JP2010042540A - Mold, method for evaluating molding, and method for determining molding condition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a mold which can temporally measure a variation in, for example, the contraction amount of a resin molding in the mold; a method for evaluating the molding using the mold; and a method for determining molding conditions using the mold. <P>SOLUTION: The mold 1 is used, which has: a contraction amount measuring part which measures the temporal variation in the contraction amount of the resin molding in the mold; and/or a contraction force measuring part which measurers a temporal variation in the contraction force of the resin molding in the mold. In the mold, preferably, the contraction force measuring part has a transmission part for transmitting the contraction force and measures the contraction force through the transmission part, and the contraction amount measuring part has a movable part 11 displaced by the contraction of the resin and measures the displacement amount of the movable part as the contraction amount. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mold capable of measuring changes over time in the amount of shrinkage of a resin molded product in a mold, a method for evaluating defects in a resin molded product using the mold, and the mold. The present invention relates to a method for determining molding conditions using a mold.

  In general, in injection molding, molten resin is filled in a mold cavity and cooled in the mold to obtain a molded product. Conventionally, various products such as optical parts, plastic building materials, weak heavy electrical parts, exterior / interior parts for OA equipment, exterior / interior parts for automobiles, and the like have been molded by injection molding.

  As described above, injection molding is one of the most excellent molding methods used in various situations. However, it is known that the injection molding method frequently causes molding defects such as cracks and voids in the resin molded product or mold release defects unless the molding conditions are set to optimum conditions. Yes. In recent years, it has been increasingly demanded to suppress the occurrence of these molding defects and improve the productivity of resin molded products by injection molding.

  In the selection of injection molding conditions, studies using CAE technology are generally performed. However, the actual condition narrowing is often advanced by trial and error based on experience and intuition. Therefore, in such work, a technique for searching for an optimum condition by combining a CAE (Computer Aided Engineering) technique and a CAO (Computer Aided Optimization) technique has been put into practical use. Although this method has a problem that a large amount of calculations must be repeated when searching for the optimum conditions, a technique for reducing the calculation load by using a response surface approximation formula, etc., has been developed, and has achieved a certain result. (Patent Document 1).

  In injection molding, there are various causes of the above-mentioned molding defects. In order to improve the productivity of resin molded products by injection molding, it is also important to elucidate the cause of molding defects and appropriately determine the quality of resin molded products. In particular, in injection molding, unexpected molding defects may occur in a resin molded product, and even in such a case, a method for accurately determining the quality of a resin molded product is disclosed (Patent Document 2).

  By the way, molding defects occurring in a resin molded product often occur due to fluctuations such as shrinkage of the resin molded product in the mold. For example, internal cracks and voids generated inside the resin molded product are one of the causes of the shrinkage behavior when the resin molded product contracts. The method described in Patent Document 1 determines optimal molding conditions by performing a simulation, and does not determine molding conditions in consideration of fluctuations in an actual resin molded product in a mold. In addition, the method described in Patent Document 2 performs trials under various conditions, and determines whether the resin molded product is good or bad based on good product data and defective product data obtained there. Similarly, the variation of the resin molded product in the mold is not considered.

  As described above, it is required to consider the shrinkage behavior of the resin inside the mold. A method for internally observing the mold is described in Patent Document 3. In Patent Document 3, a plurality of observation windows are provided in the length direction and / or circumferential direction of the mold, the inside of the mold is kept in a dark room, and white intense light having a wider wavelength width than a part of the observation window. Or the strong light of an ultraviolet lamp is incident on the mold, the light is scattered inside the melt or liquid inside the mold, and the scattered light is observed from other observation windows. An internal observation method of a mold for detecting a void is disclosed. However, this method cannot easily measure the cause of molding failure because fluctuations in the shrinkage amount of the resin molded product in the mold cannot be measured over time.

JP 2007-253495 A JP-A-2005-170056 JP-A-6-315951

  As described above, the conventional method for determining molding conditions and the method for determining the quality of a resin molded product have not been determined in consideration of fluctuations in the actual resin molded product in the mold. As described above, there is a close relationship between the variation of the resin molded product in the mold and the molding failure. Therefore, if fluctuations in the amount of shrinkage of the resin molded product in the mold can be measured over time, the cause of molding defects that occur in the resin molded product can be easily clarified, and the optimum molding conditions can be easily determined. The quality of the resin molded product can be determined.

  The present invention has been made in order to solve the above-described problems, and the purpose thereof is a mold capable of measuring a change in the amount of shrinkage of a resin molded product in the mold over time, An object is to provide a method for evaluating a molded product using the mold and a method for determining molding conditions using the mold.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, a shrinkage amount measuring unit for measuring the time-dependent variation of the shrinkage amount of the resin molded product in the mold and / or a shrinkage force measuring unit for measuring the time-dependent variation of the shrinkage force of the resin molded product in the mold. The present invention has been completed by finding that the above-mentioned problems can be solved by using a mold provided with the above. More specifically, the present invention provides the following.

  (1) A shrinkage amount measuring unit for measuring a change over time in a shrinkage amount of the resin filled in the mold and / or a shrinkage force of the resin filled in the mold over time. Mold with a contraction force measurement unit that measures fluctuations.

  According to the invention of (1), since the fluctuation of the shrinkage amount and the fluctuation of the shrinkage force of the resin molded product in the mold can be measured over time, the cause of the molding failure can be easily clarified. Further, by using the mold of the present invention, the molding conditions can be examined while grasping the variation of the resin molded product in the mold, so that the optimum molding conditions can be easily determined.

  The feature of the mold of the present invention is that it includes a contraction amount measuring unit and a contraction force measuring unit. Since there is a close relationship between fluctuations in the resin molded product in the mold and molding defects, various molding defects can be obtained by measuring these two variations in the mold over time in the mold. The reason for this can be elucidated and the optimum molding conditions can be determined.

  The contraction amount measuring unit and the contraction force measuring unit may be any units that can measure the contraction amount and contraction force of the resin molded product in the mold over time. For example, the amount of shrinkage may be measured directly by measuring the amount of shrinkage of the resin molded product in the mold, or indirectly by connecting components for measuring the amount of shrinkage to the resin molded product. Similarly, the shrinkage force may be measured directly by the shrinkage force at the time of shrinkage of the resin molded product, or indirectly measured by using a component connected to the resin molded product. The method of measuring indirectly is preferable because the amount of shrinkage and shrinkage of the resin molded product in the mold can be easily measured over time.

  Examples of the “resin” include conventionally known ones such as a thermoplastic resin and a thermosetting resin. In addition, since the present invention can measure the change in the amount of shrinkage of the resin molded product in the mold over time, the cause of molding defects can be easily clarified even with unknown materials. Even with unknown materials, it is possible to easily determine optimum molding conditions.

  “Measuring variation over time” measures the relationship between the amount of shrinkage and time of the resin molded product while the resin molded product is in the mold, and the relationship between the shrinkage force and time of the resin molded product. That is. The time for measurement is not particularly limited, and in normal molding, the time during which the resin molded product exists in the mold may be used, or the measurement may be performed for a longer time. The measurement time can be appropriately changed depending on the molding defect to be solved. For example, when it is desired to eliminate molding defects such as mold release defects, it is sufficient to take out the resin molded product from the mold in the same time as the molding of the actual resin molded product and measure the change over time until then. It is. However, when examining molding defects such as cracks and voids that occur on the surface of resin molded products, etc., measure the changes over time by holding the resin molded product in the mold for a longer time than actual molding. You may need to This is because cracks, voids, and the like are also caused by shrinkage of the resin molded product after being taken out from the mold in normal injection molding. As described above, by using the mold of the present invention, it is possible to easily eliminate molding defects that occur after removal from the mold during mass production, and to determine optimum molding conditions.

  The molding defects that can be solved by the present invention include various molding defects such as cracks, voids, mold release defects, and deformation due to resin shrinkage. The direct measurement in the present invention is only the time-dependent fluctuation of the shrinkage amount and shrinkage force of the resin molded product in the mold, and these fluctuations are related to the properties such as the viscosity of the resin molded product. Therefore, various molding defects can be eliminated by measuring the above-mentioned fluctuation over time. In addition, although any shaping | molding defect can be eliminated preferably, a void, a crack, and a mold release defect are mentioned as a molding defect especially preferable to apply this invention.

  (2) The mold according to (1), wherein the contraction force measurement unit includes a transmission unit that transmits the contraction force, and measures the contraction force via the transmission unit.

  According to the invention of (2), since the contraction force measuring unit includes the transmission unit that transmits the contraction force of the resin molded product in the mold, the contraction force of the resin molded product in the mold is controlled by the transmission unit. It is possible to measure the change over time of the shrinkage force of the resin molded product in the mold at a place where it is easy to measure such as outside the mold.

  A method for measuring the contraction force transmitted using the transmission unit is not particularly limited. For example, you may measure the pulling force when trying to pull in the transmission part when the resin molded product in the mold contracts, or as a pressing force by pressing the pressure sensor when the transmission part is pulled in You may measure.

  (3) The mold according to (1) or (2), wherein the contraction amount measurement unit includes a movable unit that is displaced by contraction of the resin, and the displacement amount of the movable unit is measured as the contraction amount.

  According to the invention of (3), since the shrinkage amount measuring part includes the movable part that is displaced by the shrinkage of the resin molded product in the mold, the resin molded product in the mold that cannot be directly measured visually is measured. A change in the amount of contraction can be easily measured. Since the fluctuation of the shrinkage amount of the resin molded product inside the mold can be measured outside the mold, the fluctuation of the shrinkage amount of the resin molded product inside the mold can be easily observed.

  (4) a movable rod connected to the resin so as to be displaceable by contraction of the resin, a support portion that linearly displaces the movable rod, and a detachable pressure sensor for measuring the contraction force, With the pressure sensor removed, the amount of displacement of the movable bar over time is measured as a change over time in the amount of contraction, and with the pressure sensor attached, the pressure sensor is The mold according to any one of (1) to (3), in which a change with time of the contraction force is measured by receiving a pressing force.

  According to the invention of (4), it is possible to easily measure the time-dependent fluctuation of the shrinkage amount in the mold of the resin molded product and the time-dependent fluctuation of the shrinkage force of the resin molded product in the mold with one mold. can do. More specifically, the amount of shrinkage of the resin molded product in the mold and the change over time in the shrinkage force of the resin molded product can be easily measured outside the mold by the movable rod.

  Since the movable rod connected to the resin molded product and displaced with the shrinkage of the resin molded product is linearly displaced, the amount of displacement can be easily measured. As a result, it is possible to easily measure the change over time of the shrinkage amount of the resin molded product in the mold. The movable rod is not particularly limited as long as it can be connected to the resin molded product and has heat resistance enough to withstand the heat in the mold. Further, the support portion for linearly moving the movable rod is not particularly limited as long as the movable rod can be linearly displaced, and for example, the movable rod is linearly displaced using a support portion such as a rail. It is done.

  By causing the pressure sensor to be pushed by the movable rod that is displaced when the resin molded product contracts in the mold, it is possible to easily measure the change over time of the shrinkage force of the resin molded product in the mold.

  (5) A molded product evaluation method for evaluating defects of a molded product using the mold according to any one of (1) to (4), wherein the shrinkage data of the resin is measured by the shrinkage measuring unit. And / or a data acquisition step of acquiring the shrinkage force data of the resin measured by the shrinkage force measuring unit, the shrinkage amount data, and the relationship between the shrinkage amount measured in advance and the possibility of defects of the molded product. Shrinkage amount defect availability data and / or shrinkage amount data comparison step and / or the shrinkage force data, and shrinkage force defect availability data indicating the relationship between the previously measured shrinkage force and the possibility of defects in the molded product , A shrinkage force data comparison step, a shrinkage amount data comparison step and / or a shrinkage force data comparison step, and a defect for judging whether the molded product is a defective product or a non-defective product The admissibility decision process The molded product evaluation method comprising a.

  According to the invention of (5), since any of the molds described in (1) to (4) is used, the amount of shrinkage and shrinkage of the resin molded product in the mold are measured over time. be able to. By comparing this measurement data with previously measured defect availability data, it is possible to determine whether or not the obtained resin molded product is a defective product without removing the resin molded product from the mold. .

  The shrinkage data is data representing the change over time of the shrinkage amount of the resin molded product in the mold, and the shrinkage data is the data representing the change over time of the shrinkage force of the resin molded product in the mold. is there.

  Even in the conventional method, defects appearing outside the resin molded product can be evaluated by taking out the molded product from the mold and observing it. However, molding defects appearing inside cannot be observed from the outside, except in the case of transparent resin or the like. In the evaluation method for a resin molded product according to the present invention, in order to determine whether or not the obtained resin molded product is a defective product based on the shrinkage behavior of the resin molded product in the mold, It can be easily evaluated whether or not there is a defect. As a result, the resin molded product evaluation method of the present invention can accurately determine molding defects occurring inside the resin molded product, and thus becomes a simpler and more accurate resin molded product evaluation method.

  The shrinkage amount defect availability data refers to, for example, the variation of the shrinkage amount of the resin molded product in the mold when the resin molded product has a defect or no defect, the resin molded product in the mold at a certain point Although there is no particular limitation as long as it is data that can determine the presence or absence of defects in the resin molded product. As the shrinkage amount defect availability data, only the data when there is a defect may be used, or only the data when there is no defect may be used, but if both are used, the resin molded product is a defective product It is preferable because it is easy to determine whether or not. Moreover, it is preferable that there is a lot of data regardless of data when there is a defect or data when there is no defect. This is because it can be more accurately determined whether or not the resin molded product is a defective product. The same applies to the contractile force defect availability data.

  The defect availability data can be used if it is known in advance. Moreover, when it is not known beforehand, it can determine easily using the metal mold | die of this invention. Specifically, first, by using the mold of the present invention, the amount of shrinkage and shrinkage force of the resin molded product in the mold are measured. Next, molding defects of the resin molded product obtained by taking out the resin molded product from the mold are observed. If there is no molding defect, the obtained data is data when there is no defect. If there is a molding defect, the obtained data is data when there is a defect. In this way, it is possible to acquire data when it becomes a defective product and data when it does not become a defective product. Note that if the mold of the present invention is used, it is possible to measure the time-dependent fluctuation of the resin molded product in the mold. By changing the molding conditions so as to adjust to such a variation that does not occur, it becomes easier to obtain conditions that do not cause defects.

  The comparison process and the defect availability determination process compare the data at the time of molding with the data when it becomes a defective product and / or the data when it does not become a defective product, and the resin molded product obtained by molding is a defective product. This is a step of determining whether or not.

  When comparing data, it is not necessary to compare all the data obtained in one molding, and if data that can be judged as defective is found, it is judged as defective at that point. be able to. By judging in this way, if the shrinkage of the resin molded product occurs even after being taken out of the mold, even if a defect occurs inside the resin molded product, there is no need to wait until the shrinkage stops, It can be quickly evaluated that the molded product is defective.

  (6) The defect of the molded product is a defect of at least one or more molded products selected from the group consisting of a crack generated on the surface of the molded product, a void generated on the surface of the molded product or inside, or a release defect. The molded article evaluation method described.

  According to the invention of (6), the defect to be evaluated is a crack generated on the surface of the molded body, a void generated on the surface of the molded body, or a defective mold release, which is closely related to the shrinkage of the resin molded product in the mold. If so, molding defects can be particularly preferably evaluated.

  (7) A method for determining molding conditions using the mold according to any one of (1) to (4).

  According to the invention of (7), the optimum molding conditions can be easily determined by using the mold of the present invention.

  In determining the optimum molding conditions, first, molding is performed using the mold of the present invention described in any one of (1) to (4). At this time, the amount of shrinkage and shrinkage of the resin molded product in the mold are measured over time. Next, the resin molded product is taken out from the mold, and it is confirmed whether there is a molding defect. If there is a molding defect, new conditions are set and molding is performed so as to fill the gap between the data obtained during molding and the desired shrinkage behavior. By repeating this, the optimum molding condition can be determined.

  As described above, according to the method for determining molding conditions of the present invention, the molding conditions can be examined not only from the final resin molded product but also considering the shrinkage behavior of the resin molded product in the mold. The optimum molding conditions can be easily determined.

  (8) A method for producing a molded product that excludes defective products using the molded product evaluation method according to (5) or (6).

  According to the invention of (8), since the molded product evaluation method described in (5) and (6) is used, defective products can be excluded with higher accuracy.

  (9) The mold according to (1) to (4), the shrinkage amount in the mold of the resin filled in the mold and / or the shrinkage force in the mold of the resin filled in the mold, By a defect availability data storage unit storing defect availability data indicating a relationship between defects of a molded product molded by the mold, and a contraction amount measured by the contraction amount measurement unit and / or a contraction force measurement unit Comparing the measured shrinkage force with the defect availability data and determining whether the molded product is defective or non-defective, and according to the determination of the determination unit An injection molding apparatus comprising: a defect molding condition storage unit that stores molding conditions; and a molding condition determination unit that determines whether the molding conditions are such that no defective product is generated.

  According to the invention of (9), since the mold according to any one of (1) to (4) is used, it is obtained by measuring the time-dependent fluctuation of the resin molded product in the mold. It can be determined whether or not the resin molded product is defective. Therefore, when determining the optimum molding conditions, the molding conditions can be easily examined without devising a resin molded product, a measuring jig, etc. from the mold.

  In particular, since the injection molding apparatus of the present invention includes a defect molding condition storage unit that stores molding conditions of defective products, it is possible to determine whether or not the product is defective by storing a number of defect molding conditions therein. The accuracy of judgment is improved.

  The defect availability data stored in the defect availability data storage unit means defect availability data such as the above-described shrinkage amount defect availability data and shrinkage force defect availability data.

  According to the present invention, it is possible to measure a change in shrinkage amount and a change in shrinkage force of a resin molded product in a mold over time. Since the molding failure and the shrinkage behavior of the resin molded product in the mold are closely related, it becomes easy to clarify the cause of the molding failure. Further, by using the mold of the present invention, the molding conditions can be examined while grasping the variation of the resin molded product in the mold, so that the optimum molding conditions can be easily determined. Furthermore, by checking the molding conditions when molding and the shrinkage behavior of the resin molded product in the mold during molding, it is not necessary to actually take out the resin molded product from the mold and check it. A determination of whether or not can be made.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings of the examples. Note that the present invention is not limited to the following embodiment, and can be implemented with appropriate modifications within the scope of the object of the present invention. In the following description, the same components are denoted by the same reference numerals, and duplicate descriptions may be omitted.

  FIG. 1 (a) is a diagram of a mold when the change in shrinkage amount of a resin molded product in the mold is measured over time, and FIG. 1 (b) is an AA of the mold in FIG. 1 (a). It is sectional drawing. FIG. 2 (a) is a diagram of a mold when a change in shrinkage of a resin molded product in the mold is measured over time, and FIG. 2 (b) is a diagram of the mold BB in FIG. 2 (a). It is sectional drawing. FIG. 3 is a view showing a mold during measurement of the amount of shrinkage when measuring the change over time in the amount of shrinkage of the resin. FIG. 4 is a view showing a mold during measurement of contraction force when measuring a change with time of the contraction force of the resin.

  As shown in FIGS. 1 and 2, the mold 1 of the present invention includes a movable part 11 that moves as the resin molded product 2 contracts, a fixed part 12 that fixes the displacement direction of the movable part, and a mold body. 13 and a position sensor 14 or a pressure sensor 15.

  The movable portion 11 applies a pressing force from the movable portion 11 to the pressure sensor 15 when the movable portion 11 is displaced by the contraction of the resin molded product 2 and the connection convex portion 111 for coupling with one end of the resin molded product 2. And a convex portion 112. As shown in FIG. 2, the pressure sensor 15 is disposed between the convex portion 112 and the fixed portion 12.

  The fixed part 12 includes a guide part 121 for sliding the movable part 11 in the X direction, and a fixing pin for fixing the other end of the resin molded product 2 in order to measure a displacement amount due to the sliding movement of the movable part 11. 122. The displacement of the movable part of the mold 1 shown in FIGS. 1 and 2 is a sliding movement in the X direction.

  The mold body 13 includes a through hole 131 for passing the movable portion 11 through the mold body 13 and a through hole 132 for passing the fixing pin 122 through the mold body 13.

<Measurement of shrinkage>
A mold 1 having only the position sensor 14 shown in FIG. The movable part 11 passes through the through hole 131 of the mold body 13. The movable part 11 and the through hole 131 are in close contact with each other so that the resin does not leak after the mold body 13 is filled with the resin. Further, when the resin molded product 2 contracts in the mold main body 13, the movable portion 13 smoothly slides through the through hole 131. Smooth sliding is preferable because the movable part 11 always slides in the same manner, and the measurement error becomes small.

  As shown in FIG. 1A, the movable portion 11 is provided with a constant interval between the convex portion 112 and the fixed portion 12 so that the movable portion 11 can move horizontally in the X direction when the resin molded product 2 contracts. First, the molten resin flows from the gate (not shown) into the mold body 13. Due to the resin that has flowed in, the connecting protrusion 111 and the fixing pin 122 are solidified within the mold body 13 so as to be buried in the resin.

  When the resin hardens in the mold body 13, the resin molded product 2 contracts as shown in FIG. 3, and as the resin molded product 2 contracts, the movable portion 11 moves in the direction of the arrow (X Slid horizontally to be drawn into the mold body 13 in the direction). The fixed portion 12 is provided with a fixed pin 122 at an end facing the one end of the resin molded product 2 where the connecting portion between the movable portion 11 and the resin molded product 2 is provided. For this reason, regarding the direction in which the movable part 11 moves when the resin molded product 2 contracts, the side facing the movable part 11 is fixed so as not to move. As a result, the amount of contraction Δ ′ of the resin molded product 2 in the mold body 13 is only moved when the resin molded product 2 contracts in the X direction in which the movable unit 11 moves. Can be replaced with the amount of movement Δ of the movable portion 11. Therefore, by measuring the movement amount Δ of the movable part 11 with time, it is possible to measure the change with time of the shrinkage amount Δ ′ of the resin in the mold body 13. In addition, the effect of the fixing pin 122 can also be obtained by providing a gate (not shown) so as to penetrate into the mold body 13 without providing the fixing pin 122.

<Measurement of contraction force>
A mold 1 having a pressure sensor 15 shown in FIG. In this example, the position sensor 14 is removed from the mold 1 shown in FIG. 1A and the pressure sensor 15 is attached, but a completely different mold body may be prepared. However, it is preferable to use the same mold body because more data can be acquired more easily.

  The process until the resin flows into the mold main body 13 and the connecting projections 111 and the fixing pins 122 are solidified in the mold main body 13 so as to be solidified is the same as in the measurement of the contraction amount.

  When the resin hardens in the mold main body 13, the resin molded product 2 contracts as shown in FIG. 4, and the movable part 11 is drawn into the mold main body 13 as the resin contracts. Force (X direction) is applied. This force is due to the shrinkage force F of the resin molded product 2. A pressing force P ′ is applied from the convex portion 112 to the pressure sensor 15 by the force that pulls the movable portion 11 into the mold body 13. Then, the change with time of the shrinkage force F of the resin in the mold 1 is measured by measuring the change of the pressing force P applied between the guide part 121 and the pressure sensor 15 with the pressure sensor being pushed. Can do. It is also possible to measure the change over time in the contraction force with the pressing force P ′. Similarly to the measurement of the contraction amount, by fixing one end of the resin with the fixing pin 122, when the resin molded product 2 contracts, the moving part 11 is opposed to the movable part 11 in the moving direction. The sides are fixed so that they do not move. For this reason, since it is possible to prevent a force from being applied in the direction (−x direction) in which the movable portion 11 is pulled out from the mold main body 13, the temporal change in the shrinkage force F of the resin in the mold is controlled by the pressure P. Alternatively, when the measurement is performed by replacing the pressing force P ′ with the change over time, the measurement becomes easier.

<Method of determining molding conditions>
First, by using the mold of the present invention, the amount of shrinkage and shrinkage of the resin molded product in the mold under a predetermined condition are measured over time by the above method. Although depending on the type of molding failure to be solved, in this case, it is preferable to keep the resin in the mold until the resin has completely contracted, and to measure the amount of shrinkage and contraction force over time. When molding an injection-molded product in a mass production process, the resin molded product is taken out from the mold before the shrinkage of the resin molded product completely stops, but the molding failure is caused by the shrinkage of the resin molded product after taking out from the mold. This is because the optimum molding condition determination can be determined by more considering the shrinkage behavior of the resin molded product.

  Next, the resin molded product is taken out from the mold and the molding failure is confirmed. The molding conditions to be tested next are determined in consideration of the type and degree of molding failure, the amount of shrinkage of the resin molded product in the mold, and the temporal change in shrinkage force. In this way, while changing the molding conditions, the optimum molding conditions that do not cause molding defects are determined. With the method for determining molding conditions of the present invention, the molding conditions to be tested next can be determined in consideration of the amount of shrinkage and shrinkage of the resin molded product in the mold over time. Easy to determine conditions.

  In particular, in order to solve cracks that occur on the surface of the molded product, which are molding defects that are closely related to the shrinkage behavior of the resin molded product, voids that occur on the surface of the molded product or inside, and mold release defects when taking out the resin molded product from the mold. The molding condition determination method of the present invention can be preferably used.

  The molding condition determination method is also a method for obtaining molding conditions, shrinkage amount data, and shrinkage force data when a molding failure occurs. Accordingly, it is possible to acquire defective product propriety data and the like that are necessary when performing a molded product evaluation method as described later.

<Molded product evaluation method>
First, shrinkage amount data and / or shrinkage force data are acquired using the mold of the present invention. For example, these data can be acquired by a method of automatically inputting the result of the shrinkage amount and shrinkage force of the resin molded product measured every 0.5 seconds to a computer.

  Next, the obtained shrinkage amount data is compared with shrinkage amount defect availability data, and the obtained shrinkage force data is compared with shrinkage force defect availability data. As described above, if the shrinkage amount defect availability data and the shrinkage force defect availability data are known in advance, they can be used. However, if it is an unknown material or the like and there is no such data, these data can be acquired using the mold of the present invention in the same manner as the above-described molding condition determination method. . Therefore, there is no data that can determine whether defects can be determined by combining the shrinkage amount defect availability data and shrinkage force defect availability data with the above method and the molded product evaluation method of the present invention. Even in this case, the molded product can be appropriately evaluated. In addition, even when new defect availability data is required for more accurate determination, it is possible to easily add these data and perform an appropriate evaluation.

  Finally, as a result of the comparison, if the data when a defect occurs in the molded product and the shrinkage amount data or shrinkage force data overlap, it can be evaluated that the molded product is a defective product. The molded product evaluation method of the present invention is characterized in that a defective product can be evaluated before the resin molded product is taken out from the mold. Furthermore, the shrinkage of the resin molded product continues for a long time as described above, but if defective product data is obtained at an early stage, it is possible to evaluate that the product is defective at that point without waiting until the shrinkage completely stops. It is also a feature that can be done. In addition, as above-mentioned, the shrinkage | contraction behavior of a resin molded product, the crack which arises on the surface of a molded object, the void which arises in a molded object surface or an inside, and the molding defect at the time of taking out a resin molded product from a metal mold | die are deeply related. For this reason, the molded product evaluation method of this invention can be preferably used about whether these molding defects exist in a resin molded product.

<Method for producing molded product>
First, the molded product is evaluated using the molded product evaluation method. Next, defective products are excluded. The evaluation method can accurately evaluate whether or not the molded product is a defective product.

  According to the method for producing a molded product of the present invention, defective products can be more accurately removed and the defect rate in the product can be reduced. In particular, if the molding defect in question is a defect that can be identified while the resin is present in the mold in a normal mass production process, it is determined that the defect is a defective product before the molded product is removed from the mold. Therefore, it is preferable because defective products can be easily excluded.

<Injection molding equipment>
The injection molding apparatus of the present invention is characterized by using the mold of the present invention. In addition to the mold of the present invention, a defect storage unit, a determination unit for determining whether or not a molded product is a defective product from shrinkage amount data and / or shrinkage force data, and a defect for storing molding conditions of the defective product By including a molding condition storage unit and a determination unit that determines whether the molding condition is a molding condition that does not cause a defective product, the injection molding apparatus is particularly preferable as an injection molding apparatus used when determining the optimal molding condition.

  The defect availability data storage unit stores the shrinkage amount defect availability data and / or shrinkage force defect availability data. The contraction amount data and contraction force data are the same as those described above.

  In particular, a defective molding condition storage unit that stores molding conditions when a defective product occurs and a determination unit that determines whether the molding conditions are such that no defective product occurs are included. It can be determined whether or not.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Mold>
The mold shown in FIGS. 1 to 4 was used. The following mold body A and mold body B were used as the mold body 13.

Mold body A: 50 mm × 50 mm × 8 mmt (8 w × 8 t: one-point side gate), φ5 movable parts 11 are arranged at a pitch of 40 mm on the opposite gate side.
Mold body B: 50 mm × 50 mm × 8 mmt (3-point side gate, gate size is the same as the thickness of the molded product). The movable part 11 having the same size is disposed at the same position as the mold A.
<Position sensor>
Non-contact position sensor: Keyence EX-305V (manufactured by Keyence)
<Pressure sensor>
Pressure sensor: TYPE 9221A (manufactured by Nippon Kisler)
Pressure sensor amplifier: Charge amplifier (manufactured by Nippon Kistler)
AD converter: KEYENCE NR-110 (manufactured by KEYENCE)
<Material>
Resin a: Polyphenylene sulfide resin (manufactured by Polyplastics, “Fortron 1140A1 HD9050”), viscosity 380 Pa · s
Resin b: Polyphenylene sulfide resin (manufactured by Polyplastics, “Fortron 1140A1 HD9050 high viscosity product”), viscosity 428 Pa · s
Resin c: Polyphenylene sulfide resin (manufactured by Polyplastics, “Fortron 6565A7”)
Resin d: Polyphenylene sulfide resin (manufactured by Polyplastics, “Fortron 6165A61”)

<Example 1>
Using mold A, the time-dependent change in the amount of shrinkage of the resin in the mold was measured to improve the mold release failure.

  The resin a and the resin b were molded three times under the conditions shown in FIG. 5 (injection pressure and pressure in the mold), and the average of the variation in the shrinkage amount of the resin molded product is shown in FIG. (A) is the result of resin a, (b) is the result of resin b. In the case of resin a, a mold release failure occurred, and in the case of resin b, a mold release failure did not occur. As is apparent from FIG. 5, the resin a has a smaller amount of shrinkage, and the displacement of the resin due to the shrinkage is smaller. By using these data and the mold of the present invention, it is possible to determine a mold release failure.

  In addition, when the mold of the present invention is used, a change in the amount of shrinkage in the mold of the resin molded product can be measured. Therefore, there is a mold release failure around 200 seconds when the change in the amount of shrinkage becomes constant. It can be determined whether or not.

<Example 2>
Using the mold B, the resin a was molded under the molding conditions shown below, and the change over time in the shrinkage force of the resin molded product in the mold was measured. The measurement results are shown in FIG. FIG. 6 (a) shows the result when hot air drying is performed at 140 ° C. × 3 hours, FIG. 6 (b) shows the result when natural drying is performed, and FIG. 6 (c) shows 160 ° C. × 8. FIG. 6 (d) shows the result when vacuum drying is performed at 120 ° C. for 8 hours. Voids were not observed only in the case of hot air drying at 160 ° C. for 8 hours.
[Molding condition]
Molding machine: SE-100D (manufactured by Sumitomo Heavy Industries)
Cylinder temperature: 320 ° C
Mold temperature: 140 ° C
Injection speed: 20mm / sec
Holding pressure: 50 MPa
Holding time: 10 sec
Cooling time: 30 sec

  As is clear from FIGS. 6A to 6D, the data when a void is generated is different from the data when no void is generated. By using these data and the mold of the present invention, it is possible to determine that a void is generated in the resin molded product by measuring the change with time of the shrinkage force of the resin molded product in the mold. In particular, it is a feature of the mold of the present invention that a void can be determined without taking out and observing a resin molded product from the mold. Further, if the molding is performed by changing the conditions so as to increase the peak of the contraction force, this problem can be solved, and it is easy to determine the optimum molding conditions.

<Example 3>
Using the mold B, the change with time of the shrinkage force in the resin flow direction of the resin molded product made of the resin c and the resin molded product made of the resin d was measured. Molding was performed under the following molding conditions. The results are shown in FIG. The case where the resin c is used is a solid line, and the case where the resin d is used is a dotted line. When resin c was used, cracks occurred in the resin molded product, and when resin d was used, cracks did not occur in the resin molded product.
[Molding condition]
The same molding conditions as in Example 2 were used.

  As is apparent from FIG. 7, in the case of a resin molded product made of the resin c, a crack occurs at the position of the inflection point and then spreads. On the other hand, in the case of a resin molded product made of resin d, the shrinkage force changes smoothly and no cracks are generated. If these data and the metal mold | die of this invention are used, it can also determine easily that a crack generate | occur | produces in a resin molded product.

(A) is a figure of a metal mold | die when measuring the fluctuation | variation of the shrinkage | contraction amount of the resin molded product in a metal mold | die over time, (b) is AA sectional drawing of the metal mold | die of Fig.1 (a). . FIG. 2 (a) is a diagram of a mold when a change in shrinkage of a resin molded product in the mold is measured over time, and FIG. 2 (b) is a diagram of the mold BB in FIG. 2 (a). It is sectional drawing. FIG. 3 is a view showing a mold during measurement of the amount of shrinkage when measuring the change over time in the amount of shrinkage of the resin. FIG. 4 is a view showing a mold during measurement of contraction force when measuring a change with time of the contraction force of the resin. It is a figure which shows the result of having measured the time-dependent change of the shrinkage | contraction amount of the resin in a metal mold | die using the metal mold | die A. FIG. FIG. 5 is a diagram of measuring a time-dependent change in shrinkage force of a resin using a mold B. (A) is the result of hot air drying at 140 ° C. for 3 hours, (b) is the result of natural drying, and (c) is hot air drying at 160 ° C. for 8 hours. (D) is the result when vacuum drying is performed at 120 ° C. for 8 hours. It is a figure which shows the result of having measured the time-dependent change of the shrinkage | contraction amount of the resin flow direction of the resin molded product which consists of resin c and resin d using the metal mold | die B. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 2 Resin molded product 11 Movable part 111 Connection convex part 112 Convex part 12 Fixed part 121 Guide part 122 Fixed pin 13 Mold main body 131,132 Through-hole 14 Position sensor 15 Pressure sensor

Claims (9)

  Measures the amount of shrinkage in the mold of the resin filled in the mold over time and / or the variation over time of the shrinkage force in the mold of the resin filled in the mold A mold equipped with a contraction force measurement unit. The contraction force measurement unit includes a transmission unit that transmits the contraction force,
The metal mold | die of Claim 1 which measures the said contraction force via the said transmission part. The shrinkage measurement unit includes a movable part that is displaced by the shrinkage of the resin,
The mold according to claim 1, wherein a displacement amount of the movable part is measured as the contraction amount. A movable rod connected to the resin so as to be displaceable by contraction of the resin, a support part that linearly displaces the movable rod, and a detachable pressure sensor for measuring the contraction force,
With the pressure sensor removed, the amount of displacement of the movable rod over time is measured as the time-dependent change in the amount of contraction,
The gold according to any one of claims 1 to 3, wherein the pressure sensor measures a change with time of the contraction force by receiving a pressing force by displacement of the movable rod in a state where the pressure sensor is mounted. Type. A molded product evaluation method for evaluating defects in a molded product using the mold according to any one of claims 1 to 4,
A data acquisition step of acquiring shrinkage data of the resin measured by the shrinkage measurement unit and / or shrinkage force data of the resin measured by the shrinkage force measurement unit,
A shrinkage amount data comparison step for comparing the shrinkage amount data with shrinkage amount defect availability data indicating a relationship between the shrinkage amount measured in advance and the possibility of defects of the molded product and / or the shrinkage force data; Contraction force data comparison step for comparing the contraction force defect availability data indicating a relationship between the contraction force measured in advance and the possibility of defect of the molded product,
A defective product evaluation method comprising: determining whether the molded product is a defective product or a non-defective product based on the shrinkage amount data comparing step and / or the shrinking force data comparing step. .   The molding according to claim 5, wherein the defect of the molded product is a defect of at least one molded product selected from the group consisting of a crack generated on the surface of the molded body, a void generated on the surface or inside of the molded body, or a release defect. Product evaluation method.   A method for determining molding conditions using the mold according to claim 1.   The manufacturing method of the molded product which excludes a defective product using the molded product evaluation method according to claim 5 or 6. A mold according to claims 1 to 4,
The relationship between the amount of shrinkage of the resin filled in the mold and / or the shrinkage force of the resin filled in the mold in the mold and the possibility of defects in the molded product molded by the mold A defect availability data storage unit that stores defect availability data to be shown;
The shrinkage amount measured by the shrinkage measurement unit and / or the shrinkage force measured by the shrinkage force measurement unit and the defect availability data are compared, and whether the molded product is a defective product or a non-defective product A determination unit for determining
A defect molding condition storage unit that stores molding conditions of the defective product according to the determination of the determination unit;
An injection molding apparatus comprising: a determination unit that determines whether or not the molding condition is such that no defective product is generated.

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