Step 1: The Original
The client supplies Artcast with an “Original”. The original can be almost any material… clay, plasticine, plaster, wood, wax, Styrofoam, etc. The Original may also be a 3D file or a 3D printed original.
Step 2: The Rubber Mould
Unless the original is wax or Styrofoam, a rubber mould will have to be made. The rubber compound is poured in liquid form at room temperature over the original, where it flows into every surface detail.
Step 2.1: The Scan
The Scan may be done by Artcast or one of our preferred suppliers. A standard 3D scan will be able to capture most surface details without much fuss. There are scanning technologies that are able to capture finer detail and some that can even capture internal details that are not visible to a line-of-sight based system. Most scans work best from matte/semi-matte and light coloured originals. Polished sculptures require more care for scanning but they can be done. Scanning is a standard process used for enlargement and reduction of sculpture. From here your scan may be milled in styrofoam, printed in a castable material, or stored for future use.
Step 3: The Wax Duplicate
After the rubber has cured and the original is removed, molten wax is poured into the rubber mould to produce a wax duplicate. It is this wax duplicate that is melted-out prior to casting.
3.1 Digital Originals
If the original comes to us as a 3D file such as an STL or STP file, a physical original must be made. Depending on cost and practicality it may be decided that the original should be made from a castable material like wax or specially designed resins. Some pieces may be more cost-effective to print in plastic and make a rubber mold. Some smaller pieces may be produced in-house but larger pieces will be produced by our highly skilled suppliers. 3D Sand casting molds may also be used depending on the application.
Step 4: The Sprueing
Wax Bars are fused to the wax duplicate to make-up the sprue system. After dewaxing, the sprue system channels the molten metal into the mould cavity.
Step 5: The Ceramic Shell
The sprued wax duplicate is coated several times with a ceramic slurry and stucco, to build up the thickness until the piece is encased in a strong outer shell.
Step 6: Dewaxing
The ceramic shell is heated using steam to melt out the wax. The shell is then cured in a furnace and preheated in preparation for casting.
Step 7: The Casting
Molten metal is poured into the ceramic shell, filling in all of the smallest details. Once the shell has cooled, it is then chipped off and the sprue system is removed.
Step 8: The Finishing
Each point where the sprue system was attached is ground down, restoring the original texture. The finished piece may be polished, patinated, prepared for plating, etc.