It’s only natural that designers and toolmakers should ask about the precision of electrical discharge machining, more commonly known as EDM. Knowing the capabilities of the process informs design decisions and influences costs. Whether the parts being made are surgical instruments, extrusion dies, or aerospace components, it’s important to know what tolerances are achievable.
Unfortunately, there’s no simple answer. While accuracies of +/- 0.00004” (0.001mm) are sometimes quoted for wire EDM, +/- 0.0002” (0.005mm) is more widely accepted. The reality is that EDM accuracy depends on a combination of workpiece characteristics, the surface finish desired, and the time available for machining. The only way to fully appreciate the potential precision of EDM is by understanding the process.
EDM is a non-contact machining process that uses electricity to remove material. The tool is separated from the workpiece by an insulating fluid, (water, in the case of wire EDM,) and an electrical potential is applied. The fluid breaks down and a spark strikes the workpiece. This blasts a particle from the surface, which is carried away by the movement of the fluid.
Wire EDM is used for cutting complex 2D shapes or profiles from electrically conductive materials. Much like the carpenter’s fretsaw, wire EDM can cut in all directions. Most wire EDM machines hold the wire vertically and move the workpiece in x and y. Many machines offer the ability to incline the wire, allowing production of draft angles on tooling and conical features.
The wire used for EDM ranges in diameter from 0.004” (0.100mm) to 0.013” (0.33mm) with 0.010” (0.254mm) being the most common. When it cuts sparking occurs over the forward 180 degrees, so the kerf width is significantly wider. Actual width depends on the power supplied but is typically about 1/3rd larger than the wire diameter. In practical terms then, a 0.10” wire cuts a path around 0.13” wide.
Speed and precision are controlled by managing cutting parameters – power and frequency – and controlling the rate of fluid flushing. Lower power and speed improve accuracy. This is because flushing moves the wire slightly, and flushing pressure is higher at higher feed rates. In addition, the wire bends slightly in a phenomenon known as barreling and at higher speeds the effect is more pronounced.
Tolerances of +/- 0.003” are achievable during a relatively quick roughing pass. Cutting the power and reducing flushing pressure for a skim achieves around +/- 0.0005”. Following up with a second skimming pass improves the precision of EDM, to around +/- 0.0002”.
Wire EDM is capable of very high precision, even in very hard materials. However, getting there requires several passes. Many products and applications don’t need such accuracy, and so may be machined by EDM in much less time.
There are several reasons why EDM is a good machining solution:
Get a quote on your wire EDM project in as little as 1 hour by using Fathom’s SmartQuote online platform. Whether you want to learn about wire EDM or get more information on another manufacturing service, Fathom is ready to help. Fathom’s wire EDM lead times are as follows:
Fathom’s powerful single-source global network is ready to support your low to high volume project. Fathom produces high-quality parts by leveraging both additive and advanced technologies in addition to wire EDM.
Fathom offers 28 manufacturing processes including wire EDM.
Fathom’s manufacturing network is supported by over 530 machines, including mills, lathes, presses, press brakes, turret punches and additive systems. Fathom dedicates 31 machines to EDM manufacturing including 16 for wire EDM, 12 for sinker EDM, and 3 for drill EDM. Fathom’s state-of-the-art equipment guarantees customers a rapid turnaround.
In addition to wire EDM, Fathom also provides hybridized services. Will wire EDM fit into your complex project? Fathom can deliver. A recent case study illustrates how Fathom manufactured 20,000 parts in 27 days using 55+ tools, including water jet cutting services.:
A customer came to Fathom with a complex project that spanned the technologies and processes of rapid production—and needed it done fast. Fathom delivered.
55+ Tools to Injection
Mold 15,000 Parts
First Article in 2 Weeks
3,000+ 3D
Printed Parts
2,000+ Metal
Fabricated Parts
3D Printing / Additive Manufacturing—PolyJet, SLS, MJF.
DFM Analysis + CAD Mods.
CNC Machining. Laser Cutting.
Stamping. Die Cutting. Post-Opp Drilling.
24-hour Turnaround Urethane Casting.
Injection + Compression Molding.
Model Finishing. Insert Assembly.
Advanced Project Management.
Fathom has 5 US-based locations that offer wire EDM, offering nationwide coverage to the entire United States. Fathom’s advanced prototyping and manufacturing services include injection molding, CNC machining, chemical etching, metal 3D printing, and more. We have provided over 200,000 quotes to leading U.S. companies and are ready to provide you with a quote today.
Wire EDM locations include:
ARIZONA
444 W. 21st St. Ste. 101
Tempe, AZ 85282
ISO 9001:2015
NIST 800-171 Compliant
ITAR
FLORIDA
14000 N.W. 58th Court
Miami Lakes, FL 33014
ISO 9001:2015 Design Certified
ISO 13485:2016
ILLINOIS
1207 Adams Drive
McHenry, IL 60051
1401 Brummel Ave
Elk Grove, IL 60007
ISO 9001:2015 Design Certified
TEXAS
1513 Sam Bass Rd
Round Rock, TX 78681
ISO 9001:2015
ISO 13485:2016
Wire EDM can manufacture parts with excellent precision, even when using the hardest of raw materials. Tighter tolerances and higher cutting accuracies can be achieved by reducing the power and flushing pressure. By lowering power and speed, tolerances of +/- 0.0005” are achievable.
| Material Thickness | Tolerance | Kerf | Part Volume | Set Up Cost | Lead Time ** | Notes |
|---|---|---|---|---|---|---|
| up to 15.750 inches thick | 0.0005" | 0.006" | 1-200 Is Best | Low | 6-8 days | Conductive Metals, Carbon |
Wire EDM should be used with any conductive metal such as titanium, aluminum, brass, alloys, and superalloys. Thanks to wire EDM’s accuracy, wire EDM has become a popular manufacturing method for various industries. Whether for part or prototype, Fathom has many materials suitable for wire EDM, including:
While wire EDM produces a mirror-like, smooth finish, some customizations may still be needed on wire EDM parts. Common finishing processes for wire EDM parts include:
Painting adds color, varnish, or ink to a part. Painting methods include powder coating, liquid coating, or e-coating. During powder coating, an electrostatically charged powder is used, resulting in a scratch-resistant and uniform coat. Liquid coating is when wet paint is applied to a surface. E-coating is the process of dipping a metal part into a bath of paint. The part and paint are electrified, and the paint adheres to the part.
Transferring adds a design or label onto a part. During transfer, a heated press transfers the design. The design may later be engraved onto the workpiece.
Assembly permanently or temporarily bonds a workpiece to other pieces to form a larger part.
Fasteners or bonding procedures may be used to fuse the parts together.
Drilling adds a round hole to a part. Depending on the type of mark that must be made, different types of drills may be used such as spotting, peck, drill presses, tapping, or milling machines.
Deburring removes unwanted raised edges or material from a part. This excess material is known as burrs. Deburring may be achieved using several methods, including electrochemical deburring, thermal deburring, and abrasive flow deburring. Electrochemical deburring uses an anodic metal dissolution to remove unwanted material. During thermal deburring, a combustible gas is added to a pressurized chamber to deburr a part. Abrasive deburring uses an abrasive slurry to deburr the part.
A: Yes, Fathom offers wire EDM machining.
A: Wire EDM is the process of machining metal that uses a tool to discharge sparks onto metal material. The discharge melts the material, creating an accurate cut.
A: Fathom’s certifications include ISO 9001:2015, ISO 9001:2015 Design, and ISO 13485:2016. For site-specific certifications, please visit https://fathommfg.com/fathom-manufacturing-certifications.
A: Yes, Fathom is ITAR certified. For site-specific certifications, please visit https://fathommfg.com/fathom-manufacturing-certifications.
A: Yes, Fathom is AS9100:2016. For site-specific certifications, please visit https://fathommfg.com/fathom-manufacturing-certifications.
A: Yes, Fathom’s certifications include NIST 800-171. For site-specific certifications, please visit https://fathommfg.com/fathom-manufacturing-certifications.
A: The cost of wire EDM depends on the complexity of the design, the quantity ordered, turnaround time, and raw material selected.
A: A wire EDM shop is a manufacturing facility that uses wire EDM equipment to produce parts.
A: Wire EDM manufacturing uses electrical discharge machinery to produce parts from hard or brittle materials.
A: Wire EDM is a highly accurate process that can achieve tolerances of +/- 0.0005”.
Ready for a Wire EDM quote or to calculate costs for an upcoming project? Fathom’s SmartQuote application provides fast quotes on any file.
