Fill and Line do not match

Hi,

Please help. I am using a 50w ruida laser blue and white machine. All axis are calibrated and I created a 10x10mm square. Min and max power are set to 15%, speed to 400mm/s.

All I do is set the layer to line, sqare is sqared and 10x10.
If I set the same layer to fill at 0° scan angle, height is ok, width is too small.
If I set the scan agle to 90° width is ok but height is to small.
Using offset fill, it is sqared but it burns all the way through at the same 15% power setting. See attached files.
No offsets are used anywhere.

What can I do?

Best regards,
Wolfgang.

20230107_174848

This looks like the common skewed engraving problem sometimes seen with Ruida machines.

Take a look here:
Configuring A Ruida - LightBurn Software Documentation

Went through that whole section and tried all recommended settings, yesterday. Did not change a thing. Does not look like skewed or shifted to one direction. Looks more like it starts marking too late and stops too early for some reason.

Did this just start happening or is it a new machine?


Somethings occurring in the X direction, when you scan at 90 deg, it follows the software. I would think this would be a Ruida issue, but they’ve fooled me before.


Can you post the X and Y screenshot settings from your Ruida configuration. Just for us to look at…

Have you tried a fill with something like a right triangle… wondering if that would tell us something…

A 10mm square is pretty small to achieve 400mm/s. It has to slow, stop, change directions and speed back up… it would depend on how much mass/acceleration the machine has.

Setting both minimum and maximum power to 15% you have taken speed/power control away from the Ruida for corners and such… You want a maximum that burns correctly at speed and a minimum that burns correctly at slow speeds. This is why your corners are burnt.


I assume this is 3mm basswood… looks familiar…

I engrave at 125mm/s @ 13% power. You are running much faster with an very slight increase in power with much more damage to the material… What kind of mA reading are you getting with your settings?

:smile_cat:

I’ve seen this where it’s not necessary skewed but just shows as being unaligned to the cut. If you made changes with no effect than perhaps not it.

Settings attached. Also tried the triangles (Line and Fill with Line at 0 and 90° scan angle).
Laser starts at 13°power. If I go lower, there is no marking…
I am not too concerned about the burned edges. This I can certainly fix. I am more
concerned that the fill is not matching the lines.
Also attached my machine settings. Only did the scan offest correction for 100 and 400 so far.
-0.75 and -1.24 looks a lot to me, or is this normal?
Ordered an amp meter, yesterday. Should arrive today. As soon as it is connected, I can
provide power readings…

Just tried doing it slower with 100mm/s. The fill is getting closer to the outline, but still not 100%. Going that slow, the fill burns 1mm deep, already…

Bought this machine on Ebay. Used, but only 3 hours on the laser. Looks like
the previous owner had similar problems…







What do things look like with no offset correction at all?

Tested with 50x5mm rectangle, cut is correct!
If I remove the backlash correction I have a 2,5mm offset between the scan lines.
Measuring the total distance 50mm is correct. After -1.25mm correction, scan lines align perfect, but 1,25mm are missing on both sides.

Is the top line in your diagram burning from left to right or from right to left?

For clarity, you’re not trying to use this for mechanical backlash correction are you? I don’t see evidence of backlash in your other cuts but would like to confirm. Offset scanning is more about delay in on/off than mechanical backlash.

Here without correction at 400mm/s in machine data 10x10mm

There is not much difference how my line test will look like, at 400mm/s, the speed just doesn’t match the distance.
Regarding the square, with my 60Watt machine I will run it with 13-14% max and 8.5-9.5% min power with 200mm/s for BB-plywood.

I do not understand why the heavy Y axis would produce perfect results at high speeds, even if the whole machine is shaking and the featherweight X is not working the way I expect it to work…

Perhaps the Y axis has a reasonable acceleration value allowing it to come to rest at the proper position without vibration, while the X axis has an absurdly high acceleration shaking that axis.

The “correct” settings for acceleration and speed must derive from experimentation and measurement, rather than assumptions about what seems reasonable.

My rule of thumb: do not assume the default values are either reasonable or practical.

His X axes is at 12,000mm/s^2 and the Y is 5,000mm/s^2… Seems not to match the maximum speed for X of 800mm/s… I’d expect it to be quicker with that kind of acceleration possible.


My machine came with Y set to 4,000mm/s^2 and X at 6,000mm/s^2 in the Ruida configuration … I could increase X to about 8,000mm/s^2 but there was too much mass on the Y axes to push it any further.

Mine X axes is set to around 45,000mm/s^2. I would think he could hear the results of the acceleration being too high… I know I can … my maximum speed is set to 1750mm/s… I know I can run at least 1650mm/s … great fun… not very productive


Maybe these are an issue, although I know my acceleration values are ok and I can still see the aberation in my output.

@ednisley do you know what you acceleration values were set when you got your machine…?

:smile_cat:

The oldest backup says:

  • X - 500 mm/s @ 10000 mm/s²
  • Y - 300 mm/s @ 3000 mm/s²

Limiting the Y speed keeps it a bit under the claimed 600 mm/s. I vaguely recall 700 mm/s listed when I bought it, but, hey, who ever checks what they got against what they bought?

You have the hotrod lightweight head that can accelerate harder. I keep meaning to push this one until it squeaks, but that’s way far down on the to-do list right now. :grin:

Suffice it to say it doesn’t really accelerate, it just sort of gradually gains momentum …

It really doesn’t hurt it… it’s just the fields moving faster than the motor can. I’m sure if it sat for long periods it wouldn’t be great.

It makes a terrible noise but adds to your knowledge of how these work… and it’s also great fun hint, hing, nudge, nudge…

If X is limited to 500mm/s that would keep it under 600mm/s by itself, wouldn’t it …?

:smile_cat:

May I ask you what type of tasks you run with up to 5-700/s?, and how far is the overrun approx.?

The blue flamingo tile I posted was 500mm/s…

Generally I run in the 200 to 500mm/s for most items… I can’t go slow enough to not ‘toast’ the lbt100 off the tile, so I run about it 500mm/s.

I shouldn’t work at some of these higher speeds with a dpi of 254, but it does, so I don’t really know what it’s doing…

Sometimes I feel it’s like Oak Island … think you figured out one answer, but realize there are now 5 more questions… :frowning:

:smile_cat:

Thanks for the reply Jack, this is an area I know absolutely nothing about.
My original nozzle is so heavy that I can feel how the machine vibrates at speeds of around 300mm/s and I don’t like that. I mainly use the machine for cutting, here it is the material that sets the speed limiter.
I know you have a nozzle holder from Russ and that also made sense to me now that I know what you use the speed for.

Well, Pythogoras sez with X at 500 mm/s, it would hit 600 mm/s on the diagonal if Y ran at 330 mm/s. I admit to being mildly astonished to realize marketers know Pythagoras, but maybe one of the engineering bears clued them in (and, I hope, now regrets it).