The lost wax casting process is one of the most effective production methods for gold silver jewelry castings. It’s an efficient way to create custom jewelry, such as rings, bracelets, pendants that dominate. This article will briefly describe how to use the vacuum pressure lost wax casting method with jewelry casting equipment to cast pure gold, silver, copper, platinum, and other metals.
Making gold silver jewelry with jewelry casting equipment
Why choose vacuum jewelry casting equipment?
The traditional gold silver jewelry casting method is easy to make your finished product easy to oxidize, produce bubbles and cracks. Compared with the traditional jewelry casting method, vacuum pressure jewelry casting is carried out in a closed environment, so you don’t have to worry about oxidation, densification, shrinkage, or the pores of the final product. Vacuum casting has high dimensional accuracy and good surface finish. Suitable for casting jewelry with complex shape, small hole and thin wall.
There are two kinds of high-quality precious metal jewelry casting machine in common use, one is suitable for gold, silver, and copper Vacuum Pressure jewelry casting equipment (downward pressure into the flask), the other is suitable for platinum, palladium, stainless steel, and other high-temperature metal Vacuum Centrifugal jewelry casting equipment (centrifugal rotation into the flask). The two kinds of casting machines are designed for different metals, but the whole production process is the same, As long as the appropriate machine is selected in the melting and casting steps.
It takes 6 steps to make ordinary jewelry:
1. Make wax mold and build wax tree
2. Make gypsum mold with flask
3. Dewaxing of gypsum mold
4. Vacuum melting & casting
5. Cleaning semi-finished products jewelry
6. Fine finishing the jewelry
Ranging from the wax mold making process to the steps involved in polishing and cleaning the desired product. This article covers all the contents and the machines to be purchased
How to make gold silver jewelry with CDOCAST jewelry casting equipment
Step1. Make wax mold and build wax tree
*The wax molds can be copied in batches by a wax injection machine or printed by a 3D printer
The first step is to prepare the wax molds. Before this step, you need to select the waxed rubber mold for the shape you need. Wax material needs to be added to the heating chamber of the machine, turn on the power, and adjust the temperature to melt the wax into liquid. The temperature adjustment depends on the melting point of the wax. Then the wax is easily injected into the rubber mold using a wax injection machine. The wax injection machine with an assembly manipulator can make the rubber mold fit better without distorting its shape. The wax injection machine is suitable for making a wax mold in batches. It’s advisable you weld the wax mold to a wax column from a wax tree. In order to make a gypsum flask later, welding the wax tree can improve the product quality and facilitate the smooth casting process.
Step2. Make gypsum mold with flask
There are some manual operations in this step. First of all, it is necessary to prepare: wax tree after welding, flasks, rubber sleeve or tape, gypsum powder, glue, water, mixer, vacuum bubble remover. Gypsum powder and water with glue mixed are used as raw materials of gypsum mold. The material needs to be stirred more evenly by the mixer and will not solidify rapidly. The agitated material is filled with gas, which is treated by vacuum bubble remover and poured into the flask with wax tree (the side of the flask is sealed with rubber sleeve or adhesive tape). Then put it into the vacuum bubble remover to remove the remaining bubbles.
After these operations, the flask needs stand until the gypsum is dried and formed, and then the next operation can be continued
Step3. Dewaxing of gypsum mold
In this step, the dried flask is clamped into the burnout furnace, and the heated wax mold melts and flows out from the bottom of the burnout furnace, and the gypsum mold is ready. It’s advisable you use a well ventilated CDOCAST small burnout furnace to ensure sufficient air flow in the heating chamber.
Step4. Vacuum melting & casting
In this step, the technology and operation of the machine are important factors to determine the quality of the jewelry products, so I strongly recommend you to understand the use process of these two vacuum jewelry casting equipments.
Vacuum pressure jewelry casting equipment for gold, k gold silver, copper, jewelry casting
Melting and casting process is the key to the whole gold silver jewelry production. Since our main focus is on vacuum pressure jewelry casting equipment, as long as you follow these steps, you will get high quality precious metal jewelry.
1. Take out the gypsum mold in the burnout furnace.
2. Put the gypsum mold into the vacuum pressure jewelry casting equipment casting chamber.
3. Start metal melting and casting under vacuum and pressure.
4. The operation of the jewelry casting equipment under the protection of inert gas can avoid oxidation in the casting process. After gold silver jewelry casting finished, take out the flask and put it on the casting pad for cooling.
Feature of vacuum pressure jewelry casting equipment
- Designed with the most advanced PID temperature control
- Strong induction electromagnetic stirring force
- Integrated design of the melting and casting chambers
- Pressurized casting design highly improves castings’ density and no porosity
Vacuum centrifugal jewelry casting equipment for Platinum, palladium and stainless steel jewelry
The high melting point of platinum has proved to be particularly challenging. Therefore, we must adopt a vacuum centrifugal jewelry casting equipment for casting this type of metal. Such as Platinum, palladium and stainless steel jewelry.
As we all know,The melting point of platinum is very high, platinum alloys lose heat rapidly when cast. . Platinum will solidify within 7 seconds after the heating stops, so the casting volume is too much, it is difficult for the liquid platinum to fill the mold, and there will be problems on the surface of the casting.
Due to the various characteristics of platinum, The vacuum pressured jewelry casting equipment is no longer suitable for the casting of platinum and palladium stainless steel metals ,we recommend adopting vacuum centrifugal jewelry casting equipment to cast high melting point metals, using high-speed rotating arm forces to throw the molten platinum liquid into the heated flask at high speed. This allows you to obtain the highest quality platinum castings.
The CDOCAST centrifugal platinum jewelry casting equipment comes with design of induction melting which can reach maximum melting temperature of 2000°C. It can be equipped with an optional vacuum pump and argon atmosphere to completely protect the workpiece from oxidation, and can be equipped with an optional infrared temperature reader to make the operator control the temperature during the full CDOCAST can cast almost all precious metals, including platinum, stainless steel, gold and steel. With its built-in internal water cooling system, EasyCast provides the functionality and convenience manufacturers need to produce precise and delicate castings.
1.Platinum casting usually adopts quartz crucibles, because quartz crucibles can withstand higher temperatures upto 2000degree. What is more, Since platinum cools very quickly , we do not recommend casting too many platinum jewelry atone time, thus,Our standard crucible size is 500g, client can increase or decrease the casting capacity appropriately, but too much or too little platinum in one batch casting will affect the jewelry quality. Then Prepare the crucible and put it in the coil. The crucible should be placed on a plate at an angle to the metal flask.
2.The platinum material used for melting can be ingots, beads or scraps. If you use waste, make sure to cut it into small pieces and compress it sufficiently in the crucible to allow it to melt properly. This machine is not recommended for platinum powder
3.Quickly take out the flask in the burnout oven., you need a very skilled worker who can accurately place the barbell in the correct position of the centrifuge casting machine in a short time to ensure that the temperature of the flask will not drop and the quality of the product will not be affected.
4.Close the door of the casting chamber and then run the vacuum pump to evacuate the air by starting the vacuum cycle, and then backfill the vacuum chamber with argon. If you want cast very fine rings, we recommend casting under vacuum. The color of the jewels cast under vacuum is better, and there are not so many bubbles inside
5.Start the melting cycle. Observe the melting process through the high temperature glass above the casting chamber and check the temperature data. When the temperature reaches about 1930-1950°C, press the casting button to start the casting process.
6.The heating coil will automatically land and the arm will start to rotate.The entire casting takes about 15 seconds.
7.After casting is completed, grab the flask with tongs, immerse it in a bucket filled with cold water for a few minutes, and take out the cast jewelry
8.Put the platinum castings taken out of the flask into the washing machine to remove the gypsum powder attached to the surface. Under the pressure of the high-pressure water gun, the gypsum powder can be easily removed.
Feature of vacuum centrifugal jewelry casting equipment
- All-in-one structural design, rugged and durable
- Suited for steel, nonferrous and precious metals, including platinum, palladium.
- Intermediate frequency induction heating stirs the molten alloy to achieve perfect uniformity
- castings comes with the feature of smooth surface and controlled loss
- Vacuum design which can make the best quality jewelry
Step5. Cleaning semi-finished products jewelry
The casting process has been completed, your jewelry has the shape you want, but it doesn’t look as beautiful as you want. In order to get exquisite jewelry, you will have to clean and polish your semi-finished jewelry.
The casting flask is cooled and dissolved in water for remove most of gypsum, but there is still a little of gypsum left on the jewelry. You can use a metal cleaning machine with a high-pressure water gun to clean the remaining gypsum on the surface of semi-finished jewelry products.
Step6.Fine finishing the jewelry
After cleaning, the jewelry surface is not bright enough. Cut off the semi-finished jewelry with the jewelry pliers, and then put into the jewelry polishing machine to polish the product surface. It should be noted that different metal polishing methods are different. CDOCAST can provide different polishing machines for the metal you use.
Finally, finish the surface according to the final design you want, such as welding, inlaying, laser marking, Embossing and so on.
Jewelry casting is a strenuous job, without sufficient preparation and investment, it is impossible to explore the profitability provided by the process. Whether you like the traditional casting process of dewaxing casting jewelry, or you are satisfied with our high quality vacuum pressure jewelry casting equipment and dewaxing jewelry casting equipment, you must have time and money.
If you are ready to spend time and money to get more return in the jewelry industry, please contact us for the most suitable solution for you.
All the major machine mentioned in this article can be purchased from CDOCAST