Method for testing melt index

Abstract

The invention discloses a method for testing a melt index. The method comprises the following steps: preheating a melt charging barrel to a preset temperature, and carrying out heat preservation for a first preset time; feeding to be measured is loaded into a containing cavity of a melting charging barrel, a piston rod is inserted into the melting charging barrel, a mass piece with the first weight is added to the piston rod, the feeding to be measured is melted into molten feeding under the pressure of the piston rod and is compacted, and therefore falling materials with the preset length are exposed out of a discharging opening of the melting charging barrel; switching the weight of the mass piece on the piston rod from the first weight to the second weight, so that the to-be-detected feed flows out of the discharge port under the pressure of the piston rod and is cut to obtain a plurality of sections of first to-be-detected samples, and calculating the melt index of the to-be-detected feed; the range of the first weight is 2.16 kg to 10 kg, and the range of the preset length is 1 cm to 30 cm. Therefore, the air in the melt charging barrel can be exhausted, the components of the to-be-tested feed are more uniform, the uniformity of the first to-be-tested sample is improved, the fluctuation of the tested melt index is reduced, and the accuracy of the test result is improved.

Description

Technical Field

[0001] The present application relates to the technical field of melt index testing, and in particular to a method for testing a melt index. Background Art

[0002] In recent years, with the development of the consumer electronics industry, products have continued to move towards lighter, thinner, smaller, and more integrated designs. These products are placing higher demands on the biocompatibility, precision, and reliability of their components. Therefore, metal injection molding (MIM) is often used to produce complex, high-precision, and miniaturized metal parts.

[0003] For feedstock preparation in the MIM process, melt index is a key indicator of feedstock fluidity. The melt index reflects the feedstock's flow properties during the molding process. A suitable melt index ensures uniform mold filling during injection molding, guaranteeing the molding quality and production efficiency of MIM products. However, existing melt index testing methods, when the feedstock composition is uneven or contains air, can cause the material extruded through the discharge port to split in two due to thermal expansion and contraction. This makes it difficult for subsequent measurement personnel to collect a uniform sample for melt index testing, resulting in poor melt index testing accuracy. Summary of the Invention

[0004] In order to solve the above-mentioned technical problem of poor accuracy in testing the melt index, the present application provides a method for testing the melt index.

[0005] To solve the above problems, the present application provides a first technical solution: a method for testing a melt index, which is applied to a melt indexer, the melt indexer comprising a melt barrel and a piston rod, the method comprising: preheating the melt barrel to a preset temperature and keeping the temperature for a first preset time; loading a feed material to be tested into a receiving cavity of the melt barrel; inserting the piston rod into the melt barrel and adding a mass member of a first weight to the piston rod, wherein the feed material to be tested is melted into a molten feed material under the pressure of the piston rod and compacted so that a blank of a preset length is exposed at a discharge port of the melt barrel; switching the mass member on the piston rod from the first weight to a second weight so that the feed material to be tested flows out through the discharge port under the pressure of the piston rod and is cut to obtain multiple segments of first test samples; and calculating the melt index of the feed material to be tested based on the mass of the multiple segments of the first test samples; wherein the first weight ranges from 2.16 kg to 10 kg, and the preset length ranges from 1 cm to 30 cm.

[0006] Optionally, the above-mentioned inserting of the piston rod into the molten barrel and adding a mass part of a first weight to the piston rod, the feed to be tested is melted into the molten feed under the pressure of the piston rod and compacted so that the blank of the preset length is exposed at the discharge port of the molten barrel, including: inserting the above-mentioned piston rod into the above-mentioned molten barrel and adding a mass part of a first weight to the above-mentioned piston rod; compacting the above-mentioned feed to be tested by the above-mentioned mass part of the first weight so that the above-mentioned blank of the preset length is squeezed out from the above-mentioned discharge port within a preset time; wherein the above-mentioned preset time is 5s.

[0007] Optionally, the melt indexer further includes a material receiving assembly; the mass member on the piston rod is switched from the first weight to the second weight so that the feed material to be tested flows out through the discharge port under the pressure of the piston rod and is cut to obtain multiple segments of the first sample to be tested, including: switching the mass member on the piston rod from the first weight to the second weight so that the feed material to be tested flows out through the discharge port under the pressure of the piston rod and is cut; controlling the material receiving assembly to move at a first preset speed so that the material receiving assembly sequentially receives multiple segments of material flowing out of the discharge port, and the multiple segments of material are at different positions on the receiving tray.

[0008] Optionally, the melt indexer further includes a scraper; the switching of the mass member on the piston rod from the first weight to the second weight so that the feed to be tested flows out through the discharge port under the pressure of the piston rod and is cut comprises: switching the mass member on the piston rod from the first weight to the second weight; controlling the scraper to cut the feed to be tested flowing out through the discharge port at a second preset speed, the second preset speed corresponding to the first preset speed.

[0009] Optionally, the above-mentioned melt indexer also includes a die; before the above-mentioned step of loading the feed material to be tested into the accommodating cavity of the above-mentioned melt barrel, the above-mentioned testing method also includes: preheating the above-mentioned melt barrel to a preset temperature and keeping it warm for a first preset time; cleaning the above-mentioned melt barrel, the above-mentioned die and the above-mentioned piston rod, and placing the cleaned above-mentioned die into the above-mentioned melt barrel.

[0010] Optionally, the above-mentioned loading of the feed to be tested into the accommodating cavity of the above-mentioned molten barrel includes: adding the above-mentioned feed to be tested into the above-mentioned molten barrel until the above-mentioned molten barrel is full, and the time when the above-mentioned molten barrel is full is the first time; the above-mentioned inserting the piston rod into the molten barrel, and adding a mass piece of a first weight to the piston rod, the feed to be tested is melted into molten feed under the pressure of the piston rod and compacted so that a preset length of blank material is exposed at the discharge port of the molten barrel, including: inserting the above-mentioned piston rod into the above-mentioned molten barrel; compacting the above-mentioned feed to be tested in the above-mentioned molten barrel by the above-mentioned piston rod; adding a mass piece of a first weight to the above-mentioned piston rod, so that the above-mentioned feed to be tested is compacted under the pressure of the above-mentioned piston rod and a preset length of blank material is exposed at the discharge port of the above-mentioned die; wherein, the time to complete the above-mentioned compaction operation is the second time, and the time difference between the above-mentioned second time and the above-mentioned first time is less than or equal to 1 minute.

[0011] Optionally, the above-mentioned calculation of the melt index of the above-mentioned feed to be tested based on the mass of multiple segments of the above-mentioned first samples to be tested includes: selecting a preset number of second samples to be tested from the multiple segments of the above-mentioned first samples to be tested; calculating the melt index corresponding to the above-mentioned second sample to be tested based on the ratio of the mass of a certain second sample to be tested to the cutting time of the above-mentioned feed to be tested, and calculating the melt index of the above-mentioned feed to be tested based on the average value of the above-mentioned melt indices of all the above-mentioned second samples to be tested, or calculating the mass mean of all the above-mentioned second samples to be tested, and calculating the melt index of the above-mentioned feed to be tested based on the ratio of the above-mentioned mass mean to the cutting time of the above-mentioned feed to be tested.

[0012] Optionally, the above-mentioned control of the material receiving assembly to move at a first preset speed so that the above-mentioned material receiving assembly sequentially receives multiple sections of material flowing out of the above-mentioned discharge port includes: when the first scale line of the above-mentioned piston rod is flush with the upper end of the above-mentioned melting barrel, controlling the above-mentioned material receiving assembly to move at a first preset speed so that the above-mentioned material receiving assembly sequentially receives the above-mentioned first sample to be tested flowing out of the above-mentioned discharge port.

[0013] Optionally, after the step of switching the mass part on the piston rod from the first weight to the second weight so that the feed to be tested flows out through the discharge port under the pressure of the piston rod and is cut, the testing method further includes: recording the number of times the molten feed is cut; controlling the material receiving component to move at a first preset speed so that the material receiving component sequentially receives multiple sections of material flowing out of the discharge port, including: when the number of times the molten feed is cut reaches a first preset value, controlling the material receiving component to move at a first preset speed so that the material receiving component sequentially receives the first sample to be tested flowing out of the discharge port.

[0014] Optionally, after the step of switching the mass part on the piston rod from the first weight to the second weight so that the feed to be tested flows out through the discharge port under the pressure of the piston rod and is cut, the testing method further includes: recording the outflow time of the molten feed; controlling the material receiving component to move at a first preset speed so that the material receiving component sequentially receives multiple sections of material flowing out of the discharge port, including: when the outflow time reaches a second preset value, controlling the material receiving component to move at the first preset speed so that the material receiving component sequentially receives the first sample to be tested flowing out of the discharge port.

[0015] Different from the prior art, the testing method of the present application is as follows: preheating a melt barrel to a preset temperature and keeping it warm for a first preset time; loading the feed material to be tested into the accommodating cavity of the melt barrel; inserting a piston rod into the melt barrel and adding a mass piece of a first weight to the piston rod, so that the feed material to be tested is melted into molten feed material under the pressure of the piston rod and compacted, so that a blank of a preset length is exposed at the discharge port of the melt barrel; switching the mass piece on the piston rod from the first weight to the second weight so that the feed material to be tested flows out through the discharge port under the pressure of the piston rod and is cut to obtain multiple sections of the first test sample; calculating the melt index of the feed material to be tested based on the mass of the multiple sections of the first test sample; the first weight ranges from 2.16kg to 10kg, and the preset length ranges from 1cm to 30cm. Therefore, the mass piece of the first weight can expel the air in the melt barrel and make the composition of the feed material to be tested more uniform, thereby improving the uniformity of the first test sample, reducing the fluctuation of the test melt index, and improving the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive efforts. Among them:

[0017] Figure 1 This is a schematic flow chart of the first embodiment of the melt index testing method provided by the present application;

[0018] Figure 2 1 is a schematic structural diagram of an embodiment of a melt indexer provided by the present application;

[0019] Figure 3 1 is a flow chart of a second embodiment of the method for testing the melt index provided by the present application;

[0020] Figure 4 1 is a flow chart of a third embodiment of the method for testing the melt index provided in this application;

[0021] Figure 5 1 is a flow chart of a fourth embodiment of the method for testing the melt index provided by the present application;

[0022] Figure 6 It is a structural schematic diagram of an embodiment of a material splicing assembly provided by the present application;

[0023] Figure 7 yes Figure 6 Schematic diagram of the spiral trajectory of the receiving position of the middle receiving tray.

[0024] In the figure, 10, melt indexer; 11, melt barrel; 12, die; 121, feed material to be tested; 122, first sample to be tested; 123, discharge port; 124, melt feed material; 13, piston rod; 14, pull rod; 15, mass part; 16, material receiving assembly; 161, driving part; 162, material receiving tray; 163, connecting shaft. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0026] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0028] The present application embodiment first provides a melt index test method, which is applied to a melt index meter, which is used to measure the melt index (MFI) of thermoplastic materials (such as plastics, MIM feeds, etc.). The melt index is used to measure the flow properties of the feed to be tested in a molten state.

[0029] See Figure 1 and Figure 2 , Figure 1 This is a flow chart of the first embodiment of the method for testing the melt index provided by this application. Figure 2 Schematic diagram of the structure of an embodiment of the melt indexer provided by this application. Figure 1 As shown, the melt indexer 10 includes a melt barrel 11 and a piston rod 13. In this embodiment, the testing method includes the following steps:

[0030] Step S11: preheating the melting barrel 11 to a preset temperature and keeping the temperature for a first preset time.

[0031] Specifically, the melt barrel 11 is provided with a receiving chamber for loading the test material 121. The melt barrel 11 may also be provided with a heater for heating the test material 121 within the melt barrel 11 to a molten state. A piston rod 13 may be placed within the melt barrel 11 to directly contact the test material 121 via a pressure surface. The piston rod 13 is used to compact the test material 121 and ensure uniform melting within the melt barrel 11. The melt barrel 11 also includes a discharge port 123. The piston rod 13 is further used to push the test material 121 through the discharge port 123. The movement of the piston rod 13 simulates the flow process of the test material 121 during an actual injection molding process.

[0032] The preset temperature can be set based on the feed fluidity of the feed material 121 to be tested. The preset temperature can be set within the range of 160°C to 220°C. For example, the preset temperature can be 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, or 220°C. After the melt barrel 11 is preheated to the preset temperature, the melt barrel 11 can be kept warm for a first preset time to maintain the preset temperature. In a possible embodiment, the first preset time can be, but is not limited to, 30 minutes.

[0033] Step S12: loading the feed material 121 to be tested into the accommodating cavity of the melting barrel 11 .

[0034] After preheating the test material 121, the test material 121 is loaded into the accommodating cavity of the melt barrel 11. Specifically, the test material 121 is a solid material that can be converted into a molten state. The test material 121 includes but is not limited to block, granular, or powdered materials. Therefore, the test material 121 can be poured into the melt barrel 11 through a feeding barrel and a funnel. When the test material 121 reaches the top of the melt barrel, the pouring is completed.

[0035] Step S13: Insert the piston rod 13 into the melting barrel 11, and add a mass piece 15 of a first weight to the piston rod 13. The feed material 121 to be tested is melted into a molten feed material 124 under the pressure of the piston rod 13 and is compacted so that a blank of a preset length is exposed at the discharge port 123 of the melting barrel 11.

[0036] After the melt barrel 11 is loaded with the feed material 121 to be measured, the piston rod 13 is inserted into the melt barrel 11 to preliminarily compact the feed material 121 to be measured in the melt barrel 11 through the piston rod 13 . Because there are gaps between the test material 121 within the melt barrel 11, the friction of the test material 121 is relatively low. After the mass member 15 of the first weight is added to the piston rod 13, the pressure provided by the mass member 15 of the first weight further pressurizes and compacts the test material 121 within the melt barrel 11, and the air between the gaps in the test material 121 is expelled. Furthermore, as the test material 121 is loaded into the melt barrel 11 for a longer time, the test material 121 gradually heats and melts at the temperature of the melt barrel 11, and the test material 121 becomes a molten molten material 124. The gaps between the molten materials 124 are further reduced, making the test material 121 at the lower end of the accommodating cavity easily squeezed out of the discharge port 123 by the pressure of the piston rod 13, and exposed outside the discharge port 123. At this time, the extruded material flowing out of the discharge port 123 is defined as blanking. Blanking usually contains a large amount of air impurities and cannot meet the testing requirements.

[0037] Under the pressure of the mass member 15 of the first weight, the density of the material in the accommodating cavity gradually increases, the gap between the molten feeds 124 decreases, and the friction between the molten feeds 124 increases, making it difficult for the feed to be tested 121 located at the lower end of the accommodating cavity to be squeezed out of the discharge port 123 by the pressure of the piston rod 13; when the pressure applied by the piston rod 13 and the mass member 15 of the first weight is equal to the friction of the subsequent molten feed 124, the subsequent feed to be tested 121 is no longer squeezed out of the discharge port 123.

[0038] Therefore, when adding the mass member 15 of the first weight to the piston rod 13, it is necessary to ensure that the weight of the mass member 15 can ensure that the predetermined length of the blank is exposed at the discharge port 123 while preventing the blank from continuing to fall. This is to reduce the impact of excessive material loss caused by the continued falling blank on the subsequent testing process. In this way, the feed material 121 to be tested in the molten barrel 11 can be fully melted, improving the accuracy of the subsequent testing of the molten feed material 124.

[0039] The first weight ranges from 2.16 kg to 10 kg. Since conventional melt indexers 10 typically use a standard test force weight as the mass member 15 during testing, for example, the mass member 15 of the first weight can be selected from weights of levels 3 to 6. The first weight includes, but is not limited to, 2.16 kg, 3.8 kg, 5 kg, or 10 kg, and the pressure applied by the mass member 15 of the first weight includes, but is not limited to, 21.18 N, 37.26 N, 49.03 N, or 98.07 N.

[0040] The preset length ranges from 1 cm to 30 cm. That is, when the mass member 15 of the first weight is attached to the piston rod 13, the length of the material falling when it is exposed at the discharge port 123 and does not continue to fall is 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm, 14 cm, 16 cm, 18 cm, 20 cm, 22 cm, 24 cm, 26 cm, 28 cm, or 30 cm.

[0041] Step S14: switching the mass member 15 on the piston rod 13 from the first weight to the second weight, so that the molten feed 124 flows out through the discharge port 123 under the pressure of the piston rod 13 and is cut to obtain multiple sections of the first test sample 122.

[0042] Specifically, after the first-weight mass member 15 is used to reduce the gaps between the molten feed materials 124 and expel the air between the molten feed materials 124, the test feed material 121 can be uniformly melted within the melt barrel 11. At this point, a second-weight mass member 15 is applied to the side of the piston rod 13 facing away from the melt barrel 11, so that the piston rod 13 applies pressure to the test feed material 121 to cause the blank to continue to fall, and the melt index test of the test feed material 121 begins. The molten feed material 124 within the melt barrel 11 flows under a first preset pressure and flows out through the discharge port 123. The molten feed material 124 flowing out of the discharge port 123 is cut by a scraper at a preset speed to obtain multiple sections of the first test sample 122. At this point, in contrast to the blank material described above, the first test sample 122 here can be understood as the molten feed material 124 that has undergone degassing and compaction, while the blank material is the molten feed material 124 that has not undergone degassing and compaction.

[0043] The second weight is greater than the first weight, so that the molten feed 124 can flow out through the discharge port 123 under greater pressure. In a possible embodiment, the melt indexer 10 may include a support frame, which is used to place the mass member 15 and drive the mass member 15 to move up and down in the height direction so that the mass member 15 contacts the piston rod 13 and applies pressure to the piston rod 13.

[0044] Step S15: Calculating the melt index of the feed material to be tested 121 based on the mass of the multiple sections of the first sample to be tested 122 .

[0045] After obtaining multiple sections of the first test sample 122 , the melt index of the test feed material 121 can be calculated based on the mass of the multiple sections of the first test sample 122 .

[0046] In an embodiment of the present application, the testing method can expel the air in the melting barrel 11 through the mass member 15 of the first weight and make the composition of the feed material 121 to be tested more uniform, thereby improving the uniformity of the first sample to be tested, reducing the fluctuation of the melt index of the test, and improving the accuracy of the test results.

[0047] In one embodiment, the melt indexer 10 further includes a die 12; before step S12, the testing method of this embodiment further includes the following steps: preheating the melt barrel 11 to a preset temperature and keeping it warm for a first preset time; cleaning the melt barrel 11, the die 12 and the piston rod 13, and placing the cleaned die 12 into the melt barrel 11.

[0048] Specifically, when the melting barrel 11 is a cleaned barrel, step S12 can be directly entered after the preheating is completed; when the feed material 121 to be tested is still stored in the melting barrel 11, since the feed material 121 to be tested usually solidifies into solid substances and remains in the containing cavity under low temperature conditions, the testing method of this embodiment also cleans the preheated melting barrel 11 to facilitate the removal of the molten residual objects in the containing cavity, reduce or avoid the influence of the residual materials from the previous test on the next test, improve the cleanliness of the melting barrel 11 and improve the accuracy of the test.

[0049] The melt indexer 10 may also include a die 12 and a cleaning rod for cleaning. The die 12 is provided with a discharge port 123 of a preset size. The die 12 is used to standardize the aperture and length to make the melt indexes of different materials comparable. The cleaning rod is a long, rod-shaped object that can be wrapped with gauze and inserted into the melt barrel 11 to quickly wipe the inside of the melt barrel 11 up and down with the gauze to clean the melt barrel 11. The melt indexer 10 may also include a cleaning rod for cleaning the die 12. The cleaning rod can also be wrapped with gauze and inserted into the die 12 of the melt barrel 11 to clean it, and the gauze can be used to clean the outside of the die 12.

[0050] In a possible embodiment, the melt indexer 10 further includes a feeder, a funnel, and a pull rod 14. The feeder is used to load the test material 121, and the funnel is used to guide the test material 121 from the feeder to the melt barrel 11 to reduce or prevent the test material 121 from spilling or spilling. Before starting the test, the melt barrel 11 and the funnel can be cleaned with gauze, a cleaning stick wrapped with gauze, or a cleaning rod to ensure the accuracy of the test results and reduce test errors. One end of the pull rod 14 is used to extend into the melt barrel 11 and secure the die 12, while the other end of the pull rod 14 is exposed to the melt barrel 11 and allows the user to operate it. After the cleaning of the melt barrel 11, the die 12, the feeder, the funnel and the piston rod 13 is completed, in this embodiment, the pull rod 14 can be pulled outward to the limit, the cleaned die 12 can be placed into the melt barrel 11 and the pull rod 14 can be pulled inward to fix the die 12, so as to complete the instrument debugging of the melt indexer 10 and enable the feed material 121 to be tested to be loaded into the melt barrel 11 for testing.

[0051] In one embodiment, see Figure 3 , Figure 3 FIG. 1 is a flow chart of the second embodiment of the method for testing the melt index provided by the present application. Figure 3 As shown, step S13 of the testing method of this embodiment further includes:

[0052] Step S131 : inserting the piston rod 13 into the melting barrel 11 , and adding a mass member 15 of a first weight to the piston rod 13 .

[0053] Specifically, after the piston rod 13 is inserted into the melting barrel 11 , the feed material 121 to be tested in the melting barrel 11 can be preliminarily compacted by the weight of the piston rod 13 itself, and a mass member 15 of a first weight is added to the piston rod 13 .

[0054] Step S132: compacting the feed material 121 to be tested by the mass member 15 of the first weight so that the discharge port 123 extrude a blank of a preset length within a preset time; wherein the preset time is 5 seconds.

[0055] When the test material 121 is compacted by the mass member 15 of the first weight, the first weight and the weight of the piston rod 13 can cause the air between the test material 121 in the receiving chamber to be discharged through the discharge port 123, and a portion of the test material 121 at the lower end of the receiving chamber to flow out and appear at the discharge port 123, so that the discharge port 123 can extrude a preset length of material within a preset time without it falling. The preset time is 5 seconds, that is, the first weight of the mass member 15 can be determined by determining whether 1 to 30 cm of material is extruded within 5 seconds after the mass member 15 is placed. For example, after adding a 2.16 kg mass member 15 to the piston rod 13, if no material is extruded from the discharge port 123 within 5 seconds, a 3.8 or 5 kg mass member 15 can be added to the piston rod 13 until the discharge port 123 extrudes 1 to 30 cm of material within 5 seconds without the material continuing to fall.

[0056] After the 1-30 cm blank extruded from the discharge port 123 stops falling, the melt barrel 11 is kept warm for a second preset time to ensure uniform melting of the test material 121 within the melt barrel 11. This reduces the risk of the test material 121 bursting due to thermal expansion and contraction after falling, which may be caused by air contained in the test material 121, thereby improving the uniformity of the cut test sample. The second preset time can be, but is not limited to, within the range of 3 to 10 minutes, for example, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes.

[0057] In one embodiment, see Figure 4 , Figure 4 FIG. 1 is a flow chart of the third embodiment of the method for testing the melt index provided by the present application. Figure 4 As shown, the melt indexer 10 further includes a material receiving assembly 16; step S14 of the testing method of this embodiment further includes:

[0058] Step S141 : switching the mass member 15 on the piston rod 13 from the first weight to the second weight, so that the molten feed 124 flows out through the discharge port 123 under the pressure of the piston rod 13 and is cut.

[0059] Specifically, the mass member 15 on the piston rod 13 is switched from a first weight to a second weight, so that the molten feed 124 can flow out through the discharge port 123 under greater pressure and be cut, so that the flowing blank can form multiple sections of the first test sample 122. The second weight can be, but is not limited to, 12 kg or 21.6 kg.

[0060] Step S142: controlling the material receiving assembly 16 to move at a first preset speed so that the material receiving assembly 16 sequentially receives multiple sections of material flowing out of the material receiving port 123 , wherein the multiple sections of material are at different positions on the material receiving tray.

[0061] Specifically, the material receiving assembly 16 is disposed below the discharge port 123 and is used to receive the sample flowing out of the discharge port 123. In a possible embodiment, the material receiving assembly 16 includes a drive member and a receiving tray that are interconnected. The receiving tray is located below the discharge port 123 and is used to receive the blanks flowing out of the discharge port 123 so that the melt index of the feed material 121 to be tested can be calculated based on the physical parameters or other parameters of the blanks. The drive member is used to drive the receiving tray to move at a first preset speed so that the multiple segments of material flowing out of the discharge port 123 are located at different positions on the receiving tray, so that the non-adherent multiple segments of the first sample to be tested 122 can be automatically obtained through the material receiving assembly 16.

[0062] Therefore, the testing method of this embodiment moves the material receiving component 16 at a first preset speed and automatically receives multiple sections of material flowing out during the test, so that the positions of the multiple sections of material on the material receiving tray are different, reducing or avoiding adhesion between the multiple sections of material, improving the reliability of the melt index test, and eliminating the need for manual receiving operations by the user, thereby improving the user experience.

[0063] Optionally, the melt indexer 10 further includes a scraper; step S141 includes: switching the mass member 15 on the piston rod 13 from a first weight to a second weight; controlling the scraper to cut the molten feed 124 flowing out through the discharge port 123 at a second preset speed, the second preset speed corresponding to the first preset speed.

[0064] The die 12 of the melt indexer 10 may include a feed port and a discharge port 123. The feed port is located near one side of the melt barrel 11 and is used to receive the feed material 121 to be tested. The feed material 121 to be tested is discharged through the discharge port 123 under the pressure of the piston rod 13. A scraper is provided on the side of the die 12 near the discharge port 123. The scraper is used to cut the blank material extruded through the discharge port 123 during the test at a preset speed to obtain multiple segments of the first test sample 122. The scraper can be provided with corresponding shearing conditions, such as the number of cuts and the cutting speed, so that the scraper can cut the feed material 121 to be tested according to the preset conditions. After the feed material 121 to be tested is extruded through the scraper's discharge port 123, the scraper cuts the feed material 121 at a second preset speed to collect multiple segments of the first test sample 122. In a possible embodiment, the second preset speed of the scraper can be selected according to the flow properties of the feed material 121 to be tested, the moving speed of the material receiving component 16, etc. For example, it can be selected to cut once per second or once per two seconds, etc.; the number of cuts of the scraper can be but is not limited to being set to greater than 10 times.

[0065] Therefore, the testing method of this embodiment sets the second preset speed when cutting the material to correspond to the first preset speed when the material receiving component 16 moves, so that when the material receiving component 16 receives two adjacent sections of material flowing out during the test, the two adjacent sections of material fall on the material receiving component 16 at different positions, thereby reducing or avoiding adhesion between the two adjacent sections of material, improving the reliability of the melt index test, and eliminating the need for manual receiving operations by the user, thereby improving the user experience.

[0066] In one embodiment, step S12 includes: adding the feed material 121 to be tested into the melt barrel 11 until the melt barrel 11 is full, and the time when the melt barrel 11 is full is a first time. Step S13 includes: inserting the piston rod 13 into the melt barrel 11; compacting the feed material 121 to be tested in the melt barrel 11 by the piston rod 13; adding a mass member 15 of a first weight to the piston rod 13, and the feed material 121 to be tested is melted into molten feed material 124 under the pressure of the piston rod 13 and compacted so that a blank of a predetermined length is exposed at the discharge port 123 of the melt barrel 11; wherein the time when the compaction operation is completed is a second time, and the time difference between the second time and the first time is less than or equal to 1 minute.

[0067] Specifically, the time it takes for the feed material 121 to be tested to fill the melt barrel 11 via the feed barrel and the hopper is defined as the first time. The piston rod 13 is used to compact the feed material 121 within the melt barrel 11. This can be achieved by controlling the piston rod 13 to move up and down multiple times to apply pressure to the feed material 121 via the pressure surface of the piston rod 13, thereby achieving initial compaction of the feed material 121. The time it takes for the compaction operation of the piston rod 13 to be completed is defined as the second time.

[0068] The testing method of this embodiment controls the difference between the first time when the molten barrel 11 is filled with the feed material 121 to be tested and the second time when the compaction operation is completed to be less than or equal to 1 minute. This can reduce or avoid problems such as the material being melted due to heat and the feed material 121 being flowed and squeezed out and unable to be effectively compacted due to the feed material 121 being loaded into the molten barrel 11 for too long, thereby improving the compaction effect of the feed material 121 to be tested and thereby improving the uniformity of the composition of the feed material 121 to be tested.

[0069] In one embodiment, see Figure 5 , Figure 5 FIG. 4 is a flow chart of the fourth embodiment of the method for testing the melt index provided by the present application. Figure 5 As shown, in this embodiment, step S15 includes:

[0070] Step S151 : selecting a preset number of second samples to be tested from the plurality of first samples to be tested 122 .

[0071] Specifically, after obtaining multiple sections of the first test sample 122, a preset number of second test samples with good uniformity can be selected from the multiple sections of the first test sample 122 on the material receiving assembly 16. The preset number can be, but is not limited to, 2, 3, 4, 5, or 6 sections. After obtaining multiple sections of the second test sample, the process proceeds to step S152 or step S153.

[0072] Step S152: Calculate the melt index of the corresponding second sample based on the ratio of the mass of a second sample to be tested to the cutting time of the feed material 121 to be tested, and calculate the melt index of the feed material 121 to be tested based on the average melt index of all second samples to be tested.

[0073] Specifically, in one embodiment, after weighing the second sample to be tested, the mass of a second sample to be tested is obtained, and the ratio of the mass of the second sample to be tested to the cutting time of the test material 121 is calculated to calculate the melt index of the corresponding second sample to be tested. The cutting time of the test material 121 can be understood as the interval between the scraper cutting two adjacent blanks, and the cutting time can be determined based on the cutting speed of the scraper. The melt index of the corresponding second sample to be tested is calculated based on the ratio of the mass of the second sample to be tested to the cutting time of the test material 121. After calculating the melt indexes of all second samples to be tested, the test result of the melt index of the test material 121 is determined based on the average value of the melt indexes of all second samples to be tested.

[0074] In a possible embodiment, the ratio of the mass of each second sample to be tested to the cutting time of the die 12 can be calculated. Based on the ratio of the mass of each second sample to be tested to the cutting time of the feed material 121 to be tested, the product of this ratio and a third preset value is calculated to calculate the melt index of the second sample to be tested. In a possible embodiment, the third preset value is 600. The specific calculation formula is as follows:

[0075]

[0076] Wherein, M is the mass of a second sample to be tested, T is the cutting time of the die 12, and MFI is the melt index.

[0077] Step S153 : Calculate the mass average of all the second samples to be tested, and calculate the melt index of the feed material to be tested 121 based on the ratio of the mass average to the cutting time of the feed material to be tested 121 .

[0078] Specifically, in another embodiment, after weighing the second samples to be tested, the mass average of all the second samples to be tested is calculated, and the ratio of the mass average of the second samples to be tested to the cutting time of the feed material to be tested 121 is calculated, and the product of the ratio and the third preset value is used as the melt index of the feed material to be tested 121. Specifically, the calculation can be performed by substituting the mass average obtained above into the above formula (1), which will not be repeated here.

[0079] Different from the prior art which requires obtaining the mass of all the samples to be tested within a specified time to calculate the melt index, the testing method of the embodiment of the present application selects a uniform preset number of second samples to be tested from multiple segments of the first samples to be tested 122, and weighs the second samples to be tested to calculate the melt index of the feed to be tested 121 based on the mass of the second samples to be tested. This can improve the uniformity of the second samples to be tested, reduce the fluctuation of the melt index of the test, and improve the accuracy of the test results.

[0080] In one embodiment, step S142 includes: when the first scale line of the piston rod 13 is flush with the upper end of the melting barrel 11, controlling the material receiving assembly 16 to move at a first preset speed so that the material receiving assembly 16 sequentially receives the first sample to be tested 122 flowing out of the feed port 123.

[0081] Specifically, one end of the piston rod 13 is used to be inserted into the molten barrel 11 and contact the feed material 121 to be tested, and the other end of the piston rod 13 is used to contact the mass member 15 so that the mass member can apply corresponding pressure to the feed material 121 to be tested. The piston rod 13 is provided with at least a first scale line and a second scale line, which are respectively used to indicate different height positions of the piston rod 13 within the molten barrel 11, with the second scale line located above the first scale line. After the mass member 15 of a second weight is added to the piston rod 13, the feed material 121 to be tested is heated and melted within the molten barrel 11 and extruded from the discharge port 123 of the die 12. The piston rod 13 slowly moves downward until the first scale line of the piston rod 13 is flush with the upper end of the molten barrel 11.

[0082] Among them, the upper end of the melt barrel 11 can be understood as the edge position of the top opening of the melt barrel 11. Since the uniformity of the feed to be tested 121 in each section of the melt barrel 11 varies, the melt index of the rear section of the feed to be tested 121 is more instructive for the injection molding process. However, receiving the extrudate of the rear section of the feed to be tested 121 can easily lead to insufficient number of feed sections received, resulting in too much randomness in the measurement. Therefore, the testing method of this embodiment controls the material receiving assembly 16 to move at a first preset speed when the first scale line of the piston rod 13 is flush with the upper end of the melt barrel 11, so that the material receiving assembly 16 sequentially receives the first sample to be tested 122 flowing out of the feed port 123. Therefore, it can be ensured that the first sample to be tested 122 received belongs to the rear position in the melt barrel 11, and the fixed material receiving position can ensure that the first sample to be tested 122 received each time is in the same section of the melt barrel 11, so as to further reduce the volatility of the melt index, improve the uniformity of the first sample to be tested 122, and thus improve the accuracy of the test results.

[0083] In one embodiment, after step S141, the testing method further includes recording the number of cuts of the molten feed material 124. Step S142 includes controlling the receiving assembly 16 to move at a first preset speed when the number of cuts of the molten feed material 124 reaches a first preset value, so that the receiving assembly 16 sequentially receives the first test sample 122 flowing out of the feed port 123.

[0084] Specifically, when the molten feed 124 is extruded through the discharge port 123 of the die 12 and cut by the scraper, the number of cuts of the molten feed 124 is simultaneously recorded. Since the molten feed 124 contained in the melt barrel 11 is limited, the number of cuts that can be achieved for the molten feed 124 in the melt barrel 11 is limited. The testing method of this embodiment can control the material receiving assembly 16 to receive the cut and dropped first sample 122 when the number of cuts reaches a first preset value, so as to ensure that the received first sample 122 is located at the rear of the melt barrel 11 and that the first sample 122 received each time is located at the same section of the melt barrel 11. By fixing the receiving position of the first sample 122, the volatility of the melt index is reduced, the uniformity of the first sample 122 is improved, and the accuracy of the test results is thereby improved.

[0085] For example, when the molten feed 124 in the melting barrel 11 can usually be cut 10 times, in order to be able to test the melt index of the rear section of the molten feed 124, the testing method of this embodiment can take the sample to be tested that is cut for the fourth time from the die 12, so as to reduce the influence of the molten feed 124 in the front section of the melting barrel 11 on the volatility of the melt index, and ensure that the first sample to be tested 122 taken each time belongs to the same section of the melting barrel 11.

[0086] In one embodiment, after step S141, the testing method further includes recording the outflow time of the molten feed material 124. Step S142 includes controlling the material receiving assembly 16 to move at a first preset speed when the outflow time reaches a second preset value, so that the material receiving assembly 16 sequentially receives the first test sample 122 flowing out of the feed port 123.

[0087] Specifically, when the molten feed 124 is extruded through the die 12 and cut by the scraper, the time for the molten feed 124 to flow out of the die 12 is simultaneously recorded. Since the molten feed 124 contained in the melt barrel 11 is limited and the flow time of the molten feed 124 is limited, the testing method of this embodiment can control the material receiving assembly 16 to receive the first test sample 122 flowing out of the die 12 when the flow time of the molten feed 124 reaches a second preset value, so as to ensure that the received first test sample 122 is located at the rear of the melt barrel 11 and that the first test sample 122 received each time is located at the same section of the melt barrel 11. By fixing the receiving position of the first test sample 122, the volatility of the melt index is reduced, the uniformity of the first test sample 122 is improved, and the accuracy of the test results is thereby improved.

[0088] For example, when the die 12 is set to cut once per second, the molten feed 124 in the melting barrel 11 takes 15 seconds from the start to the end of the test. In order to be able to test the melt index of the rear section of the molten feed 124, the testing method of this embodiment can control the material receiving component 16 to receive the first sample to be tested 122 5 seconds after the scraper cuts, so as to reduce the influence of the molten feed 124 in the front section of the melting barrel 11 on the volatility of the melt index, and ensure that the first sample to be tested 122 received each time belongs to the same section of the melting barrel 11.

[0089] The embodiment of the present application further provides a melt indexer 10 , which is used to test a feed material 121 to be tested using the testing method of any of the above embodiments.

[0090] In one embodiment, see Figure 6 , Figure 6 This is a structural diagram of an embodiment of the material splicing assembly provided by this application. Figure 6 As shown, the melt indexer 10 includes a material receiving assembly 16, which includes a driving member 161 and a material receiving tray 162 that are interconnected. The material receiving tray 162 is located below the discharge port 123. The driving member 161 is used to drive the material receiving tray 162 to move at a first preset speed so that the material receiving tray 162 sequentially receives multiple samples flowing out of the discharge port 123, and the multiple samples are located at different positions on the material receiving tray 162.

[0091] Optionally, the material receiving assembly 16 further includes a connecting shaft 163 , and the driving member 161 is connected to the material receiving tray 162 via the connecting shaft 163 , and the driving member 161 is used to drive the material receiving tray 162 to rotate at a first preset speed.

[0092] The projection of the discharge port 123 on the receiving tray 162 does not completely overlap with the projection of the connecting shaft 163 on the receiving tray 162, and the central axis of the discharge port 123 does not intersect with the extension line of the connecting shaft 163. Therefore, when the first section of sample flows out of the discharge port 123, the first section of sample falls on the disk surface of the receiving tray 162 located on the side of the connecting shaft 163. The driving member 161 drives the receiving tray 162 to rotate via the connecting shaft 163, and the second section of sample flowing out of the discharge port 123 can fall on the next empty disk surface on the side of the connecting shaft 163. This can reduce or prevent the first section of sample and the second section of sample from adhering to each other, while effectively saving the space occupied by the receiving tray 162 during its movement.

[0093] In one embodiment, the center of connecting shaft 163 coincides with the center of receiving tray 162, meaning the center of receiving tray 162 lies on an extension of connecting shaft 163. Connecting shaft 163 drives receiving tray 162 to rotate and perform circular motion around its geometric center, and the motion trajectory of any receiving position on the surface of receiving tray 162 forms a circle centered on the shaft. Therefore, receiving assembly 16 can prevent adjacent sample segments from adhering to each other by utilizing the fixed motion trajectory of receiving tray 162, enabling precise control of the rotational position of receiving tray 162 and reducing structural complexity.

[0094] In another embodiment, the center of the connecting shaft 163 does not coincide with the center of the receiving tray 162, that is, the connecting shaft 163 is located to one side of the center of the receiving tray 162. Due to the eccentricity between the connecting shaft 163 and the center of the receiving tray 162, when the receiving tray 162 performs a circular motion around the connecting shaft 163, the motion trajectory of any receiving position on the surface of the receiving tray 162 can be, but is not limited to, an elliptical or non-circular trajectory. Therefore, while ensuring that adjacent samples do not stick together, the receiving tray 162 of the same area can receive more samples, thereby improving the utilization rate of the receiving tray 162, and further improving the space utilization rate of the melt indexer 10.

[0095] Among them, see Figure 7 , Figure 7 yes Figure 6 Schematic diagram of the spiral trajectory of the receiving position of the receiving tray. Figure 7 As shown, the driving member 161 is used to drive the receiving position of the receiving tray 162 to move along the trajectory of the spiral line, and the starting point of the spiral line coincides with the projection of the discharge port 123 on the receiving tray 162.

[0096] The starting point of the spiral line can be located at the midpoint of the receiving tray 162, or at a position near the midpoint of the receiving tray 162. The starting point of the spiral line coincides with the projection of the discharge port 123 on the receiving tray 162. For example, the samples received during the material receiving process are defined as the first sample, the second sample, the third sample, ..., the Nth sample, in sequence. The first sample passes through the discharge port 123 and falls on the first position of the receiving tray 162. The second sample passes through the discharge port 123 and falls on the second position of the receiving tray 162. The third sample passes through the discharge port 123 and falls on the third position of the receiving tray 162. ..., the Nth sample passes through the discharge port 123 and falls on the Nth position of the receiving tray 162. The first position is located at the starting point of the spiral line, and the first position, the second position, the third position, ..., the Nth position are arranged in a spiral shape on the receiving tray 162. Therefore, this embodiment can maximize the use of the material receiving area on the receiving tray 162 by controlling the material receiving position on the receiving tray 162 to present a spiral motion trajectory, thereby further improving the disk surface utilization rate on the receiving tray 162 and the space utilization rate of the melt indexer 10.

[0097] The following examples illustrate the test methods and results of the examples of this application.

[0098] First embodiment:

[0099] 1. Set the temperature control temperature of the melting barrel 11 to 210°C and keep it warm for 30 minutes after reaching the preset temperature;

[0100] 2. Use a cleaning rod wrapped with gauze to insert it into the melt barrel 11 and quickly wipe it up and down until the melt barrel 11 is clean; use a cleaning rod and gauze to clean the die 12; use gauze to clean the feeder and funnel; pull the pull rod 14 outward to the limit to place the cleaned die 12 into the melt barrel 11;

[0101] 3. Use the feeder and funnel to load the titanium alloy into the melt barrel 11 until it is just full. Once full, insert the piston rod 13 into the melt barrel 11 and use the piston rod 13 to compact the titanium alloy up and down for 20 seconds. After compaction, add a 5-level weight (5kg mass) to the support frame to drive the 5-level weight to load and contact the piston rod 13 through the support frame. Under the pressure of the piston rod 13, the titanium alloy melts into molten feed and is compacted so that the discharge port 123 squeezes out 1cm of blanking material within the preset time and the blanking material does not continue to fall. Load and hold for 5 minutes.

[0102] 4. Replace the level 5 weight with a level 8 weight (a mass of 21.6 kg), and set the scraper to cut 20 times, selecting one cut per second according to the feed fluidity, start the scraper and weight loading to allow the titanium alloy to flow in the molten barrel 11 and be extruded through the discharge port 123 of the die 12.

[0103] 5. When the first scale line of the piston rod 13 is flush with the upper end of the melting barrel 11, the rotating receiving plate receives the first sample to be tested 122, and when the extruded material is completely dropped, the last section of the material is removed.

[0104] 6. Select four uniform sections of the second sample to be tested from the first sample to be tested 122 in the receiving tray and weigh them to obtain the mass mean M. According to the cutting time T of the molten feed 124, the melt index can be obtained using the formula MFR = 600×M / T.

[0105] 7. Repeat the above operation five times to obtain the melting index results of the titanium alloy after five tests, as shown in Table 1 below.

[0106]

[0107] Table 1

[0108] As can be seen from Table 1, the test method of this embodiment repeats the test on the titanium alloy five times, and the variance of the melt index obtained fluctuates by 159.44 g / min, which is much lower than the standard value (±500 g / min) of the feed melt index fluctuation in the existing melt index meter 10. The test method of this embodiment can significantly reduce the volatility of the melt index.

[0109] Second embodiment:

[0110] 1. Set the temperature control temperature of the melting barrel 11 to 200°C and keep it warm for 30 minutes after reaching the preset temperature;

[0111] 2. Use a cleaning rod wrapped with gauze to insert it into the melt barrel 11 and quickly wipe it up and down until the melt barrel 11 is clean; use a cleaning rod and gauze to clean the die 12; use gauze to clean the feeder and funnel; pull the pull rod 14 outward to the limit to place the cleaned die 12 into the melt barrel 11;

[0112] 3. Use the feeder and hopper to load the stainless steel into the melt barrel 11 until it is just full. Once full, insert the piston rod 13 into the melt barrel 11 and compact the stainless steel up and down with the piston rod 13 for 20 seconds. After compaction, add a 4-level weight (3.8 kg mass) to the support frame. The support frame drives the 5-level weight to load and contact the piston rod 13. Under the pressure of the piston rod 13, the stainless steel melts into molten feed and is compacted so that the discharge port 123 extrude 2 cm of blank material within the preset time without the blank material continuously falling. Load and hold for 5 minutes.

[0113] 4. Replace the level 5 weight with a level 8 weight (a mass of 21.6 kg) and set the scraper to cut 20 times, selecting one cut per second or two cuts per second according to the fluidity of the feed. Start the scraper and weight loading to allow the stainless steel to flow in the molten barrel 11 and be extruded through the discharge port 123 of the die 12.

[0114] 5. When the first scale line of the piston rod 13 is flush with the upper end of the melting barrel 11, the rotating receiving plate receives the first sample to be tested 122, and when the extruded material is completely dropped, the last section of the material is removed.

[0115] 6. Select four uniform sections of the second test sample from the first test sample 122 on the receiving tray and weigh them to obtain the mass mean M. Based on the cutting time of the molten feed 124, the melt index can be obtained using the formula MFR = 600×M / T.

[0116] 7. Repeat the above operation five times to obtain the melting index results of stainless steel for five tests, as shown in Table 2 below.

[0117]

[0118] Table 2

[0119] As can be seen from Table 2, the test method of this embodiment, after five repeated tests on stainless steel, obtained a melt index variance fluctuation of 149.84 g / min, which is much lower than the standard value (±500 g / min) of the feed melt index fluctuation in the existing melt index meter 10. The test method of this embodiment can significantly reduce the volatility of the melt index.

[0120] Third embodiment:

[0121] 1. Set the temperature control temperature of the melting barrel 11 to 190°C and keep it warm for 30 minutes after reaching the preset temperature;

[0122] 2. Use a cleaning rod wrapped with gauze to insert it into the melt barrel 11 and quickly wipe it up and down until the melt barrel 11 is clean; use a cleaning rod and gauze to clean the die 12; use gauze to clean the feeder and funnel; pull the pull rod 14 outward to the limit to place the cleaned die 12 into the melt barrel 11;

[0123] 3. Use the feeder and hopper to load the aluminum alloy into the melt barrel 11 until it is just full. Once full, insert the piston rod 13 into the melt barrel 11 and compact the aluminum alloy up and down with the piston rod 13 for 20 seconds. After compaction, add a three-level weight (2.16 kg mass) to the support frame. The support frame drives the five-level weight to load and contact the piston rod 13. Under the pressure of the piston rod 13, the aluminum alloy melts into molten feed and is compacted so that the discharge port 123 extrude 1 cm of blank material within the preset time without the blank material continuously falling. Load and hold for 5 minutes.

[0124] 4. Replace the level 5 weight with a level 8 weight (a mass of 21.6 kg), and set the scraper to cut 20 times, selecting one cut per second or two cuts per second according to the fluidity of the feed, start the scraper and weight loading to allow the aluminum alloy to flow in the molten barrel 11 and be extruded through the discharge port 123 of the die 12.

[0125] 5. When the first scale line of the piston rod 13 is flush with the upper end of the melting barrel 11, the rotating receiving plate receives the first sample to be tested 122, and when the extruded material is completely dropped, the last section of the material is removed.

[0126] 6. Select four uniform sections of the second sample to be tested from the first sample to be tested 122 in the receiving tray and weigh them to obtain the mass mean M. According to the cutting time T of the molten feed 124, the melt index can be obtained using the formula MFR = 600×M / T.

[0127] 7. Repeat the above operation five times to obtain the melting index results of the aluminum alloy after five tests, as shown in Table 3 below.

[0128]

[0129] Table 3

[0130] As can be seen from Table 3, the test method of this embodiment performs five repeated tests on the aluminum alloy, and the obtained melt index variance fluctuates within 46.64 g / min, which is much lower than the standard value (±500 g / min) of the feed melt index fluctuation in the existing melt index meter 10. The test method of this embodiment can significantly reduce the volatility of the melt index.

[0131] Therefore, unlike the prior art, the melt index testing method of the embodiment of the present application can use the piston rod 13 to compact the test feed 121 in the melt barrel 11 and then cut it to expel the air in the melt barrel 11 and make the composition of the test feed 121 more uniform, reducing the impact of air or bubbles in the test feed 121 on the test results and improving the uniformity of the test sample. The extrudate of the test feed 121 at the rear section of the melt barrel 11 is taken as the test sample and the material receiving position is fixed to improve the uniformity of the first test sample 122. A preset number of second test samples are selected from multiple sections of the first test sample 122 to improve the uniformity of the second test sample, reduce the fluctuation of the test melt index, and improve the accuracy of the test results. Therefore, the melt index meter 10 of the embodiment of the present application can control the deviation of the melt index to ±100 g / min, improve the stability of the test of the test feed 121, and significantly reduce the fluctuation of the test melt index.

[0132] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for testing melt index, characterized in that: Applied to a melt indexer, the melt indexer includes a melt barrel and a piston rod, and the testing method includes: Preheating the melting barrel to a preset temperature and keeping it warm for a first preset time; Loading the feed material to be tested into the accommodating cavity of the melting barrel; Inserting the piston rod into the melt barrel and adding a mass piece of a first weight to the piston rod, the feed material to be tested is melted into molten feed material under the pressure of the piston rod and compacted, so that a blank of a preset length is exposed at the discharge port of the melt barrel; Switching the mass member on the piston rod from the first weight to the second weight, so that the molten feed flows out through the discharge port under the pressure of the piston rod and is cut to obtain multiple sections of first test samples; Calculating the melt index of the feed material to be tested based on the mass of the multiple segments of the first sample to be tested; The first weight ranges from 2.16 kg to 10 kg, and the preset length ranges from 1 cm to 30 cm.

2. The testing method according to claim 1, wherein: The method includes inserting the piston rod into the melt barrel and adding a mass piece of a first weight to the piston rod, wherein the feed material to be tested is melted into molten feed material and compacted under the pressure of the piston rod so that a blank of a preset length is exposed at the discharge port of the melt barrel, including: Inserting the piston rod into the melt barrel and adding a mass piece of a first weight to the piston rod; The feed material to be tested is compacted by a mass member of the first weight, so that the discharge port extrude the blank of the preset length within a preset time; Wherein, the preset time is 5s.

3. The testing method according to claim 1 or 2, characterized in that: The melt indexer also includes a material receiving assembly; the mass member on the piston rod is switched from the first weight to the second weight so that the molten feed flows out through the discharge port under the pressure of the piston rod and is cut to obtain multiple sections of the first sample to be tested, including: switching the mass member on the piston rod from the first weight to the second weight, so that the molten feed flows out through the discharge port under the pressure of the piston rod and is cut; The material receiving assembly is controlled to move at a first preset speed so that the material receiving assembly sequentially receives multiple sections of material flowing out of the discharge port, and the multiple sections of material are at different positions on the material receiving tray.

4. The testing method according to claim 3, wherein: The melt indexer further includes a scraper; switching the mass member on the piston rod from the first weight to the second weight so that the molten feed flows out through the discharge port under the pressure of the piston rod and is cut, comprising: switching the mass member on the piston rod from the first weight to the second weight; The scraper is controlled to cut the molten feed flowing out through the discharge port at a second preset speed, and the second preset speed corresponds to the first preset speed.

5. The testing method according to claim 1, wherein: The melt indexer also includes a die; before the step of loading the feed material to be tested into the accommodating cavity of the melt barrel, the testing method further includes: Preheating the melting barrel to a preset temperature and keeping it warm for a first preset time; The melting barrel, the die and the piston rod are cleaned, and the cleaned die is placed into the melting barrel.

6. The testing method according to claim 1, wherein: The step of loading the feed material to be tested into the accommodating cavity of the melting barrel comprises: Adding the feed material to be tested into the melting barrel until the melting barrel is full, the time when the melting barrel is full is the first time; The method includes inserting the piston rod into the melt barrel and adding a mass piece of a first weight to the piston rod, wherein the feed material to be tested is melted into molten feed material and compacted under the pressure of the piston rod so that a blank of a preset length is exposed at the discharge port of the melt barrel, including: inserting the piston rod into the melt barrel; Performing a compacting operation on the feed material to be tested in the molten barrel by means of the piston rod; A mass piece of a first weight is added to the piston rod, and the feed material to be tested is melted into molten feed material under the pressure of the piston rod and is compacted so that a blank of a preset length appears at the discharge port of the molten barrel; The time for completing the compaction operation is a second time, and the time difference between the second time and the first time is less than or equal to 1 minute.

7. The testing method according to claim 3, characterized in that: The step of calculating the melt index of the feed material to be tested based on the mass of the first sample to be tested in multiple sections includes: Selecting a preset number of second samples to be tested from the plurality of segments of the first samples to be tested; Calculate the melt index of the corresponding second sample to be tested based on the ratio of the mass of a second sample to be tested to the cutting time of the feed to be tested, and calculate the melt index of the feed to be tested based on the average value of the melt indexes of all the second samples to be tested, or The mass average of all the second samples to be tested is calculated to calculate the melt index of the feed material to be tested based on the ratio of the mass average to the cutting time of the feed material to be tested.

8. The testing method according to claim 3, wherein: The controlling the material receiving assembly to move at a first preset speed so that the material receiving assembly sequentially receives multiple sections of material flowing out of the discharge port includes: When the first scale line of the piston rod is flush with the upper end of the melting barrel, the material receiving assembly is controlled to move at a first preset speed so that the material receiving assembly sequentially receives the first sample to be tested flowing out of the discharge port.

9. The testing method according to claim 3, wherein: After the step of switching the mass member on the piston rod from the first weight to the second weight so that the molten feed flows out through the discharge port under the pressure of the piston rod and is cut, the testing method further includes: Recording the number of cuts of the molten feed; The controlling the material receiving assembly to move at a first preset speed so that the material receiving assembly sequentially receives multiple sections of material flowing out of the discharge port includes: When the number of cutting times of the molten feed reaches a first preset value, the material receiving component is controlled to move at a first preset speed so that the material receiving component sequentially receives the first sample to be tested flowing out of the discharge port.

10. The testing method according to claim 3, characterized in that: After the step of switching the mass member on the piston rod from the first weight to the second weight so that the molten feed flows out through the discharge port under the pressure of the piston rod and is cut, the testing method further includes: Recording the outflow time of the molten feed; The controlling the material receiving assembly to move at a first preset speed so that the material receiving assembly sequentially receives multiple sections of material flowing out of the discharge port includes: When the outflow time reaches a second preset value, the material receiving component is controlled to move at a first preset speed, so that the material receiving component sequentially receives the first sample to be tested flowing out of the discharge port.

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