Jeff and John have been tuning me up quite a bit. But there is still quite a bit of work to get it dialed in.
Eleksmaker A3 Pro with 2.5W laser module
Mana SE controller with PWM output
Added pulldown resistor on PWM output to eliminate firing during startup
TMC2130 upgraded drivers voltage set to 0.8V X and 1.6V for Y (still experimenting)
Fan for cooling controller
Upgraded optics (3 element AR coated lens at 3" focus (per Jeff's suggestions)
$30=255 Max spindle speed, RPM (255)
$31=0 Min spindle speed, RPM (0)
$32=1 Laser mode, boolean (1)
$120=500.000 X Acceleration, mm/sec^2 (800.000)
$121=500.000 Y Acceleration, mm/sec^2 (800.000)
Steps/mm is 80.00, will change to 40.00 when using 8 microsteps (later)
To Do: Homing/Limit switches, Upgraded Gates belts
Currently I've loosened the belts to debug the canvasing effect.
The motors may be a little weak, as I think detents of the steppers are overcoming the holding force of the steppers.
I'm using PEP6 with Analog PWM, and 25% frame rate change and extended frame of 25 pixels. The material I'm testing with is scrap MDF from Home Depot that was in a shopping cart on its way to the dumpster when I asked how much and the guys generously said "Take it". The material is a very light material that burns very clean (not a lot of variation) and is perfect for testing. For this material I'm using 2800mm/min and 0.1mm pixel resolution on a 45Deg angle.
Focus, Focus, Focus
With the upgraded optics installed it took quite some time to find the focal point. I used a piece of black anodized al to prevent scattering and then found when the dot went from big to small. I was only able to get about a thread in, so I used gas pipe teflon to help it stay stable as regular teflon was too thin and it would just wiggle around. Then once I got it close by eye, I used a test burn to find the exact point (I guess I used 1/8 turn increments or less).
Flatness, Flatness, Flatness
I guess the focus depth of the lens is narrow because I needed a really flat stage. I got a table which was an old smog machine based and a scrap piece of marble from Habitat for Humanity both for $20. I still have one corner which is definitely off a little, which I'll be fixing today. I found I need to do test burns in each corner.
Still fighting backlash- new gates belts are on order. Under Special options there is Align X and Align Y that Jeff pointed me to that can do the job for sure, but I'm still messing with my belts, so I figured I concede some run time until I get a stable setup. To do so, I wrote a python program to only engrave in 1 direction and it would do a rapid movement of 5000mm/min to efficiently get back to the start point (reduce run time from 2x to 1.4x or so) as I felt it would take some time to tune in the backlash settings.
- Eleksmaker A3 Pro with 4.7k pulldown Resistor
- PulldownResistor_HDR_Small.jpg (335.2 KiB) Viewed 4167 times
- Machine Stand
- MachineStand_HDR_Small.jpg (334.15 KiB) Viewed 4167 times