How does an OTS casting turbine wheel come into being?
1. Make a mold according to a turbine wheel sample or 3D drawing.
2. Press the wax into the mold and a wax pattern arises, then removing the burrs from the wax pattern, especially these at the blades.
We also apply 3D printed wax wheel pattern to these clients who need short time leading and small quantities for new model development.
3. Connect the wax patterns to the gating system, we simulation with CAD to decide number of wax pattern for each gating system before the foundry.
4. A robot takes care the slipcasting (there might be up to 20 layers of ceramic slip on each pattern), then wait them to dry.
5. Melt the wax out from the ceramics shell mould with overheated steam, then melt the inconel713C alloy into the empty shell in vacuum furnace. There is an important step that we keep the pouring hole being down when put the alloy bar into it to avoid impurity entering into the shell.
6. Break the shells in a mechanical way, cut the alloy wheels from the gating system and then proceed blasting.
7. Detect the bubble, foreign substance and crack by visual check / luorescent penetrate inspection for every single turbine wheel rough cast.
Or X-Ray NDT Inspection for special requirement.
8. Deburr if necessary, then pack the wheel to be delivered to turbine shaft wheel manufacturer or resaved to warehouse.