Page 23 - Vol_1_Chapter_III

Planing is commonly used for machining large and heavy workpieces, such as large metal plates, machine beds, and surfaces requiring high flatness
and finish. It is particularly useful in industries like construction, shipbuilding, and heavy machinery manufacturing, where large components need
to meet stringent dimensional and surface requirements.
However, planing has some limitations, such as slower material removal rates compared to milling and turning processes and the requirement for
dedicated planer machines for large workpieces. As a result, planing is not as prevalent as other machining methods but remains a valuable process
for specific applications.
Electrical Electrical Discharge Machining (EDM) is a non-traditional machining process used to shape and machine electrically conductive materials. It is also
Discharge known as spark erosion, spark machining, or wire erosion. EDM is particularly useful for materials that are difficult to machine using conventional
Machining methods, such as hardened steel, titanium, and exotic alloys.
The basic principle of EDM involves the controlled removal of material from the workpiece through a series of electric discharges or sparks that
(EDM)
occur between an electrode (tool) and the workpiece, which are both immersed in a dielectric fluid (usually deionized water). The process takes
place in a controlled and highly localized manner, allowing for precise and intricate shapes to be machined.
There are two main types of EDM:
• Ram EDM (Sinker EDM): In this method, a specially shaped electrode (usually made of copper or graphite) is used, and it is lowered into the
workpiece. The electrode and workpiece are separated by a small gap, and when an electric potential is applied, the electrical discharge
occurs, removing material from the workpiece. (Source of image:
• Wire EDM: In this method, a thin, electrically conductive wire (usually made of brass or coated with brass) is used as the electrode. The wire https://www.rejenttool.com/electrical-
is fed through the workpiece in a controlled manner, and as the wire approaches the workpiece, the electric discharge erodes the material to discharge-machining-edm)
create the desired shape.

Chemical Chemical Machining (CM), also known as chemical milling or chemical etching, is a non-traditional machining process used to selectively remove
Machining material from a workpiece using chemical reactions. Unlike traditional mechanical machining methods that involve physical contact and cutting
(CM) tools, chemical machining relies on the controlled use of chemicals to achieve the desired shape and finish.
The chemical machining process involves several key steps:
• Masking: A mask or protective coating is applied to the areas of the workpiece that need to be preserved from the chemical reaction. The
mask is typically made of materials resistant to the etching chemicals, such as photoresist or special tapes.
• Etching: The workpiece is exposed to a chemical solution (etchant) that reacts with and dissolves the unprotected areas of the workpiece. The
etchant is chosen based on the material being machined and the desired rate of material removal.
• Neutralization and Cleaning: After the desired material removal is achieved, the workpiece is thoroughly cleaned and the remaining etchant
is neutralized to prevent further chemical reactions. (Source of image:
• Mask Removal: The mask is removed to reveal the final machined features. https://www.modulusmetal.com/services/
Chemical machining offers several advantages: machining/electrical-and-chemical-
• Capable of machining intricate and complex shapes that may be difficult or impractical to achieve using traditional methods. machining/)
• Minimal mechanical stresses, heat, and burrs generated during machining.
• Suitable for a wide range of materials, including metals, ceramics, and polymers.
• However, chemical machining also has limitations:
• Limited material removal rate compared to some traditional machining methods.
• Precision and accuracy may be affected by factors such as etchant concentration and temperature control.
• Environmental and safety concerns due to the use of chemicals.

Copyright © by DIGIGREEN All Rights Reserved Volume I – Chapter III: Digital and Green Machining and Forming 19