How is jewelry made? Part 1

From design to casting: This is how diamond jewelry is made.

Beautifully sparkling, finely crafted down to the smallest detail. Diamonds that, when set in the precious metal, are still shown to their best advantage and are not restricted in their radiance. The production of a piece of diamond jewelry requires a lot of sensitivity and a multitude of production steps. But how does the process of making a piece of jewelry actually work? We looked over the shoulder of our goldsmith for you and explain the first steps of production to you in our Part 1.

2. Creating a model

In the second step, a detailed “master model” is made from file wax. The desired piece of jewelry is carved out of the material using a cutter, file and graver. For rings, the inner diameter is filed to the correct ring size in this step. If the model was designed in the CAD 3D program, it is worked out in a plotter (an output device that creates vector graphics on various materials). The model can then be created by a robot that builds up the wax model using the finest drops of wax or by means of a laser beam that hardens wafer-thin layers of wax layer by layer. This wax model can then be used for casting and can only be used once.

3. Vulcanizing a rubber mold

The next step is to make a negative model made of rubber or silicone. Such models are mainly used in regular production. To do this, the wax model of the ring is first embedded in an aluminum frame between raw rubber scraps or in plates and covered with pressed plates. The rubber pieces are connected under pressure and heat (at 150-165°C) in a specially designed vulcanizing press. Once the mold has cooled, it is cut open with a scalpel and provided with a sprue.

4. Wax spraying

Wax is injected into the rubber mold at a temperature of 50-60 °C. The more complicated the parts, the higher the injection pressure is set. The wax model can then be removed and placed on a wax tree.

5. Setting up the wax tree

The wax models are attached to a stick made of model wax so that a grape-shaped structure is created. To complete the amount of metal required for casting, the wax tree is weighed and the casting weight is calculated.

6. Embedding

A thin metal tube (cuvette) is placed over the wax tree and the previously mixed investment material is poured into it. So that the mass fits closely to all wax models of the wax tree down to the last corners and branches without any air bubbles, the whole thing is placed on an electrically operated shaking table and at the same time the air is sucked out under the associated vacuum bell.

7. Lost wax and burning out

Once the cuvette has been stored for about 1 to 2 hours without being shaken and the investment material has solidified, the wax is melted out before the rest of the wax is burned out. The temperature for burning out is around 730° Celsius. The entire burnout cycle takes approximately 12 hours. The casting begins quickly the next morning.

8. The melting and pouring

For casting, the cuvette is cooled down to around 600° C and metal is melted in a crucible at 950 - 1050° C. The molten metal is then poured into the cuvette. There it fills the cavities due to its gravity. The temperature during casting depends on the casting metal and the fineness of the castings (the finer, the higher). The whole thing happens in the cast iron oven. There are two possible methods: With the vacuum system, the liquid metal is pressed into the cuvette using vacuum and pressure. In the centrifugal casting system, this is done by centrifugal force as the flask is clamped into a rotating casting arm and spun.