Jim - consumable life with short torch on duration

[beefy]

Hi Jim,

been communicating with a guy about my hole centre marking circuit board that fires the torch for a very short duration to leave nothing more than a nice little crater mark.

The guy thinks using the torch this way will wear out the consumables fast. Would you say turning the torch on for a fraction of a second (at proper pierce height) will wear out ANY of the consumables any faster than a standard pierce (+ cut) would.

I told the guy that the "sparks" actually blow outwards at the beginning of a pierce and only start shooting upwards as the pierce crater gets deeper and they have nowhere to go except do a U-turn at the bottom of the now forming hole. And seeing as my hole centre mark is nothing more than a dimple in the surface, my "sparks" will be only shooting outwards doing no damage to the consumables.

Have I said anything which is incorrect.

Keith.

[jimcolt]

It is not the sparks or the hot metal that affect consumable life (assuming you pierce using the pierce height and pierce delay time listed in the Hypertherm operators manual), rather it is the electrical and thermal shock to the inside of the nozzle and the hafnium emitter on the electrode. It is the starting of the torch...not the piercing of the metal that has a bigger effect on consumable life. Since your marking process requires the torch goes through its starting process...then I suspect each center point mark likely produces similar wear to a properly executed pierce. Fortunately the newer Hypertherm systems use a step flow and ramped current process at the start of every cut cycle that minimizes the starting effect. Use your process with older technology...or the low cost imports and very short consumable life is likely.

The best thing for most plasma torch consumable life is to start once then cut continuously....if you can do this you will get far more feet of cut from a set of consumables than you would if you had to start or pierce on every part. Some nesting softwares can automatically recognize certain parts with no internal cutouts...and do "chain cutting" to achive the best consumable life.

Jim Colt

[beefy]

Thanks very much Jim,

great information.

Keith.