1250 missing torch ignitions

[beefy]

I'm playing with marking hole centres, NOT piercing holes centres.

So to do this I basically have code to switch the torch on, then switch it straight off again.

I set up a row of 10 little holes only 5 mm apart centre to centre. The torch would fire on the first one, miss the next one, fire on the one after, miss the next one, and carry on like this all the way to the end.

I was falsely accusing Mach of being buggy but went and checked the torch on LED at the 1250 and it was lighting for every time the torch should be firing (I take my words back dear Mach). So I found out it was the 1250 not firing every second hole.

I put a 4 sec delay after each torch off command and then the torch fired every time.

So my big question is does the ignition circuit in a 1250 need a certain time period to "charge up" before it can fire again. If this is the case is their an approx. specification which says how much time is needed between "ignitions" to allow this circuit to charge up.

Keith.

[jimcolt]

It is not a "charge up" issue. If you notice....there is no airflowing at the torch on a first pierce, and it fires instantly. Once the torch fires the air flow goes into cooling post flow (it is 10 or 20 seconds on a Powermax1250...I don't remember exactly!)....and to refire it first must stop the airflow to the torch (this allows the moving electrode to reposition in order to re-ionize the air), then re start the airflow.....all of which takes about 1/2 to 3/4 second.

If your system was set up using the arc transfer output signal from the Powermax (wires 12 and 14 on the interface connector)....then it will hold the start signal until it sees the plasma is transferred to the material. My guess is that your marking process is using timing rather than the verification of arc transfer....and it does not allow for the slight variation in start time from the original start to the subsequent starts.

Jim Colt Hypertherm

I'm playing with marking hole centres, NOT piercing holes centres.

So to do this I basically have code to switch the torch on, then switch it straight off again.

I set up a row of 10 little holes only 5 mm apart centre to centre. The torch would fire on the first one, miss the next one, fire on the one after, miss the next one, and carry on like this all the way to the end.

I was falsely accusing Mach of being buggy but went and checked the torch on LED at the 1250 and it was lighting for every time the torch should be firing (I take my words back dear Mach). So I found out it was the 1250 not firing every second hole.

I put a 4 sec delay after each torch off command and then the torch fired every time.

So my big question is does the ignition circuit in a 1250 need a certain time period to "charge up" before it can fire again. If this is the case is their an approx. specification which says how much time is needed between "ignitions" to allow this circuit to charge up.

Keith.

[beefy]

Thanks very much Jim.

I never thought about the arc trying to establish while the post cut cooling air is still flowing. It was staring me in the face and I never seen it. Once again your support makes me happy I paid for a Hypertherm.

You are very correct about me using timing without any feedback that the arc has established. I'm trying to get nothing more than a quick sharp crack at minimum amps to leave me with an indentation in the top of the metal (my plasma made centre punch mark). So basically I'm giving a torch on signal of a fraction of a second. I'm even considering making an electronic interface circuit because I can't get a short enough torch on signal from Mach3.

Cheers,

Keith.