Unable to get picture to engrave correctly

LightBurn Software Questions
1

I have an Eleksmaker A3 Pro with 2.5 watt diode laser. Running GRBL .9.
I feel I have my settings correct as the preview looks good but the results are just burn marks. I have attached all my settings, preview and results below. Thanks for any help given. Chris

$0=10 (step pulse, usec)
$1=25 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=1 (dir port invert mask:00000001)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=0 (status report mask:00000000)
$11=0.010 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=0 (hard limits, bool)
$22=0 (homing cycle, bool)
$23=0 (homing dir invert mask:00000000)
$24=25.000 (homing feed, mm/min)
$25=500.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=1.000 (homing pull-off, mm)
$100=80.000 (x, step/mm)
$101=80.000 (y, step/mm)
$102=80.000 (z, step/mm)
$110=2000.000 (x max rate, mm/min)
$111=2000.000 (y max rate, mm/min)
$112=5000.000 (z max rate, mm/min)
$120=1000.000 (x accel, mm/sec^2)
$121=1000.000 (y accel, mm/sec^2)
$122=200.000 (z accel, mm/sec^2)
$130=381.000 (x max travel, mm)
$131=330.000 (y max travel, mm)
$132=5000.000 (z max travel, mm)

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2

Set the Power Scale back to 100%, set your Min Power to 1%, and lower the DPI to 250. Your maximum speed is pretty low, and with a very high DPI like that you’re putting a lot of power down in a very small area. You might also be out of focus, but it’s hard to tell from the pictures shown here. If you’re trying to make something small, you could go higher with the DPI but lower the Max Power down to about 50% and try that.

3

Thanks. Are you talking about changing $110 & $111 rate to a higher threshold like 6000 and then change cutting speeds to match or at least higher that 2000?

4

I was suggesting that you lower the power to compensate for the relatively low speed, but increasing the limits and the speed could help as well, assuming the machine can go that fast.

5

OK. I will lower power scale to 50% and also raise my limits and then play with speed. The image is about 4 inches for testing but I want to get an 6 inch for final.

6

Leave power scale at 100% and just set the Max Power to 50 - simpler that way, and then you don’t have to remember to change it for every image.

7

Done. Trying test now.

8

So, when i either do a fill or image, my max speed is only 500mm/min. When I do a line, I can get much faster. Is there another setting I need to change in GRBL? It looks like my DPI selection is driving how fast my max speed is. I just changed to 100dpi and it moves much faster but that does not really help me. I can try a bigger picture with 250DPI and see if that works.

9

Welcome to 8 bit processors. :slight_smile:

Higher DPI means more GCode instructions, and an 8-bit / 16MHz chip simply can’t process them very fast. Vector scans are just a couple GCode instructions for each line, but grayscale or dithering can require an instruction for each pixel. 254 DPI means 1 pixel every 0.1mm. At 100mm/sec (6000mm/minute) that’s 1000 GCode instructions to be processed per second, and an 8 bit board running GRBL can probably manage about half that, maybe less.

10

Good times! You recommend a better board? It is an Eleksmaker SE v3.2. I plan to also get the CO2 K40 soon so I may just wait to upgrade that one and keep this stock.

11

The diode itself is ultimately going to limit how fast you can go, so you’re likely better off to wait. A Smoothieboard running GRBL-LPC is a good option - not too expensive, and will run very fast.

12

like this: https://usa.banggood.com/BIGTREETECH-SKR-V1_3-Control-Board-32-Bit-ARM-CPU-32bit-Mainboard-Smoothieboard-For-3D-Printer-Parts-Reprap-p-1476462.html?rmmds=search&cur_warehouse=CN

Or this: https://www.amazon.com/KINGPRINT-Smoothieware-Controller-Board-Printer/dp/B07LG1BKCB/ref=asc_df_B07LG1BKCB/?tag=hyprod-20&linkCode=df0&hvadid=312188620282&hvpos=1o3&hvnetw=g&hvrand=11075930967840894845&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9010792&hvtargid=pla-624331960719&psc=1&tag=&ref=&adgrpid=61740030226&hvpone=&hvptwo=&hvadid=312188620282&hvpos=1o3&hvnetw=g&hvrand=11075930967840894845&hvqmt=&hvdev=c&h
vdvcmdl=&hvlocint=&hvlocphy=9010792&hvtargid=pla-624331960719

you would need stepper motor drivers: https://www.amazon.com/KINGPRINT-DRV8825-Stepper-Driver-Printer/dp/B075XH1TSJ/ref=pd_bxgy_3/138-8597897-0150307?_encoding=UTF8&pd_rd_i=B075XH1TSJ&pd_rd_r=608e2263-f4e9-4c46-b5e6-541603ed3475&pd_rd_w=rIxgs&pd_rd_wg=aG0gd&pf_rd_p=a2006322-0bc0-4db9-a08e-d168c18ce6f0&pf_rd_r=M81YSFR0YPVTNY7G3N8N&psc=1&refRID=M81YSFR0YPVTNY7G3N8N

13

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