a feed portion, a compression portion, and a weighing portion from the rear to the front. Each zone of the heating cylinder 2 has a first zone H1 corresponding to the feed portion, a third zone corresponding to the compression portion, and a fifth zone corresponding to the metering portion. The second zone H2 and the fourth zone H4 Corresponds to a connecting portion between the feed portion and the compressing portion, and a connecting portion between the compressing portion and the measuring portion. Incidentally, in the injection molding machine according to the present embodiment, the screw 3 can be replaced in the same manner as the conventional injection apparatus. As for the screw 3, the length of a feed part, a compression part, and a measurement part changes with kinds. In the injection molding machine according to the present embodiment, when the screw 3 is replaced, the lengths of the first to fifth zones H1, H2,... Are automatically changed so as to be suitable for the screw 3. In other words, when the screw 3 is replaced, the zones H1, H2,... To which the first to sixteenth band heaters 7a, 7b,.

  In order to realize such switching of the zones H1, H2,... Of the first to sixteenth band heaters 7a, 7b,. The specification data includes, for example, screw diameter, maximum plasticizing capacity, injection pressure limit value, etc., and any specification data regarding the screws 3, 3,... May be used in the present embodiment. The data is zone information about the screws 3, 3,. The specification data including such zone information is stored in the RFID, that is, the wireless IC chip 11 and attached to the screw 3. When the screw 3 is attached, the specification data is read from the wireless IC chip 11 in the detection unit 12 on the injection device 1 side. In the present embodiment, the specification data is zone information, and is data designating which zone H1, H2,... Belongs to the first to sixteenth band heaters 7a, 7b,. The switcher 17 sets the first to sixteenth band heaters 7a, 7b,... Based on the read zone information to the designated zones H1, H2,. In the example shown in FIG. 1, the first to fourth band heaters 7a, 7b,..., 7d are in the first zone H1, the fifth and sixth band heaters 7e, 7f are in the second zone H2, The seventh to tenth band heaters 7g,..., 7j are in the third zone H3, the eleventh and twelfth band heaters 7k, 7l are in the fourth zone H4, and the thirteenth to sixteenth zones 7m,. Are set in the fifth zone H5. The first to sixteenth PWM controllers 15a, 15b,..., 15p perform temperature control according to the set zones H1, H2,. As described above, when the screw 3 is replaced, the injection molding machine according to the present embodiment automatically zoning the heating cylinder 2 to fit the screw 3, so that the heating cylinder 2 is appropriately temperature-controlled. It will be possible.

  Next, a second embodiment of the present invention will be described. FIG. 2 shows an injection device 1 ′ of an injection molding machine according to the second embodiment, but the same members as those of the injection device 1 according to the previous embodiment are denoted by the same reference numerals and description thereof is omitted. To do. In the second embodiment, a temperature sensor is not provided for each band heater, and only the first to fourth temperature sensors 8A, 8B,... Are embedded. These first to fourth temperature sensors 8A, 8B,... Correspond to the first to fourth zones H1, H2,..., Respectively, and the first to fourth PWM controllers 15A, 15B,. The temperature is entered in…. In the second embodiment, the band heaters are provided with the first to sixteenth band heaters 7a, 7b,... As in the previous embodiment, but these are divided into two types. The band heater belonging to the first type is fixedly assigned to a predetermined zone. That is, the first and second band heaters 7a and 7b are assigned to the first zone H1 and controlled by the first PWM controller 15A, and the fifth and sixth band heaters 7e and 7f are assigned to the second zone H2. The eighth and ninth band heaters 7h and 7i are assigned to the third zone H3 and controlled by the third PWM controller 15C, and are controlled by the second PWM controller 15B. The heaters 7k and 7l are assigned to the fourth zone H4 and controlled by the fourth PWM controller 15D, and the fourteenth and fifteenth band heaters 7n and 7o are assigned to the fifth zone H5 and are controlled by the fifth PWM. It is controlled by the controller 15E. On the other hand, the zone to which the band heater belonging to the second type belongs is switched according to the type of the screw 3 to be attached. That is, the seventh band heater 7g is selectively switched from the second and third zones H2 and H3 so that the third and fourth band heaters 7c and 7d are selectively switched from the first and second zones H1 and H2. The tenth band heater 7j is selectively switched from the third and fourth zones H3 and H4, and the thirteenth band heater 7m is selected from the fourth and fifth zones H4 and H5. Each can be switched automatically. Switching of the band heater belonging to the second type is performed by the switch 17 'of the controller 14'. Also in the injection molding machine according to the second embodiment, the zoning of the heating cylinder 2 is optimally performed by the screw 3 to be attached, and the temperature can be appropriately controlled.

  The injection molding machine according to the embodiment of the present invention can be variously modified. For example, although it has been described that there are 16 band heaters, it may be smaller or larger. Also, the zoning of the heating cylinder 2 can be modified. In the description of the present embodiment, the zone of the heating cylinder 2 has been described as being divided into five in the axial direction, but may be divided into three, four, or six. In the description of the present embodiment, when the screw 3 is attached, the specification data is read from the wireless IC tag 11, and the zones H1, H2,... To which the first to sixteenth band heaters 7a, 7b,. It explained so that it could be switched to. That is, the point that the length of each zone H1, H2,. On the other hand, the number of zones of the heating cylinder 2 can be modified so as to change depending on the type of the screw 3 to be attached. In other words, the number of zones is also stored as a kind of specification data. When a predetermined type of screw 3 is attached, the number of zones is set to three, and when another type of screw 3 is attached, the number of zones is set. You may make it five.

  Furthermore, the injection molding machine according to the present embodiment can be modified. In the present embodiment, the specification data of the screws 3, 3,... Has been described as being zone information. However, other data may be adopted as the specification data. For example, as specification data, screw diameter, screw material, maximum plasticizing capacity, temperature setting limit value of each zone, maximum measuring stroke, maximum screw rotation speed, maximum screw rotation torque, maximum injection speed, injection pressure limit value, holding pressure Limit values, suck back speed limit values, plasticizing ability, etc. can be considered. .. Are stored in the wireless IC tag 11, and if specification data is obtained from the attached screws 3, 3,..., Control is performed based on the specification data. be able to. For example, if the maximum screw rotation torque is stored as the specification data, the screws 3, 3,... Are controlled within the maximum torque rotation torque when the resin is kneaded to prevent the heating cylinder 2 and the screw 3 from being damaged. Can be extended. If the maximum injection speed is stored as the specification data, it can be controlled at a safe injection speed.

1 Injection device 2 Heating cylinder 3 Screw
7a, 7b, ... 1st to 16th band heaters 8a, 8b, ... 1st to 16th temperature sensors 11 Wireless IC chip 12 Detection unit 14 Controllers 15a, 15b, ... 1st to 16th PWM controllers 17 Switch H1 , H2, ... 1st to 5th zones

Claims (4)

In an injection molding machine comprising a heating cylinder and a screw that is rotatably driven in the axial direction and the rotation direction in the heating cylinder, the screw being replaceable,
The screw is provided with a wireless IC tag storing specification data regarding the screw,
When the screw is attached to the injection molding machine, the specification data is read, and the injection molding machine is controlled based on the specification data. 2. The injection molding machine according to claim 1, wherein the heating cylinder is divided into a plurality of zones in an axial direction so that the temperature of each zone is independently controlled, and a plurality of bands larger than the number of zones are set. An injection molding machine, wherein a heater is provided and a zone to which each band heater belongs is automatically switched based on the read specification data. 3. The injection molding machine according to claim 2, wherein the band heater is provided in the heating cylinder at equal intervals in the axial direction. The injection molding machine according to claim 2 or 3, wherein the heating cylinder is provided with the same number of temperature sensors as the plurality of band heaters corresponding to each of the band heaters. Injection molding machine.

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