This research aims to Test Melt Flow Index Spiral Test according to Standard ASTM : D 3123-94. To compare with this Standard the Melt Flow Index Spiral Test of HDPE PP and ABS which determined by the manufacturer was tested in various sizes. The test and the results were as follow:

The purposes of the research were to create and find out the efficiency validation of computer assisted instruction focused on the Plastic Injection Adjusting Machine and Injection Molding Maintenance for the standard 90/90 and to analyze the students’ learning achievement after using computer assisted instruction. The samples were 20 first year diploma tool & die students at Rajamangala Institute of Technology North Bangkok Campus. The students pretested and then studied by using the computer assisted instruction focus on the plastic Injection Adjusting Machine and Injection Molding Maintenance. Finally the students post tested. After that the data was calculated to find out the computer assisted instruction efficiency and analyzed the students’ learning achievement after studying. The result revealed that the computer assisted instruction efficiency was reached the standard 90/90 and the students’ learning achievement increased significantly at 0.05.

Comparing the shrinkage values of HDPE 2 – 4 % that limited from manufacturer are as the following: 1. Comparing the shrinkage of 60 X 60 mm. specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 1.1 Comparing the shrinkage of the specimen with 2 mm. thick The result showed that the shrinkage between at the point nearby the entrance is different from at the point further from the entrance and it is also different from the limited value from the manufacturer. 2. Comparing the shrinkage of 12.7 X 27 mm. specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 2.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among the point nearby the entrance the point further from the entrance and the limited value from the manufacturer. 3. Comparing the shrinkage of 100 mm. round specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 3.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among the point nearby the entrance the point further from the entrance and the limited value from the manufacturer. Comparing the shrinkage values of PET 0.2 - 0.4% that limited from manufacturer are as the following: 1. Comparing the shrinkage of 60 X 60 mm. specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but it is not different from the limited value from the manufacturer. 1.2 Comparing the shrinkage of the specimen with 2 mm. thick The finding revealed that the shrinkage value between the point nearby the entrance and the point further from the entrance are different but the same as the limitation from the manufacturer. 2. Comparing the shrinkage of 12.7 X 27 mm. specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but the same as the limited value from the manufacturer. 2.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 3. Comparing the shrinkage of 100 mm. round specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but it is not different from the limited value from the manufacturer. 3.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The finding revealed that the shrinkage value of the follow injection the across injection and the limited value from the manufacturer are the same. Both comparing HDPE and PET have statistical significance at 0.05

The purposes of the research were to create and find efficiency validation ofcomputer assisted instruction focused on the mold plastic injection making kind two plate for the standard 90/90 and analyze the students learning achievement after using computer assisted instruction. The samples were the 15 first year diploma tool & die students Rajamangala Institute of Technology North Bangkok Campus. The researcher experimented by using pretest and then using the computer assisted instruction focus on the mold plastic injection making kind two plate mold base make mold and adjust next the students did the posttest. After that the researcher calculated to find the computer assisted instruction efficiency and analyzed the students learning achievement after studying. The result revealed that the computer assisted instruction efficiency was efficient for standard 90/90. And after studying by using computer assisted instruction the students learning achievement increased significantly at 0.05.