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Electrical Discharge Machining (EDM) is a nonconventional metal removal machining method that employs the use of an electrode to machine the desired shape into a workpiece under carefully controlled conditions. EDM offers several advantages over conventional, "chip-making" machining methods including:

1. The ability to machine extremely narrow notches.
2. The ability to access hard-to-reach locations such as pipe/tube IDs without the need to section the workpiece.
3. The ability to hold very close dimensional tolerances.
4. The ability to machine harder materials and exotic alloys.
5. The ability to machine irregular shapes not otherwise possible.

All conductive materials are able to be EDM'd. EDM notches can be machined on both the OD and ID of pipe and tube. Notches can be machined on IDs as small as 0.040". Transverse (circumferential) notches are normally made with electrodes precisely ground to the respective radius of the workpiece. This ensures uniform notch depth along the notch length. Notches can also be made to match an irregular surface.
ID notches can be placed in tubes as small as 0.040. Surgical implant UT tube standard shown has an ID of .052 and contains two ID and two OD notches.

The basic notch shapes available are detailed below. All notch shapes below can be longitudinally or circumferentially oriented, and can be located on the OD or ID of hollow cylindrical products.


Square Notch
This notch is also referred to as a "Buttress" notch, and has parallel-sided walls and minimal corner radius at notch bottom. Typical of notches over 0.010" wide. Available in depths from 0.0001"; widths from 0.010"; and lengths from 0.005" through 3.00"

This notch has parallel-sided walls at the entry surface and a corner radius at notch bottom resembling a "U-shape". Typical of notches under 0.010" wide. Available in depths from 0.0001"; widths from 0.0014"; and lengths from 0.005" through 3.00".

This notch has angled side walls that meet at the notch bottom. Typical V-notch included angles (a) are 40°, 45°, 60°, 70°, 75° and 90°, with 60° being the most common. V-notch half-angle should complement beam angle for maximum response. Available in depths from 0.002"; and lengths from 0.020" through 2.00".

Ultra-narrow Notch
The absolute narrowest notch available today. Available in widths from 0.0009", depths from 0.0001"; lengths from 0.005" through 1.00". Some depth limitations exist on ultra-narrow notches depending on configuration and alloy. Call Technical Sales to discuss possibilities.