JP6083362B2 - Method for replacing intrusion resin in injection device of injection molding machine - Google Patents

Description

  The present invention relates to a method for replacing an intrusion resin in an injection apparatus of an injection molding machine.

  In the molding work of injection molded products using an injection molding machine, resin materials used as raw materials, such as changes in resin materials accompanying changes in injection molded products, and changes in the color of resin materials, even for the same injection molded products It is necessary to replace the resin. The resin replacement operation will be briefly described. In the molding cycle, after the injection filling is completed, the molding operation is stopped, and the injection device is separated from the resin injection hole of the fixed mold. Then, the screw in the injection device is advanced to the vicinity of the injection advance limit position, rotated with a predetermined back pressure applied, and the resin material remaining in the injection device is discharged (purged) from the nozzle at the tip of the injection device. . After the resin material is no longer discharged from the nozzle, supply of a new resin material is started. After that, when the new resin material is plasticized (melted) and discharged from the nozzle, plasticization of the new resin material in the injection device is interrupted, and the injection device is again fixed to the mold. To the resin injection hole. Thereafter, a molding operation using a new material is started, and the resin replacement operation is completed. A method for performing such a resin changing operation is referred to as an intrusion resin changing method.

  Separately from the above, placing emphasis on the discharge of the resin material remaining in the injection device, the injection device is once separated from the fixed mold, and the screw rotation operation, retraction operation, and advance operation are combined. After the resin material remaining in the nozzle is almost completely discharged (purged) from the nozzle, if a new resin material is supplied or if the injection-molded product is the same, the material of the injection device is simply kept while continuing the molding operation. There is also a method of switching the resin material supplied to the supply unit, but in these resin replacement methods, it takes a lot of time to completely switch from the previous resin material to the new resin material, and the resin discharged during that time There has been a problem that the material and the resin molded product to be molded are wasted due to the mixed state of the old and new resin materials. In addition, the resin changing work including the intrusion resin changing method largely depends on the operator's visual confirmation, experience and intuition, and there are many manual operations by checking and operating each time. Therefore, with the automation of molding operations, in recent years, automation of these resin changing operations has been desired.

  Patent Document 1 discloses an injection molding machine that can automatically select a suitable resin change operation control condition when changing resin. Patent Document 2 discloses a purge operation for accurately detecting when the resin discharged from the plasticizer is exhausted when the purge operation is automatically performed in the plasticizer (injection device) of the injection molding machine. A stopping method is disclosed. Further, Patent Document 3 discloses that even when a mixed resin generated at the time of resin switching is used as a material for a molded product, a defect does not appear on the surface of the molded product, and molding with the mixed resin can be performed together with a resin switching operation. An injection molding method is disclosed.

JP 2008-195023 A JP 2006-088557 A JP 2001-018253 A

  In the injection molding machine of Patent Document 1, it is possible to automatically select a suitable resin change operation control condition at the time of resin change. There is no description on whether the resin changing operation is automated. Further, in the method of stopping the purge operation of Patent Document 2, when the purge operation is automatically performed, the plasticizer can be accurately detected by detecting when the resin discharged from the plasticizer (injection device) runs out. It is said that it can prevent problems such as increased internal wear and residual resin burn (burn), but resin replacement work including purge operation, such as when to start supplying new resin materials This is not necessary when automating Furthermore, in the injection molding method of Patent Document 3, by connecting two injection units (injection devices), the mixed resin generated at the time of resin switching is the core layer, and the desired resin (new resin material) is the skin layer. The above-mentioned problem in resin replacement is solved by forming a sandwich molded product. However, an injection molding machine dedicated to sandwich molding, which has a plurality of injection units (injection devices) and an injection unit coupling device that couples these injection units, is premised, and this injection molding method is used in a general-purpose injection molding machine. It is difficult to do. The sandwich molded product is a resin molded product molded so that the core layer (inner layer) is substantially completely included in the skin layer (surface layer).

  The present invention has been made in view of the above-described problems. Specifically, even in a general-purpose injection molding machine, the resin switching time can be shortened and the resin replacement operation can be automated. An object of the present invention is to provide a method for replacing an intrusion resin in an injection device of an injection molding machine.

In order to achieve the above object, an intrusion resin replacement method for an injection device of an injection molding machine according to the present invention,
A screw rotation load factor Z1 _L after the first resin is supplied to the material supply unit of the injection device and the plasticized first resin is continuously discharged from the nozzle of the injection device;
After the first resin is continuously discharged, the supply of the first resin to the material supply unit is stopped, and the first resin is not discharged from the nozzle of the injection device. From the screw rotation load factor Z0 of
Screw rotation load in a state in which the first resin is filled from the nozzle of the injection device to a distance L _{X in} the screw longitudinal direction with respect to the screw longitudinal direction distance L from the nozzle of the injection device to the material supply unit Rate Z1 _X ,
It is defined by the formula Z1 _X = (Z1 _L −Z0) / L × L _X + Z0,
In the intrusion resin change from the first resin to the second resin, after monitoring the screw rotation load factor Z and stopping the supply of the first resin to the material supply unit, the screw rotation load factor Z is In the above formula, the first resin is not substantially completely discharged, and a screw longitudinal distance in which a space not filled with resin is formed between the first resin and the second resin to be supplied later Up to L _X , the supply of the second resin is started within the range of the set value A of the screw rotation load factor Z in the state where the first resin is filled.

That is, the data Z1 _L (Zet One _L ) and Z0 (Zet Zero) are obtained in advance by test molding or the like, and in the screw in the injection device, how far the first resin is discharged (purged) from the nozzle in the screw longitudinal direction. Is converted into a screw rotation load factor Z (zette). From this formula, the discharge state of the first resin (the remaining state of the first resin in the injection device) is grasped from the screw rotation load factor Z, and the first resin and the second resin are not completely discharged. The supply of the second resin can be started within the range of the set value A, which is the timing at which the first resin is discharged, up to a distance at which a space not filled with resin is formed between the resins.

  This set value A is due to metal contact between the screw in the injection apparatus and other components such as a heating cylinder, because the first resin is discharged too much and the screw is in a substantially complete cantilever state in the injection apparatus. While preventing wear and damage, by forming a space in which the resin is not filled between the first resin and the second resin to be introduced later, the mixed state of the first resin and the second resin is changed. This is the timing for starting the supply of the second resin, which can be avoided until the final stage of the resin change and the mixing state of the first resin and the second resin in the resin change can be suppressed to the shortest (time) and minimum (amount). As a result, the resin change time from the first resin to the second resin in the resin change can be greatly shortened.

Further, in the intrusion resin changing method for an injection device of an injection molding machine according to the present invention, the upper limit value of the set value A is expressed by the above equation, where L _X is a compression portion of the screw from the nozzle of the injection device. The screw rotation load factor Z _AU when the distance to the starting position of
The lower limit of the set value A, in the formula, L _X are preferably from the nozzle of the injection device and the screw rotating load factor Z _AL when the distance to the start position of the metering portion of the screw.

In general, the screw of an injection device is supplied from the material supply unit side in accordance with the characteristics of the resin material used for injection molding, from the supply unit (feed zone), the compression unit (compression zone), and the metering unit (metering zone). ) (Screw diameter, length, flight specifications, etc.) are designed. Therefore, as described above, the upper limit value Z _AU (Zet AY) and the lower limit value Z _AL (Zet AEL) of the set value A are based on the position of L _X (LX) that can be easily obtained from the design specifications of the screw. If it can be set, the set value A corresponding to the screw of the injection device of the injection molding machine to be used can be set before the molding operation regardless of the experience and intuition of the operator who operates the injection molding machine. It is suitable for automation of work.

Furthermore, in the intrusion resin replacement method for an injection device of an injection molding machine according to the present invention, when the screw rotation load factor Z0 is obtained in advance, the first resin is not discharged from the nozzle of the injection device. A screw rotation load after the second resin is supplied to the material supply unit of the injection device and the plasticized second resin is continuously discharged from the nozzle of the injection device. Find the rate Z2 _L ,
The set value of screw rotational load factor Z for starting the production in the second resin B, it is preferred to the screw rotating load factor Z2 _L.

Normally, in the resin change, whether or not the switching between the old and new resin materials is completely completed is determined by the operator visually checking the plasticized resin material discharged from the nozzle of the injection device or the molded resin molded product. It is performed by a method of making a judgment based on confirmation, or by using empirical data such as the elapsed time from the switching time of the new and old resin materials and the number of moldings. On the other hand, as described above, the set value B of the screw rotation load factor Z for starting production with the second resin is changed from the screw rotation load factor Z2 _L (Zet-to- _L ), that is, from the nozzle of the injection device to the second resin. By using the screw rotation load factor Z after a continuous discharge state, the point at which the switching of the new and old resin materials to be completed is completed before the molding operation, regardless of visual confirmation or empirical data by the operator. This is suitable for automating the resin changing operation.

On the other hand, in the above formula, the screw rotation load factor Z _C when L _X is the distance from the nozzle of the injection device to the end point position of the screw metering section is set as the set value C, and the screw rotation load factor Z is When the set value C is reached, it is preferable that at least one of the screw rotation stop and the alarm operation is performed.

As described above, when the first resin is discharged too much and the screw is in a substantially complete cantilever state in the injection device, the screw and other components such as a heating cylinder are in metal contact in the injection device, There is a risk of wear and damage to the contact area. Such is also dangerous condition the screw is substantially complete cantilever, as the set value C of the screw rotating load factor Z, the screw rotating load factor Z _{C (Zettoshi),} readily obtained from the screw design specifications if it is possible to set based on the position of the L _X, regardless of the operator's experience and intuition, it is possible to set before the molding operation, can be performed automatically the operation of the rotation stop and an alarm of the screw, It is suitable for ensuring the safety of automation of resin replacement work.

Similarly, when the screw rotation load factor Z2 _L is obtained in advance, after the first resin is no longer discharged from the nozzle of the injection device, the second resin is supplied to the material supply unit, The time T2 required until the plasticized second resin is continuously discharged from the nozzle of the injection device is obtained,
If the screw rotation load factor Z does not reach the set value B after the required time T2 has elapsed from the start of the supply of the second resin, or before the required time T2 has elapsed since the start of the supply of the second resin, Even when the rate Z reaches the set value B or exceeds the set value B, it is preferable that at least one of the screw rotation stop and the alarm operation is performed.

  In the former case, there is some abnormality on the upstream material supply unit side, the second resin may not be supplied as set, and the resin may be out of service. In the latter case, there is a possibility that the second resin is supplied in excess of the set value and the resin is clogged. If such a dangerous state can be determined to be a dangerous state by combining data obtained in advance, it can be set before the molding operation regardless of the operator's experience and intuition, and the rotation of the screw Stopping and alarming can be performed automatically, which is suitable for ensuring safety of automation of resin changing work.

An intrusion resin changing method for an injection device of an injection molding machine according to the present invention is as follows:
A screw rotation load factor Z1 _L after the first resin is supplied to the material supply unit of the injection device and the plasticized first resin is continuously discharged from the nozzle of the injection device;
After the first resin is continuously discharged, the supply of the first resin to the material supply unit is stopped, and the first resin is not discharged from the nozzle of the injection device. From the screw rotation load factor Z0 of
Screw rotation load in a state in which the first resin is filled from the nozzle of the injection device to a distance L _{X in} the screw longitudinal direction with respect to the screw longitudinal direction distance L from the nozzle of the injection device to the material supply unit Rate Z1 _X ,
It is defined by the formula Z1 _X = (Z1 _L −Z0) / L × L _X + Z0,
In the intrusion resin change from the first resin to the second resin, after monitoring the screw rotation load factor Z and stopping the supply of the first resin to the material supply unit, the screw rotation load factor Z is In the above formula, the first resin is not substantially completely discharged, and a screw longitudinal distance in which a space not filled with resin is formed between the first resin and the second resin to be supplied later In order to start the supply of the second resin within the range of the set value A of the screw rotation load factor Z in the state where the first resin is filled up to L _X, even if it is a general-purpose injection molding machine, It is suitable for automating the resin changing operation while shortening the resin switching time.

It is a schematic sectional drawing which shows the injection apparatus of the injection molding machine based on Example 1 of this invention. It is the schematic which shows the inside of the injection apparatus of the injection molding machine in which the 1st resin was in the state discharged | emitted continuously after starting supply of 1st resin. It is the schematic which shows the inside of the injection apparatus of the injection molding machine which became the state from which the supply of 1st resin was stopped from the state of FIG. 2 and the 1st resin was not discharged | emitted. In the injection device, in the longitudinal direction of the screw, in order to supplementary explanation of the graph showing the relationship between the distance L _X from the nozzle filled with the first resin and the screw rotation load factor Z1 _X in that state, and the same graph, It is the schematic which shows the inside of the injection device of an injection molding machine. Schematic showing the inside of the injection apparatus of the injection molding machine when the supply of the second resin is started when the screw rotation load factor Z is the upper limit value of the set value A after stopping the supply of the first resin in the resin changing operation. FIG. Schematic showing the inside of the injection apparatus of the injection molding machine when the supply of the second resin is started when the screw rotation load factor Z is the lower limit value of the set value A after the supply of the first resin is stopped in the resin changing operation. FIG. It is the schematic which shows the inside of the injection apparatus of the injection molding machine from which the supply of 2nd resin was started from the state of FIG. 3, and the 2nd resin was in the state discharged | emitted continuously. It is the schematic which shows the inside of the injection apparatus of an injection molding machine when the screw rotational load factor Z reaches | attains the setting value C in resin replacement | exchange operation | work. It is the schematic which shows the inside of the injection apparatus of the injection molding machine assumed when the screw rotation load factor Z does not reach the setting value B after the predetermined time T2 elapses from the supply start of the second resin in the resin changing operation. It is the schematic which shows the inside of the injection apparatus of the injection molding machine assumed when the screw rotation load factor Z reaches | attains the setting value B before predetermined time T2 progress after supply start of 2nd resin in resin replacement | exchange operation | work.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. For ease of explanation, FIG. 1 does not show the configuration other than the injection device such as a fixed plate, a fixed mold, and a movable mold of the injection molding machine. 2 to 10 are schematic views showing the inside of the injection apparatus of the injection molding machine shown in FIG. 1, and therefore, components other than those necessary for explanation are not shown.

  An intrusion resin changing method for an injection device of an injection molding machine according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 6. Since this intrusion resin changing method is an intrusion resin changing method in a general-purpose injection molding machine, no special configuration is required on the injection device side. Therefore, first, a basic configuration of an injection device 1 of a general injection molding machine will be described with reference to FIG.

  A nozzle 13 is disposed at the end of the heating cylinder 15 (not shown) on the stationary platen (left side in FIG. 1), and a material supply unit 14 is disposed above the outer peripheral surface of the other end (right side in FIG. 1). The heating cylinder 15 has a screw 16 disposed therein so as to be rotatable about its longitudinal axis, and the resin flow path 10 is formed between the inner peripheral surface of the heating cylinder 15 and the outer peripheral surface of the screw 16. . Here, in order to simplify the description, the nozzle 13 side (left side in FIG. 1) of the heating cylinder 15 is defined as “front” of the injection device 1, and the other side (right side in FIG. 1) is defined as “rear” of the injection device 1. 16 and the movement of the resin material in the respective directions are referred to as “advance” and “retreat”.

  Next, details of each basic configuration will be described. Heating means 15 a such as an electric heater is disposed around the outer peripheral surfaces of the heating cylinder 15 and the nozzle 13. Further, the material supply unit 14 above the rear outer peripheral surface of the heating cylinder 15 is generally a material supply hopper whose upper part can be opened widely, and a resin in the hopper is provided by a level sensor or the like disposed in the hopper. While monitoring the amount of material, the resin material is often supplied in batches from the outside. However, when the frequency of resin change or resin color change is high, or when automating the resin change operation, a material supply device is attached upstream or a material supply means such as a material supply pipe is directly connected as necessary. Or connected.

  A screw head 17 is formed at the front end of the screw 16, and the resin pellet supplied from the material supply unit 14 by rotating the screw 16 in the resin flow path 10 on the outer peripheral surface after the screw head 17. A flight 16a for continuously flowing a resin material such as the resin material 10 to the front nozzle 13 side in the resin flow path 10 is formed.

  Here, while the pellet-like (granular) resin material supplied from the material supply unit 14 flows to the front nozzle 13 side in the resin flow path 10, the heat energy from the heating means 15 a and the rotating flight 16. Is heated by shearing heat energy generated by contact with the resin material or between the resin materials, and is converted into a molten state (plasticized state). Therefore, the screw 16 of the injection apparatus 1 is supplied from the material supply unit 14 side according to the characteristics of the resin material to be used, from the supply unit 16F (feed zone), the compression unit 16P (compression zone), and the metering unit 16M (metering). Each zone (screw diameter, length, flight specification, etc.) is designed.

  In a normal molding cycle, the nozzle 13 is docked to a fixed mold (not shown), and the shut-off switching valve provided in the nozzle 13 side or the connection hole on the fixed mold side is closed, as shown in FIG. At the position of the screw 16 (injection screw advance limit position), the screw 16 is rotated. In this way, the plasticized resin material is continuously stored in the storage portion on the nozzle 13 side, and the screw 16 is retracted as the storage amount increases (metering step). Then, after the desired amount of molten resin is stored in the storage section, the rotation of the screw 16 is stopped, the shut-off switching valve is opened, and then the screw 16 is moved forward at a predetermined injection pressure and injection speed to store it. The molten resin in the part is injected and filled into a mold cavity (not shown) (injection filling step). In the weighing process and the injection filling process, a check ring 18 (also referred to as a check ring) is arranged between the screw head and the flight 16a so as to be movable in the longitudinal axis direction of the screw 16. The flow of the molten resin in an unintended direction is prevented. In addition, let the screw head part 16H be from the front end of the measurement part 16M of the screw 16 (end point position of the measurement part 16M) to the front end of the screw head 17 including the check ring 18.

  On the other hand, in the intrusion resin changing method, as described above, in the molding cycle, after the injection filling is completed, the molding operation is stopped, the injection device is once separated from the fixed mold, and then at the injection screw advance limit position. The screw is rotated, and the old and new resin materials are discharged from the nozzle of the injection device to change the resin. The intrusion resin changing method according to Example 1 of the present invention will be described with reference to FIGS. 2 to 6.

In Example 1, the resin is changed from the first resin 14a to the second resin 14b. First, the screw rotation load factor Z1 _L and the screw rotation load factor Z0 are obtained by test molding or the like instead of main molding. Specifically, as shown in FIG. 2, the screw 16 is rotated to supply the first resin 14 a to the material supply unit 14. As described above, the screw 16 is advanced to the injection screw advance limit position or the vicinity thereof, rotated with a predetermined back pressure applied, and the screw 16 is retracted as in the measuring step in a normal molding cycle. I won't let you.

When the supply of the first resin 14a and the rotation of the screw 16 are continued, the inside of the injection device 1 is filled with the first resin 14a, and the plasticized first resin 14a is continuously discharged from the nozzle 13. The screw rotation load factor Z in this state is measured, and this is set as the screw rotation load factor Z1 _L. Here, in FIG. 2 (hereinafter, the same applies to other drawings), the first resin 14a is indicated by small round dots. However, the small round dots do not indicate the state as a resin material such as pellets, but an injection device. The area | region filled with the 1st resin 14a in 1 is shown.

In the case of an electric injection device, the screw rotational load factor Z is not particularly limited as long as it is a numerical value representing the rotational load factor of the screw 16, such as the rotational torque and rotational speed of the screw rotary motor, and the current value and voltage value. There is no. In the hydraulic injection device that rotates the screw 16 with a hydraulic motor or the like, the hydraulic oil pressure of the hydraulic oil supply line to the screw rotation driving means such as the hydraulic motor may be used. Further, even after only the first resin 14a is continuously discharged, the screw rotation load factor Z during monitoring does not always show a stable value, and there may be some fluctuations. In consideration of such fluctuations, it is preferable to adopt an average value or the like within a predetermined time, or use the average value as a reference value and make the fluctuation range an allowable range. Screw rotation load factor Z1 _L is also similar.

Next, after the screw rotation load factor Z1 _L is measured, the supply of the first resin 14a to the resin supply unit 14 is stopped while the rotation of the screw 16 is continued. By stopping the supply of the first resin 14a, as shown in FIGS. 3A and 3B, the first resin 14a in the injection apparatus 1 is continuously discharged, and finally, FIG. ), The first resin 14a is not in the range where the flight 16a of the screw 16 is formed. In this state, since the screw head portion 16H has no flight 16a or the like, the first resin 14a in the screw head portion 16H cannot be discharged from the nozzle 13 even if the rotation of the screw 16 is continued. And the screw rotational load factor Z in this state is measured, and this is made into the screw rotational load factor Z0. Similarly to the screw rotation load factor Z1 _L , it is preferable that the screw rotation load factor Z0 is an average value taking into account the fluctuation of the screw rotation load factor Z within a predetermined time, or an allowable range is determined.

Here, when the screw longitudinal direction distance from the nozzle 13 of the screw 16 of the injection device 1 to the material supply unit 14 is L, the entire inside of the injection device 1 is filled with the first resin 14a, that is, the first resin. 14a is screw rotational load factor Z in a state which is filled from the nozzle 13 of the injection device 1 to the distance L of the screw longitudinal direction is Z1 _L. On the other hand, the state in which the first resin 14a is not discharged from the nozzle 13 of the injection device 1, that is, the state in which the first resin 14a is discharged (purged) from the nozzle 13 of the injection device 1 to a distance 0 (zero) in the screw longitudinal direction. The screw rotation load factor Z at is Z0.

Based on these assumptions, in the state in which the first resin 14a is discharged, unless the numerical values related to the rotational load factor of the screw 16 (screw rotational torque, rotational speed, screw back pressure, etc.) are intentionally changed, The screw rotation load factor Z1 _X in a state where 1 resin 14a is filled from the nozzle 13 of the injection device 1 to the distance L _{X in the} screw longitudinal direction (0 <L _X <L) is Z0 <Z1 _X <Z1 _L In addition, a linear relationship is established between Z1 _X , Z0, and Z1 _L. This is shown in FIG. The upper graph of FIG. 4 shows the distance L _X (resin remaining distance from the nozzle) from the nozzle 13 filled with the first resin 14a and the screw rotation load in that state in the longitudinal direction of the screw in the injection apparatus 1. 4 is a graph showing the relationship of the ratio Z1 _X , and the lower part of FIG. 4 shows an injection molding machine in which the first resin 14a is filled from the nozzle 13 of the injection device 1 to a distance L _{X in the} screw longitudinal direction in the graph. It is the schematic which shows the inside of the injection device.

Thus, from the graph of FIG. 4, the screw rotating load factor Z1 _X in a state which is filled from the nozzle 13 of the injection device 1 to a distance _{L X} of the screw longitudinally formula _{Z1 X = (Z1 L -Z0)} / It can be defined by L × L _X + Z0 (hereinafter referred to as formula α (alpha)). With this formula α, when changing the intrusion resin, it is possible to monitor the screw rotation load factor Z and grasp the discharge state of the first resin 14a (the remaining state of the first resin 14a in the injection device 1). Become. This is important for determining the timing for starting the supply of the second resin 14b regardless of the experience and intuition of the operator who operates the injection molding machine.

The timing for starting the supply of the second resin 14b is that the first resin 14a is discharged too much and the screw 16 is in a substantially complete cantilever state in the injection apparatus 1, and the first resin 14a and the second resin 14b are supplied. In order to avoid a mixed state with the resin 14b, it is preferable to be a timing at which a space not filled with the resin can be formed between the first resin 14a and the second resin 14b. Since the discharge state of the first resin 14a can be grasped from the screw rotational load factor Z to be monitored by the above-described Z1 _L and Z0 and the above-described formula α, the screw of the injection device 1 of the injection molding machine to be used is used. The above timing is determined as a set value A having a predetermined range related to the screw rotation load factor Z based on the design specifications of 16, and the second time when the screw rotation load factor Z reaches the range of the set value A. It is possible to start the supply of the resin 14b.

Specifically, as shown in FIG. 5A, the distance L _{X in the} screw longitudinal direction from the nozzle 13 of the injection apparatus 1 is the starting position of the compression section 16P of the screw 16 (the end position of the supply section 16F). Until the first resin 14a is discharged, the supply of the second resin 14b is started. The screw rotation load factor Z _{AU at} this timing can be obtained by substituting a numerical value (from the design specification of the screw 16) that becomes the starting position of the compression portion 16P of the screw 16 into L _X in the above-described formula α.

That is, decrease screw rotation load factor Z being monitored, if starting the supply of the second resin 14b at the stage of reaching the Z _AU, as shown in FIG. 5 (b) and FIG. 5 (c), the The first resin 14a is discharged from the nozzle 13 while maintaining a space (air layer) that is not filled with the resin between the first resin 14a in the injection device 1 and the second resin 14b that has been supplied. Then, the second resin 14b flows to the nozzle 13 side. When the first resin 14a remains in the screw head portion 16H and is no longer discharged from the nozzle 13, only the second resin 14b flows to the nozzle 13 side, reducing the distance of the space between the first resin 14a and the first resin 14a. The air layer in the space is compressed. After that, as shown in FIG. 5D, the second resin 14b reaches the screw head portion 16H, and the first resin 14a is discharged from the nozzle 13 so as to be pushed by the second resin 14b, and at the same time compressed. The first resin 14a is ejected (discharged) from the nozzle 13 by the jetting force of the air layer thus formed. The jet of the first resin 14a from the nozzle 13 by the jet output of the compressed air layer is suitable for improving the discharge effect of the first resin 14a. Thereafter, after the discharge in the mixed state of the first resin 14a and the second resin 14b continues for a predetermined time, the second resin 14b is continuously discharged from the nozzle 13 to the second resin 14b. The resin change is completed.

  Thus, at the above timing, the screw 16 is in a stable state in which the front is rotationally supported by the first resin 14a and the rear is rotationally supported by the second resin 14b. Moreover, the space which is not filled with resin can be ensured between the 1st resin 14a and the 2nd resin 14b, and the mixed state of the 1st resin 14a and the 2nd resin 14b is avoided until the last stage of resin change. Can do. By such resin replacement, the mixed state of both resins can be suppressed to the shortest (time) and minimum (amount). Here, in FIG. 5 (hereinafter, the same applies to the other figures), the second resin 14b is displayed with gray shading, but the gray shading indicates a state as a resin material such as a molten state. Instead, it shows a region filled with the second resin 14b in the injection apparatus 1. As shown on the left side of FIG. 5D, the display is different from the dot display of the first resin 14a in view of the fact that the mixed state with the first resin 14a can also be shown.

  Moreover, in the screw of the injection device of a general injection molding machine, the transport speed (flow speed to the front of the screw) of the resin in each part of the supply unit 16F, the compression unit 16P, and the measurement unit 16M by the rotation of the screw 16 is According to the behavior of each resin in the molten (plasticized) state, the supply unit 16F is the fastest, and the compression unit 16P and the metering unit 16M become slower in this order.

Here, the distance L _X of the screw longitudinally from the nozzle 13 of the injection device 1, a distance with a supply portion 16F of the screw 16, the first resin 14a is to initiate the supply of the second resin 14b in discharged timing In some cases, depending on the timing, due to the difference in the transport speed of the resin of each part of the screw 16 described above, the space between the two resins is extremely reduced during the resin change, and the first resin 14a becomes Before flowing to the screw head portion 16H, the front end of the flow portion of the second resin 14b catches up with the rear end of the flow portion of the first resin 14a, and the first resin 14a and the second resin 14b are likely to be mixed. When such a mixed state of both resins occurs, the jet power generated by the compressed air layer is also reduced, and the discharge effect of the first resin 14a is inevitably reduced. Therefore, as described above, the screw rotating load factor Z _AU based on start position of the compression section 16P (end position of the supply portion 16F) of the screw 16, to start the supply of the second resin 14b, the screw rotating load factor Z The upper limit value of the set value A is preferably used.

On the other hand, as shown in FIG. 6 (a), from the nozzle 13 of the injection device 1 screw longitudinal distance L _X is a until measuring section 16M of the origin position of the screw 16 (the end position of the compression portion 16P), the The supply of the second resin 14b may be started at the timing when the first resin 14a is discharged. Screw rotation load factor Z _AL at this timing also, in the above formulas alpha, obtained by substituting a numerical value as a starting point the position of the measuring portion 16M of the screw 16 (from the design specifications of the screw 16) to L _X. Also at this timing, since the first resin 14a is filled in at least the metering portion 16M in the front of the injection apparatus 1, the screw 16 is stably supported at two front and rear positions similarly to the previous timing. As shown in FIGS. 6 (b) and 6 (c), a space that is not filled with resin is secured between the first resin 14a and the second resin 14b more than the previous timing. can do.

However, when the supply start of the second resin 14b is delayed more than this timing (on the nozzle 13 side from the starting position of the measuring portion 16M of the screw 16), the first resin 14a is discharged too much and the screw 16 is in a cantilever state. The possibility of becoming close to increases. Therefore, the screw rotation load factor Z _AL, to start the supply of the second resin 14b, it is preferable that the lower limit of the set value A of the screw rotating load factor Z.

  When the first resin 14a remains in the screw head portion 16H and is not discharged from the nozzle 13, only the second resin 14b flows to the nozzle 13 side, and the distance of the space portion between the first resin 14a and the first resin 14a is increased. Shrinking, the air layer in the space is compressed. Thereafter, as shown in FIG. 6D, the second resin 14b reaches the screw head portion 16H, and the first resin 14a is discharged from the nozzle 13 so as to be pushed by the second resin 14b. It is ejected (discharged) from the nozzle 13 by the jet output of the compressed air layer. Subsequent resin replacement is the same as the resin replacement at the previous timing. In FIG. 6, since the distance of the space portion is longer than that in the case shown in FIG. 5 and the jet power of the compressed air layer is also large, the discharge effect of the first resin 14a remaining in the screw head portion 16H becomes larger. The efficiency of resin replacement can be increased.

  In the first embodiment, the timing for starting the supply of the second resin 14b is based on the design specifications of the screw 16 of the injection device 1 of the injection molding machine to be used, regardless of the experience and intuition of the operator. The specific example of determining the set value A having a predetermined range related to the load factor Z has been described. However, it is denied that the determined range of the set value A is appropriately changed based on the experience and intuition of the operator. Not what you want.

  Next, an intrusion resin changing method for an injection device of an injection molding machine according to Embodiment 2 of the present invention will be described with reference to FIG. The difference between the second embodiment and the first embodiment is that a set value B of the screw rotation load factor Z for starting production with the second resin 14b is determined. Other configurations of the injection device of the injection molding machine and the intrusion resin changing method are basically the same as those in the first embodiment. Therefore, the same components are denoted by the same reference numerals as those in the first embodiment, and overlapping descriptions are provided. Omit.

  In the method for replacing the intrusion resin of the injection device of the injection molding machine according to the first embodiment of the present invention, the screw of the injection device 1 of the injection molding machine to be used irrespective of the experience and intuition of the operator who operates the injection molding machine. The timing for starting the supply of the second resin 14b can be determined based on the 16 design specifications. However, if automation of the intrusion resin replacement operation is premised, the operator's experience and intuition will also be given regarding the timing when the resin replacement from the first resin 14a to the second resin 14b is completed and the production using the second resin 14b is started. More preferably, it can be determined without depending on.

Specifically, like the screw rotation load factor Z1 _L and the screw rotation load factor Z0 described in FIGS. 2 and 3 of the first embodiment, a new screw rotation load factor Z2 _L is obtained in advance by test molding or the like. determined advance, the screw rotational load factor Z2 _L, is to determine the set value of screw rotational load factor Z to start production of the second resin 14b B

  First, after the screw rotation load factor Z0 is obtained, that is, as shown in FIG. 3C, the first resin 14a is not discharged from the nozzle 13 of the injection apparatus 1, and then the state shown in FIG. As shown, the supply of the second resin 14b to the material supply unit 14 is started.

Then, when the supply of the first resin 14a and the rotation of the screw 16 are continued, the second resin 14b flows to the nozzle 13 side in the resin flow path 10 as shown in FIG. 7B. Thereafter, as shown in FIG. 7C, when the second resin 14b reaches the screw head portion 16H, the first resin 14a is compressed by the second resin 14b and the second resin 14b as described above. The nozzle 13 is ejected (discharged) by the ejected air layer. Thereafter, after the discharge in the mixed state of the first resin 14a and the second resin 14b continues for a predetermined time, as shown in FIG. 7D, the second resin 14b is continuously discharged to the second resin 14b. The resin change is completed. Here, a screw rotation load factor Z in this state is measured, which is referred to as screw rotation load factor Z2 _L. Similarly to the screw rotation load factor Z1 _L , it is preferable that the screw rotation load factor Z2 _L be an average value taking into account the fluctuation of the screw rotation load factor Z within a predetermined time or determine an allowable range.

In the actual resin changing operation, the operator visually checks the resin discharged from the nozzle and the resin molded product to be molded, and determines whether the resin mixing state has been eliminated. Or, depending on the experience and intuition of the operator, set the resin material discharge time and number of molding shots after starting the supply of a new resin material, and when the setting is reached, the resin mixing state is resolved As a result, production with a new resin material is started. However, in the second embodiment, as described above, the resin is changed from the first resin 14a to the second resin 14b in advance by test molding or the like, and the second resin 14b is continuously discharged from the nozzle 13. to previously obtain a screw rotating load factor Z2 _L after the state, to do this with the set value B to start production in the second resin 14b.

  In the actual resin changing operation, the screw rotation load factor Z after the supply of the second resin 14b is started gradually increases as the resin amount in the injection apparatus 1 increases, and the range of the set value B Production of a resin molded product using the second resin 14b is started. As a result, it is possible to determine the timing for starting the production using the second resin 14b regardless of the experience and intuition of the operator, and in the production started at that timing, defects caused by the mixed state of the resin material are minimized. be able to.

As shown in the drawing the right shown in FIG. 7 (a) to FIG. 7 (d), the time of obtaining the screw rotational load factor Z2 _L, from the start of the supply of the second resin 14b, the second resin 14b from the nozzle 13 It is preferable to obtain a required time T2 until the state of continuous discharge is reached. The use of the required time T2 will be described later.

  Next, an intrusion resin changing method for an injection device of an injection molding machine according to Embodiment 3 of the present invention will be described with reference to FIG. Example 3 differs from Example 1 and Example 2 in order to prevent metal contact between the screw 16 and other components such as a heating cylinder in the injection device due to the cantilever state of the screw 16. This is a point for determining the set value C of the screw rotation load factor Z for stopping the rotation of the screw 16 and performing an alarm operation. Since the configuration of the injection device of the other injection molding machine and the intrusion resin changing method are basically the same as those in the first and second embodiments, the same reference numerals as those in the first and second embodiments are used for the same components. As we use it, we will omit duplicate explanations.

  Assuming automation of the intrusion resin changing operation, it is also important to detect mechanical malfunctions in the material supply unit 14 and the material supply line upstream thereof. These mechanical defects can be detected by electrically monitoring the operating state of each device and the sensor of the device. However, since the resin material to be used is a pellet-like (granular) solid, even if the device on the material supply unit 14 and the material supply line upstream thereof is operating normally, Problems such as blockage and fluctuations in supply amount may occur.

  The discovery of such a material supply failure without mechanical failure on the material supply unit 14 or the material supply line upstream thereof largely depends on the experience and intuition of the operator. Therefore, in addition to the timing for starting the supply of the second resin 14b in the first embodiment and the timing for starting the production using the second resin 14b in the second embodiment, the resin replacement work from the first resin 14a to the second resin 14b. It is more preferable that there is a safety management item that does not depend on the experience or intuition of the operator regarding the supply failure of the resin material assumed in FIG.

  FIG. 8A shows that the second resin 14b is not supplied to the material supply unit 14 due to some factor in the resin changing operation from the first resin 14a to the second resin 14b, and the screw 16 is in the screw head portion 16H. Only the first resin 14a remains and the screw 16 is rotating. As described above, in this state, even if the rotation of the screw 16 is continued, the first resin 14 a is not discharged from the nozzle 13.

  Therefore, if this state continues, since almost no resin material remains upstream from the screw head portion 16H, the resin pressure of the residual first resin 14a in the plasticized (molten) state in the screw head portion 16H is Lower than during normal discharge of material. As a result, as shown in FIG. 8B, the residual first resin 14a in the screw head portion 16H reduces the rotational support force on the front portion of the screw 16 (P portion in the figure), and the front portion of the screw 16 Therefore, it is difficult to suppress the deflection force, and metal contact between the screw 16 (particularly, the check ring 18 and the flight 16a in front of the screw 16) and the inner surface of the heating cylinder 15 may occur in the P portion.

In view of such a situation, as shown in FIG. 8A, the first resin 14 a until the distance L _{X in the} screw longitudinal direction from the nozzle 13 of the injection device 1 reaches the end point position of the measuring unit 16 </ b> M of the screw 16. At the timing when is discharged, the rotation of the screw 16 is stopped and an alarm is activated. The screw rotation load factor Z _{C at} this timing is a numerical value (from the design specification of the screw 16) that becomes the end point position of the measuring portion 16M of the screw 16 in L _X in the formula α for obtaining the screw rotation load factor Z1 _X described above. Is obtained by substituting.

Then, the screw rotation load factor Z _C is set to a set value C for stopping the rotation of the screw 16 and performing an alarm operation, and the screw rotation load factor Z after the supply of the second resin 14b is started is the second resin 14b. If the value does not reach the range of the set value B for starting the production of the resin molded product according to, but decreases to the set value C, the rotation of the screw 16 is stopped and an alarm is activated.

  When the first resin 14a remains only in the screw head portion 16H, the first resin 14 is not discharged even if the screw 16 is in a rotating state. On the other hand, if the first resin 14a remains in the measuring unit 16M for a predetermined distance, the residual resin in the screw head unit 16H is caused by the flow force of the first resin 14a in the measuring unit 16M toward the nozzle 13 side. The resin pressure of the first resin 14a is maintained high to some extent, and the rotational support force in front of the screw 16 by the residual first resin 14a is also maintained to some extent. From these situations, in order to prevent metal contact between the screw 16 and the inner surface of the heating cylinder 15, the timing at which the rotation of the screw 16 is stopped and the alarm operation is performed is determined by the first resin 14a and the end point position of the measuring unit 16M of the screw 16. It is reasonable to set the timing until it is discharged, and it can be determined regardless of the experience and intuition of the operator.

  As can be seen from FIG. 8A, this state is the same as the state of obtaining the screw rotation load factor Z0 shown in FIG. 3C described in the first embodiment. Therefore, the screw rotation load factor Z0 may be set as the set value C as it is. Further, the setting value C may be a numerical value lower than the screw rotation load factor Z0 as a setting value for automatically stopping the rotation of the screw 16, and from the screw rotation load factor Z0 as a setting value for performing an alarm operation in consideration of safety. It may be a high number.

  Next, an intrusion resin changing method for an injection device of an injection molding machine according to Embodiment 4 of the present invention will be described with reference to FIGS. 9 and 10. In the fourth embodiment, safety management items such as the set value C of the screw rotation load factor Z in the third embodiment that cause the screw 16 to stop rotating and perform an alarm operation are presented separately.

  The problem caused by the resin material used in the third embodiment being a solid such as resin pellets is not only in the apparatus on the material supply unit 14 or the material supply line upstream thereof, but also in the injection apparatus 1. There is also a possibility that it may occur inside. Specifically, the resin material is not completely plasticized, and it is the occurrence of an out-of-resin state or a clogged state in the range from the material supply unit 14 to the supply unit 16F and the compression unit 16P.

  The discovery of such defects is largely dependent on the experience and intuition of the operator. In the fifth embodiment, such a problem is determined by a management item based on a combination of data obtained in advance without depending on the experience and intuition of the operator.

The data to be combined is the set value B (Z2 _L ) and the required time T2 of the screw rotation load factor Z for starting production with the second resin 14b described in the second embodiment. Predetermined time T2, as shown in FIG. 7, when obtaining the screw rotational load factor Z2 _L, to initiate the supply of the second resin 14b from a state where the first resin 14a within the injection device 1 has been substantially completely discharged In the time until the second resin 14b is continuously discharged from the nozzle 13, that is, in the intrusion resin changing operation from the first resin 14a to the second resin 14b, the supply of the second resin 14b is started. This is the maximum time required for smooth transition from resin to work completion.

In the first combination, in the intrusion resin changing operation from the first resin 14a to the second resin 14b, the screw rotation load factor Z is not changed even after the required time T2 has elapsed from the start of the supply of the second resin 14b. This is a case where the set value B (Z2 _L ) for starting production with the two resins 14b is not reached. This is referred to as “resin running out condition determination condition”. For example, in the resin changing operation, the supply of the first resin 14a is stopped and the discharge of the resin from the nozzle 13 is continued. Thereafter, as shown in FIG. 9A, after the screw rotational load factor Z reaches the range of the set value A (Z _AL <A <Z _AU ), the supply of the second resin 14b is started. If the second resin 14b is properly supplied and appropriately flows to the nozzle 13 side, the second resin 14b is continuously discharged from the nozzle 13 as shown in FIG. . It is necessary for the screw rotation load factor Z to reach the set value B (Z2 _L ) from such a change in the state of FIG. 9A to FIG. 9B, that is, the supply start of the second resin 14b. Considering the supply start timing of the second resin 14b, the predetermined time T should surely be shorter than the predetermined time T2 when the supply of the second resin 14b is started after the first resin 14a is almost completely discharged. It is.

However, when satisfying the “resin running out condition determination condition” as described above, first, as shown in FIG. 9C, some resin supply failure occurs immediately after the start of the supply of the second resin 14b. Although the supply failure has been resolved, the required time T2 has elapsed from the start of the supply of the second resin 14b only by moving forward the space where the resin generated at that time is not filled (resin-run state Q portion). However, it is assumed that the screw rotation load factor Z does not reach the set value B (Z2 _L ) without discharging the first resin 14a from the nozzle 13.

Further, when the “resin running out condition determination condition” as described above is satisfied, as shown in FIG. 9D, some resin supply failure occurs after a while after the supply of the second resin 14b is started. The first resin 14a or the mixed resin of the first resin 14a and the second resin 14b is discharged from the nozzle 13 due to the resulting out-of-resin state Q part ′, but the required time T2 from the start of the supply of the second resin 14b. It is assumed that the screw rotation load factor Z has not reached the set value B (Z2 _L ) even after elapse of time.

On the other hand, in the second combination, in the intrusion resin changing operation from the first resin 14a to the second resin 14b, the screw rotation load factor Z is increased before the required time T2 elapses from the start of the supply of the second resin 14b. However, this is a case where the set value B for starting production with the second resin 14b has been reached or exceeded the set value B (Z2 _L ). This is defined as “resin clogging condition determination condition”.

When satisfying the “resin clogging condition determination condition” as described above, first, as shown in FIG. 10A, before the supplied second resin 14b reaches the screw head portion 16H, Since the resin clogged state has occurred in this part for some reason, the screw rotation load factor increases and before the required time T2 elapses from the start of the supply of the second resin 14b without discharging the first resin 14a from the nozzle 13. Further, it is assumed that the screw rotation load factor Z reaches or exceeds the set value B (Z2 _L ).

In addition, when the “resin clogging condition determination condition” as described above is satisfied, after the supplied second resin 14b reaches the screw head portion 16H, as shown in FIG. Since the resin clogged state has occurred in the portion for some reason, the screw rotation load factor increases and the second resin 14b is discharged from the nozzle 13, but before the required time T2 elapses from the start of the supply of the second resin 14b. In addition, it is assumed that the screw rotation load factor Z reaches or exceeds the set value B (Z2 _L ).

  Note that, as described above, the predetermined time T2 is the maximum value of the required time required for the smooth transition from the start of the supply of the second resin 14b to the completion of the resin replacement operation. It is conceivable that the screw rotation load factor Z reaches the set value B before the required time T2 elapses from the start of the supply of the resin 14b. Therefore, when the “resin clogging condition determination condition” is satisfied, first, only the alarm is activated, or the case where the screw rotation load factor Z exceeds the set value B before the required time T2 elapses is emphasized. Then, an increase amount of the screw rotation load factor Z from the set value B may be added to the management item.

  As described above, the “resin out condition judgment condition” and the “resin clogging condition judgment condition” based on the combination of the set value B of the screw rotation load factor Z and the required time T2 can be used to rotate the screw regardless of the experience and intuition of the operator. Stop and alarm conditions can be set before the molding operation, and these safe operations can be performed automatically. In combination with the set value C of the screw rotation load factor Z that causes the rotation stop and alarm operation of the screw 16 of the third embodiment, it is more suitable for ensuring safety of automation of the resin changing operation.

DESCRIPTION OF SYMBOLS 1 Injection apparatus 13 Nozzle 14 Material supply part 14a 1st resin 14b 2nd resin 16 Screw 16F Supply part (feed zone)
16P compression section (compression zone)
16M Measuring section (metering zone)

Claims (6)

An intrusion resin changing method in an injection device of an injection molding machine,
In advance,
A screw rotation load factor Z1 _L after the first resin is supplied to the material supply unit of the injection device and the plasticized first resin is continuously discharged from the nozzle of the injection device;
After the first resin is continuously discharged, the supply of the first resin to the material supply unit is stopped, and the first resin is not discharged from the nozzle of the injection device. From the screw rotation load factor Z0 of
Screw rotation load in a state in which the first resin is filled from the nozzle of the injection device to a distance L _{X in} the screw longitudinal direction with respect to the screw longitudinal direction distance L from the nozzle of the injection device to the material supply unit Rate Z1 _X ,
It is defined by the formula Z1 _X = (Z1 _L −Z0) / L × L _X + Z0,
In the intrusion resin change from the first resin to the second resin, after monitoring the screw rotation load factor Z and stopping the supply of the first resin to the material supply unit, the screw rotation load factor Z is In the above formula, the first resin is not substantially completely discharged, and a screw longitudinal distance in which a space not filled with resin is formed between the first resin and the second resin to be supplied later Intrusion resin replacement in an injection apparatus of an injection molding machine that starts supplying the second resin within the range of the set value A of the screw rotation load factor Z in a state where the first resin is filled up to L _X Method. The upper limit value of the set value A is the screw rotation load factor Z _AU when L _X is the distance from the nozzle of the injection device to the starting position of the compression portion of the screw in the above formula,
2. The lower limit value of the set value A is a screw rotation load factor Z _AL when L _X is a distance from a nozzle of the injection device to a starting position of the measuring unit of the screw in the formula. The intrusion resin changing method in the injection device of the injection molding machine described in 1. When obtaining the screw rotation load factor Z0 in advance,
After the first resin is not discharged from the nozzle of the injection device, the second resin is supplied to the material supply unit of the injection device and plasticized from the nozzle of the injection device. The screw rotation load factor Z2 _L after the state is continuously discharged,
The set value of screw rotational load factor Z for starting the production in the second resin B, wherein the screw rotational load factor Z2 _L, according to any one of claims 1 and 2, an injection molding machine Method for replacing intrusion resin in an injection device. In the above formula, the screw rotation load factor Z _C in the case where L _X is the distance from the nozzle of the injection device to the end point position of the screw measuring unit is set as a set value C, and the screw rotation load factor Z is set as the set value. The intrusion resin changing method in an injection apparatus of an injection molding machine according to any one of claims 1 to 3, wherein when reaching C, at least one of rotation stop and alarm operation of the screw is performed. When obtaining the screw rotation load factor Z2 _L in advance,
After the first resin is no longer discharged from the nozzle of the injection device, the second resin is supplied to the material supply unit, and then the plasticized second resin is continuously discharged from the nozzle of the injection device. Find the required time T2 until it becomes a state,
When the screw rotation load factor Z does not reach the set value B after the lapse of the required time T2 from the supply start of the second resin, at least one of the screw rotation stop and the alarm operation is performed. Item 5. A method for replacing an intrusion resin in an injection apparatus of an injection molding machine according to any one of Items4.   When the screw rotation load factor Z reaches the set value B or exceeds the set value B before the required time T2 elapses from the start of the supply of the second resin, the screw rotation is stopped and an alarm is activated. The method for replacing an intrusion resin in an injection apparatus of an injection molding machine according to claim 5, wherein at least one of them is performed.

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