JP3829130B2 - Injection thrust measuring method and apparatus - Google Patents

Description

The present invention relates to an injection thrust measuring method and apparatus for measuring an injection thrust of an injection molding apparatus that provides a molded product by injecting molten metal into a mold.

  2. Description of the Related Art Injection molding apparatuses have become widespread as apparatuses for injecting molten metal or resin into a mold and cooling and solidifying the molten metal in the mold to obtain a molded product. In this type of injection molding apparatus, the injection pressure when the molten metal is injected and the pressure of the molten metal in the mold can be made as constant as possible in order to continuously obtain substantially equivalent molded products. desired. Examples of the evaluation method or apparatus proposed from such a viewpoint include those described in Patent Document 1 or Patent Document 2. Among these, Patent Document 1 statistically obtains a correlation between the work amount of the injection device and the weight of the molded product in order to infer whether or not a good molded product is continuously and stably produced. It has been proposed. Specifically, in Patent Document 1, the work amount of the injection device is obtained by integrating the injection pressure applied to the melt molding material by the screw.

  On the other hand, in Patent Document 2, in order to accurately grasp the molten metal pressure in the heating cylinder at the time of injection molding, preliminary injection molding is performed in a state where there is no resin in the heating cylinder, and at this time, the injection speed is set in advance. It has been proposed to store the rising torque and the mechanical resistance torque that are generated in the meantime until they reach the controller. The difference between the rising torque and mechanical resistance torque stored in the control device and the rising torque and mechanical resistance torque at the time of main injection molding when the molten resin is put into the heating cylinder and main injection molding is performed. If calculated, the operator can grasp the molten metal pressure in the heating cylinder.

JP-A-3-268912 Japanese Patent Laid-Open No. 6-134832

  Since the method described in Patent Document 1 is evaluated during the injection molding, there is a problem that the injection pressure or the like cannot be evaluated in advance before the injection molding is performed.

  In addition, in the method described in Patent Document 2, the molten metal pressure is estimated by measuring the rising torque and the mechanical resistance torque in the no-load state without introducing the molten metal made of resin. However, in this case, a large difference is recognized between the estimated molten metal pressure and the actual molten metal pressure when the molten metal is filled in the mold.

Therefore, it is recalled that the mold is actually filled with the molten metal and injected, and the injection pressure at this time and the pressing force of the injection cylinder against the molten metal, so-called injection thrust, are obtained. However, in this case, the molten metal is used to produce a molded product that cannot be used as a final product, which is disadvantageous in terms of cost. After all, in order to perform measurement using a mold used at the time of actual injection molding, a great cost is required.

The present invention has been made to solve the above-described problem, and an injection thrust measuring method and apparatus capable of easily and simply measuring a force with which an injection cylinder pushes out a molten metal, that is, a so-called injection thrust, at low cost. The purpose is to provide.

To achieve the above object, the present invention provides a injection thrust nests that I De thrust measurement method Measurement of the injection cylinder in an injection molding apparatus to melt the sleeve is injected into the mold by injection rod of the injection cylinder ,
A first step of filling a fluid into the dummy sleeve;
A second step of discharging the fluid filled in the dummy sleeve from the discharge portion by pressing with a dummy rod that is displaced in conjunction with the injection rod;
A third step of creating a graph plotting the displacement speed of the injection rod or the dummy rod measured in the second step and the injection thrust transmitted to the injection rod or the dummy rod;
Have
Change the dimensions of the discharge part and repeat the first to third steps,
An estimated curve of displacement speed versus injection thrust in the injection cylinder is created from a bending point in the displacement speed versus injection thrust diagram for each dimension of the discharge section in the graph.

By such a measuring method (hereinafter also referred to as an evaluation method) , the injection thrust of the injection molding apparatus can be estimated easily and simply before the molding die is attached to the injection molding apparatus. For this reason, at the time of an actual injection molding operation, it is possible to estimate the injection pressure of the molten metal from the estimated injection thrust and the displacement speed of the injection rod. As a result, it is possible to ascertain whether or not the injection molding operation is being performed under a predetermined condition, so that the quality of a continuously molded molded product can be made substantially constant.

In this evaluation method, the displacement speed of the injection rod or dummy rod is determined as the distance from the displacement start point to the displacement end point when the displacement of the injection rod or dummy rod becomes an intermediate amount , in other words, the displacement amount. It is preferable to measure when it becomes half of the above . This is because, at this time, the speed of the displacing injection rod or dummy rod becomes substantially constant and maximum, so that an accurate displacement speed can be measured.

And it is preferable to use water as a fluid. This is because water is generally inexpensive, which allows injection thrust measurement to be performed at low cost. Moreover, it is a safe liquid without explosiveness, flammability, and ignitability.

Further, the present invention provides a y de thrust measuring device that measure the injection thrust of the injection cylinder in an injection molding apparatus for injection from the sleeve to melt the mold by the rod of the injection cylinder,
And dummy sleeve for filling the fluid body,
A dummy rod displaced in the dummy sleeve in conjunction with the injection rod;
A discharge portion provided in order to discharge the pressing has been the fluid at the tip of the dummy sleeve dummy rod,
Injection thrust measuring means for measuring the injection thrust of the injection rod that receives the resistance of the fluid via the dummy rod when the dummy rod is displaced in conjunction with the injection rod to discharge the fluid ;
Speed detecting means for detecting a displacement speed of the ejection rod or the dummy rod when the dummy rod is displaced in conjunction with the ejection rod to discharge the fluid ;
It is characterized by having.

  With this configuration, the displacement speed of the injection rod or the dummy rod and the injection thrust can be easily and simply measured before the molding die is incorporated into the injection molding apparatus.

  The dummy sleeve preferably has a sleeve main body and a gate member connected to the sleeve main body and provided with a discharge portion. In this case, the fluid discharge load can be adjusted without replacing the entire dummy sleeve by exchanging the gate member with different dimensions of the discharge portion.

  According to the present invention, it is possible to know the injection thrust of an injection molding apparatus before manufacturing a molded product. At the time of actual injection molding operation, it is possible to estimate the injection pressure at which the molten metal is injected from the estimated injection thrust and the displacement speed of the injection rod. It is possible to grasp whether or not the process is performed under a predetermined condition. As a result, the quality of a continuously molded product can be made substantially constant.

Hereinafter, preferred embodiments of the injection thrust measuring method according to the present invention will be described in detail with reference to the accompanying drawings in connection with an apparatus for carrying out the method.

An overall schematic side view of the injection thrust measuring apparatus according to the present embodiment is shown in FIG. The injection thrust measuring device 12 attached to the injection molding device 10 includes a dummy rod 18 that is displaced in conjunction with an injection rod 16 that constitutes an injection cylinder 14, and a substantially cylindrical dummy sleeve that is filled with water as a fluid. And 20. The dummy rod 18 is surrounded by the frame 22, and the dummy sleeve 20 is positioned and fixed to the fixed platen 24 and is pressed and supported by the movable platen 26.

  A front end portion of the injection rod 16 and a rear end portion of the dummy rod 18 are accommodated in a cover member 28, and a load cell 30 is interposed between the injection rod 16 and the dummy rod 18. In other words, the front end portion of the injection rod 16 and the rear end portions of the load cell 30 and the dummy rod 18 are held by the inner wall of the cover member 28. Therefore, the load rod 30 and the dummy rod 18 are moved forward and backward. As a result, the cover member 28 is displaced together.

The tip 34 of the dummy rod 18 is connected via a connecting member 32. The tip 34 reaches the vicinity of the right end of the dummy sleeve 20 in FIG. 1 when the dummy rod 18 is displaced to the maximum extent toward the movable platen 26.

  The dummy sleeve 20 includes a substantially cylindrical sleeve main body 36 and an annular gate member 40 provided with a first discharge port 38. A diameter portion 42 is provided. When the dummy sleeve 20 is passed through the through hole 44 of the fixed platen 24, the large diameter portion 42 is blocked around the through hole 44, whereby the dummy sleeve 20 is prevented from being detached and positioned. A bearing 46 is interposed between the through hole 44 and the sleeve body 36.

  As shown in an enlarged view in FIG. 2, annular annular grooves 48 a and 48 b are provided on both end faces of the gate member 40, and each annular groove 48 a and 48 b has an O-ring for preventing water leakage. 50a and 50b are inserted. The first discharge port 38 is provided at a substantially central portion above the wall portion of the gate member 40. The gate member 40 and the sleeve body 36 are connected to each other by a bolt (not shown) arranged outside the O-rings 50a and 50b.

  A holding member 52 is attached to the right end portion of the dummy sleeve 20. That is, an inner chamber 54 is formed at the left end portion of the holding member 52, and the entire gate member 40 and the sleeve main body 36 are kept in the inner chamber 54 until one end surface of the gate member 40 is seated on the side wall portion of the inner chamber 54. It passes through the opening of the chamber 54.

  Moreover, the 2nd discharge port 56 is provided in the lower wall part of the inner chamber 54, as shown in FIG. 3 which is a III-III sectional view taken on the line of FIG. That is, the first discharge port 38 of the gate member 40 communicates with the second discharge port 56 via the inner chamber 54.

  A connecting hole 58, a passage 60, a communicating hole 62, and a mounting hole 64 are provided in this order from the right end of the holding member 52 to the inner chamber 54. A liquid feed pipe 68 is connected through a mounting screw of a substantially L-shaped pipe joint 66. On the other hand, a valve body 70 having a tapered portion corresponding to the tapered portion of the communication hole 62 is inserted into the communication hole 62. One end of a coil spring 72 is seated on a step provided on one end surface of the valve body 70, and the coil spring 72 is pressed by a cap member 74 fitted in the mounting hole 64. Contained. For this reason, the coil spring 72 always urges and urges the valve element 70 toward the passage 60 side.

  An insertion hole 76 is provided in a substantially central portion of the cap member 74, and an ejection pipe 80 provided with an ejection hole 78 is inserted into the insertion hole 76.

  Further, the holding member 52 is provided with a detection path 82, and an internal pressure measuring device 84 is attached to the large-diameter opening portion of the detection path 82 formed in the upper wall portion of the holding member 52 via a screw. It has been.

  A bracket 86 cut out so that the bottom and the inside thereof do not interfere with the liquid feeding pipe 68 is connected to the holding member 52 configured as described above.

  Two guide bars 88a and 88b are bridged from the fixed platen 24 to the movable platen 26 (see FIG. 1), and the movable platen 26 approaches the fixed platen 24 by being guided by the guide bars 88a and 88b. Or, it is displaced in the direction of separation.

  A speed sensor (not shown) for detecting the displacement speed of the displaced dummy rod 18 is supported substantially at the center of the frame 22. The speed sensor and the load cell 30 are electrically connected to a control circuit (not shown).

Next, an injection thrust evaluation method executed using the thus configured injection thrust measuring device 12 will be described.

First, the injection thrust measuring device 12 is configured, and the movable platen 26 is directed toward the fixed platen 24 to approach it. Finally, the end portion of the bracket 86 is pressed against one end surface of the movable platen 26, and the large diameter portion 42 of the sleeve main body 36 is blocked, whereby the dummy sleeve 20 is positioned and fixed.

Next, water is supplied through the liquid feeding pipe 68 and the pipe joint 66. The supplied water enters the passage 60 via the connection hole 58 and presses the valve body 70. By this pressing, the valve body 70 is displaced toward the ejection pipe 80 while compressing the coil spring 72, and accordingly, the tapered portion of the valve body 70 is separated from the tapered portion of the communication hole 62. As a result, the connection hole 58 communicates with the connection hole 62 via the passage 60, so that water is finally ejected from the ejection hole 78. The internal pressure measuring device 84 displays the pressure when water is filled.

  When water is continuously supplied and the inside of the dummy sleeve 20 is filled with water, the water starts to be discharged from the first discharge port 38 provided in the upper wall portion of the gate member 40. The discharged water is discharged from the second discharge port 56 provided in the lower wall portion of the pressing member 52.

  Next, the injection molding apparatus 10 is energized, and the injection rod 16 is moved forward in the right direction in FIGS. 1 and 2. Along with this, the dummy rod 18 connected via the cover member 28 is interlocked and displaced toward the right in FIGS. 1 and 2.

  Due to this displacement, the water filled in the dummy sleeve 20 is pressed against the chip 34 and discharged through the first discharge port 38 and the second discharge port 56. At this time, the tip 34 and thus the injection rod 16 receive resistance.

  The load cell 30 accommodated in the cover member 28 measures the resistance force applied to the dummy rod 18 at this time, in other words, the injection thrust. This measured value is sent as a signal to a control circuit electrically connected to the load cell 30. At the same time, the displacement speed of the dummy rod 18 is measured, and the measured value of the displacement speed is also sent as a signal to the control circuit.

  Here, in the present embodiment, the displacement speed of the dummy rod 18 is measured when the displacement amount of the dummy rod 18 becomes substantially intermediate. At this time, the displacement speed of the dummy rod 18 becomes substantially constant and maximum. Therefore, an accurate displacement speed can be detected by performing measurement at this point.

  The displacement speed measured in this way is plotted on the graph as shown in FIG. 4 with the horizontal axis and the injection thrust as the vertical axis. In FIG. 4, this plot is indicated by symbol 記号.

  Finally, the tip 34 reaches the vicinity of the gate member 40 as indicated by the phantom line in FIG. 1, and most of the dummy rod 18 is inserted into the sleeve main body 36, so that all the water in the dummy sleeve 20 is completely removed. Discharged. Similarly, the cover member 28 reaches the vicinity of the left end portion of the dummy sleeve 20 as indicated by a virtual line.

  Next, the injection rod 16 is moved backward to return the dummy rod 18 and the tip 34 to the initial position. After the dummy sleeve 20 is filled with water in the same manner as described above, the pressing force against the injection rod 16 is increased, and the injection rod 16 is moved forward again. That is, the injection rod 16 is moved forward with a larger injection thrust, and water is discharged through the first discharge port 38 and the second discharge port 56 as described above. Whether or not water is filled can be determined by determining whether or not the pressure displayed on the internal pressure measuring device 84 is equal to the pressure at the previous filling.

  The injection thrust and displacement speed in this case are plotted on the graph of FIG. In general, the displacement speed of the dummy rod 18 increases as the injection thrust increases.

  When the above operation is repeated, the displacement speed does not increase even if the injection thrust is increased. That is, the displacement speed is saturated. As shown in FIG. 4, this state can be grasped because a bending point appears in a curve connecting displacement speed-thrust plots.

  After the bending point appears on the graph in this way, next, the holding member 52 is removed from the dummy sleeve 20, and the gate member 40 is exposed. Then, another gate member having a smaller dimension of the first discharge port 38 than that of the gate member 40 is attached, and the above operation is repeated. The relationship between the injection thrust and the displacement speed of the dummy rod 18 in this case is shown in FIG.

  In this case, since the first discharge port 38 has a small size, it is difficult to discharge water. Therefore, the discharge load becomes large, and therefore the displacement speed of the dummy rod 18 becomes small even with the same injection thrust as before the replacement of the gate member.

  After a bending point appears on the graph in the same manner as described above, another gate member whose size of the first discharge port 38 is smaller than that of the gate member is attached. In this case, the injection thrust and the displacement speed of the dummy rod 18 are (Symbol Δ, symbol ○). In FIG. 4, the symbol ◆ represents the injection thrust of the injection rod 16 when the dummy sleeve 20 is not filled with water.

  In this way, the discharge load of water is adjusted by changing the size of the first discharge port 38, and the relationship between the injection thrust and the displacement speed of the dummy rod 18 in each case is examined and plotted on the plotted graph. A line L is drawn at the bent point. This drawn line L is an estimated curve of displacement speed-injection thrust in the injection molding apparatus 10.

Thus, according to this Embodiment, since it measures using water instead of a molten metal, evaluation can be implemented at low cost. In addition, since water is not explosive, flammable, or ignitable, it can be evaluated in a safe environment.

  In addition, in this case, the discharge load can be adjusted by a simple operation of exchanging the gate member 40. Therefore, an estimation curve of displacement speed-injection thrust can be easily created.

  In addition, since the injection thrust of the injection molding apparatus 10 can be known before manufacturing the molded product, the extent of the molten metal is determined from the estimated injection thrust and the displacement speed of the injection rod 16 during the actual injection molding operation. It is possible to estimate whether or not the injection is performed at the injection pressure, and thereby it is possible to grasp whether or not the injection molding operation is performed under a predetermined condition. Eventually, the quality of the molded product that is continuously molded can be made substantially constant, which improves the product yield. Furthermore, when changing parameters such as the injection speed when injecting molten metal, there is also an advantage that it is easy to guess how to set a good molded product.

  In the above-described embodiment, the displacement speed of the dummy rod 18 is measured. However, the displacement speed of the injection rod 16 may be measured.

  Further, although water is used as the fluid filling the dummy sleeve 20, it is not particularly limited to this. For example, a gas may be used, but a liquid that is liquid at room temperature is preferable because a larger load can be applied.

1 is an overall schematic side view of an injection thrust measuring apparatus according to the present embodiment. It is a partially expanded cross-section explanatory drawing of the injection thrust measuring apparatus of FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is the graph which plotted the displacement speed measured by changing the dimension of the 1st discharge port of a gate member variously, and the injection thrust.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Injection molding apparatus 12 ... Injection thrust measuring apparatus 14 ... Injection cylinder 16 ... Injection rod 18 ... Dummy rod 20 ... Dummy sleeve 28 ... Cover member 30 ... Load cell 34 ... Tip 36 ... Sleeve main body 38 ... 1st discharge port 40 ... Gate Member 52 ... Holding member 54 ... Inner chamber 56 ... Second discharge port 68 ... Liquid feed pipe 70 ... Valve element 72 ... Coil spring 80 ... Jet pipe 84 ... Internal pressure measuring instrument

Claims (4)

A injection thrust nests that I De thrust measurement method Measurement of the injection cylinder in an injection molding apparatus to melt the sleeve is injected into the mold by injection rod of the injection cylinder,
A first step of filling a fluid into the dummy sleeve;
A second step of discharging the fluid filled in the dummy sleeve from the discharge portion by pressing with a dummy rod that is displaced in conjunction with the injection rod;
A third step of creating a graph plotting the displacement speed of the injection rod or the dummy rod measured in the second step and the injection thrust transmitted to the injection rod or the dummy rod;
Have
Change the dimensions of the discharge part and repeat the first to third steps,
An injection thrust characterized in that an estimation curve of displacement speed versus injection thrust in the injection cylinder is created from a bending point in the displacement speed versus injection thrust diagram for each dimension of the discharge section in the graph. Measuring method. 2. The measuring method according to claim 1, wherein the displacement speed of the injection rod or the dummy rod is measured when the displacement amount of the injection rod or the dummy rod becomes half of the distance from the displacement start point to the displacement end point. An injection thrust measuring method characterized by: A y de thrust measuring device that measure the injection thrust of the injection cylinder in an injection molding apparatus for injection from the sleeve to melt the mold by the rod of the injection cylinder,
And dummy sleeve for filling the fluid body,
A dummy rod displaced in the dummy sleeve in conjunction with the injection rod;
A discharge portion provided in order to discharge the pressing has been the fluid at the tip of the dummy sleeve dummy rod,
Injection thrust measuring means for measuring the injection thrust of the injection rod that receives the resistance of the fluid via the dummy rod when the dummy rod is displaced in conjunction with the injection rod to discharge the fluid ;
Speed detecting means for detecting a displacement speed of the ejection rod or the dummy rod when the dummy rod is displaced in conjunction with the ejection rod to discharge the fluid ;
An injection thrust measuring device comprising: In the measurement apparatus according to claim 3, wherein the dummy sleeve, an injection thrust measuring apparatus characterized by having a sleeve body and a gate member in which the discharge portion is connected to the sleeve body is provided.

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