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Author Topic: What has gone wrong????  (Read 11072 times)

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Offline Hood

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Re: What has gone wrong????
« Reply #20 on: March 13, 2014, 04:10:53 AM »
 I like differential step/dir signals and also 24v I/O, much more noise immune.


Hood

Offline Davek0974

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Re: What has gone wrong????
« Reply #21 on: March 13, 2014, 05:08:30 AM »
Hmm, that sounds like a complete different control system?

Offline Davek0974

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Re: What has gone wrong????
« Reply #22 on: March 13, 2014, 11:25:37 AM »
Just had a chat with the suppliers and they feel the generator is not switching to full power i.e. I am cutting (or trying to) with pilot arc power which is about 20A on this model

They are sending me a new (tested good) hand-held torch for test purposes and while waiting they have advised me to try upping the air pressure to 75psi just for a test.

But basically at 30A and 1.5mm sheet, it should practically vaporise the damn thing at the slow speeds I have been trying!!

Will know more tomorrow.

Offline Hood

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Re: What has gone wrong????
« Reply #23 on: March 13, 2014, 03:24:35 PM »
Hmm, that sounds like a complete different control system?

Ideally yes but you could also do a lot of it yourself if you need to. I used to have to do that on my machines as all that was available was 5v i/o boards and single ended step/dir. I made up line drivers for the step/dir but my drives accepted  differential, if yours dont then you would also need to make up receivers as well. 24V I/O can be done different ways but it can get messy with relays etc. The controllers from CS-Lab do it all for you in a small neat package but likely you would only want to consider going that route if you cant get the better of your problems.
Hood

Offline Davek0974

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Re: What has gone wrong????
« Reply #24 on: March 14, 2014, 05:40:08 AM »
I think this BOB is toast really, its the original one and the LED for the relay is off when initialised but after it warms up, the LED is half-on. It still switches the relay as required but the LED goes from full to half power not full to off.

When i started testing I had the BOB powered from the stepper drive PSU, this I now know was bad idea so I am hoping it was this that did the toasting.

I have a new BOB sitting here, just not sure to try it or not.

I now have fitted a small PSU purely for the BOB and its on a filtered supply too, cant do much more than that.

My other issue turned out to be the machine torch, its a duff one, the new test hand-torch they sent me today cuts really well.

Offline Davek0974

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Re: What has gone wrong????
« Reply #25 on: March 17, 2014, 09:33:41 AM »
Well, i'm getting baffled again, the new torch arrived this morning and results seem to be better but something is still wrong.

In this picture...
http://www.landyzone.co.uk/lz/members/davek0974-albums-problems-picture15119-photo-1.jpg

The long cut is made at 20A @ 4000mm/min, its a nice fine cut about 0.5mm kerf with zero dross front and back.

After that success I thought I'd load up a little test file i've been messing around with and try that after editing the sheetcam settings to suit the new parameters...
http://www.landyzone.co.uk/lz/members/davek0974-albums-problems-picture15120-photo-2.jpg

Now, this was the second run as the first one at 4000mm/min was worse so i dropped to 3750mm/min but all i got was a pile of dross and partial cuts.

Both tests were pierced at 4mm (mfg recommendation) and cut at 1.75mm (mfg says 1.5 - 2.0mm)

Now this tells me that something is badly wrong but my lack of experience does not tell me what.

Any pointers here???

Also, I have set a pierce delay of 0.1 sec in sheetcam but mach3 seems to stay for at least a second or so.???
Does Mach3 have a default minimum pierce delay??

Offline Davek0974

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Re: What has gone wrong????
« Reply #26 on: March 17, 2014, 10:26:38 AM »
Well it seems it is lack of current, this was run at 30A...


Its pretty good I think, I have axis wobble to fix but the cut is clean there is no dross front or back apart from a small amount where it slowed down for the corners.

Still 100% better than the first go.

Although I am happier now, I still fail to see why 20A will cut an excellent straight line but produce so much dross and crap on a simple shape at similar speeds??

Oh, and I still need to fix the pierce delay issue, I have 0.1s set but its holding so long that the torch starts popping before moving due to lack of metal in front of it.