Messages

91

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 18, 2016, 07:24:30 AM »

Dan:

   Laser machining uses the same concepts as normal CNC. I consider the focal point to be a small
ball endmill of .1mm id diameter. Like nay endmill, if you go too slow you burn, at the right speed you dont.

 This photo shown was with a 10 watt laser, run fast, and many passes (. the photo is how it came of the table,
no cleaning was necessary.. so long as the speed is right, it doesnt burn.

Art

92

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 17, 2016, 04:21:19 PM »

I leave you with a final test image in teak,

 40mm x 40mm , 475inches/min

Art

93

Mach4 General Discussion / Re: Mach4 Printer Port Discussions

« on: April 17, 2016, 12:32:19 PM »

Eddie:

  Sorry to hear its turned out to be a hassle. It should scale pretty linear between the two ( min and max) and as the last letter showed, his machine did that
fine, but it cannot do any closed loop operations. (though I understand the edict of "If it aint broke.."..

Art

94

Mach4 General Discussion / Re: Mach4 Printer Port Discussions

« on: April 16, 2016, 11:28:47 PM »

Hi:

  Sorry, but I dont have much expertise in using Mach4, but others int eh forum under general Mach4 use may be able to help..
I am not part of Mach4's development, so dont have any knowledge of the various variables and such.

Art

95

Mach4 General Discussion / Re: Mach4 Printer Port Discussions

« on: April 16, 2016, 10:22:25 PM »

>>If I understand correctly Mach4 sends a axis homing command and Darwin which completes the task on it's own. I read and see the driver applies the homing offset that is setup in Mach4 homing configuration page. Then which is responsible for completing the homing move by moving to the zero point? Unless I'm missing something at this point I don't think either side (Mach4 or Darwin) is excepting the final move as it's responsibility but, someone needs to work out the final move and incorporate. I have a script and button at this point to use.

   Neither side accepts responsibility for the final move, you need to press GotoZero after the home offset is applied.  This was the spec when Darwin was designed.

>>Next is along the same thing is with the spindle speed being reported to Mach4 and keeping track of the actual rotation speed. I use the Super-PID with PWM input and Indexed spindle output. I have the input PWM speed control working fine. I have the index pulse returning to Mach4 as seen on the diagnostic tab. The Mach4 manual hints to the fact the index input is used for monitoring the speed but I have not found where it actually uses it as feed back to compare the the requested speed. So once again unless I missing something which side is responsible of the task to complete the feedback loop for a closed loop system?

  Darwin isn't capable of any operations in terms of closed loop. It would of course respond if told to change the speed by a script or other module that
does do closed loop calculations, but its out of Darwin's scope to do anything other than supply the PWM signal to run the spindle as a linear
function of the min/max setup in Mach. Its the only calibration possible for Darwin.

Thx
Art

96

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 13, 2016, 02:02:29 PM »

Heres one at 12,000.



Art

97

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 13, 2016, 07:14:39 AM »

>>Mike, how can you possibly live without a laser ?   Grin


 How can anyone? lol

Art

98

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 13, 2016, 07:13:46 AM »

>>The 8000 mm/min is particularly impressive, that's galvo performanc

  , actually, I slowed it down for 3d, my photos are now done at up to 25000 mm/min.

Art

99

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 13, 2016, 07:12:00 AM »

Tweakie:

  >>Are you using a variable PWM (linked to axis speed) to provide the Acceleration

  The PWM is controlled on a 1ms waypoint basis. So each time I sent waypoint data, I also
send a PWM for that ms. The program looks into a database for each location to get its power
point for that ms ( an image in this case), and then scales that power by a formula based on
feedrate and euclidian distance of the upcoming ms's motion. So for example, if an F8000 is in effect,
 and 50% laser power is selected, the program calc's the energy per mm going out, and maxes at 50% when we
hit 8000/ 60000 = .13mm's per ms. So all power is then scaled from 0 - .13mm/sec with .13 being
50% power output, this is recalcuated each ms.
   All that fixes very well accel and decel and keeps power very smooth here for the most part,
but I intend now to add a quadratic correction formula to the power curve to smooth it more
to take into account nonlinearity of a particular laser.
    I know Ill never make it perfect, but Im of the feeling the more calibrations you have, the better
it "should" get. Its not a bad initial testing for only a 10 watt engraver.. Thats 2mm deep, Im
aiming for 19.  , doing multipass should let me get results more similar to a 100 watt..just slower.

Art

   

100

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 12, 2016, 12:01:32 PM »

ohh, thats with a 14 watt laser output at 8000mm/min, using distance step correction for acceleration and deceleration correction.

Art