The study of silver metal used in the non-plated jewelry industry was found to be dull or black but it was a basic feature of silver. To react with air easily in Thailand. The hot weather must be maintained regularly. The concept that we can study the development of silver metal with resistance to tarnish to slow down will have a positive effect on the jewelry industry. The team has developed a concept to bring other elements to meet the potential. The element used here is palladium (Pd) because the palladium is in the same group as the nickel and platinum groups in the periodic table. It is a metal (Nobel Metal) which is very durable corrosion. Usually white is natural and when used to polish the skin is glistening and in most cases in the jewelry industry is often used as part of the alloy such as making the natural gold color close to the platinum. The authors performed the experiments by introducing silver metal with palladium in an appropriate ratio and tested it with artificial stone. And save the record. It is divided into 4 periods of 5-20 days in normal temperature. The results of the study showed that 92.5% copper 6.8% and 0.7% palladium had a shade of L value of 59% over 20 days. It can be used to produce silver jewelry at a lower tarnished rate. In the jewelry industry

The results of the experiments were found that the temperature of the castings was higher than that of the silver alloys. The workpiece temperature is 500C the workpiece is good 26%. The workpiece is 74%. The temperature is 550C. The workpiece is 26%. The workpiece is 74%. The temperature is 600C. The workpiece is 40%. The workpiece is 60%. The workpiece is a fin. There are many factors that cause fins on the workpiece. Use of low-strength mortar In addition the use of excessive compression or heat transfer resulting in the expansion and shrinkage is not equal. This causes the cracking of the metal water to expand at a temperature of 650 ° C. The fine specimen 56% of the workpiece loses 44%. This temperature results in the smallest workpiece caused by the uneven surface. Cause of the cooling rate in each part of the casting is not equal. And at 700 degrees Celsius it is best to cast silver ornaments with pink color because the results show that the work is minimal. There are 70% good work piece 30%

Case Study Development of Welding Machine for Sterling Silver Jewelry Parts With 500-amp electrical arc system for welding closing porous jewelry after casting. The problem can be solved by welding closing porous or by the jewelry. It is an alternative to repairing the work piece. The efficiency of electrical arc welding equipment can be repaired to a certain extent. Based on the results of the experiments the welding and repairing porous porcelain parts were rated at 500 amperes by random sampling of 4 time slots 5 seconds 10 seconds 15 seconds and 20 seconds. Examine the most appropriate porous or porous workpiece for 20 seconds with 18 complete workpieces capable of sealing or milling. A good percentage of 90 percent of the performance of an electrical arc welding machine for welding sealing or cutting.

This Research is a Development of 8k White Gold low Alloy Metal Components for Jewelry Pieces. By Study and Analyze the Influence of Silver Alloy Gold Alloy Bronze Alloy Zinc Alloy and Tin Alloy. Which Affect Microstructure and Mechanical Properties. (The Different of Color Scales) And Resistance Behavior of Lowered 8k White Gold Alloy in Varies Ratio. The Results Showed that Tests and Analysis to Find the Quantities of Elements has found out that Chemical Components of 8k White Gold Low Alloy Metal had a Little Different Quantities when Compared Between Before and After Centrifugal Casting Process. The Tests and Analysis Results of Mechanical Properties of Test Pieces Showed that the Hardness and Tensile Strength of 8k White Gold Low Alloy Metal with Mixture of 33.33%Au+50.67%Ag+10%Cu+5%Zn+1%Sn had Minimum Ultimate Tensile Strength Equal 0.54 kN/mm2 Minimum Elongation Percentage of 55% and Maximum Hardness of 137.0 HV. The Test Results also Show that the Mechanical Properties of the Material are Brittle Material. When Perform a Forming Process the Pieces will be Easily Broken which was Meant that the Forming Process would be Difficult. But The Color Level of the Test Pieces at this Composite Ratio had the Best Metal Color Level. The Brightness L * = 74.87 was a * = -0.89 b * = 13.74 and the Value of ΔE with the Lowest Color Difference Level of 1.35. Compared to other Varies Ratio. It Showed that 8k White Gold Low Alloy Metal Test Pieces were Very Green and Came out Slightly Yellow Compared to the Blue Line that Approached the Standard Line. These Properties were the Physical Properties Required in 8k White Gold Low Alloy Metal Jewelry Pieces Production. Also there were the Results of 8k White Gold Low Alloy Metal in Two Formulas 8k 33.33%Au+50.67%Ag +8%Cu+7%Zn+1%Sn 33.33%Au+50.67%Ag+8%Cu+8%Zn+0%Sn. These Formulas had Tensile Strength in the Range of 1.10 0.60 kN /mm2 Elongation Percentage in the Range of 70 61% and Hardness of 115.6 123.3HV Respectively. The Results of the Mechanical Properties Test of the Test Pieces Showed that 8k White Gold Low Alloy Metal 33.33% Au+50.67%Ag+8%Cu+7%Zn+1%Sn has Similar Tensile Strength but Maximum Elongation Percentage of 70% and Minimum Hardness of 115.6HV. Which was Suitable for Forming Because of good Ductility and Stretchness Properties (Ductile Material). Forming would be Easy. These were Good Mechanical Properties for Forming Precious Metals.

This research is a study of the optimum heat temperature for baking sintered castings for burnout removal of EC 500 type ash wax from cast mortar. Improving jewelry casting process to reduce waste from silver jewelry production process. By studying the temperature of the mortar. To burn remove wax from the mortar and clean the gaps. Then try to bring silver water instead of metal casting. The results of a baked casing study using the EC500 housing prototype from the study showed that the EC500 wax material is melted from all solids to ash wax by heating at 850 ° C to burn. Remove ash wax which makes the cavity clean. When the casting was casted with 925 sterling silver the most complete workpiece after the improvement of the waste jewelry casting process was found to be 1 piece 1 percent 99 pieces or 99 percent.