The entire Z gantry is really wobbly. It appear to be because the screws holding it in place are coming loose. The vibration from the movement of the print head, appear to be shaking the screws loose. Bad part is, the screws are in the corner bracket behind the controller board connecting to the Y axis. Impossible to get to.
I recommend you all keep an eye on these screws. It doesn't look like they used any thread-locking compound when assembling the machines.
I just have printed my first 3 or 4 prints with my recently received printer and I do have the issue as well.
But I would like to mention as others did already more or less, that a forward leaning z-axis can't cause this problem although the movement along the y-axis wouldn't be horizontal because the layer before the movement wasn't horizontal either. Every layer is parallel with a static inclination of the z-axis.
What is probably causing this is a moment due to the belt tension when moving fast which causes to incline the y-axis.
Loose screws would make it more severe of course.
@ Cetus please advise how to fix the issue with the screws getting loose. And slight z-hop while moving fast would help a litte at least.
I've disassembled and tightened all screws today. I used thread lock as well to secure the screws in place. I aligned all axis, so they now are perfectly perpendicular to each other. I also added the additional Z axis brace that Udo designed.
The machine now has a different sound. With the screws nice and tight, there is more resonance in the machine than before.
Anyways, even with all these adjustments, I still have the issue with the head hitting the prevously printed part. It still only start to do it, ones the print reaches a certain size.
Which could indicate, that it's only as momentum builds that the issue occur.
There is a very sligh wobble on the build plate. When I hold two diagonal corners and very lightly try and wobble the build plat up and down, there is a very slight wobble, which can both be felt and heard. I have tightned the screws in the build plate as much as I dare. Any more and I'll break a screw or a tread in the guide block.
I don't see any obvious deformations of the build plate, and platform the build pate screws on to looks clean and flat as well.
I think this may be the issue. If there is such a wobble, even a very small one, then the added momentum from the weight of the part could cause the build plate to move up when under hard accelleration. that is causing one end of the plate to move up, and other to dip down. That would certainly cause the print nozzle to hit the previous printed part.
Either way, I'm out of ideas for how to resolve this issue. I don't thnk I can print anything taller than about 20mm at this point.
@Cetus, any ideas of how to resolve this. Will you be adding a z-hop on fast cross part movements to the slicer?
Cetus3D 1.1 will be released soon, a Z axis correction function is added, so you can correct for the inclined Z axis.
Why the nozzle is hitting previous printed part, currently we dont have a clue. Since all the movement are guide by the linear rail, wobbling of x and y are unlikely. Wobbling Z could occur as there is a error of stepping in a belt driven Z axis but should be very small.
If you are printing with material that shrinks when cooled, the print may deform and hit nozzle but usually happen in ABS prints.
I don't have a Z axis incline issue any longer. The Z axis was fixed mechanically, and is now perfectly perpendicular to the bed.
I'm printing with Cetus PLA, with the Cetus PLA settings.
I agree that the rails should allow for very precise movements, which should address this issue. But yet, I'm still getting this issue. I can't print anything taller than roughly 20mm tall currently. Any taller and the nozzle will hit the part hard enough to loose steps or knock the part loose from the printbed.
I printed the calibration cube last night, which is only 20mm square. Even on that print it happened. But it is most evident on larger parts, where the nozzle is moving longer distances. Print someting about 180mm long, with holes in the model. Last print I did that had this issue is a USB stick and memory card holder. I have uploaded the model to Thingiverse, so others can test as well. Look for the problem to start appearing when the model reaches about 5 mm in height.
Have you been able to reproduce the issue in the lab?
I recommend use the latest software's calibration function ans show us the calibration model printed.
If finally cannot be fixed and find the casue,please also send a video to support@cetus3d.com to discuss for a replacement. We may need you to return the printer so that we can have a look.
Up Studio (latest version) with calibration has been out for a while, it worked on my Cetus and it now prints straight! When will Cetus Studio be released because Cetus has the most benefir from this..
One other possibility that I can think of is the Cetus software's bed leveling calibration. If one part of the bed is calibrated so that the nozzle lowers when moving to that region and that calibration is off enough so that the nozzle lowers too much, it could result in the issue you are having.
I'm not sure how well the software actually calculates the mesh leveling (I've been suspect of its effectiveness when printing without a raft), it may be worthwhile either redoing the bed leveling calibration or setting all points on the bed level with the highest point just to see if you get any different results.
rdlaner, I've tried both calibrations, i.e. calibration only the center point of the print plate, and as well as calibrating all points on the build plate. I've seen that version 1.1.0.2 was just released today. I don't think the axis aligment calibration will help much though. I have taken my printer appart and reassembled it, so that it's now square. It looks like my printed was put together in haste. A screw where stripped, some were not tightened at all it seams like, and all axis where out of square. But I've retapped where the screw were stripped, reassembled the printer so all axis are now square, and used thread lock to ensure it stay in aligment now.
The only thing left I can think of, is that I do feel a little wooble in the build plate. I think that most likely this is the issue. A rail that doesn't have quite enough pretension on it.
I hope to have time this weekend, to re-print a calibration cube, update the software, and then print the cube again to compare the before and after. I'll also see if I can find a way to illustrate the build plate wobble.
I should add, that I think the raft is inteded to both help stick the print to the print bed better, but also to take out any small aligment issues. So that first layer is nice and flat, and doesn't have the same offsets that the print bed may have.