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  1. #111
    Quote Originally Posted by Davek0974 View Post
    CandCNC advised me to up the pulse width to 5us and that seems to have sorted it out, all drives now running the same way.
    So you were just on the wrong side of the pulse edge then. Could only really be this or the BOB inverting signals really.! Changing the pulse width doesn't always work thou unfortunately so you've been fortunate.!

  2. #112
    Yes its an oddity i think,

    A Mach guru has just pointed out that the BOB has opto isolated outputs and the drives have opto isolated inputs so i am driving an opto with an opto, he seemed to feel that was not a good idea generally.

  3. #113
    Quote Originally Posted by Davek0974 View Post
    Yes its an oddity i think,

    A Mach guru has just pointed out that the BOB has opto isolated outputs and the drives have opto isolated inputs so i am driving an opto with an opto, he seemed to feel that was not a good idea generally.
    Nah not at all it's common as muck with Just about every BOB worth it's salt having opto's has will any decent drives and there'll be few machines that don't run with both.!

    Unfortuantlly it's more a sign of poor drive or BOB with slow opto's.!!

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  5. #114
    If every bit and bob and driver has opto isolation why not cut out the middle man and have a fibre optic connection ? I'll bet there are some machines with bespoke electronics that do it.

  6. #115
    Quote Originally Posted by cropwell View Post
    If every bit and bob and driver has opto isolation why not cut out the middle man and have a fibre optic connection ? I'll bet there are some machines with bespoke electronics that do it.
    Probably purely a cost issue, this stuff is not really found on the high-end machines, I have no doubt those ones would have fibre where needed.

    :)

  7. #116
    Ok, we have action

    Mixed bag of results, sort of exciting and disappointing all at the same time.

    The good parts...
    It works, speed is no issue,
    The ripple effect in my cuts has disappeared,
    It does not shake and wobble all over the place,

    The bad parts...
    The voltage is still way off of book specs, no change,
    Can't get a clean cut on aluminium yet,
    Need to work on divots,

    Here we go...
    Pierce & Cut heights are all as per book and this was checked several times by stopping mid cut and measuring the gap.

    35mm washer, 45A 107v, 4000mm/min. Nasty divot as no cut rules yet just perpendicular lead in and no lead out.



    Add a 2mm overburn and turn torch off 2mm before end - divots now pretty good.



    Same speed, acceleration as listed, small shape again - 35mm sq. Same 2mm overburn etc but divot is terrible again????? There is a marked improvement between the 1st and 2nd cuts but little change between 2nd and 3rd so i set the acceleration at 1500mm/s/s. I can improve the internal corners a bit by setting Mach to stop CV on angles > 89 degrees but don't know if that is a good idea or not??/



    3mm aluminium - 6400mm/min 45A 106v, lots of top dross, tried slower but made little difference. Had better cuts on old machine



    1.2mm stainless is not too bad, 7900mm/min 45A or 4800mm/min 30A 109v

    10mm steel, 0.9s delay, 117v, 500mm/min 45A.

    Had one nozzle blow out completely, was getting poor cuts and found the orifice practically missing, no idea how that happened at all, as i'm testing I have been very careful of wrong pierce heights etc.

    So, as i said, a mixed bag really. The divots are concerning, I need to get that bit nailed as well as the aluminium.

    If anyone wants to chime in with some useful settings, please do. Is there a group test file that those with some spare minutes could cut for comparison???

  8. #117
    Swing-out keyboard, seems to work ok...






    Big success, thanks to a member on another forum for his settings on the 3mmAluminium...


    Pretty clean I think.



    1.2mm Stainless, not too impressed yet, might have to get some 30A consumables and try that out, not sure I can cut my stuff unless I can get this better.





    Now, the last major issue - that damn unequal bevel, here is a bit of 3mm steel with a 3mm slot, these parts need to slot together. You can see one side is good the other is bad, this aligns with the Y axis.



    Heres some more, 3mm again, placed on table as in picture. I have marked the angled edges.



    Now, I could fudge this by leaning the torch over to compensate but that is a bodge and will only ever get me two bevelled edges. So, what can do this, the consumables are new and today I have checked the condition of them between every cut after yesterdays blow-out. Overall the cut quality is impressive - the new machine is smooth and this is reflected in the cuts but this problem migrated from the old machine so must be torch related?????

    Also, I can improve internal corners by switching "Stop CV on Angles >89" on in mach3 settings BUT this then gives me a jerk at the start of every arc and radius cut, I think this can be seen in one of the pictures above. So I can't run that setting as a default and as very few jobs are fully square, its practically pointless. Can Exact-Stop be triggered from Sheetcam??? Is it really this difficult?? What do you guys do for sharp internals???

    SO many settings and tweaks, doing my head in. I think I can crack the divot problem, a lead-out plus torch off before end of cut seems to be reasonable but I can tune this over time.

    This bevel issue is bad though I think.

  9. #118
    Yesterdays little fun test...



    3mm Stainless, 108v, 45A, 3800mm/min, pretty clean...
    The bottom 4 lines are on the new table, the top mess is the result i had on the old table which made me build the new one!!!



    Test shape, old m/c vs new m/c...
    I know the slot is buggered - this was because i used the test file for mild steel and forgot to tweak the settings on the slot part first


    You can at least see the waste in the slot, that a 3mm slot and the waste is about 1mm.



    So, not too bad today, also been messing with divots, internal holes. Tried a 5mm overburn with the torch off 1mm before the end, so the end of the cut is 6mm from torch off and you can still see a mark. Will keep messing with that one but at least she's up and running again.

    I have twisted the torch mount to correct the odd bevel or at least balance it out, I'm leaving the torch at the current angle - it's working so until i find a reason, i'll live with it
    I



  10. #119
    30A consumables arrived today, gave them a spin on 1.2mm 304 stainless and got excellent results As good as the finecuts on the 30XP were at least.

    Both pics as they came off the table...

    Top...



    Bottom...



    Voltage was low as normal it seems, 76v instead of book 98v but speed was bang on at 4000mm/min, pierce height 2.5mm, cut height 0.5mm. Still need to dial the THC in as its a bit unstable on thin stuff but at least it works and the table is now producing paying work.

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