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EDM Surface Finishing

  • Cost Effective Manufacturing Option
  • Production-Grade Repeatablity
  • Ideal for Complex, Small-Scale Designs
Quotes for 25+ Manufacturing Processes.
Wire EDM part example with its design on SmartQuote
Wire EDM Services
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Complex Parts
Cost Effective
Set Up & Production
EDM Surface Finishing

Fathom uses the latest in wire EDM surface finishing technology to deliver high-quality parts to its customers. Whether time-sensitive, highly complex, high-precision, or short production run related, Fathom will meet the requirements of your project.

Surface Finish Achievable with EDM / /

Surface finish is often called out on part prints. Sometimes it’s because it influences appearance, more often because it affects how surfaces slide over one another. Bearing surfaces and those used for sealing are examples of where finish is important.

An EDM surface finish (aka electrical discharge machining) is different to that produced by conventional machining. Cutting processes produce a finish with directionality. This is determined by the movement of the cutting tool. At the microscopic level even ground surfaces have evidence of this “lay”, and it affects how a product performs. Sliding friction is typically lower in the direction of “lay” than across it. “Lay” also affects the long-tern durability and performance of seals acting on the surface.

With EDM there is no “lay” and EDM finish quality can be mirror-like.

Erosion Rather than Cutting – How It All Works / /

Electrical discharge machining works by creating arcs of electricity between the tool and workpiece. (Picture microscopic lightning bolts.) As each arc touches the workpiece intense heat and pressure vaporizes material and blasts it from the surface, leaving behind a small pit. Each pit is only microns deep, but thousands are created every second. The result is progressive erosion of the workpiece.

The material removed is carried away by a flowing dielectric (insulating) fluid and filtered out elsewhere in the EDM machine. Increasing electrical power and frequency results in more powerful arcs that remove more material. Higher flushing pressure is needed to remove the material and the resulting pits are larger and the surface rougher.

EDM Finish Benefits and Requirements / /

EDM is unaffected by material hardness. This means a range of exceptionally hard and tough materials are machineable. The only requirement is that they be electrically conductive. Tool steel, tungsten carbide and Inconel are all good examples.

EDM Finish Quality / /

As with conventional metal cutting, surface roughness is inversely proportional to cutting power and speed. In other words, the key to achieving better EDM finish quality is to cut slower.

When a very high-quality finish is called for required, usual practice is to follow a high-speed roughing cut with one or more finishing – skimming, to use EDM terminology – cuts. As a guide, a roughing pass results in a finish of around 60 – 120 RMS (about 60-120 micro-inch Ra.) Following up with three skimming passes will bring it down to 15 RMS (approximately 12 micro-inch Ra.)

With more passes it’s possible to approach 5 RMS (4 micro-inches Ra,) although this depends in part on material density. More dense materials, like tungsten carbide, can be EDM’d to a very smooth finish. In many applications taking several passes avoids the expense of secondary operations like grinding.

Unique Attributes / /

An EDM surface finish is different to one produced by conventional material removal processes. Rather than exhibiting directionality, the texture is random, which is beneficial in many applications. Furthermore, by taking multiple skimming passes, EDM finish quality can become almost mirror-like.

Why Choose EDM for Finishing? / /

There are several reasons why EDM works well for finishing. Here are a few:

  • More effective cutting capabilities
  • Capable of small radius cuts
  • No direct contact
  • Ability to cut many different types of conductive metals
  • Facility to cut delicate, intricate parts
  • Prototyping up to high volume machining

Wire EDM Surface Finishing Quote Times / /

Use Fathom’s SmartQuote online platform for a fast quote in as little as 1 hour, usually within 24 hours. Are you ready for a wire EDM quote or do you want to learn about other manufacturing services? Contact Fathom today. Fathom’s wire EDM lead times are as follows:

  • Parts as fast as 6-8 days

EDM Surface Finishing Services Offered by Fathom / /

Use Fathom for your next wire EDM job. Fathom’s single-source global network will provide a rapid turnaround on your low- to high- volume projects. By utilizing additive and advanced technologies, Fathom can provide its customers with high-quality parts.

Fathom offers 28 manufacturing processes including wire EDM.

Additive Manufacturing

  • FDM
  • SLS
  • SLA
  • Polyjet
  • MJF
  • DMLS
  • DLS
  • STEP (Evolve)

CNC Machining

  • CNC (3 & 5 Axis)
  • CNC Lathe
  • Precision Grinding
  • Wire & Sinker EDM

Injection Molding

  • Injection Molding
  • Tooling
  • Compression Molding

Metal Cutting and Forming

  • Thermoforming
  • Sheet Metal Punching
  • Sheet Metal Cutting
  • Metal Forming
  • Laser Cutting
  • Water Jet Cutting
  • Chemical Etching
  • Welding
  • Micro Cutting


  • Die Casting
  • Urethane Casting
  • Composite Layups
  • Extrusion
  • Post Processing & Finishing
    • Pad Printing
    • Powder Coating
    • Bead Blasting
    • Surface Grinding
    • Polishing
    • Anodize
    • Powder Coat Passivate
    • Chemfilm
    • Vacuum Metallization
    • Silkscreen
    • Plating
    • Tumbled

Wire EDM Machines Used by Fathom / /

Fathom’s manufacturing facilities include over 530 machines; mills, lathes, presses, press brakes, turret punches, additive systems and more. Thirty-one of Fathom’s machines are used for EDM manufacturing. Fathom’s 31 equipment includes 16 machines dedicated to wire EDM, 12 for sinker EDM, and 3 for drill EDM. Fathom’s large network of sophisticated equipment allows us to give our customers a quick turnaround.

Does your project call for wire EDM? Fathom can deliver. In addition to wire EDM, Fathom also offers hybridized services. A recent case study illustrates how Fathom manufactured 20,000 parts in 27 days using 55+ tools, including water jet cutting services.:

Case Study //

Real Customers. Real Results.

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.

20,000 Parts // Within 27 Days
55+ Tools to Injection Mold 15,000 Parts First Article in 2 Weeks

55+ Tools to Injection
Mold 15,000 Parts

First Article in 2 Weeks

3,000+ 3D Printed Parts

3,000+ 3D
Printed Parts

2,000+ Metal Fabricated Parts

2,000+ Metal
Fabricated Parts

Hybridized Services Used //

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’s Locations for Wire EDM / /

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:

444 W. 21st St. Ste. 101
Tempe, AZ 85282
ISO 9001:2015
NIST 800-171 Compliant

1207 Adams Drive
McHenry, IL 60051

1401 Brummel Ave
Elk Grove, IL 60007
ISO 9001:2015 Design Certified

1513 Sam Bass Rd
Round Rock, TX 78681
ISO 9001:2015
ISO 13485:2016

Wire EDM Specifications and Tolerances / /

Wire EDM is known for higher cutting accuracies and tighter tolerances. To achieve a higher accuracy, lower power and speed may be used. By reducing the power and flushing pressure, a tolerance of +/- 0.0005” can be achieved. Even when cutting the hardest raw materials, wire EDM offers excellent precision.

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 Materials List / /

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:

  • Copper
  • Carbide
  • Tungsten
  • Bronze
  • Carbon steel
  • Inconel
  • Stainless steel
  • Hastalloy
  • Kovar
  • Titanium
  • Carbon graphite
  • High alloy steel

Wire EDM Finishing Processes / /

Some finishing may be required on wire EDM parts even though the process can produce a smooth, mirror-like finish. Common finishing processes for wire EDM parts include:


Painting adds color, varnish, or ink to a part. There are three methods of painting which include powder coating, liquid coating, or e-coating. During powder coating, the powder is electrostatically charged which leaves a scratch-resistant and uniform coat on the metal part. Wet paint is used during liquid coating and is applied to the surface of the part. 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.


Transfers add a design or label to a workpiece. To add the design to the part, a heated press is used to apply pressure and transfer the design. Transferring may also be used to add a design to a part that will later by engraved.


Assembly is required when the unit manufactured is part of a larger piece. The part may be bonded temporarily or permanently to other parts using fasteners or bonding procedures.


Drilling adds a round hole to a part. A drill press, tapping, or milling machine may be used to add a hole. Spotting or peck drills may also be used, depending on the kind of mark that needs to be made.


Deburring removes any raised edges or unwanted material known as burrs. Electrochemical, thermal, or abrasive flow deburring may be used. During electrochemical deburring an anodic metal dissolution may be used to remove unwanted material. Thermal deburring uses a combustible gas in a pressurized chamber to deburr a part. Abrasive flow deburring uses an abrasive slurry to deburr the part.

EDM Surface Finishing FAQs / /

Q: Does Fathom offer Wire EDM machining?

A: Yes, Fathom offers wire EDM machining.

Q: What is 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.

Q: Is Fathom ISO certified?

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.

Q: Is Fathom ITAR certified?

A: Yes, Fathom is ITAR certified. For site-specific certifications, please visit https://fathommfg.com/fathom-manufacturing-certifications.

Q: Is Fathom AS9100:2016 certified?

A: Yes, Fathom is AS9100:2016. For site-specific certifications, please visit https://fathommfg.com/fathom-manufacturing-certifications.

Q: Is Fathom NIST 800-171 certified?

A: Yes, Fathom’s certifications include NIST 800-171. For site-specific certifications, please visit https://fathommfg.com/fathom-manufacturing-certifications.

Q: What is EDM surface finish?

A: EDM surface finish has no directionality or “lay” and can be mirror-like.

Q: What surface finish is EDM?

A: EDM produces a smooth, mirror-like finish.

Q: What is EDM in injection molding?

A: The EDM method may be used to make tools that will be used for injection molding.

Q: What is meant by surface finishing?

A: The surface finish of a part is its texture. The surface finish may be rough or smooth.

How to Get Wire EDM Quotes / /

Are you ready to get a quote on your wire EDM project? Do you need to calculate costs? Use Fathom’s SmartQuote application for fast quotes on any file.

Across National
Time Zones

Precision manufacturing
from coast to coast.

1050 Walnut Ridge Drive
Hartland, WI 53029

444 W. 21st St. Ste. 101
Tempe, AZ 85282

46758 Lakeview Blvd
Fremont, CA 94538

7770 Washington St.
Denver, CO 80229

14000 N.W. 58th Court
Miami Lakes, FL 33014

1207 Adams Drive
McHenry, IL 60051

1401 Brummel Ave
Elk Grove, IL 60007

13758 Johnson Street NE
Ham Lake, MN 55304

1920 Slaterville Rd.
Ithaca, NY 14850

401 W. Shore Blvd.
Newark, NY 14513

1513 Sam Bass Rd.
Round Rock, TX 78660

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