If your cutting always have a small part at the beginnin not cut through, which means your machine probablely moves before pierce completed.
CNC controller usually check arc feedback signal from plasma or THC before starting cut motion, but some controllers have no such function like Mach3 controller, or some customers dont use this function even the CNC controller has it.
The work process as follow,
CNC output arc start signal-----THC receives it and start IHS to find plate position and set pierce height-------pierce, set enough time to pierce through plate-----THC or plasma offer feedback signal to CNC after pierce( If CNC not take this signal, it should set enough pierce time in CNC, enable CNC wait enough time until pierce completed.)-------start cutting motion.
From above work process you can see the problem reasons can be as follow,
1. Pierce time not enough........set longer pierce time on THC,........ but dont set it too long, enough to pierce through the plate is ok.
2. If CNC not check arc feedback signal.... please set enough pierce delay time in CNC... better way is let CNC check this feedback signal if CNC has this function.
Arc start signal is produced by CNC, which starts the cutting cycle and end the cycle. plasma is receving target of this signal. THC is just the signal transfer station.
If the cutting has problem at the start or end, you should consider the CNC and plasma first, because the signal can pass THC during cutting, the transmission should be ok at the start and end too.
Above information is just for reference, please contact us when you are on specific case.