Thread: It's begun....

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  1. #41
    Thanks for the speedy reply Jonathan,

    Should I also disconnect the earth lead from the bed to my star point? I figure if I earth the spindle and the bed to different points I may get a loop (my mounts and pretty much everything else are metal, although the bearing blocks may not be so good at continuity). This earthing thing is a little confusing and I'm allergic to large currents ;-)

  2. #42
    Quick update and firstly thanks to all those on here who have helped me out, both on PM and in my Build Log.

    I have just successfully completed a couple of sprial drilling operations into some ali extrusion and ye gods it feels good. Holes look to be nice and circular and in the right place and the inside finish on them is excellent. I used GWizard to give me some feeds and speeds and so far the machine is withstanding the forces, so again thanks to those who helped me turn my original design into something stronger.

    Time for some celebrationary dinner and then contemplate which part I should have a go at making, out of the pile of CAD I have been building up over the last few months.

    BTW - I may have missed it but is there a way of jogging in Mach3 to a specified distance on an axis other than writing GCode for it?

    Cheers


    Chris

  3. #43
    Ideally you shouldn't rely on the linear bearings to provide the current path to earth, so earth both.

    You can jog a specified distance by using the MDI tab and typing the Gcode commant, which is easy enough since you can see the co-ordinates the machine is at, so just type G0 Xsomething Ysomething etc to move to where you want. You can also set jogging to moving set distances instead of continuously, so for instance every time a jog key is pressed the axis moves 1mm (or whatever you set).
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  4. #44
    Thanks Jonathan,

    Reason for the question is I am zeroing by jogging up to the work piece on each side and setting that axis to zero and wanted to jog by 2.5mm afterwards in x/y to take account of my 5mm end mill, but I guess I should be using the tool offset for this.

    I have also seen people using lasers (collet mounted and offset mounted) and web cams (with cross hairs) for zeroing and of course the more "pro" ruby tipped probes - any idea who might sell the probes and/or lasers? I have the aspiration to try probe scanning at some point as well, so the latter might suit me more than the laser technique.

    Gotta love being on the learning curve.....its half the fun.


    Chris

  5. #45
    Do your self a favor and go buy Gerry's screen set here: The CNC Woodworker - Mach3 2010
    Then make a simple touch probe plate from single sided PCB. Connect to a spare input and set the probe Input inside Mach to look at it.
    Then enter the thickness of the PCB into the screen set and it will take care of everything else.
    It will save you hours of time just with setting the Z height alone never mind all the other built in probe routines which will find corners, edges, circle centres, parallel edges best 15 you'll ever spend.!!

    Oh and it has MDI on every screen which is priceless if like me you use it a lot.!!
    Last edited by JAZZCNC; 04-12-2012 at 02:39 AM. Reason: Mmmm

  6. #46
    Perfect - thanks for that - more like Excel/Word rather than Lotus123/Wordperfect :-)

    Chris

  7. #47
    Quote Originally Posted by Washout View Post
    Reason for the question is I am zeroing by jogging up to the work piece on each side and setting that axis to zero and wanted to jog by 2.5mm afterwards in x/y to take account of my 5mm end mill,
    After zeroing you can go on to MDI, raise the tool up obviously, type G0 X2.5 Y2.5 and zero the axes again. Assuming you zeroed both in the positive direction, the machine is now zeroed. You will probably often want to add a little bit, (G0 X3 Y3) to make sure any cutout pass does make a cut all the way round and not just miss the edge.
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  8. The Following User Says Thank You to Jonathan For This Useful Post:


  9. #48
    Quote Originally Posted by Jonathan View Post
    After zeroing you can go on to MDI, raise the tool up obviously, type G0 X2.5 Y2.5 and zero the axes again. Assuming you zeroed both in the positive direction, the machine is now zeroed.
    Even easier way than that if your using the default 1024 screen set. First set the Safe Z in Config (which you really should do for safety reasons regardless) and make sure it works in Work coordinates.
    Then all you have to do is type the offset (-2.5 in your case) direct into the X,Y DRO by clicking on each DRO (Must press Enter to apply it) then simply clicking GOTO ZERO button just below DRO's.
    You will still need to have the Z axis Zero set equal to the top or above material. The Z axis will retract first to Machine Zero coords because of SAFE Z then move the X,Y axis then return Z axis to Zero work coords.

  10. The Following User Says Thank You to JAZZCNC For This Useful Post:


  11. #49
    Thanks for that,

    The new interface is much cleaner and I especially like the new jog tab rather than the old one hiding most of the DROs.

    I've now had the machine cut the holes to attach its bed extrusions to the frame and it did that really well apart from on mishap where for some reason the mchine decided it was going to rapid and ramp to the first drilling spot. It made a nice gouge in the extrusion before I realised what was happening and hit my e-stop (which worked perfectly). I didn't snap the tool which is a blessing and I guess the 5mm carbide end mill went into the material by about 4mm before I caught it. A quick reset and zero and all was well , so not quite sure what happened as it had just cut the countbores on a seperate G-Code job before hand.

    Anyway after resetting and cutting a bunch of holes to finish the bed without mishap, I have just "air cut" my first 3D part and it seemed to work OK. I do have another question though:

    I'm using GWizard to help with feeds and speeds and for the drilling operations and counterbores the 18,000rpm, 750mm/min feed and 515 plunge rate GWizard suggested seemed to work really well. For the 3D roughing operation I'm about to try I'm using an 8mm Carbide End mill (3flute) and it is suggesting 13,000rpm, 2,000 mm/min and 750 plunge - does this sound right guys, as it seems to be very aggressive?

    If there is ever a UK CNC meet up, I am going to owe you guys a small brewery.....

    Cheers


    Chris

  12. #50
    Quote Originally Posted by Washout View Post
    Anyway after resetting and cutting a bunch of holes to finish the bed without mishap, I have just "air cut" my first 3D part and it seemed to work OK. I do have another question though:

    I'm using GWizard to help with feeds and speeds and for the drilling operations and counterbores the 18,000rpm, 750mm/min feed and 515 plunge rate GWizard suggested seemed to work really well. For the 3D roughing operation I'm about to try I'm using an 8mm Carbide End mill (3flute) and it is suggesting 13,000rpm, 2,000 mm/min and 750 plunge - does this sound right guys, as it seems to be very aggressive?
    Can't answer really without knowing material, DOC.

    Warning thou regards G-wizzard.? The calcs are based on using a milling machine which is much stronger than what you'll probably be using so I'd always knock a bit off to account for this.! How much mostly depends on your machine but 25% would be a good safe start.

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