kinginnovator

Awesome!! Again thanks for your patience.. it was night and day on this last print.. I just started fresh completely over to eliminate all the rest if the variables.. looking forward to see what she can do ..

Ok everyone... I loaded a brand new copy of Marlin and also went back to cure 4.13 and the skewing went away!! I even printed at some very impressive speeds (see video link)... I honestly have no real clue to what is different or what changed... I still have lots more testing to do.. I really appreciate everyone's help and you guys are the very best!!! https://photos.app.goo.gl/PnNv4mk8LXoS1YH46

Nevermind.. I found it.. About to print a file from this version.. Fingers crossed!

Here are the version options? I don't see it?

Edit out those tiny movements? Like in the g code?

This is an older picture. We got rid of the slide bearings in the x,y and have gone to a track bearing setup.. lighter and much simpler.. if I can control the skew this eliminates alot.. In theory it shouldn't be mechanical.. I can print a single line tube 4 inches with no skew repeatable. I just might try klipper too at this point if I'm able to... we'll see... going to dive into everything today and even try an older version of Cura possibly...

I will definitely try this! Very possible it could be tiny changes from the older version! Thanks 👌

The set screws go into a pre drilled hole guaranteeing no slippage..

I've tried everything... No luck.. Please see list of true's below: 1. I can control the direction of the skew based on seam location. 2. If I choose random seam the skew goes away but I suspect every layer will be a bit off from the previous. 3. I can print a single wall/path line to any geometry without any skewing. 4. I can print a single layer perfectly over and over and over and over.. All the truths above are the bounding box to solving this pandora of fun!!! I have acceleration set to 80mm/sec super slow. I've tried higher accelerations with the exact same results. I've turned off jerk movement and also tried with it on. Wipe distance has been (0).. Most everything has been set to (0).. GR5 said this " Or sometimes it's on a z move possibly. Particularly buggy is if you move Z and another axis at the same time as the original programmers didn't expect this. But cura probably won't do this anyway. But it could be moves just before or after the layer change." This could be it???? My gut tells me it's happening at this moment of movement (see picture again)... This is the only thing I can think of that's different than printing a single layer line/path only.. Btw yes If I print spiral the problem should go away but that is not a solution to the actual problem that will effect all prints hear forward.... small test ring.3mf

Okay finally getting somewhere! I printed a test ring (double path wall). By manually choosing the seam location (front,back and right ) in 3 different prints I can control the direction of the skew (see picture). I also made a short video. I've also included the gcode and cura file. I think that it's actually printing perfect layers but something is shorting the distance most likely when it starts a new layer at the seam location when it tries to make a tiny quick movement to start the new layers outer path. This could be do to the inertia within a larger system like this not being able to correctly respond to such a tiny movement. What are your thoughts on this? Is there a way to compensate for all tiny movements as such or atleast alter the gcode to compensate? All ideas are welcome.. https://photos.app.goo.gl/AE3CrfcWjPtKfzah8 CFFFP_small ring.gcode CFFFP_small ring.3mf

This is a great idea! I will do this tomorrow for sure to 'see into' what could possibly be causing this.... It makes zero sense if I can print perfect circles and walls in both directions but then have skewing happen on more complex shapes.. I know this will take time to figure out... My hunch is something that normally would work fine for a smaller printer (much less inertia) is hidden in the code and was never meant for something this large. I know that when I select randomize for the z seam this appears to solve everything via randomizing each layers start and stop locations and gives an overall average on the layers with everything working out in the end.. But I really need to pin point this because it's driving me crazy to have come so far yet have this happen at this time.. It's very expensive to build such a machine.. I really appreciate your ideas, knowledge and caring of my current situation and It will not go unnoticed!

Hey thanks! Its actually fed by a flexible shaft drive cable from an external stepper (nema 24). The shaft has a worm gear at the end that drive both Bondtechs simultaneously. This allows for some seriously high flows (as much as or more than a pellet system). Yes 2 heaters each 400watt potential.. This is all designed to achieve more that what's ever needed lol..

I can do this soon.. I noticed that cura will put seems in the direction of home. Is there a way to put the seems opposite of this? If I can show you guys that I can control the direction of the skew then this is atleast a step in the right direction..

Ok.... So I printed the same part at 45 and both sides skewed this time not a single side. This makes sense because they share the same direction. But I noticed in the firmware where the stop/start lines are at each layer change and I've been following a hunch. So I set z seam to random instead of shortest path and the skewing went away... So I decided to see if I could investigate further on this by printing a very long wall in both the X and Y direction (picture). No skewing took place in either to my surprise.. At this point there is definitely something different happening about the program in how it sees a more complicated geometry. Yes you mention the layers of complications going on behind the scenes yes. I need to figure out a geometry that can point the finger at the monkey aka (demon lol) hiding. The last wall part had no travel moves or possibly so much else when compared to the square frame.. Any ideas on what time of geometry I could use to say "ah ha!" I use Fusion 360.. Ive owned 8 other (small) printers before this one so I definitely think I could be dealing with a very tiny demon where acceleration isn't the same in a smaller machine when scaled to this. There has to be some geometric shape I could print to test the next step.. Remember when I when to random Z seam everything went away and this makes total sense if the same layer isn't repeated electrically/mechanically..

Thanks for responding.. I'm extremely aware of mechanical skewing. This is not it.. I can print a perfect cylinder over and over and over without any problems. I'm pretty sure if I orientate the part 45 it would go away based on the x,y moving at the same rate just like in a circle they would. The problem is specific to movements based on geometry and how cura does the paths. I do believe there is a possible problem with acceleration somewhere and steps being lost or gained. My acceleration is set to it's lowest 80mm/sec.. I bet if I print a square part without that center geometry and just a frame it will print perfect. I will try this and get back to you. Jerk is off because I can print perfect cylinders.. How would changing layers be related to acceleration? After a layer change does it do something special in it's acceleration? What do you mean also by central bar where cura does 2X? I've limited my acceleration withing cura to be around 120 for travels. I will print this at a 45 and see what happens. Will send pics shortly.