I've been printing more at 0.1mm and there are bands that were scarcely perceptible at 0.25mm. Generally they amount to one layer that has shifted the tiniest amount to the right and front.... just enough to create a line. Usually after one layer it then returns to where it was before. I've tried: - tightening all the different aspects of the motion system; - checking the hotend and nozzle are secure; - examining the belts; - verifying the steppers are at the top end of their range; I don't think it's the Z-axis because the bands vary from part to part. And because I can't "force" bands to appear by pushing a bit on the side of the bed during printing. The bands are however more frequent when there is more "going on" on the layers. So it makes me think it's somehow related to the X-Y motion. However decreasing the speed - both of printing and of XY movements - makes no difference. All ears for suggestions!
Just finished my first print at 0.1 mm this morning for the violin I was printing. Here is a pic of it for comparison @R Design
This is the worst example I could find. The bands are horrible, partly because of the diagonal morning sunlight and partly - I think - because I forgot to chamfer / fillet the corners of the part and so perhaps the nozzle direction changes were very brusque?
How are your bearings on the bed? Are they smooth all the way or could it be they get slightly stuck with uneven motion. Maybe this is showing only in very small z movements. Just a thought.
When I put it together the bearings seemed OK. But you're right, with these bearings we're always going to have doubts. And doubts is a killer. Went through a Z- recalibration once, but didn't go so far as to strip out the lead screws....
I got some misumi bearings and they ride smooth as silk. Even wondering if the balls are rolling at all. But then again. I'm still not finished with my build
On the thingiverse page for the BB under remixes Greg's posted a Z-axis IR sensor alternative that might interest you if the build is not too far advanced: the sensor goes not on the print head but on the print bed!
@Stian Indal Haugseth I think you're right: I started looking at print bands under the USB microscope and decided that there is some Z variation between layers bands where bands are occurring. Took out the lead screws and a) there is some stickiness; b) there's a bad noise coming from one of the bearings; This is a case of a bearing getting worse / going bad in usage (I think it was OK at the start). These things are obviously a false economy. So now I'm going to look through the forum and try to understand where to get these Misumi things. But if I remember rightly you can't order them in Europe if you don't have a company or something?
I have only 1 left. I can get more, but first check locally (no idea where you are if it makes sense for you to ask me)
OK thanks. I'm in Brussels. FIrst I'll get the 2 that Alex has. Hopefully that way I can be printing again on Friday. Also that will give me a chance to examine them. My understanding is that for 3d printing there's no need for high performance bearings. It should be enough that they don't jam! However having one that was working OK "turn bad" on me - and the inconvenience that brings - is giving me second thoughts about the Chinese route. I mean, even if you have a draw full of Chinese bearings, it's not easy to check whether maybe one needs changing.
