Material selection for mold making are not only material prices wages but also there are other factors such as thermal strength shine and resistance to temperature changing that caused distortion and cracks. Preform injection molding from Polyethylene Terephthalate (PET) consumes time for drying granulated plastic in 4 – 6 hours at 140 - 160°C and injects at 280 – 300 °C. This is a very high temperature to inject into mold at 10 – 15°C in cool area. The material for mold making must be able to resist to thermal shock. Today molding machines are made of grade P20 steel (Standard JIS) to produce preform that takes long cycle time due to poor cooling. The research aims to compare the pricing time in mold making to preform injection time that made of aluminum -A7075 grade and grade P20 steel. The experiment is to make a mold that made of aluminum A7075 grade and grade P20 steel injects 15 gram preform. The PET is used to blow into a blow mold with pressure at 30 – 35 bar (Two – Stage) that are 2 bottles of 350 ML. The results of material selection for preform mold making showed that aluminum A7075 grade is cheaper 27.04% the mold price is cheaper 23.6% and consumes less cycle time than grade P20 steel.

The purpose of this research is to study the heavy metal removal from wastewater from laboratory by using adsorption process with firebricks. Waste water was collected among three courses of laboratory such as analytical chemistry principle chemistry and chemistry for engineers. The optimized absorption efficiencies of multi-elements with stirring time volume ratio and temperature were 2 hours 10 g/100 mL and room temperature respectively. It was found that absorption efficiencies of lead (Pb) copper (Cu) zinc (Zn) chromium (Cr) were 65.1 54.8 63.4% and ND respectively.

WC powder was obtained from recycling cemented carbide scraps. This metal power contained tungsten carbide (WC) at 89.17% titanium (Ti) at 4.90% tantalum (Ta) at 3.56% niobium (Nb) at 1.31% and molybdenum (Mo) at 0.93%. Its particle size and distribution was in the range of 0.03-85.31 µm. After quality improvement of the metal powder by ball milling screening and separating the compounds the result showed that the particle size of the metal powder was decreased to 0.01-0.10 µm (10-100 nm). The average size of the powdered particle was 28 nm. The tungsten powder was in more perfect condition by 95.85%

The purposes of the research were to create and efficiency validation of computer assisted for the courses of practiced to cutting sheet metals based standard 90 / 90 and analyse the leaning achievement of the student after by using computer assisted instruction. The subjects in the study were 17 first year diploma students enrolled in Rajamangala University of Technology Phra Nakhon. The Researcher using the experiment by let the students do until test before class And then study by using computer assisted instruction focused on practiced to basic turning. After that let students do the unit test again at the class and calculate to find out the efficiency of the computer assisted instruction and analyse the leaning achievement of students after study. The research result revealed that the efficiency of the computer assisted Instruction was efficient in standard 90 /90. Moreover. after learning achievement At significant level of 0.05

The purposes of the research were to create and find efficiency validation of computer assisted instruction focused on the practice to prepare specimens in Metallurgy for the standard 90/90 and analyze the student learning achievement after using computer assisted instruction. The samples were the 20 first year Bachelor of Science in Technical Education students enrolled in Industrial Engineering Rajamangala Institute of Technology North Bangkok Campus. The researcher experimented by using pretest and then using the computer assisted instruction focus on the practice to prepare specimens in learning next the students did the posttest. After that the researcher calculated to find the computer assisted instruction efficiency and analyzed the students leaning 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 0.01