STEM – Small holes, big challenge
S.T.E.M. is an acid electrolytic drilling technique for making long deep precision holes in hard, corrosion resistant metals.
The technology is rare and similar to electrical discharge machining (EDM) in that a high current is passed between an electrode and the part, through an electrolytic material removal process having a negatively charged electrode, a conductive fluid, and a conductive work piece.
There is little tool wear associated with this process and unlike EDM, however, no sparks are created. High metal removal rates are possible with STEM Drilling, with no thermal or mechanical stresses being transferred to the part.
This process can offer shaped (i.e. not just round), simultaneous multi-hole drilling, completely stress free and suitable for the hardest materials.
This process is ideal where the design calls for no recast layer and hence no potential weakening of the parent material, making this process ideal for creating cooling holes in turbine components.
STEM technology enables us to produce a range of drilling profiles, including radial holes, trailing edge holes, film cooling holes, platform and tabulated holes. Drilling is safe, deep and extremely precise, with depth to diameter ratios up to 300:1 and diameters as small as 0.5mm/0.020”.
Components made using this technology include; Turbine blades and vanes for both Aero and IGT
Alternative technologies for drilling holes
- Capillary drilling – for precise holes smaller than 0.3mm/0.0012” diameter.
- Laser drilling – for holes greater than 0.3mm/0.0122 diameter in material less than 15mm thick and capable of drilling thousands of holes in a single component.
- Fast hole drilling – for holes greater than 0.3mm/0.012” diameter and up to 100mm deep can also accommodate blind holes