The importance of vacuum in the injection process

The importance of vacuum in the injection process

The lost-wax casting process allows the production of jewels and fashion accessories with the utmost precision and a full repeatability, with no waste.

It is a complex process, which requires innovative machinery and top-quality waxes. For the best results, however, we need something more: we must prevent air in the rubber mold and the injected wax.

How can we achieve this result? With our Masterix injectors, the only injectors that can create vacuum both in the tank and in the rubber mold.

Lost-wax casting process: all the steps

Before analyzing the vacuum issue, we should summarize the stages of the lost-wax casting process.

  • Starting from a master, we create a vulcanized silicone mold
  • Injectors create the vacuum inside the rubber mold and fill it with wax
  • Once filled, the rubber molds are placed on the coolers. When the wax has hardened, we open the molds and take out the pieces
  • We weld these wax pieces to a wax tree
  • We dip the wax tree into a plaster solution to create the shell
  • The plaster is placed into the oven, the wax inside it melts and runs off the bottom base of the tree
  • We cast the molten metal inside the plaster shell
  • We open the plaster shell and collect all the pieces attached to the tree, which undergo mechanical processing or special finishing

Why is it so important to create the vacuum?

As we have already said in our insight about the lost-wax casting process, the first stage, that is the wax injection inside the rubber mold, is crucial for the end result.

Microbubbles inside the mold or in the injector tank will result in flaws, impossible to cover up in the following stages.

Vacuum in the tank and in the silicon rubber mold: how do we create it?

In Masterix, we use cutting-edge technology to create vacuum both in the wax tank and in the mold. In this way, we can be absolutely sure that the wax fills the whole space with the utmost precision, especially when the shapes to be produced are particularly complex and thin. Our injections are perfect, every single time.

As we have already said, it is crucial to prevent air from both the tank and the mold. If air would remain in just one or the other, indeed, bubbles might still end up in the wax piece, causing imperfection in the end results.

Creating the vacuum, though, we avoid any risk of flaw or imperfection and the piece turns out perfect, because excellent results are always guaranteed.

To create vacuum, we use high-performance pumps, which draw off air both from the tank, removing humidity from the molten wax to be injected, and from the mold. Vacuum is automatically monitored, and only if the level is actually 100% we proceed with the wax injections and the following stages of the lost-wax casting process.

Error-free, streamlined production

Wax injection in the total absence of microbubbles allows us to achieve the highest quality standards and drastically reduce waste.

As we said, if we had worked with air in the injector tank or in the rubber mold, the wax piece would have been flawed, and therefore also the end result in precious metal.

Obviously, a jewel that is not precise in its shape - or has an uneven surface - can not be delivered to the customer. We have to melt the precious metal again and start over the process from the beginning, with a great waste of time and resources. And a needless waste, above all, since working with vacuum prevents all of this.

Our injectors create the perfect vacuum and avoid the problem at its source. None of the wax pieces will present microbubbles or imperfection. In this way, the production is totally optimized, because error and waste of time and material are effectively prevented.

In conclusion, choosing injectors that can create the vacuum

  • Improves all the quality standards
  • Optimizes production

As we said, both the injector tank and the rubber mold must be totally vacuum-sealed, or the injection could not be perfect.

Lost-wax casting process is the most accurate, fast and convenient way to manufacture jewelry and fashion accessories. Only cutting-edge machinery, though, can guarantee top-quality end results. That’s precisely what happens without Masterix injectors, which can remove all air from the tank and form the rubber mold.