Plasma arc can produce a temperature as high as 33,000°°C. Plasma refers to a gas which has been raised to such a high temperature that it gets ionized and becomes electrically conductive. The plasma torch consists of a conversed focus of arc that operates between tungston electrode and workpiece. The torch is directed onto the workpiece where high velocity of plasma gas melts and removes the work material. Nitrogen and argon are generally used for plasma gas. The conceptual diagram of PAM is shown in Figure 23.10.
Figure 23.10 A Conceptual Diagram for PAM
Advantages
- It has higher metal removal rate campared to other unconventional machining such as EDM and LBM.
- It is effective in all electrically conductive materials regardless of their hardness.
- In this maching process, heat effected zones are limited.
- This is faster process but the speed decreases with increase in thickness of materials.
- The process can be easily automated.
Limitations
- The surface damage of work material may occur due to oxidation and overheating.
- It requires high initial investement.
- The thickness of material is limited by current capacity of the torch.
Applications
It is most suitable for profile cutting of metals like stainless steel, aluminium, mild steel, alloy steel, titanium, bronze, etc.
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