M566 What's a good number?

[deckingman]

Starting to tune my Corexy. I have a strange "clonking" behaviour when doing small radius corners. Difficult to describe but I can hear and feel it. Suspect it might be due to my instantaneous speed setting so I was just wondering what sort of value would be a good starting point.

[dc42]

I suggest you start with the default 600 for X and Y. You should only need to increase it if you print circles that were generated with too few line segments so that there is a large change in direction at the segment boundaries.

[deckingman]

Thanks David. Actually I found the problem which was far more fundamental - a severe case of over extrusion causing blobs which were more pronounced on the corners. While I am on the subject of instantaneous speed change, my Z axis weighs a massive 7Kg and consists of 3 off screws with a continuous loop belt driven by a single motor. It works fine with max speed set to 240 (but it will go faster) and acceleration set to 20 (can also go faster). I've set M566 to a really low number of 10 mm/min. Seems to work but is that OK?

[W3DRK]

I actually get this "clunking" kind of sound too, it always seems to occur on curved skirts generated by Simplify 3D. In some cases seems to almost stall or pause very briefly. It only occurs when printing skirts…parameters print perfectly. And skirts generated by Slic3r do not seem to cause this issue either.

It's very similar to this Duet user's description and video here: http://forums.reprap.org/read.php?416,711181 although with my steppers being almost silent, the pauses sound more like clunks on my Duet WiFi powered Kossel.

It also happens on my Duet 0.8.5 controlled ORDBot, exactly like the video in the thread linked above. Both of my printers are using firmware version 1.15e.

My M566 is set to 1200.

[croadfeldt]

I get this as well on skirts from Simplify 3D. So far I've NOT seen any printing artifacts from it other than the skirt being a bit blobby on the corners.

The crazy thing is, I've been printing the same piece repeatedly over the last couple of days. It will happen on one print but not the next and vice versa. What I can't pin point though is if it's doing it with the same gcode file. I routinely tweak settings, but I wouldn't think the skirt gcode would change.

Either way, I've chocked it up to a peculiarity and since it only happens on the skirts, I've not worried too much about it.

[dc42]

The usual cause of clunking sounds is that the print head has turned through a significant angle e.g. 30 or 45 degrees and you have a high jerk speed configured. S3D tends to generate this sort of pattern in skirts, unlike the smooth curves that slic3r generates. I use an octagon test pattern to check for excessive jerk setting.