JPH02238917A - Analyzing method of molding condition in injection molding machine having visualized heat cylinder - Google Patents

Abstract

PURPOSE:To make it possible to set a theoretical molding condition by collecting a temp. distribution data of a resin in a heating cylinder or a printed image data of a resin behavior through an observation window and analyzing a condition of a plasticization and measuring process or an injection process based on the data. CONSTITUTION:An analytical and arithmetic unit 43 consisting of a microcomputer operates temp. data and printed image data input through an observation window 15 by using an arithmetic program prepd. in advance. E.g. calculation of temp. gradient and detection of an abnormal temp. part are performed by operating a temp. distribution of each part. In addition, a printed image concn. distribution, flow speed of a marker and behavior of a check ring are operated and analyzed and rate of distribution of solid phase-flow phase, rate of occurrence of voids in a molten resin, rate of flow of the marker in a plasticized and melted resin material, rate of discoloration of the resin material and a movement of the check ring are also operated and analyzed. These operational results are stored with each set condition of charge and injection processes, the kind of the resin material used and a screw design and the optimum molding condition for each resin is found by changing variously each molding condition.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for analyzing molding conditions in an in-line screw type injection molding machine having a visualization heating cylinder, and particularly relates to a method for analyzing molding conditions in an in-line screw type injection molding machine having a visualization heating cylinder. etc. through the observation window installed in the heating cylinder.
This article relates to a molding condition analysis method for injection molding machines that analyzes molding conditions. [Prior Art] In order to consistently and consistently produce high-quality molded products in an in-line screw type injection molding machine, conditions regarding plasticization metering (charging) and injection of resin materials are essential. Of course, as a premise, the design of the screw shape is also important. (a) The composition ratio of the screw's feed zone, compression zone, and metering zone. (b) L/D L: Total length of screw D = Diameter of screw (c) Compression ratio (CR = h 1/h2) h1: Depth of screw groove in supply section h2: Depth of screw groove in metering section (M material Ratio of the amount of resin accumulated in the screw groove of the supply section and the amount of resin accumulated in the screw groove of the metering section.) (d) P/D P: Screw thread pitch D: Make sure that the screw diameter etc. The screw design is determined based on this consideration, and the quality of plasticization measurement is first determined by this. Strictly speaking, the optimal screw shape is determined for each resin to be molded, but in general, a general-purpose screw design that can be used with as many resin materials as possible is selected. That is, in (a) above, the length of the normal supply section is reduced by 50 to 60%.
Consideration was taken to stabilize the charging speed by increasing the size and to prevent the resin from being pressurized as much as possible until the temperature reaches the melting point. Shear heat generation is controlled by the length of the compression section. Also, in (b) above, when L/D is lengthened, the charge speed, resin temperature, a! L/D is usually set at 20 to 22, although this improves the stability of the kneading process and is compatible with the overall equipment. In addition, in (c) above, if low-temperature molding is required, CR is made small to suppress shear heat generation at the crosstalk section, and conversely, to increase crosstalk, CR is
is increased. Furthermore, P/D in (d) above is usually selected to a value of about 1.0 in consideration of the transfer amount and the efficiency in the molten state. In addition to this, the wall thickness and outer diameter of the heating cylinder are also important in ensuring stable transmission of heat from the heater. The screw design mentioned above is based on past experience.
Simulation calculations are performed on a computer, but as mentioned above, the screw is generally a general-purpose screw that can be applied to a wide variety of resin materials.In an in-line injection molding machine equipped with such a screw, It is extremely important to determine the molding conditions under which the equipment should be operated depending on the resin material. The molding conditions include: - Heater temperature in each zone during plasticization metering (charging). ■Measuring stroke. ■How do you vary the screw rotation speed with respect to the metering stroke? ■How to vary the back pressure with respect to the metering stroke. ■Amount of sack pack and its speed. There are factors such as ■Injection pressure during injection. ■How to vary the injection speed with respect to the injection stroke. ■ Holding pressure switching position. ■There are 6 factors to determine how to vary the holding pressure during holding pressure. [Problem to be solved by the invention] By the way, in conventional injection molding machines, it was not possible to directly see the inside of the heating cylinder. Using a method of error and error, the molded product was observed through trial shots and the molding conditions were set. In other words, since conventionally the inside of the heating cylinder cannot be observed, (a) during plasticization metering (charging), the heated resin material is heated by the heater while being transferred by the screw.
How melt plasticization progresses: how it melts and changes from a solid state to a fluid phase due to the shear force caused by screw rotation. (mouth) Uniform plasticization after becoming a fluid phase. (c) The state of the rise in resin temperature inside the heating cylinder, that is, the resin temperature distribution and the presence or absence of abnormal temperature areas. (2) Whether the gas generated when the resin is melted and plasticized is properly degassed. (e) Check whether the resin that has become a fluid phase is stagnation while flowing forward between the valleys of the screw, or the flow rate. (f) Movement of the check ring at the start of injection. (g) Uniformity of resin coloring when coloring agent is mixed. Important checkpoints such as these were completely hidden in a black box, and it was impossible to observe or measure them to determine the molding conditions. On the other hand, attempts have been made to use computer simulation calculations to determine molding conditions, but this is due to the rheological properties of plastic. Flow analysis is not easy, and access to the checkpoints mentioned above relies mostly on skill and experience. Setting the optimal molding conditions requires skill and extensive experience, and requires time and effort. It cost a lot of money. however. In the recent plastic industry, the types and formulations of resin materials are becoming more complex and sophisticated, and instead of the traditional method of setting molding conditions by trial and error, more theoretical molding conditions are being set. There is a growing momentum to seek new methods. The present invention was developed in view of the above circumstances, and its purpose is to enable more theoretical setting of molding conditions based on the results of direct observation and analysis of the resin behavior inside the heating cylinder. The purpose of this research is to provide a method for analyzing molding conditions in injection molding machines. [Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention includes a heating cylinder in which a screw is arranged to be rotatable and movable back and forth, and a transparent body is arranged in a part of the peripheral wall of the heating cylinder. In a method for analyzing molding conditions in an injection molding machine having a visualization heating cylinder provided with an observation window for internal observation, for example, the above II.
The surface temperature distribution data of the resin inside the heating cylinder is captured through the observation window, and image data such as resin behavior is captured through the observation window using an imaging means such as a video camera, and the captured data is transmitted to the microcomputer. For example, the temperature difference of the resin within a predetermined area, the distribution degree of the solid phase, the degree of bubble generation in the molten resin, the flow condition of the marker in the plasticized and melted resin material, etc. , the degree of coloration of the resin material, the movement of the check ring, etc. are measured and calculated, and based on this, the conditions during the plasticizing metering (charging) process and the injection process are analyzed. [Operation] The analysis calculation device consisting of a microcombiner is
The temperature data and image data captured through the system are processed using a pre-written calculation program. In other words, for example, the temperature distribution of each area is calculated to calculate the temperature gradient, detect the presence or absence of abnormal temperature areas, and also check the image density distribution (brightness, color distribution), marker flow rate (resin flow rate), etc. We perform calculation analysis of ring behavior, etc., and determine the degree of distribution of the solid phase and fluid phase, the degree of bubble generation in the molten resin, the flow condition of the marker in the resin material to be melted, the degree of coloring of the resin material, and the check ring. Compute and analyze the movement of. These calculation results are stored together with the above-mentioned setting conditions during the charging and injection strokes, the type of resin material used, the screw design, etc., and by changing the molding conditions variously, the most suitable molding conditions determined for each resin can be determined. Found out. [Example 1] The present invention will be explained below using an example shown in FIGS. 1 to 9. Figure 1 is a block diagram showing the components for analyzing molding conditions, Figure 2 is a partially cutaway front view showing the injection device of the injection molding machine, and Figure 3 is a partial view showing the main parts of the injection device. Fig. 4 is a front view of the main part cut away, and Fig. 4 is a cross-sectional side view of the main part taken in the direction perpendicular to the axial direction of the heating cylinder. First, the schematic configuration of the injection device of the injection molding machine will be explained using Fig. 2. In FIG. 2, 1 is a base, 2 is a support set on the base 1, and a headstock holding the rear end of the heating cylinder 3 is attached. Reference numeral 4 denotes a screw, which is disposed in the heating cylinder 3 so as to be able to rotate and move back and forth, and is rotationally driven by a drive source 5 for one rotation of the screw, and its forward and backward movement is controlled by a drive source 6 for injection. ing. In addition, 7 is a drive transmission mechanism disposed between the rear end of the screw 4 and both of the drive sources 5 and 6, 8 is a hopper for supplying resin material to the heating cylinder 3, and 9 is a heating cylinder 3. The band heater 10 is a nozzle attached to the tip of the heating cylinder 3. The resin material supplied from the hopper 8 to the rear part of the screw 4 in the heating cylinder 3 is kneaded and plasticized by the rotation of the screw 4 and transferred forward, and as the molten resin is stored at the tip side of the screw 4, The screw 4 retreats while the back pressure is controlled, and the screw 4
When one shot worth of molten resin is stored on the tip side of (
At the end of measurement), the rotation of screw 4 is stopped.
Then, at the injection start timing after a predetermined time, the screw 4 is advanced, and the molten resin is injected and filled from the nozzle 10 into the cavity of the mold (not shown). In this embodiment, the screw 4 is rotated in forward and reverse directions during the charging stroke (for example, the forward rotation period is 3 and the reverse rotation period is 1).
), or it is also possible to rotate the screw while vibrating during the charging process.This allows for more charging condition setting items, increasing the variety of charging conditions, and also allows fine-grained control. is possible. (For the former forward/reverse rotation charge, the applicant of the present application previously proposed the
No. 128, and regarding the latter rotating charge accompanied by vibration, Japanese Patent Application No. 1983-1, which was also proposed earlier by the applicant.
Please refer to No. 177129, respectively, if necessary. ) Next, the structure around the heating cylinder 3 will be explained with reference to FIGS. 3 and 4. As shown in FIG. 3, the rear end of the heating cylinder 3 is fixed to a headstock 11 fixed to the support base 2 via a mounting plate 12. A circular hole 13 having a circular cross section is continuously bored in the peripheral wall of the heating cylinder 3 along the axial direction from the front end side (left side in the drawing) toward the rear end side. In this embodiment, the circular hole 13 is formed so as not to be completely penetrated to the rear end side. The circular hole 13 may completely penetrate the peripheral wall of the heating cylinder 3 in the axial direction. As shown in FIG. 4, two slits 14 and 14 are formed in communication with the circular hole 13 at the top and bottom of the figure. Part 2
The two slits 14.14 are located on the extension line of the diameter of the circular hole l3, and are continuously bored along the axial direction from the front end side to the rear end side of the heating cylinder 3, like the circular hole l3. ．． Note that the circular hole 13 and the slit 14 are formed by wire cutting, for example. As shown in FIGS. 3 and 4, on the outer surface side of the peripheral wall of the heating cylinder 3, a plurality of elongated tR observation windows 15 are formed along the axial direction from the outer surface of the peripheral wall to the circular hole l3 by, for example, end milling. Each hole is perforated. In this embodiment, l is provided corresponding to the feed zone, compression zone, and metering zone of the screw 4, respectively.
Three II observation windows 15 are provided, but the number of observation windows 15 is arbitrary. (This lI! inspection window l5 is formed in the non-wrapped portion of the band heater 9.) Also, on the inner surface side of the peripheral wall of the heating cylinder 3, the circular hole l3 is reached from the inner surface of the peripheral wall. Elongated notch l6 along the axial direction
However, multiple holes have been drilled. This notch 16 is bored by end milling at the same time as the 8 m window 15, for example, at a position corresponding to the observation window 15 so as to have approximately the same length in the axial direction as the observation window 15. 17 is a cylindrical glass body inserted into the circular hole 13 of the heating cylinder 3, and is made of, for example, transparent heat-resistant, high-strength, high-purity quartz glass, and its cross section matches the cross-sectional shape of the circular hole 13. It is set to do so. In this embodiment, three glass bodies 17 are sequentially inserted into the circular hole 13 from the open part on the front end side of the heating cylinder 3 with a spacer 18 interposed between the glass bodies 17, and the glass bodies 17 on the front end side are inserted in order. The end face is pressed by pressure contact means (for example, a tightening nut), not shown, via the spacer 18 as necessary. As a result, each glass body l7 is positioned and fixed without loosening in the axial direction. In this embodiment, the spacer l8 is made of an asbestos-based material with appropriate elasticity, but may also be made of a material with heat resistance and appropriate elasticity (for example, copper, brass, etc.). You can select any one from. Reference numeral 19 denotes a plurality of screw holes drilled above and below the observation window 15. As shown in FIG. 3, the screw hole 19 is formed to be perpendicular to the slit l4 and to pass through the slit portion. This screw hole l9 has a female thread carved in the inner part that penetrates the slit part, and a tightening screw (bolt) 20 is screwed and fastened into the female thread.
A force is applied in the direction of narrowing the slit 14. As a result, the inner surface of the circular hole 13 wraps around and fastens the outer circumferential surface of the glass body 17, creating a perfect seal. In this embodiment adopting the above configuration, each observation window 15
Not only can the behavior of the resin in the feed zone, combination zone, and metering zone in the heating cylinder 3 be observed through the glass body 17, but since the glass body 17 is cylindrical, the glass body 17 It functions as a convex lens, making it possible to magnify and observe the behavior of the resin, improving visibility. Furthermore, since the glass body 17 is cylindrical, even if the glass body 17 receives a pressing force against the inner surface of the outer side of the circular hole 13 due to the resin pressure inside the heating cylinder 3, the circular hole 13 Since the arcuate surfaces of the body 17 are pressed against each other, the suppressing force is dispersed, no local stress is applied to the glass body 17, and breakage of the glass body 17 is prevented as much as possible. The same applies to thermal stress and stress caused by the tightening screw 20, and the stress is almost uniformly diffused, so that the glass body 17 is guaranteed to have a long life without the risk of breakage. Furthermore, due to the sealing effect of the tightening screw 20,
There is no risk of resin leakage. In this embodiment, the cylindrical glass body 17 is used, but it may also be prismatic.
7 may be replaced with sapphire or the like. In this case, since sapphire is expensive, the observation window 15 is set small. Furthermore, although three observation windows 15 are provided in this embodiment, the number and location of the observation windows 15 are arbitrary. FIG. 1 is a block diagram mainly showing the configuration for photographing and analyzing resin behavior, resin temperature, etc. in each zone in the heating cylinder 3 through the observation window 15. In the figure, reference numeral 30 denotes a video camera equipped with a solid-state image pickup device, an image pickup tube, etc., installed opposite the observation window 15.
Reference numeral 31 designates a strobe light emitting unit which is also installed opposite the observation window 15, and is controlled to emit light by a strobe controller 32 which receives a synchronization signal from the video camera 30. The image taken by the video camera 30 is once recorded on a video table recorder (hereinafter referred to as VTR) 34, and this image data is taken into a data buffer 35 and then
The digital signal is converted into a digital signal by the /D converter 36 at an appropriate sampling rate, and sent to an analysis/arithmetic unit to be described later. In addition, 37 is the color C connected to the VTR 34.
Images taken by the video camera 30 can be checked by the operator on a monitor consisting of an RT display, if necessary. 38 is a thermovising machine installed opposite to the above-mentioned Ill inspection window 15. Equipped with a temperature detector such as HgCdTe or InSh, the temperature of the resin in contact with the observation window 15 is captured as image data and temporarily recorded on the VTR 39. and. The image data recorded on the VTR 39 is taken into the data buffer 40 and then transferred to the A/D converter 4.
The digital signal is converted into a digital signal at an appropriate sampling rate by 1, and is sent to an analysis/arithmetic unit, which will be described later. In addition, 42 is VTR394: connected color CRT
A monitor consisting of a display allows the operator to directly view the temperature distribution image captured by the thermovision 38 as necessary. Note that both the video camera 30 and the thermovision 38 have a zoom function, and may be provided with a rotating table or the like, if necessary, although not shown. Further, in this embodiment, since three observation windows 15 are provided as described above, three II
When observing the Q window 15 at the same time, the video camera 30
, thermovision 38, etc. are arranged according to this, and when observing each observation window 15 individually with a time shift, the video camera 30, thermovision 38, etc. are used for observation that requires observation. It is moved each time to a position facing window l5. 43 is an analysis calculation device for analyzing data obtained from the video camera 30 and the thermovision 38, which includes a frame buffer 44 and a temperature distribution calculation means 45.
, image density distribution calculation means 46, flow velocity calculation means 47,
Check ring behavior calculation means 48, data storage section 49,
It is equipped with a table 50, a molding condition calculating section 51, etc. From the thermovision 38, an analysis calculation device 43 is sent via a VTR 39, a data buffer 40, and an A/D converter 4l.
The image data sent to the frame buffer 44
After being stored once, the data is supplied to the temperature distribution calculation means 45, and the temperature distribution calculation means 45 calculates the resin temperature distribution in each zone within the heating cylinder 3 based on this data. Further, the temperature distribution calculating means 45 refers to the contents of the table 50 in which case study temperature distribution information is stored in advance, and determines whether the temperature of each part is within a set range and whether the temperature gradient is within an allowable range. It performs determination processing such as whether or not there is an abnormal temperature within the temperature range, or whether there is an area where abnormal temperature occurs. From the video camera 30, the VTR 34. The image data sent to the analysis calculation unit 43 via the data buffer 35 and the A/D converter 36 is similarly once stored in the frame buffer 44, and then stored in the image density distribution calculation unit 43.
6. It is supplied to the flow rate calculation means 47 and the check ring behavior calculation means 48 at predetermined timings, respectively. Image density distribution calculation means 46 calculates brightness distribution and color distribution,
The distribution degree of the same phase and fluid phase due to the difference in brightness between the solid phase (resin pellets) and the fluid phase, the degree of bubble generation due to the gas generated when the resin is melted, the distribution degree of markers mixed in the resin, the resin The degree of mixing of the colorant mixed therein is calculated by referring to the solid phase-liquid phase identification information, bubble identification information, marker identification information, coloring concentration identification information, etc. stored in advance in the table 50. ．． The image density distribution calculating means 46 also refers to the permissible range information stored in the table 50 as a case study in advance, and performs a process of determining whether or not the above calculation result is within the permissible range. The flow velocity calculation means 47 processes the supplied image data of a plurality of frames, refers to the marker identification information stored in advance in the table 50, and calculates the flow velocity of the resin from the flow velocity of the marker mixed in the resin. Calculate the flow velocity for each part. This also allows you to check whether or not there are resin retention points.
Calculates and determines the retention position, size of retention area, etc. Furthermore, the flow velocity calculation means 47 uses the table 50.
It also performs determination processing such as whether the above calculation result is within the tolerance range by referring to tolerance range information stored in advance as a kesis study. The check ring behavior calculation means 48 calculates the movement of a known check ring (check valve member) attached to the distal end neck of the screw 4 from the supplied image data of a plurality of frames stored in the table 50 in advance. The calculation is performed by referring to the check ring identification information obtained. Further, the check ring behavior calculating means 48 refers to check ring behavior tolerance range information stored in advance as a case study in the table 50 to determine whether the check ring is in a predetermined operating position at a predetermined timing. Then, it also performs judgment processing such as whether the above calculation result is within the allowable range. The results of the calculations performed by the temperature distribution calculation means 45, image density distribution calculation means 46, flow rate calculation means 47, and check ring behavior calculation means 48 are taken into the data storage section 49. The data storage unit 49 also contains the details of the screw design described above regarding the used screw 4, the type of resin material used, the charge described above, and the setting conditions during the injection stroke (molding setting conditions), that is, ■Heater temperature of each zone (nozzle section, front, middle, back of cylinder, bottom of hopper). ■Measuring stroke. ■How did you vary the screw rotation speed and back pressure with respect to the metering stroke? ■Time ratio of forward/reverse rotation of the screw. ■Intensity and frequency of vibration superimposed on screw rotation. ■Amount of suckback and its speed. ■Injection pressure size and rise time. ■How the injection stroke and injection speed were varied with respect to the injection stroke. ■ Holding pressure switching position. [Phase] How was the holding pressure varied during holding pressure? This information is also stored. It should be noted that this information is achieved by input operations using a manual key device (not shown) or by supplying information from a control device 52 consisting of a microcombeater that controls the entire injection molding machine. The data storage section 49 sequentially stores the calculation results of each of the calculation means 45 to 48 described above when test shots are repeated with varying molding setting conditions. And each calculation means 45~
The above-mentioned molding conditions (1) to [phase] when the calculation results of No. 48 indicate the most preferable state are stored in a predetermined storage area as the optimum molding conditions. For example, for each shape design of the screw and heating cylinder, the resin material is sequentially changed to polycarbonate, acrylic, styrene, etc., and the charge amount for each resin material is changed by 10% between 10 and 100%. Then, the results of case studies of the above-mentioned molding conditions (1) to [phase] are stored in a predetermined storage area as the optimum molding conditions. The molding condition calculation section 5l includes a data storage section 49.
When molding a new unanalyzed resin, it calculates and sets molding conditions based on the known molding conditions of a similar resin material by referring to the optimal molding condition data for each resin stored in . Referring to the above-mentioned processing results from the image data obtained from the trial shots, the molding conditions are calculated so that the molding conditions for the unanalyzed resin approach the optimal values. The calculation results from the molding condition calculation section 51 are sent to the control device W152 of the injection molding machine described above, whereby the molding conditions can be variably set. In addition, the above-mentioned analysis calculation unit having the functional units described above! ! 43 is. It actually consists of a microcomputer, which includes various I/O interfaces, a ROM that stores the main program and fixed data, and a RAM that reads and writes various flags, measurement data, conversion processing data, etc.
It is self-evident to those skilled in the art that it is equipped with a μCPU (micro central processor unit) that controls the entire system, and that each of the above-mentioned functions is performed by a program created in advance. Further, the calculation results of the analysis calculation unit 43 can be displayed on a display device I! consisting of a color CRT display, if necessary. 53, and is sent to an output device such as a printer 54°, so that the operator can visually check the analysis results. The analysis calculation unit 43 is also connected to an external memory 55 such as a magnetic disk device, so that predetermined data can be exchanged as needed. Next, several examples of analysis methods for forming conditions will be explained with reference to Figs. 5 to 9. 5(a), (b), and (c) are explanatory diagrams showing images obtained by the video camera from the observation window 15 of the heating cylinder 3. FIG. Each of the figures shows the distribution state of the same phase and fluid phase of the resin, with a region 56 shown as a white outline representing the solid phase, and a region 57 marked with dots representing the fluid phase. In addition, all of the figures show the combination zone, and appropriate parts on the downstream side in the resin feeding direction are picked up in the order of (a), (b), and (c). In order to achieve good melting and plasticization, 100% melting must be completed at the end of the combination zone as shown in Figure (e), and the melting completion position must be stable, and the melting start position must also be stable. It is desirable that it be stable. Furthermore, it is desirable that melting progresses gradually between the melting start position and the melting completion position, without being too fast or too slow, and with a constant melting rate. Therefore, the image density distribution calculation means 46 subdivides the combination zone and refers to the ratio of the solid phase to the fluid phase in each part, and the molding condition calculation section 5l also divides the combination zone into parts and refers to the ratio of the solid phase to the fluid phase in each part. The above-mentioned molding conditions (1) to (1) are applied so that the melting start position and the melting completion position are stable, the melting is neither too early nor too slow between the two positions, and the melting rate is constant and gradually progresses. Change and adjust the necessary factors in [Phase]. FIG. 6 is a sectional view of the tip of the heating cylinder 3. In the figure, 4a is the tip head of the screw 4, 4b is the neck, 4C is a screw thread, 58 is a check ring attached to the neck 4b, and 57 is the stored molten resin (fluid phase). The inside of the heating cylinder 3 can be observed through the observation window 15 indicated by the two-dot chain line in the figure. FIG. 7 is an explanatory diagram showing an image obtained by the thermovision 38 from the observation window 15 shown in FIG. 6. In the figure, if the temperature of region Z1 is TI, the temperature of region z2 is T2, and the temperature of region Z3 is T3, then TI>T2>T
It can be seen that the temperature distribution of the stored molten resin 57 is not uniform. It is desirable that the temperature distribution of the stored molten resin 57 is uniform, and the temperature distribution calculating means 45 calculates, for example, the average temperature T awe of the entire stored molten resin region and the temperature difference range R=Tmax−T self i
n, and the molding condition calculation section 5l also calculates R/Ta.
The above-mentioned molding conditions ■ ~ [phase]
Change and adjust the necessary factors. Note that the temperature distribution is similarly observed in other observation windows 15,
If abnormally high or abnormally low temperatures occur in any part, the molding conditions will be changed to deal with this. 8 is an explanatory diagram showing an image obtained by the video camera 30 from the festival viewing window l5 shown in FIG. 6. The figure shows a known sack in which the pressure of the molten resin 57 is temporarily reduced by forcibly retracting the screw 4 by a minute amount after completion of metering in order to prevent the drooling phenomenon in which the molten resin 57 leaks from the nozzle 10. This shows an image when back control is performed. (For details on suckback control, if necessary, please refer to Japanese Patent Application No. 63-248958, which was previously proposed by the applicant.) In the figure, 59 indicates air bubbles generated by reducing the resin pressure. The image density distribution calculation means 46 calculates the degree of bubble generation. Air bubbles caused by suckback 5
9 is desirably as small as possible. For example, the molding condition calculating section 51 calculates the amount of suckback so as to stop the forced retraction of the screw 4 when even the slightest bubble 59 is generated. Note that an image indicating the degree of generation of bubbles 59 is obtained in the other observation window 15 as well. 59, and if it is determined that the deaeration is defective, the charging conditions are changed by the molding condition calculation unit 5l to deal with this. Furthermore, although not shown, the observation window l5 shown in FIG.
It is obvious that image data showing the movement of the check ring 58 can be obtained from the above, and the behavior of the check ring 58 can be determined by the check behavior calculating means 48. FIG. 9 is an explanatory diagram showing image data obtained from the observation window 15 at the center of the heating cylinder 3 by the video camera 30 when a predetermined amount of markers are mixed into the resin material (resin pellets). As a marker, a colored resin pellet having a higher melting temperature than the molding resin to be measured and analyzed, or a colored inorganic chip having approximately the same specific gravity as the molding resin is used, and this is transported from the hopper 8. For example, a small amount may be injected intermittently to capture the behavior of the marker. 9. In FIG. 9, reference numeral 60 indicates a marker mixed into the resin, and arrow A indicates the resin feeding direction, indicating that the markers 60 are almost uniformly distributed. However, the flow behavior of molten resin is complicated, and it is known from experience that resin tends to stick to the rear side of the thread 4C of the screw 4. That is, resin may sometimes remain in the region S shown by the dotted line in the figure, and in this case, the image density distribution calculation indicates that a part of the marker 60 remains without being transferred forward. The presence/absence and location of resin retention is identified by the analysis over time by the means 46. Also,
By calculating the flow velocity (average flow velocity or steel-specific flow velocity) of the marker 60 by the flow velocity calculation means 47, the average flow velocity of the resin and the retention points where the flow velocity is slow can be calculated and calculated.
It is determined. Of course, it is desirable that this retention be as small as possible, so the charging conditions are changed by the molding condition calculation unit 51 to deal with this. Although not shown, a masterbatch made of a colored resin of the same material as the resin used for measurement and analysis is mixed in a few percent, and the image data obtained by photographing this with the video camera 30 is used to obtain the image density distribution. If the calculation means 46 calculates the density of the coloring, it is possible to determine the uniformity of plasticization. Then, for example, the molding condition calculation section 51 changes and sets the charging conditions to deal with this so that the maximum density difference/density average value within a predetermined area is suppressed to a predetermined range or less. It goes without saying that if a colorant is mixed in, it will be of great help in analyzing resin behavior during barging (resin change, color change). Although the present invention has been described in detail with reference to the illustrated embodiments, those skilled in the art will be able to make various modifications without departing from the spirit of the present invention, and the processing within the analysis calculation device 43 may be modified in various ways depending on the program created. It can take any form. [Effects of the Invention] As described above, according to the present invention, based on the results of directly observing and analyzing the behavior of the resin inside the heating cylinder,
It is possible to provide a method for analyzing molding conditions in injection molding machines, which enables more theoretical setting of molding conditions and also greatly contributes to the design and evaluation of screws, and has great industrial value.

[Brief explanation of drawings]

The drawings all relate to one embodiment of the present invention; FIG. 1 is a block diagram showing a configuration for analyzing molding conditions, FIG. 2 is a partially cutaway front view showing an injection device of an injection molding machine, and FIG. Figure 3 is a partially cutaway front view of the main part of the injection device, and Figure 4 is a front view of the main part showing the main part of the injection device.
The figure is a cross-sectional side view of the main part of the heating cylinder taken in a direction perpendicular to the axial direction, Figure 5 is an explanatory diagram showing the state of distribution of solid phase and fluid phase obtained with a video camera, and Figure 6 is the heating cylinder. Fig. 7 is an explanatory diagram showing the image obtained by thermovision, Fig. 8 is an explanatory diagram showing the appearance of bubbles obtained by a video camera, and Fig. 9 is an explanatory diagram showing the appearance of bubbles obtained by a video camera. This is an explanatory diagram showing the flow and distribution of markers. 1... Pace, 2... Abutment, 3... Heating cylinder, 4... Screw. 4a...Tip head. 4b...
neck. 4c... Screw thread, 5... Drive source for screw rotation, 6... Drive source for injection, 7.
...Drive transmission mechanism, 8...Hopper 9
...Band heater, 10...Nozzle.
11...Headstock. 12...Mounting plate. 13...Circular hole. 14...Slit, l5...Observation window. 16...Notch. 17... Glass body. 18... Spacer, 19... Screw hole, 20... Tightening screw, 30... Video camera, 31...
... Strobe light emitting unit, 32 ... Strobe controller, 34 ... Video table recorder, 35
...Data buffer, 36...A/D
Converter, 37...Monitor, 38...Thermovision, 39... ．． ．． ．． ．． Video tape recorder, 40...Data buffer, 4l...
A/D converter, 42...Monitor, 43...
... Analysis calculation device, 44 ... Frame buffer, 45 ... Temperature distribution calculation means, 46 ...
- Image density distribution calculation means, 47...Flow velocity calculation means, 48...Check ring behavior calculation device, 49...Data storage unit, 50... Table, 51... Molding condition calculation section, 52...
... Injection molding machine control device, 53 ... Display device, 54 ... Printer, 55 ... External memory, 56 ... Solid phase, 57 ...Fluid phase (molten resin), 58...Check ring, 5
9...Bubble, 60...Marker 4th! ! Figure 5 Figure 7 Z2 Z3 z2

Claims (6)

[Claims] (1) Injection molding with a visualization heating cylinder in which a screw is arranged in the heating cylinder so that it can rotate and move back and forth, and a part of the peripheral wall of the heating cylinder is provided with an observation window for internal observation with a transparent material. In the machine, at least one of the temperature distribution data of the resin inside the heating cylinder or image data such as resin behavior is collected through the observation window, and based on the collected data, the data is measured during the plasticizing metering process (during the charging process) or during the injection process. A method for analyzing molding conditions in an injection molding machine having a visualized heating cylinder, characterized in that conditions during stroke are analyzed. (2) In claim 1, from the image data,
A method for analyzing molding conditions in an injection molding machine having a visualization heating cylinder, characterized by measuring and calculating the degree of bubble generation in molten resin. (3) In claim 1, a chip made of a colored resin having a higher melting temperature than the resin material or a colored inorganic substance having approximately the same specific gravity as the resin material is mixed as a marker into the resin material to be plasticized and melted. A method for analyzing molding conditions in an injection molding machine having a visualization heating cylinder, characterized in that the flow condition of the marker is analyzed from the image data to measure and calculate the presence or absence of resin retention points. (4) The visualization heating cylinder according to claim 1, characterized in that a coloring agent is mixed into the resin material to be plasticized and melted, and the degree of coloring of the resin material is measured and calculated from the image data. Molding condition analysis method for injection molding machines with (5) Molding conditions in an injection molding machine having a visualization heating cylinder according to claim 1, wherein the movement of a check ring located at the neck of the tip of the screw is measured and calculated from the image data. analysis method. (6) A method for analyzing molding conditions in an injection molding machine having a visualization heating cylinder according to claim 1, characterized in that resin temperature differences at various parts within a predetermined region are measured and calculated.