Fast Hole EDM
Our Fast Hole EDM capabilities are a complete solution for cooling hole drilling that cannot be matched by any other source
Electrical discharge machining, or EDM, is a reductive process that eliminates the need for a traditional tool head and all of the problems that come with it.
Our Fast Hole EDM Machines
We have been drilling air core cooling holes in high pressure turbine components since 1980. Our 5- and 6-axis Fast Hole EDM Machines can create shape holes on the surface of an airfoil as well as the standard round cooling holes as small as .004 in diameter, up to .5 inch in diameter, and at any depth required.
All of Hi-Tek's Fast Hole EDM machines use deionized water as a dialectic medium. Submersing the parts in deionized water allows for a better entrance and exit of the electrode.
By using an electrical spark to remove material from hard, conductive metals, EDM makes it possible to create small cavities, holes, and sophisticated negative-space forms.
Fast Hole EDM
The use of laser ablation technology allows us to precisely clear the thermal coating, a much more precise process than _____ preventing us from having to ship the part to another facility mid-process
Hot gas path components inside turbines rely on thermal-barrier coatings to allow sustained operation at elevated temperatures. The newest and most economical production model for turbine vanes, direct through coating drilling, involves applying the thermal barrier coating prior to drilling the diffuser and metering holes. With our proficiency in laser ablation technology, we can clear the top layer of the thermal barrier coating in the precise hole shape and pattern to allow for fast hole EDM drilling of the cooling holes.
This process requires a sophisticated level of laser programming to remove only the microscopically thin top layer while leaving the conductive bond coating layer in place. Our 5-axis laser enables us to manipulate the beam head to ablate the coating and create clean diffuser shapes without causing any ancillary delamination or damage to the thermal barrier coating. We perform extensive in-process measurement and inspection to ensure the accuracy of the shapes and the true hole position. Once the top layer of the coating is ablated, we drill the metering holes using fast EDM technology, which allows us to accurately drill deep holes with contoured openings in tough materials at high speed.
We use this combination of laser ablation and fast hole EDM drilling in the manufacture of turbine vanes for multiple engine sets used in power generation. Production also involves 5-axis CNC creep feed and CBN grinding and pulsed EDM to create the seal slots and notches. We also carry out extensive airflow testing, document all of the measurement data, and use non-destructive test methods to confirm surfaces are free from defects. These turbine vanes exceed the strict quality standards established for hot gas path engine components.
Hi-Tek has a met lab staffed with engineers that has decades of experience. Tests that are typically performed in the lab include failure testing, corrosion testing, chemical analysis, weld testing, and metallography
Thermal processes such as EDM, Laser, Material Joining, etc. have stringent requirements for such things as recast layer, heat affected zones, microcrack limits, etc.
In 1985, Hi-Tek realized the need to have an in-house Met Lab resource. Since then the equipment has been continually updated to stay on the leading edge of the process. Hi-Tek maintains appropriate Met Lab approvals from all our customers as required.
Fast Hole EDM Produces High Accuracy for Specialized Applications
We rely on the EDM machining process because it allows for high accuracy and is applicable for any conductive material. The process permits the creation of rounded or irregularly shaped cavities, meeting our customers' most challenging requirements. Since fast-hole EDM has such a small, focused area, it's excellent for performing highly detailed work in these durable parts. This is especially suitable for high-stress industries like aviation and power generation turbines where precision is crucial.
Our Fast Hole EDM devices are built to the specifications we've devised through decades of operation. By constructing our tooling from the ground up to meet our stringent requirements, we're able to solve problems that defy other commercially available options. This also allows us to machine specialty components. For example, we custom built a Fast Hole EDM Machine specifically for drilling cooling holes in circular parts, such as casings and rings at up to a 40" outside diameter.
Another significant advantage of our EDM sinker machinery lies in its use of a multi-axis carriage. This capable setup makes it possible to drill holes precisely regardless of their axial orientations or the surface curvatures of the blades they're embedded in. Such alignment accuracy is of critical importance in a field where minor gas flow inefficiencies might lead to advanced wear or the development of potentially catastrophic hot spots.
Here are the benefits fast hole EDMs have over conventional EDMs:
Diverse axial orientation capability
Capable of creating round holes from .004" diameter to .5"
Holes are created very quickly with very good surface finishes and low recast layers
Can produce round, conical and shaped airfoil holes to accommodate the designs required by the Aerospace and Gas Turbine Industries
A single point electrode can EDM mill shaped hole geometries while producing a round hole through the airfoil wall in a single step
Our primary focus with the equipment we produce is guaranteeing that everything is done accurately and efficiently the first time through. Re-cast and metallurgical disruptions get in the way of meeting project deadlines and other requirements. We work tirelessly to minimize these issues so that our customers can remain on-track during complex projects.
Materials we can work with include stainless steel, Hastelloy, Inconel, and Waspaloy, substrates commonly used throughout the aerospace and gas turbine industries. As new superalloys come onto the marketplace, we'll work to incorporate them into our processes to maintain pace with the latest customer requirements.