Step 4 of 4
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Plasma / ion nitriding — control, distortion, and the parts that need it
Why a 420 stainless mold cavity that gas nitride ruins comes out of a plasma cycle intact, what the four plasma levers actually do, and which parts the process is the correct call for.
Step 4 of 4Pulsed plasma and the equipment generation
Modern plasma equipment runs pulsed DC, not steady DC. The bias switches on and off in microsecond windows at adjustable duty cycles. The reason is hollow-cathode arcing: deep blind features and tight inside corners on complex geometries concentrate the glow discharge and overheat locally on steady DC. Pulsing breaks the arc before it can form. Plateg, Rübig, and other plasma OEMs build pulse control into their standard furnaces. A vendor still running unpulsed DC on complex tool-and-die geometries is one generation behind, and the parts will show it as localized overheat or hardness spread.
Quick check
A complex H13 die with deep narrow blind holes is sent for plasma nitride. The vendor's equipment is unpulsed DC from the 1990s. What is the predictable failure mode?