Question

when should the tip be replaced in the pac torch?

when the opening is 75% oversized
when the opening is 25% oversized
after 10 hours of use
when the opening is 50% oversized

Explanation:

Identify the component and function

The question asks when the cutting tip of a Plasma Arc Cutting (PAC) torch should be replaced. The Plasma Cutting Tip is a critical consumable that constricts the plasma arc to focus its energy on the workpiece.

Analyze wear indicators

Over time, the high-velocity plasma gas and intense heat erode the orifice (opening) of the cutting tip. This erosion causes the opening to become oversized or out-of-round, which degrades cut quality, reduces cutting speed, and can damage other torch components.

Determine the replacement threshold

Standard industry guidelines and manufacturer specifications state that a plasma cutting tip should be replaced when the orifice becomes approximately 50% oversized compared to its original, new diameter.

Match with options

• "When the opening is 75% oversized": Too late, cut quality will be severely degraded.
• "When the opening is 25% oversized": Too early, leading to unnecessary consumable costs.
• "After 10 hours of use": Wear depends on starts, gas quality, and current, not just time.
• "When the opening is 50% oversized": This is the standard industry threshold for replacement.

Answer:

• When the opening is 75% oversized
• When the opening is 25% oversized
• After 10 hours of use
• When the opening is 50% oversized (Correct answer)