I am aware that the “PWM Rising Edge Valid” option is in ruida controller. My question would be what’s the equivalent option in this particular settings panel or this particular controller?
here’s a test i did last night. I did the same engraving with only difference being the order in witch the layers were engraved (first outline then fill or fist fill then outline) to se how it affected the results.
The results were basically the same in both cases. The observation that makes me believe that it is that particular problem is how the external line is misaligned as it travels but when it returns to the initial point it aligns again with the fill layer. This observation is consistent with all my tests. Another observations:
- large engravings lead to more pronounced misalignment.
- the stretching of the misaligned layer is always in the same axis and only that axis.
- changes in the acceleration and velocity values do not solve the problem.
Messi.lbrn2 (288.1 KB)
Ok, I can look at it.
1st thing - why two different layers for fill and line? Add the line layer the fill layer like this…
Try running the job like that - and tell us how it goes.
ok - now I see what you are trying to do - my suggestion outlines the individual shapes and does not give the whole out line of the project. THis is what my preview looks like
Let me do a quick burn on my Ortur laser and see what comes out.
Ok - my burn turned out with no problem. What does your preview screen look like? Does the problem show on the preview?
I am out of ideas - sorry.
i have already tried it before and its the exact same result. The misalignment also occurs in layers with multiple pases (each pass gets more stretched)
no, the problem does not show in the preview. everything seems perfect in the software side of things. I strongly belive this is the problem detailed in the resource How do I fix skewed or slanted engraving? but the option that solves it is not present in my settings due to my engraver using other controller. But there must be an option analogous to the Ruida “PWM Rising Edge Valid” option in grbl, right? thats what im looking for since thats where i think the problem resides based on many other posts of people with similar problems (all solved by the same Ruida “PWM Rising Edge Valid” option)
The Ruida option flips the polarity of the STEP pulse going to the motor driver
You can do the same thing in GRBL by setting or clearing the appropriate bit in the $2 parameter:
I thought this was a hardware configuration?
Iinternally setup for your hardware board.
I’d like to think the stock firmware that came with a stock Creality would be correctly configured for the stock hardware, but at this point I’m willing to believe anything can happen right out of the box.
No harm in trying … as long as you remember which way it was when you started. 
okay so, as seen in the picture of my machine settings panel, the $2 options for each axis can be turn on and off. i cant set any values. There are 4 $2 options, one for each axis and another one for an A axis which i dont have any idea what it is. I did 4 tests, one with each individual $2 set true and a final one with all of them set true. (ignoring the Z axis options for obvious reasons)
So… not the most charming results i must say.
the results with the “A step pin invert” were no different so i didn’t include them.
An observation i forgot to mention, if i increase the interval of the fill layer it increases the stretching/misalignment by A LOT. This leads me to think that every time the laser does a full pass in the X axis and moves up in the Y axis, it slightly offsets the position of the laser respect to the position where the software thinks it is. This results in the offset increasing in proportion to the engraving size, decrease in interval size or anything that makes the machine do more passes per engraved area.
What was the original value of the $2 setting?
You should flip only one bit in that value and leave the rest unchanged. Changing all of them will trigger the same problem in the other axes.
Although your photos show the figure standing upright, the LightBurn layout has the arms extending to the right. To help keep all of us oriented, please orient the photos the same way as the layout so a problem with the Y axis remains up-and-down, not left-and-right.
This is beginning to look more like a mechanical problem than a configuration problem.
The CV01 is a unique machine …
What is X?
Any possible chance the entire machine is moving ever so slightly?
There weren’t any values, its a toggle option. i can only set it true or false for each axis and the A axis thing. (they were all false by default)
With the exception of the acceleration values (that were edited to try and solve the issue as i mention earlier, didn’t change a thing) the rest of the values seen in the photo are in their default configuration.
i wish this were the case, just to see something different. When i toggled all of the axis the result was the same. Actually, the result was the same in every singe case no mater which $2 setting i set true or false. If there is a solution in the software side of things, this option seems to be no good or maybe i am doing something wrong.
i have to say that i don’t know for sure if this is actually GRBL. i don’t know anything at all about different controllers. is it possible that this isn’t GRBL and it is some other controller? i really don’t know a thing about identifying controllers.
god i hope not. if this would be the case i can’t get spare parts for troubleshooting, i would have to be sure where the problem is before buying the part (i live in a small province inside argentina)
If there is any way to troubleshoot this so i could know where the problem is, im open to anything i can try.
sorry for the orientation mistake. will correct in future pictures.
This was the first thing I tried. The machine does not move or tilt during engraving
With the exception of the trail, Lightburn will only talk to a grbl controller.
Unless you purchased the dsp key, it wouldn’t work… I think we can safely assume it’s grbl…
I was thinking of the numeric equivalent of the $2 setting, which is the binary equivalent of all those bits. Come from doing things on Hard Mode for too long, I suppose.
You had asked how to flip the STEP polarity for a particular axis on a GRBL device and we’ve established how that’s done. If changing the polarity for the Y axis doesn’t solve the problem, then randomly changing it for other axes will not make forward progress.
All desktop lasers use some mutant offspring of GRBL, although few manufacturers comply with the terms of the GRBL license allowing them to use it. What you see in the Console window when you turn the machine on comes directly from the laser controller. It will identify itself as some version of GRBL.
Mostly, fixing the problem will involve tightening a loose screw. Finding that loose screw always seems remarkably difficult.
Well, that’s basically what we’re doing right now.
If flipping the polarity of the STEP signal did not change the machine’s behavior, then that’s not the problem.
Looking at the machine’s hardware, I’m with @cggorman: if that thing isn’t screwed firmly to a sheet of plywood under whatever it’s engraving, it’s very likely walking around.
Let’s eliminate an obvious problem. Mark the position of those four feet on the platform(*) by tracing around them. Run the offending engraving, then verify the feet are exactly where they started; being off by a tiny amount will be magnified at the end of that long arm with the laser.
If you have any doubts (and you should have doubts), then laser-cut some thin plywood / MDF / thick cardboard into plates fitting around the base of the legs, with snug pockets for the feet. Screw those plates to the platform so the laser cannot move and let us know if that improves the situation.
If it doesn’t, then start checking the machine’s mechanical setup. Although this is for a Sculpfun laser, you’ll recognize most of the parts and the list will show you where to find common problems:
Good hunting …
(*) I assume you’re not running it on the dining room table.
Update.
As i mentioned earlier, i know the machine is not moving around during engraving. I have a dedicated table for the engraver and its legs are fitted in pieces of wood carved in the shape of the legs. This pieces are glued (and now also screwed) to the main table in which the engraving happens. To make sure not even the legs are moving in their fittings in the carved wood, i have filled the wood carving with glue to make sure that is not happening either. The results didn’t change after this so its safe to say the machine is not moving or tilting during engraving.
Meanwhile i have made an interesting discovery. Contrary to what i believed, the machine doesn’t get offset by the passes on the X axis. The fill layers themselves are the ones being engraved wrong, the cut layer has been precise this whole time. My test was basically to engrave squares of known dimensions and once engraved measure them. It turns out the fill layer is off and the cut or line layer is actually very precise. in pictures below its possible to see that the fill layer is at leas 1mm off in a 5 cm square while the cut layer remains precise.
i hope this to be key information for troubleshooting what the hell is going on. i cant help it to think that this is still a software issue. A mechanical thing wouldn’t pop up just in one layer but then let the machine work just fine for other layers. although the behavior of the engraving is very different between layers, so i cant fully discard the mechanical theory. Since i have no idea about the software side of things, all i can do is tune up the machine on the mechanical side to make sure that’s not the issue.
I have yet to go through all the items of this guide to tune up the machine. I’ll be posting more updates if any of them change things for good. Thanks for the help so far, i really hope we can solve this down the road.
This looks to me like the speed and/or acceleration of the image layer is high enough to either cause something mechanical to slip or you are loosing steps. You can slow the image layer down to something absurdly low (50-100mm/min) and see if that helps, but you still need to confirm every fastener and belt is tight to make any meaningful software (speed) adjustments.
Now we all know it!
Looks like a good, solid anchor. When you find & fix the actual problem, you can remove all that and see what happens.
You’re gonna have to get over that assumption, because it is demonstrably, flat out, absolutely wrong.
I commend to your attention a recent discussion:
Look very carefully to find the hidden screw you’ve overlooked before.
Okay, i have already done all the mechanical adjustments to the machine except for the axis calibration step. Since the problem presents in layers rather tan axis a recalibration would lead to one layer’s correction but an offset for the other layer.
The belt of the Y axis wasn’t centered in the gear, all of the rest mechanical adjustments seem to be ok. By this i mean i didn’t see anything wrong, but i did the maintenance anyways. The results:
Still no good. but now the machine is fully tuned up so i can test things like this.
and the result
Still no good.
Any other ideas?