@Thanet58 , Phil I agree a lot with George…
that is a small compressor with low reserve…is your compressor running during the cuts?
What is strange in all this is that you are not getting errors when the torch does not fire…
modify the file so that 3 slots are cut in one go. then we can put the compressor theory to rest. because compressor size is irrelevant to distance. Pipe size is what matters with distance
my vote is solenoid
you can manually fire the machine torch by shorting the 2 pins on the cnc connector. I don’t know the voltage that circuit runs at so don’t go jamming a paperclip in there lol
How can compressor size be irrelevant? What difference would pipe size make, it there is no air to fill it?
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Thanks everyone for their suggestions.
Responses to suggestions
Tried but no improvement
Yes, but no improvement just increased spatter at the pierce point
The compressor at 14 CFM is well over double the Primeweld recommended 5.5CFM. The pipe run is long though so maybe because the pipe bore is narrow the step demand on the second firing is too much as George suggests
The compressor is over specified compared to Primeweld’s recommended 5.5 CFM. Because the compressor is a long way away I cant hear it stop/start. But I don’t think its a compressor output or reservoir volume limitation. With the air flow switch set, the pressure is maintained at 65 psi indefinitely so the compressor is keeping up. But what does happen is when the air flow switch is moved to on, the gauge pressure drops by 6-7 psi. This suggests that the pipe/filters/dryer are presenting some resistance to the air demand.
Yes, a very good suggestion and one I tried earlier today. The results follow later.
Today’s Experiments
I tried 3 experiments based on manually triggering the machine torch with a switch wired across pins 1 & 2 on the CNC port.
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Torch moved 6" away from the work piece so that it would pilot but not arc - I could operate the switch very fast (less than 1s on-off) and the pilot would reliably interrupt the post-flow and generate the pilot arc. The pilot arc wouldn’t stay on for longer than 4s but I assume that is a duty cycle limit set by the Cut 60. But the arc would re-fire immediately after the 4s cut-off. Suggests the air solenoid is operating correctly?
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Torch moved to 1.5mm from the work piece and the above repeated with the torch stationary . Now the arc fired and could be stopped-started quite quickly. But if I left the torch arcing for say 10s it wouldn’t re-start. It took maybe 3 or four more switch operations to get it to blowback and fire. So a very strong influence from how long the torch was on for before an attempted re-start. So a thermal issue in the torch or a transient air issue as George suggested?
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As above but Torch moved by FireControl over 18" using the linear cut generator and in dry run mode. I controlled firing with the switch. Short cuts (1-2s) enabled re-fire quickly, longer cuts of 10s inhibited the next re-fire. But a long single cut over 18" was fine.
I have just one thing left to try. That is to place a better regulator just before the Cut 60 with 115 PSI input and output set to 90 PSI. Hopefully that would stabilise the air pressure to the Cut 60 regulator even if the 115 PSI input fluctuated due to the line length. Make sense?
Thank you all for reading these long posts. Its hard to condense them with so many variables and suggestions.
Phil
As an aside from my main post, Ed’s light hearted comment about the signalling voltage is worth a mention. In fact it looks to me that the input impedance across pins 1 and 2 of the CNC is very high so a paper clip would be just fine as the input takes next to no current!
I noticed that when I connected a digital multimeter across those pins the torch fired unless I used the 20 MOhm range.
Even the 2MOhm range triggered the torch which is odd given that the controlling element is a relay with either zero or infinity resistance. If Pins 1-2 have a high input impedance then it would make the Cut 60 more susceptible to false firing with EMI pickup.
This has nothing to do with my main post but it might be worth verifying with Primeweld what the input impedance is, particularly given the well noted sensitivity of the Cut 60 to odd behavior under CNC.
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You say the plasma cutter is connected to a dedicated 240V/32A power supply. May I ask were you live? or are you running off a generator ?
machine torch needs 70-75 psi, or you will get random misfires. You just confirmed your air pressure problem… You set at 65 psi but when toggle you have 6-7 psi drop in pressure, now your torch is down to 60 psi. Not going to work at that pressure.
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I run all my plasma cutters at 120 psi in and 65 to 75 out depending on amp setting. The Primewel in most cases will not fire a machine torch below 60 psi.
Most plasma cutters have a filter built in them. But they have a plastic bowl on them and are only rated at 125 psi.
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not true. i run a machine torch on the cut60 and use pretty much book settings of 55 psi for 16g.
to add, i do have to set the psi to around 60 to then get 55 continuous when i press the air test switch. but it shouldn’t be set over 5 or so psi from the setting being used.
it’s gotta be something warping in the torch when it heats up and binding up the electrode
I believe you said no issues with the hand torch. compare how much slop there is and if the electrode moves freely
even without it pumping he’s not going to run out of air that fast. I did a quick test with my torch and some maths later a 30 gallon tank should take 4.5 minutes to go from 150psi to 75psi
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i would try setting the incoming PSI to the cutter to 100-110. I have ran mine up to 120 for a long time until i added a spare 30gllon auxiliary tank and that tank outputs max 100psi to cutter.
I have tested a lot of Primeweld plasma cutters and different torch’s and found that they all do not work at the same pressure. Some hand torch’s have worked as low as 40 psi and machine torch’s at 50 psi. I do know that most of the Primeweld units will not let it fire a torch below 55 psi. The one I have will fire a hand torch at 45 psi and machine torch at 55 psi.
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You will continue to chase problem then… I cut with hand torch for a year with factory air settings with no problems, added machine torch would misfire right off the get go or do a few cuts then misfire or nothing at all. I took plasma machine cover off increased internal air regulator to 70 psi. has not misfired or not fire for 3 years now…
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my comment to RAT was that the cutter doesn’t or shouldn’t need 70-75 psi to function properly with a machine torch.
well just saying from my experience, i use the same settings with either hand or machine torch. I actually have 2 machine torches, one from Mechanic, which i bought first and one from primeweld that sent me one to test out and they work exactly the same.
plus Op also said he had same issues with the hand torch.
I have the plasmadyn x45 on Titanium 45 plasma cutter, it won’t operate under 70 psi. All the Hypertherm I have used over the years was 70-85 psi., millers and Lincoln. My Hypertherm powermax 45 xp is 75 on my XR table.
Just trying to give the man a few ideas to try.
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This is my guess from everything that @Thanet58 has said unless he puts a pause after a cut the torch will not fire. That tells me the pressure is below the setting the plasma cutter has to fire the torch till the air pressure build up over that setting then it will fire the next cut. Now as long as the torch is cutting it may cut for a long time till the pressure drops below the plasma cutter shut off point.
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I live in the UK so have 240V/50Hz. A single phase 32A spur is the highest capacity connection available in a normal house/workshop
I’m sorry for the slow responses - the Forum protocol has a security measure to stop robot answers. I had exceeded the frequency/number as a first poster so I was blocked for a couple of hours.
Not quite, I set 65 psi with the air switch on. When the switch is off the gauge reads 70-72 PSI and drops to 65 on test or when the pilot or arc is firing.