The EDM drilling process is complex compared to others in manufacturing. And it has very specific uses. It is often used for uncommon hole-drilling tasks that require minimal material impact and extreme accuracy. Because of this, EDM is used mainly in the aerospace, electronics and medical device industries. These are sectors that engage in precision engineering projects that require a higher level of exotic materials with little room for error.
What is EDM Drilling?
Electrical discharge machining, known as EDM, is similar to CNC machining. However, rather than using sharp cutting tools to subtract from materials, EDM uses electrical sparks to punch through materials. The power of EDM makes it more suitable for harder materials like tungsten.
EDM drilling relies on electrodes to get the job done. These electrodes allow a rapid current to be passed between them, resulting in plasma. There are a few different types of electrodes you will need for a project. These are known as small-hole electrodes and come in various forms:
- Single-hole electrodes are hollow and less expensive for making holes in materials.
- Multi-channel electrodes are better for making blind holes and burning away excess.
- Y-type and web-type multi-channels use less material and are more material-efficient.
Single/Multi-Channel Electrodes
If you need to create a hole all the way through a material, then single-hole electrodes work best. But you can use multi-channel electrodes for going part way through. Additionally, you can use wire inserts to burn away more material than with a single-hole electrode approach.
CNC machining and drilling have many useful advantages. But sometimes, EDM offers a superior finish for the job at hand. For instance, EDM is able to work with curved surface, something CNC struggles with. It is also better for dense materials, and it doesn’t create burring.
Selecting an EDM Drilling Service
EDM drilling is complex enough. Yet it becomes exponentially more challenging when working out what you need against what is practically achievable. As such, there are many considerations you must make when planning a project that requires the use of EDM drilling.
If you don’t plan your project accordingly, you will have no idea what you need. And this can lead to buying the wrong devices, materials and resources, including your EDM machine. So, there are some key considerations to make when going through your current project strategy:
- The scale of your production requirements against what your EDM machine can do.
- Whether you are qualified to operate the machine or you need to hire a service.
- Consider the cost of the EDM machine you need versus what you can afford.
- Local services that can offer what you need for a fraction of the overall cost.
Outsourcing EDM Manufacturing
If your business is relatively small, you can, of course, purchase smaller machines such as AgieCharmilles CUT C 350 wire EDM. Yet large-scale manufacture will require significant investment. Fortunately, you can outsource projects to experts such as A&M Pure Precision.
However, like any task you outsource, you need a reliable service for EDM manufacturing. You need the right service that understands methods, such as using the right electrodes for each material. For instance, tungsten carbide electrodes are better for exotic materials than brass.
How Does EDM Drilling Work?
The EDM process involves a few steps to create a current high enough to produce plasma. A brass or copper electrode is mounted onto a drill chuck at the Z axis. Then pressurised ionised water is flushed through the electrode tube to complete a preset drilling cycle time.
Like CNC, there are many types of EDM processes. Some of the most widely used include machining, surface fishing, and wire or sinker EDM. Wire EDM is practical for cutting right through a material, whereas sinker EDM systems are used for going only part-way through.
EDM is very useful and efficient. But like any cutting system, there are advantages and disadvantages. For instance, EDM is unaffected by material hardness, leaves no burrs and is useful for fragile parts. But it is expensive and can only be used on conductive materials.
Applications of EDM Drilling
The usefulness of EDM precision engineering makes it invaluable for specific low-production manufacturers where quality is more important than quantity. Additionally, EDM has evolved to meet the demands of changing industries where there is pressure to improve performance.
EDM devices are very reliable and efficient, with minimal chance of errors. The precision of EDM machines is remarkable for slicing, cutting and drilling. Deeper cuts to the strongest of materials are only possible with EDM machines. You can use EDM to create a unique finish, such as mirroring on a surface.
EDM makes excellent moulds and dies because they can use harder materials.
There are many practical applications for EDM drilling. However, the precise nature of it lends itself very well to the aerospace industry. EDM is used mostly in aerospace to produce cooling holes in specific parts such as turbines, aero blades and metallic moulds, dies and bearings.
Of course, EDM has wider uses. Other industries that apply EDM include the medical field, vehicle manufacture and electronics. For example, the automotive industry uses EDM for drilling fuel injector nozzles, which is also useful for delivering medical fluids in complex procedures.
Only EDM can deliver the type of accuracy that complex industries require. This is achievable through a combination of efficient processes, machine speed and extremely precise control over drilling depth. Hole sizes range from 0.5 mm to 1.5 mm with tolerances of up to ±0.050 mm.
Conclusion
EDM machining allows you to drill tiny yet precise holes into very hard materials with ease using plasma. The nature of the process causes minimal damage to the outlying material and is extremely precise. As such, intricate manufacturing for medical devices, electronic components and space vehicles takes advantage of the accuracy and efficiency of EDM. Yet it is more costly than other CNC types, and often it is best to find an EDM service rather than buy EDM devices.
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