Atmospheric or vacuum plasma
Sealed chamber or torch on the conveyor? The choice is not decided by physics, but by the geometry of your parts and the cycle time of your line.
- Vacuum: the plasma envelops the part from every angle. Unbeatable on complex geometries, but the treatment runs in batches.
- Atmospheric: the head mounts on the robot and treats parts as they travel down the conveyor. No chamber, no door to close, no pump-down.
- The real trade-off comes down to three points: part geometry, robotic integration and cycle time. The physics of the treatment itself is comparable.
Two technologies, two philosophies
You need to improve adhesion on a critical component. Plasma is the solution your R&D has validated. But once you face the equipment suppliers, the dilemma sets in: do you enclose your parts in a sealed chamber (vacuum) or bring the plasma straight to your conveyor (atmospheric)?
The match-up: point by point
Part geometry
Ability to treat cavities and blind holes.
The gas reaches absolutely everywhere — ideal for complex medical components or coils.
Robotic integration
Compatibility with 6-axis or SCARA automation.
The plasma head bolts straight onto the robot end effector. The treatment slots into the existing tool path.
Cycle time (throughput)
Execution speed on a production line.
Immediate. No dead time spent closing a door and pumping down a vacuum chamber.
Application case: sealing an inverter
Picture the assembly line for a high-voltage power controller for electric vehicles. The aluminium housing has to be sealed with a silicone gasket (FIPG) to guarantee absolute IP67 protection against water and dust.
- The vacuum approach: it would mean stopping the line, grouping housings into batches of 50, loading them into a machine, waiting for pump-down, then feeding them back onto the conveyor. Incompatible with automotive takt time.
- The atmospheric solution: the robot arm that lays down the silicone bead carries a plasma nozzle. On the first pass, the robot activates the aluminium channel. On the second pass, immediately after, it lays the silicone. Adhesion is excellent, with no break in the material flow.
- The treatment slots into the robot's existing tool path: no extra station, no manual rework.
- No break in the material flow: parts never leave the conveyor.
- Activation and gasket deposition happen in two consecutive passes, inside the same cell.
The vocabulary, decoded
Batch treatment
Parts are grouped, taken off the line, treated together in a chamber, then fed back in.
In-line treatment
Treatment happens in the flow, on the conveyor, without interrupting production.
Takt time
The cycle time imposed on each station of a line to keep up with delivery rate.
FIPG
Formed In Place Gasket: a sealing bead dispensed directly onto the part, then cured in place.
A note on method. The figures quoted are orders of magnitude observed in an atmospheric pressure DBD configuration. They vary with the material, the geometry of the part and the line speed: we measure and document the exact parameters on your own samples before making any recommendation.
More in this series
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