Author Topic: Increase spot definition/clairlity  (Read 3808 times)

Mogal

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Increase spot definition/clairlity
« on: November 27, 2019, 03:20:07 PM »
Hello all,
I have an Elekslaser A3 Pro 2.5watt.
I've had it for a couple years now, but really, never used it.
Due mostly because of the spot definition/clarity.

Is there anything I can do to help define the spot clarity?
New lens or something?

I'm actually considering a higher powered diode. maybe the 5.5/7 watt diode.

Any help would be appreciated!
Attached is a pic of the spot produced.

Thanks!

pascalp

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Re: Increase spot definition/clairlity
« Reply #1 on: November 27, 2019, 04:08:03 PM »
Keep in mind that the spot isn't a circle, most of the time it's a rectangle and generally is size increase with the power of the diode.
With a 5.5-7W you may (or not) get a bigger spot of the same shape.


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Zax

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Re: Increase spot definition/clairlity
« Reply #2 on: November 27, 2019, 05:32:49 PM »
That's unusual for a 2.5W, they are usually pretty round. The higher power diodes are often rectangular.

Optics to correct this would be expensive so the best you can do is focus it small (so it appears more round).

The EleksMaker 1.6 and 2.5W lasers are usually round from my experience but of course that's only a sample size of 3 (2 x 2.5 and 1 x 1.6).  I have a 2W and a 12W (joke, it's more like 3W) and they are terrible so I only use the EleksMaker brand.

Hokuro

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Re: Increase spot definition/clairlity
« Reply #3 on: November 28, 2019, 12:10:33 PM »
have you tried disassembling the lens and cleaning both the laser diode and the lens?
my english is very bad, please be patient. :)

Mogal

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Re: Increase spot definition/clairlity
« Reply #4 on: November 28, 2019, 12:52:16 PM »
Thanks for the info. I have not taken it apart yet, but I will.
Currently 3d printing out some upgrade parts for it.

In the meantime, I'm learning about the focal points/distances wave lengths ect...
Also bought a carbon filter that will hopefully cut down on the smoke/fumes!
Also designing an air nozzle to help blow the smoke out of the way.

Did I just get unlucky with the spot clarity? I would really like to have a better defined spot.
So I think my options are either a new lens, or new laser?
- If I get anew laser, I'd like something a little more powerful.
- Looking to get through 1/8" ply would be great.
- I have Zax's T2 Laser software. (any way to change the steps per mm? considering putting on 16 tooth in lue of the 20 tooth gears)
- Is there not an option to change out the lens to change the focal distance? and hence the size of the spot? (pros/cons?)

ggallant571

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Re: Increase spot definition/clairlity
« Reply #5 on: November 28, 2019, 06:10:27 PM »
Cutting 1/8 ply with a 2.5W diode laser in one pass is just a dream with the current state of optics. First the glues and the char like to form a rock solid mass. Second the beam is wider on both sides of the focus point meaning you need spend energy  burning the walls. Perhaps we will get laser/optics with a much narrower beam.

As for getting T2 to work with different drive mechanism, that exits in the existing GRBL parameters and yes there are lenses with different focal points.
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Zax

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Re: Increase spot definition/clairlity
« Reply #6 on: November 29, 2019, 05:24:11 AM »
I have Zax's T2 Laser software. (any way to change the steps per mm? considering putting on 16 tooth in lue of the 20 tooth gears)

There's a calibration menu built in T2Laser which will do this for you very simply.


Mogal

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Re: Increase spot definition/clairlity
« Reply #7 on: November 29, 2019, 10:07:08 AM »
Thanx Zax, I'll look into that a little more. Is it worth doing? (going from 20 tooth to 16 tooth?)

I've discovered the laser power goes from 0-1000 NOT 0-255. NICE! But still can't quite get through 1/16" ply.
Pics of my test piece and setup. (The red pieces are the new 3D printed parts from yesterday)

P.S. For some reason I can not download -anything- from this site. I get a network error?!

Zax

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Re: Increase spot definition/clairlity
« Reply #8 on: November 29, 2019, 11:20:11 AM »
I don't see any benefit going from 20 to 16T.

The laser power is based on Grbl spindle max setting, but the output from the Nano is 8-bit so 0-255.

T2Laser firmware and default settings use laser power is 0-255 so you have a direct 1:1 conversion, if you set $30 to 1000 then Grbl must down scale the laser power to the 8-bit output which can cause banding as several power settings are actually the same and rounding errors occur.

You aren't getting any more power or precision, just potential problems.


ggallant571

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Re: Increase spot definition/clairlity
« Reply #9 on: November 29, 2019, 11:49:54 AM »
I think the underlying hardware register in the CPU chip is actually 10-bits wide. Was easy for GRBL to scale 256 to 1024 with a simple shift operation. For my host application, I scale all my colors to one of 32 shades of grey prior to emitting the GCODE. The laser can't distinguish and it reduces the workload on the poor Nano!!!
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Zax

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Re: Increase spot definition/clairlity
« Reply #10 on: November 29, 2019, 12:09:33 PM »
That's incorrect, the ATmega328p has 8-bit PWM. My point is that using 1000 as some do for the laser max requires down scaling and induces rounding errors and possible banding. Images are also typically 8-bit based grey scale which translates to the output so using 1000 makes no sense.

Mogal

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Re: Increase spot definition/clairlity
« Reply #11 on: November 29, 2019, 04:52:50 PM »
Uhm, I'm all confused now. I just don't know enough about these little boards yet.

When I set the laser to 255, I can barely (ie: NOT) cut through corrugated cardboard at two passes and 100mm/min.
After reading some forums about the scale of power (ie: 0-255 vs 0-1000) I decided to try the 1000, and the
laser was WAY brighter, cut through the cardboard easily(one pass) and scored the CNC bed pretty good.

Is it over driving the laser setting it 1000? Is it doing any damage, lessening the laser life?
I am not able to cut through 1/16" plywood at 255, but at 1000, it (mostly) does. Just have to lightly break it free.

firmware is 1.1e, I believe its the EleksMana SE board - I flashed this firmware  roughly 2 years ago.

ggallant571

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Re: Increase spot definition/clairlity
« Reply #12 on: November 29, 2019, 07:56:15 PM »
Please dump and post your grbl parameters. I find the easiest way is to use a terminal emulator such as teraterm. You can also issue primitive gcode commands from there for specific testing
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ggallant571

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Re: Increase spot definition/clairlity
« Reply #13 on: November 29, 2019, 09:03:44 PM »
Zax is 100% correct about the PWM being 8 bits for the laser connected on D11 which uses Timer 2. I've lately been doing 10-bit PWM using the 16-bit timers on a mega2560 and made the bad assumption that all timers are created equal.
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Zax

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Re: Increase spot definition/clairlity
« Reply #14 on: November 30, 2019, 05:44:27 AM »
In T2Laser, click Display Grbl Parameters in the Machine menu. It is easier to enable debug mode first so you can see the full list without scrolling, the max value is $30. If your $30=1000 then you've changed the default parameters, probably from running another program that updated your Grbl without asking. T2Laser never changes values unless you select it in the menu.