Banding and Plasma Arc Issues and Striking Voltage

UPDATE: According to SPT, the fanning of the arc is not necessarily going to effect the output. 

This is how the banding presented itself

This is from a Thunder Laser USA Nova 51-100 outfitted with an SPT C100 tube matched with a Zye MYJG100 LPSU which has been calibrated to the tube. This video shows the fan-out of the arc around the anode. .

This behavior is not because of a fault, but rather the inherent properties of DC excited CO2 laser tubes. These tubes have a striking voltage (ionization threshold) at which they will fire. The larger the tube the higher the threshold. 

Here is more on DC excited laser tubes: DC Excited CO2 Laser Tubes

ENGRAVING BELOW 29% WITH ARC FANOUT AND BANDING PRESENT:

This is the arc and resulting plasma at the anode when banding is present in the output. We eliminated coolant temp and line noise as variables. This occurred around 20% (Thunder specific controller) and was normal at around 29% power.

ENGRAVING ABOVE 29% WITH STEADY ARC AND NO BANDING:

This more concentrated arc is stabilized. It can dance around the anode, that is normal, but the density and intensity should remain relatively uniform. This condition exhibited no banding and the output was normal and consistent.

Here is the output with no banding:

You can find out more about how a Glass CO2 tube works here: DC Excited CO2 Laser Tubes

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