Injection screw for rigid vinyl chloride
12325165 ยท 2025-06-10
Assignee
Inventors
Cpc classification
International classification
B29C45/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A rigid vinyl chloride injection screw which kneads and injects rigid vinyl chloride includes a flight and a groove. L/D is set to be 19.1 where L is an effective screw length and D is a diameter of the injection screw. tf/tm is set to be 2.5 where tf is the width of the flight at a supply portion and tm is the width of the flight at a measure portion. hf/hm is set to be 2.1 where hf is the depth of the groove at the supply portion and hm is the depth of the groove at the measure portion. A compression ratio that is calculated from ((Ptf)hf)/((Ptm)hm) is set to be 1.74 where P is a pitch of the injection screw.
Claims
1. A rigid vinyl chloride injection screw which kneads and injects rigid vinyl chloride comprising: a flight; and a groove, wherein an effective screw length is distinguished at a supply portion, a compression portion, and a measure portion, a width of the flight within the supply portion is set to be wider than a width of the flight within the measure portion, and a depth of the groove at the supply portion is set to be larger than a depth of the groove at the measure portion, wherein L/D is set to be 19.1 where L is the effective screw length and D is a diameter of the injection screw, wherein tf/tm is set to be 2.5 where tf is the width of the flight within the supply portion and tm is the width of the flight within the measure portion, wherein hf/hm is set to be 2.1 where hf is the depth of the groove at the supply portion and hm is the depth of the groove at the measure portion, and wherein a compression ratio that is calculated from ((Ptf)hf)/((Ptm)hm) is set to be 1.74 where P is a pitch of the injection screw.
2. A rigid vinyl chloride injection screw which kneads and injects rigid vinyl chloride comprising: a flight; and a groove, wherein an effective screw length is distinguished at a supply portion, a compression portion, and a measure portion, a width of the flight within the supply portion is set to be wider than a width of the flight within the measure portion, and a depth of the groove at the supply portion is set to be larger than a depth of the groove at the measure portion, wherein L/D is set to be in a range that is 17.0 to 19.5 where L is the effective screw length and D is a diameter of the injection screw, wherein tf/tm is set to be in a range that is 2.3 to 3.0 where tf is the width of the flight within the supply portion and tm is the width of the flight within the measure portion, wherein hf/hm is set to be in a range that is 2.0 to 2.2 where hf is the depth of the groove at the supply portion and hm is the depth of the groove at the measure portion, and wherein a compression ratio that is calculated from ((Ptf)hf)/((Ptm)hm) is set to be in a range that is 1.63 to 1.81 where P is a pitch of the injection screw.
3. The rigid vinyl chloride injection screw according to claim 2, wherein the L/D is 17.0.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Several preferable embodiments of the present disclosure will be described in detail with reference to the accompanying figures in which:
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DETAILED DESCRIPTION OF THE EMBODIMENTS
(11) Embodiments of the present disclosure will be described below with reference to the accompanying figures.
(12) [Model 3]
(13) As illustrated in
(14) When a width of the flight 11 at a supply portion, a width of the flight 11 at a compression portion, and a width of the flight 11 at a measure portion are defined as tf, tc and tm, respectively, the width of the flight 11 at the supply portion is set to be twice to three times to the width tm of the flight 11 at the measure portion. The width tc of the flight 11 at the compression portion gradually changes from the width tf of the flight 11 at the supply portion to the width tm of the flight 11 at the measure portion.
(15) In addition, a diameter of the injection screw is defined as D, a pitch is defined as P, and an effective screw length is defined as L.
(16) The effective screw length L is the sum of a length Lf of the supply portion, a length Lc of the compression portion, and a length Lm of the measure portion.
(17) A depth of the groove at the supply portion, a depth of the groove at the compression portion, and a depth of the groove at the measure portion are defined as hf, hc, and hm, respectively.
(18) TABLE 5 shows the specifications of the injection screw 10 according to the model 3. Note that those of the model 2 are also shown as references.
(19) TABLE-US-00005 TABLE 5 (MODEL 2) MODEL 3 SYMBOL LENGTH, ETC. SYMBOL LENGTH, ETC. INJECTION SCREW DIAMETER D 80 mm D 80 mm FLIGHT WIDTH t 8 mm tf 20 mm tc 20 mm > 8 mm tm 8 mm PITCH P 80 mm P 80 mm EFFECTIVE SCREW LENGTH L 1525 mm L 1525 mm SUPPLY PORTION LENGTH Lf 600 mm Lf 797 mm COMPRESSION PORTION LENGTH Lc 725 mm Lc 480 mm MEASURE PORTION LENGTH Lm 200 mm Lm 248 mm GROOVE DEPTH AT SUPPLY PORTION hf 12.8 mm hf 12.35 mm GROOVE DEPTH AT COMPRESSION PORTION hc 12.8 mm > 6.4 mm hc 12.35 mm > 5.9 mm GROOVE DEPTH AT MEASURE PORTION hm 6.4 mm hm 5.9 mm RATIO L/D 19.1 L/D 19.1 RATIO Lf/D 7.5 Lf/D 10.00 RATIO Lc/D 9.1 Lc/D 6.00 RATIO Lm/D 2.5 Lm/D 3.1 RATIO hf/D 0.160 hf/D 0.154 RATIO hm/D 0.080 hm/D 0.074 COMPRESSION RATIO 2.00 1.74
(20) According to the model 3, the width tf of the flight at the supply portion was increased that was 20 mm, and the width tm of the flight at the measure portion was maintained as 8 mm.
(21) Moreover, while the effective screw length L was maintained at 1525 mm, the length Lf of the supply portion was increased that was 797 mm, the length Lc of the compression portion was reduced that was 480 mm, and the length Lm of the measure portion was set to 248 mm.
(22) Moreover, the depth hf of the groove at the supply portion was made slightly shallow that was 12.35 mm, and the depth hm of the groove at the measure portion was made slightly shallow that was 5.9 mm.
(23) The compression ratio is calculated from ((Ptf)hf)/((Ptm)hm).
(24) From the calculation that is ((8020)12.35)/((808)5.9)=1.74, the compression ratio is thus 1.74. In comparison with the model 2, the compression ratio of the model 3 was reduced.
(25) Rigid vinyl chloride was injected on a trial basis using the above-described injection screw 10. At this time, circuit pressure relating to the rotation of the injection screw 10 and the temperature of the nozzle (see
(26) Note that at the initial stage of shots, since there are many variable factors, a state at the eighth shot conceivable as substantially stable was examined.
(27) TABLE 6 shows the results. Note that those of the model 2 are also shown as references.
(28) TABLE-US-00006 TABLE 6 (MODEL 2) MODEL 3 INJECTION SCREW FIG. 6 FIG. 2 SPECIFICATIONS TABLE 3 TABLE 5 RESIN MATERIAL RIGID VINYL CHLORIDE RIGID VINYL CHLORIDE SCREW ROTATION SPEED 10 rpm 10 rpm CIRCUIT PRESSURE AT EIGHTH SHOT 14.6 MPa 12.3 MPa NOZZLE TEMPERATURE AT EIGHTH SHOT 170.6 C. 169.7 C. COLOR CHANGE PRESENCE/ABSENCE SLIGHT COLOR CHANGE PRESENT NO COLOR CHANGE PRESENT EVALUATION NO GOOD GOOD
(29) According to the model 2, although the compression ratio was 2.00, according to the model 3, since the compression ratio decreased to 1.74, the following advantageous effects to be described below are accomplished from the model 3.
(30) First, the circuit pressure changed from 14.6 MPa to 12.3 MPa.
(31) Next, no color change was observed. That is, a disadvantage that is a color change is addressed. The temperature of the nozzle changed from 170.6 C. to 169.7 C. It is thought that such a disadvantage is addressed because the temperature of the nozzle decreased.
(32) That is, according to the model 3, the width tc of the flight at the measure portion was kept unchanged at 8 mm, but the width tf of the flight at the supply portion was set to 20 mm, and thus the compression ratio decreased. Hence, a disadvantage that is a color change is addressed. In addition, the plasticization was excellent, and the rotation torque was reduced.
(33) Consequently, a rigid vinyl chloride injection screw that is suitable for rigid vinyl chloride is provided by the model 3.
(34) That is, according to the model 3, the injection screw 10 that employs the structure to be described below is provided.
(35) The injection screw 10 which kneads and injects rigid vinyl chloride includes the flight 11 and the groove 12. In the rigid vinyl chloride injection screw 10, the effective screw length L is distinguished at the supply portion, the compression portion, and the measure portion. The width tf of the flight at the supply portion is set to be wider than the width tm of the flight at the measure portion. The depth hf of the groove at the supply portion is set to be larger than the depth hm of the groove at the measure portion.
(36) L/D is set to be 19.1 that is obtained from a calculation that is 1525/80=19.06 where L is the effective screw length and D is the diameter of the injection screw.
(37) tf/tm is set to be 2.5 that is obtained from a calculation that is 20/8=2.5 where tf is the width of the flight at the supply portion and tm is the width of the flight at the measure portion.
(38) hf/hm is set to be 2.1 that is obtained from a calculation that is 12.35/5.9=2.09 where hf is the depth of the groove at the supply portion and hm is the depth of the groove at the measure portion.
(39) The rigid vinyl chloride injection screw is provided which has a compression ratio that is that is calculated from ((Ptf)hf)/((Ptm)hm) is set to be 1.74 (the detailed calculation has been described above, thus omitted) where P is the pitch of the injection screw.
(40) Next, on the basis of the model 3, extension of the model is attempted. For such a purpose, a model 4 and subsequent models were examined. TABLE 7 shows the results.
(41) TABLE-US-00007 TABLE 7 SYMBOL (MODEL 3) MODEL 4 MODEL 5 MODEL 6 COMMON EFFECTIVE SCREW LENGTH L: 1525 mm INJECTION SCREW DIAMETER D: 80 mm L/D: 19.1 PITCH P 80 mm 80 mm 80 mm 80 mm FLIGHT WIDTH tf 20 mm 18 mm 16 mm 24 mm tf/D 0.25 0.22 0.20 0.30 tm 8 mm 8 mm 8 mm 8 mm tm/D 0.10 0.10 0.10 0.10 tf/tm 2.5 2.3 2.0 3.0 GROOVE DEPTH hf 12.35 12.35 12.35 12.35 hm 5.9 mm 5.9 mm 5.9 mm 5.9 mm hf/hm 2.1 2.1 2.1 2.1 COLOR CHANGE NONE NONE SLIGHTLY NONE PRESENT PLASTICIZATION EVALUATION EXELLENT EXELLENT EXELLENT EXELLENT EVALUATION GOOD GOOD NO GOOD GOOD COMPRESSION RATIO 1.74 1.80 1.86 1.63 SYMBOL MODEL 7 MODEL 8 MODEL 9 MODEL 10 MODEL 11 COMMON EFFECTIVE SCREW LENGTH L: 1525 mm INJECTION SCREW DIAMETER D: 80 mm L/D: 19.1 PITCH P 80 mm 80 mm 80 mm 80 mm 80 mm FLIGHT WIDTH tf 28 mm 20 mm 20 mm 20 mm 20 mm tf/D 0.35 0.25 0.25 0.25 0.25 tm 8 mm 8 mm 8 mm 8 mm 8 mm tm/D 0.10 0.10 0.10 0.10 0.10 tf/tm 3.5 2.5 2.5 2.5 2.5 GROOVE DEPTH hf 12.35 12.85 13.15 12.05 11.35 hm 5.9 mm 5.9 mm 5.8 mm 6.0 mm 6.2 mm hf/hm 2.1 2.2 2.3 2.0 1.8 COLOR CHANGE NONE NONE PRESENT NONE NONE PLASTICIZATION BAD EXELLENT EXELLENT EXELLENT BAD EVALUATION EVALUATION NO GOOD GOOD NO GOOD GOOD NO GOOD COMPRESSION RATIO 1.51 1.81 1.89 1.67 1.53
[Model 4]
(Difference and Similarity Relative to Model 3)
(42) According to the model 4, the width tf of the flight at the supply portion was narrowed to 18 mm. The other specifications were the same as those of the model 3.
(43) (Evaluation on Model 4)
(44) According to the model 4, although the compression ratio slightly increased that was 1.80, no color change occurred. Since the plasticization was excellent, the evaluation is thus concluded as good.
(45) [Model 5]
(46) (Difference and Similarity Relative to Model 3)
(47) According to a model 5, the width tf of the flight at the supply portion was further narrowed to 16 mm. The other specifications were the same as those of the model 3.
(48) (Evaluation on Model 5)
(49) According to the model 5, the compression ratio increased to 1.86. Hence, a color change was observed. Consequently, the result and evaluation are no good.
(50) [Model 6]
(51) (Difference and Similarity Relative to Model 3)
(52) According to a model 6, the width tf of the flight at the supply portion was elongated to 24 mm. The other specifications were the same as those of the model 3.
(53) (Evaluation on Model 6)
(54) According to the model 6, the compression ratio was 1.63. Since the compression ratio decreased, no color change occurred. Since the plasticization was excellent, the evaluation is thus concluded as good.
(55) [Model 7]
(56) (Difference and Similarity Relative to Model 3)
(57) According to a model 7, the width tf of the flight at the supply portion was further elongated to 28 mm. The other specifications were the same as those of the model 3.
(58) (Evaluation on Model 7)
(59) According to the model 7, the compression ratio was 1.51. The compression ratio decreased and no color change occurred. However, the plasticization was inadequate. This may be because of the insufficient compression. The result and evaluation are thus concluded as no good.
(60) [Model 8]
(61) (Difference and Similarity Relative to Model 3)
(62) According to a model 8, the depth hf of the groove at the supply portion was made deep that was 12.85 mm. The other specifications were the same as those of the model 3.
(63) (Evaluation on Model 8)
(64) According to a model 8, the compression ratio was 1.81. Although the compression ratio slightly increased, no color change occurred. Since the plasticization was excellent, the evaluation is thus concluded as good.
(65) [Model 9]
(66) (Difference and Similarity Relative to Model 3)
(67) According to a model 9, the depth hf of the groove at the supply portion was made further deep that was 13.15 mm. The other specifications were the same as those of the model 3.
(68) (Evaluation on Model 9)
(69) According to the model 9, a color change was observed. This may be because of the increase in compression ratio increased to 1.89. The result and evaluation are thus concluded as no good.
(70) [Model 10]
(71) (Difference and Similarity Relative to Model 3)
(72) According to a model 10, the depth hf of the groove at the supply portion was made shallow that was 12.05 mm. The other specifications were the same as those of the model 3.
(73) (Evaluation on Model 10)
(74) According to the model 10, since the compression ratio decreased to 1.67, no color change occurred. Since the plasticization was excellent, the evaluation is thus concluded as good.
(75) [Model 11]
(76) (Difference and Similarity Relative to Model 3)
(77) According to a model 11, the depth hf of the groove at the supply portion was made further shallow that was 11.35 mm. The other specifications were the same as those of the model 3.
(78) (Evaluation on Model 11)
(79) According to the model 11, the compression ratio was 1.53. Since the compression ratio decreased, no color change occurred. However, the plasticization was improper. This may be because of the insufficient compression. The result and evaluation are thus concluded as no good.
(80) (Matters that Became Clear from Model 4 to Model 11)
(81) The following points became clear from the model 4 to the model 11.
(82) It is recommended that the ratio of the width of the flight (tf/tm) should be 2.3 to 3.0.
(83) It is recommended that the ratio of the depth of the groove (hf/hm) should be 2.0 to 2.2.
(84) It is recommended that the compression ratio should be 1.63 to 1.81.
(85) Next, the recommended range of the ratio (L/D) will be examined. In order to do so, a model 12 and subsequent models were examined. TABLE 8 shows the results.
(86) TABLE-US-00008 TABLE 8 SYMBOL (MODEL 3) MODEL 12 MODEL 13 MODEL 14 MODEL 15 MODEL 16 COMMON INJECTION SCREW DIAMETER D: 80 mm PITCH P: 80 mm COMPRESSION RATIO: 1.74 FLIGHT WIDTH tf 20 mm 20 mm 20 mm 20 mm 20 mm 20 mm tm 8 mm 8 mm 8 mm 8 mm 8 mm 8 mm tf/tm 2.5 2.5 2.5 2.5 2.5 2.5 GROOVE DEPTH hf 12.35 mm 12.35 mm 12.35 mm 12.35 mm 12.35 mm 12.35 mm hm 5.9 mm 5.9 mm 5.9 mm 5.9 mm 5.9 mm 5.9 mm hf/hm 2.1 2.1 2.1 2.1 2.1 2.1 EFFECTIVE SCREW LENGTH L 1525 mm 1560 mm 1615 mm 1445 mm 1360 mm 1325 mm SUPPLY PORTION LENGTH Lf 797 mm 822 mm 867 mm 757 mm 697 mm 687 mm COMPRESSION PORTION LENGTH Lc 480 mm 490 mm 500 mm 460 mm 440 mm 430 mm MEASURE PORTION LENGTH Lm 248 mm 248 mm 248 mm 228 mm 223 mm 208 mm CIRCUIT PRESSURE 12.3 MPa 12.7 MPa 13.1 MPa 11.8 MPa 10.8 MPa 10.3 MPa COLOR CHANGE NONE NONE NONE NONE NONE NONE PLASTICIZATION EXELLENT EXELLENT EXELLENT EXELLENT EXELLENT BAD CIRCUIT PRESSURE EVALUATION GOOD GOOD NO GOOD GOOD GOOD GOOD EVALUATION GOOD GOOD NO GOOD GOOD GOOD NO GOOD L/D 19.1 19.5 20.2 18.1 17.0 16.6
[Model 12]
(Difference and Similarity Relative to Model 3)
(87) According to the model 12, the effective screw length L was 1560 mm which was extended by 35 mm. L/D became 19.5. Lf, Lc, and Lm were also changed in accordance with a change in such a length. The other specifications were the same as those of the model 3.
(88) (Evaluation on Model 12)
(89) According to the model 12, since the effective screw length L increased, the circuit pressure slightly increased that was 12.7 MPa, but no color change occurred. The plasticization was excellent. It is defined that an expected value of the circuit pressure is equal to or smaller than 13.0 MPa. Since the circuit pressure was 12.7 MPa, the evaluation is thus concluded as good.
(90) [Model 13]
(91) (Difference and Similarity Relative to Model 3)
(92) According to a model 13, the effective screw length L was further increased that was 1615 mm. L/D became 20.2. Lf, Lc, and Lm were also changed in accordance with a change in such a length. The other specifications were the same as those of the model 3.
(93) (Evaluation on Model 13)
(94) According to the model 13, since the effective screw length L was further increased, the circuit pressure increased that was 13.1 MPa, but no color change occurred. The plasticization was excellent. However, since the circuit pressure became 13.1 MPa that exceeds the expected value of the circuit pressure that is 13.0 MPa, the evaluation is thus concluded as no good.
(95) [Model 14]
(96) (Difference and Similarity Relative to Model 3)
(97) According to a model 14, the effective screw length L was shortened that was 1445 mm. L/D became 18.1. Lf, Lc, and Lm were also changed in accordance with a change in such a length. The other specifications were the same as those of the model 3.
(98) (Evaluation on Model 14)
(99) According to the model 14, since the effective screw length L was decreased, the circuit pressure decreased that was 11.8 MPa, and no color change occurred. The evaluation is thus concluded as good.
(100) [Model 15]
(101) (Difference and Similarity Relative to Model 3)
(102) According to a model 15, the effective screw length L was further shortened that was 1360 mm. L/D became 17.0. Lf, Lc, and Lm were also changed in accordance with a change in such a length. The other specifications were the same as those of the model 3.
(103) (Evaluation of the Model 15)
(104) According to the model 15, since the effective screw length L was further decreased, the circuit pressure decreased that was 10.8 MPa, and no color change occurred. The evaluation is thus concluded as good.
(105) [Model 16]
(106) (Difference and Similarity Relative to Model 3)
(107) According to a model 16, the effective screw length L was further shortened that was 1325 mm. L/D became 16.6. Lf, Lc, and Lm were also changed in accordance with a change in such a length. The other specifications were the same as those of the model 3.
(108) (Evaluation on Model 16)
(109) According to the model 16, since the effective screw length L was further decreased, the circuit pressure decreased that was 10.3 MPa. The inadequate plasticization was observed although no color change occurred. This may be because of the insufficient effective screw length L. The result and evaluation are thus concluded as no good.
(110) (Matters which Became Clear from Model 12 to Model 16)
(111) The following points became clear from the model 12 to the model 16.
(112) It is recommended that the ratio of the length of the screw (L/D) should be 17.0 to 19.5 in view of L/D in the lowest row of TABLE 8, and the evaluation thereabove.
(113) The following points became clear when the models 4 to 11 and the models 12 to 16 are comprehensively considered.
(114) (Matters which Became Clear from Model 4 to Model 16)
(115) It is recommended that the ratio of the length of the screw (L/D) should be 17.0 to 19.5.
(116) It is recommended that the ratio of the width of the flight (tf/tm) should be 2.3 to 3.0.
(117) It is recommended that the ratio of the depth of the groove (hf/hm) should be 2.0-2.2.
(118) It is recommended that the compression ratio should be 1.63 to 1.81.
(119) Note that the model 5 shown in TABLE 7 has (tf/tm) that is 2.0, which is out of the above-described range (2.3 to 3.0).
(120) The model 7 shown in TABLE 7 has (tf/tm) that is 3.5, which is out of the above-described range (2.3 to 3.0).
(121) The model 9 shown in TABLE 7 has (hf/hm) that is 2.3, which is out of the above-described range (2.0 to 2.2).
(122) The model 11 shown in TABLE 7 has (hf/hm) that is 1.8, which is out of the above-described range (2.0 to 2.2).
(123) According to the model 13 shown in TABLE 8, (L/D) is 20.2, which is out of the above-described range (17.0-19.5).
(124) According to the model 16 shown in TABLE 8, (L/D) is 16.6, which is out of the above-described range (17.0-19.5).
(125) Regarding the model 4, the model 6, the model 8, the model 10, the model 12, the model 14, and the model 15, the specific values fall within the above-described range group.
(126) That is, according to the model 4, the model 6, the model 8, the model 10, the model 12, the model 14, and the model 15, the injection screw 10 that employs the following structure is provided.
(127) The injection screw 10 which kneads and injects rigid vinyl chloride includes the flight 11 and the groove 12. In the rigid vinyl chloride injection screw 10, the effective screw length L is distinguished at the supply portion, the compression portion, and the measure portion, the width of the flight hf at the supply portion is set to be wider than the width tm of the flight at the measure portion, and the depth tf of the groove at the supply portion is set to be larger than the depth tm of the groove at the measure portion.
(128) L/D is set to be in a range that is 17.0 to 19.5 where L is the effective screw length and D is the diameter of the injection screw.
(129) tf/tm is set to be in a range that is 2.3 to 3.0 where tf is the width of the flight at the supply portion and tm is the width of the flight at the measure portion.
(130) hf/hm is set to be in a range that is 2.0 to 2.2 where hf is the depth of the groove at the supply portion and hm is the depth of the groove at the measure portion.
(131) The compression ratio calculated by ((Ptf)hf)/((Ptm)hm) is set to be in a range that is 1.63 to 1.81 where P is the pitch of the injection screw.
(132) Experientially, the inventors of the present disclosure have already obtained a technical knowledge such that when the measure portion is long and the compression portion is long, the temperature of a resin material increases, and thus a defect occurs.
(133) Accordingly, as for the length Lf of the supply portion, the length Lc of the compression portion, and the length Lm of the measure portion, a model 17 and subsequent model were examined. TABLE 9 shows the results.
(134) TABLE-US-00009 TABLE 9 SYMBOL (MODEL 3) MODEL 17 MODEl 18 MODEL 19 MODEL 20 COMMON INJECTION SCREW DIAMETER D: 80 mm PITCH P: 80 mm COMPRESSION RATIO: 1.74 FLIGHT WIDTH tf 20 mm 20 mm 20 mm 20 mm 20 mm tm 8 mm 8 mm 8 mm 8 mm 8 mm tf/tm 2.5 2.5 2.5 2.5 2.5 GROOVE DEPTH hf 12.35 mm 12.35 mm 12.35 mm 12.35 mm 12.35 mm hm 5.9 mm 5.9 mm 5.9 mm 5.9 mm 5.9 mm EFFECTIVE SCREW LENGTH L 1525 mm 1525 mm 1525 mm 1525 mm 1525 mm L/D 19.1 19.1 19.1 19.1 19.1 SUPPLY PORTION LENGTH Lf 797 mm 777 mm 867 mm 827 mm 877 mm Lf/D 0.52 0.51 0.57 0.54 0.58 COMPRESSION PORTION LENGTH Lc 480 mm 410 mm 420 mm 490 mm 500 mm Lc/L 0.31 0.27 0.28 0.32 0.33 MEASURE PORTION LENGTH Lm 248 mm 338 mm 238 mm 208 mm 148 mm Lm/L 0.16 0.22 0.16 0.14 0.10 COLOR CHANGE NONE SLIGHTLY NONE NONE NONE PRESENT PLASTICIZATION EXCELLENT EXCELLENT EXCELLENT EXCELLENT SLIGHTLY BAD EVALUATION BETTER GOOD BETTER BETTER GOOD
[Model 17]
(Difference and Similarity Relative to Model 3)
(135) According to the model 17, Lf was shortened that was 777 mm, Lc was shortened that was 410 mm, and Lm was elongated that was 338 mm. The other specifications were the same as those of the model 3.
(136) (Evaluation on Model 17)
(137) According to the model 17, since the length Lm of the measure portion largely increased, a minor color change was observed. This may be because of an increase in temperature of the resin material due to the increase of Lm. However, a color change is slight, which is within an acceptable range, and thus the evaluation is concluded as good.
(138) [Model 18]
(139) (Difference and Similarity Relative to Model 3)
(140) According to a model 18, Lf was remarkably elongated that was 867 mm, Lc was shortened that was 420 mm, and Lm was remarkably shortened that was 238 mm. The other specifications were the same as those of the model 3.
(141) (Evaluation on Model 18)
(142) According to the model 18, since the length Lm of the measure portion remarkably decreased, a color change did not occur at all. This may be because of a decrease in temperature of the resin material due to the remarkable decrease of Lm. Consequently, the evaluation is concluded as better that is more than good.
(143) [Model 19]
(144) (Difference and Similarity Relative to Model 3)
(145) According to a model 19, Lf was slightly elongated that was 827 mm, Lc was slightly elongated that was 490 mm, and Lm was remarkably shortened that was 208 mm. The other specifications were the same as those of the model 3.
(146) (Evaluation on Model 19)
(147) According to the model 19, since the length Lm of the measure portion remarkably decreased, a color change did not occur at all. This may be because of a decrease in temperature of the resin material due to the remarkable decrease of Lm. Consequently, the evaluation is concluded as better that is more than good.
(148) [Model 20]
(149) (Difference and Similarity Relative to Model 3)
(150) According to a model 20, Lf was elongated that was 877 mm, Lc was slightly elongated that was 500 mm, and Lm was remarkably shortened that was 148 mm. The other specifications were the same as those of the model 3.
(151) (Evaluation on Model 20)
(152) According to the model 20, a slight plasticization defect was observed. This may be because of the decrease of Lm. However, the plasticization defect is little and is within in allowable range, and thus the evaluation is concluded as good.
(153) Since the model 3 has the same evaluation result as those of the models 18 and 19, and has the better evaluation result than those of the models 17 and 20, the evaluation is indicated as better in TABLE 9.
(154) (Matters which Became Clear from Model 3, and Model 17 to Model 20)
(155) Since the model 3 and the model 17 to the model 20 have the evaluations that are concluded as good or better, all of such models are adoptable. However, the model 3, the model 18, and the model 19 have the better evaluations than those of the models 17 and 20. The following points became clear from such model 3, model 18, and model 19.
(156) It is desirable that the length Lf of the supply portion should be (0.52 to 0.57) times as much as the effective screw length L, i.e., (52% to 57%) thereof.
(157) Moreover, it is desirable that the length Lc of the compression portion should be (0.28 to 0.32) times as much as the effective screw length L, i.e., (28% to 32%) thereof.
(158) Furthermore, it is desirable that the length Lm of the measure portion should be (0.14 to 0.16) times as much as the effective screw length L, i.e., (14% to 16%) thereof.
(159) An injection screw according to the present disclosure is suitable for an injection molding of rigid vinyl chloride.