Lol. Those pictures aren’t really the best for showing the issue. It’s also a lot more difficult to see on an “inside” circle, but there definitely is a crease there and things are slightly off round. It’s basically the same issue that PMA showed with his photos but his is much worse. In any case, I’ll figure this out on my own I guess.
It’s hardware related, related to motion of x, y and or motor steps, things like that, anything else wouldn’t make sense.
There’s only one way to really figure it out, and that’s to start upgrading parts, one at a time.
Like you mentioned, there are only so many things that can cause it.
I’m definately not a novice when it comes to things mechanical so all the things you’ve mentioned I looked at BUT, it could be just something that I overlooked etc. The offround is very slight so it makes it hard to pin point, it might be a combination of a few extremely minor things. I do notice the Y axis has a little more friction when sliding on the rods, there could be a few other things but as far as belts slipping, that’s definately not the issue. Pulley maybe but I doubt it, they’re all snugged up super tight…
Changing axis steps? it should already be set to the optimal setting for the 1/16 steppers?
Ofcourse, having a second eye look at it would definitely help. I just really hate the idea of sending it out, especially when it prints almost 100%. What’s involved in sending it for evaluation? who pays for shipping? I bought the kittaz so I don’t have a large box to ship in “pre assembled” format like the Taz 4.
Also, smooth rod alignment? this doesn’t seem like something that can be adjusted, unless I’m missing something…
Pretty much just “plug and play” nes pas?
Per our return policy found here: https://www.lulzbot.com/support/return-policy you are responsible for return shipping. Before you consider doing that though, it’d be worth checking over things again, or having a fresh set of eyes look at things.
Ok, thanks. But really doubt I’ll send it back, Just not worth the cost and trouble of sending it out. It’s something I’ll probably tinker with anyway. I usually end up modding most of my stuff anyway so I’ll figure it out by upgrading parts as I go. One thing I noticed is that I forget 2 screws in the Ybelt holder that sits in the middle of the table(must have overlooked it at assembly)…logically that would make a ton of sense as the culprit, as it wouldn’t loosen the belt per say but would allow some slight shift while performing direction changes under Y movement…which to me, is what the problem looks like…so fixed that, just havn’t got around to printing anything yet…i’ll update when I do.
So I finally got around to cooking off a print after adding the two missing screws to the Y belt clamp and making sure everything was snugged up including the linear bearings. I have to be careful not to put the bearings too tight though because it seems to add too much friction to Y…
Anyway, here are the results of a fan plate I printed which has a huge hole…printing a small hole would have been much better but so far, with this print, I don’t notice any creases or offset problems…which technically, makes sense…so until I troubleshoot something smaller, it looks like the Y belt clamp was the problem…i’ll update once I have a few more prints run through it though…
P.s yes I know the first layer didn’t print wide enough, I adjusted the Z height afterwards…
Just got finished the final print in a 3 part print. Two of the parts are very tight fitting circles with a .015" friction fit at the circumfrance. It really helps to have perfect circles in a situation like this…which, I believe I have now
So just to re iterate, the problem was off round circles, in this case it looks like the problem was a slightly loose Y belt clamp, I had forgotten two screws during assembly and it was slightly loose…I tightened everything up and so far circles(at least large circles) are looking much better… hope this helps.
Well, unfortunately it’s still showing up on smaller diameters but it seems ever so slightly better.
It’s just a gremlin I guess I’lol have to live with. I end up doing finishing work on most of my important prints anyway, primer, filler, paint, drill hole diaMeters out etc. So it gets covered up anyway.
To that list I’d add that the spring pin that holds the pulley on the stepper motor shaft, if that pin is loose, or the pin hole in the pulley or motor shaft is “enlarged through mechanical means” aka smooshed, that might also cause a set-amount backlash in that axis. Maybe? No?
If you print the same circle part in the center of the bed, is the crease the same as if you print it at either end of the Y travel?
The first time I built the Y bed, the smooth rods were skewed ever so slightly. The Y travel was smooth in the center, but started to get stiff at the ends because of the skew. It was fairly straight forward to straighten out once I realized what was going on. FWIW, I wrote up some steps for the Y bed. https://forum.lulzbot.com/t/new-kittaz-y-axis-tips-excellent-prints/1141/1
YES!!! The Y bed is WAYYYY stiffer at either end of travel, it was so bad at first I had to loosen the screws on the bearing holders just so it wouldn’t bind while moving towards the Y end stop!! Oops. probably forgot to mention that.
Now, I guess after some use, it seems to be better, I played around with tightening and loosening certain parts and got it sliding a little better… but If tighten up the bearing holder screws super super tight and snug, it will get pretty boarderline tight while traveling towards either end…
But as a cause for off round circles and creases…I just don’t know…
I just noticed the off roundness on a large gear I recently printed with my TAZ 4.1. The gear is ~9" in diameter and it’s ~.05" oblong. This is eyeballed by watching the gears mesh with the pinion. I’m wondering if it could be a E step calibration in one of the axis or possibly that the z-axis steppers are slightly tilting the x-axis rods and I compensated the bed accordingly. Seems this might cause the X-axis to print short. I’m going to try leveling the bed backwards. First leveling to the Al plate, then the y axis normally then the x by twisting the z steppers.
I’m curious about one thing. Does the autoleveling algorithms that the mini uses have a compensation in x and y?
Having a blast with the printer. Would like to get this zeroed out to print this large gear. For small stuff, it’s not an issue and the TAZ zaps out plastic beautifully.
backlash is one of the first thing that you check for something like this…it’s not backlash…