Odd Rostock Max V2 layer issue

[caseydanger]

Hi! I originally posted this in the Rostock Max V2 forum. I think it fits better here so I deleted the previous post and I'm posting it here. Moderators, please let me know if I goofed up.

I've got a Rostock MAX v2, built from a kit in Jan 2015 and since upgraded with injection molded cheapskates, ball-cup arms, an HE280 hotend with fan shrouds, the newer EZRstruder, and a 12v 30a industrial power supply. I love this big, beautiful bastard and it's served me well over the years.

Recently I've finally taken the time to really try and dial in my settings and get everything as perfect as possible. The one thing I can't seem to get rid of is this issue that seems to present itself as a micro layer shift or some sort of extrusion problem. I've attached a photo of the issue I'm seeing. I'm printing with Hatchbox White 1.75mm PLA at 210ºC, 40ºC bed temp, at a layer height of .15mm, line width of .4mm with a stainless steel .4mm nozzle, at 40mm/s for speed. Sliced with the latest version of Cura.

The first layer is going on smooth and adhering well to the bed with no ridges or anything. I've done several extrusion tests with the hollow 10x20x20 box and measuring with calipers I'm right on the money for what I expect. I realize 210 is on the the high side but out of all the retraction tests I did, the 210 print had the least amount of stringing, though very fine strings were still present. Stringing is another problem I've been having. No amount of temperature adjustment, retraction length/speed adjustment can get rid of it completely.

Things I've tried:

• Tightened belts
• Cleaned the tower tracks and cheapskates
• Fiddled with travel speed settings from 100 - 300mm/s
• I moved the filament spool from the stock hanger and placed it on little bearing tracks I printed as the swinging of the spool seemed to cause the whole frame to sway.
• I did check the HE280's ptfe tube for that common plug problem and it DID have a small .5mm plug on the end. I reseated with the recommended method of using a razor to cut the ptfe tube at 90º, loosening the top nut of the hotend two turns, shoving the tube in, and tightening it all back down. That helped reduce the issue somewhat, but it's still there.
• I got all my Tower endstop offsets under 10, previously my Z was very high, 100+.

I normally try to solve issues myself reading absolutely everything I can find and this is me at my wits end trying to solve this problem. Some users on reddit seem to indicate that this is the best I can get on my rostock max at this layer height, but I don't believe that's true.

Is there something I'm missing? Any help would be greatly appreciated. Thank you.

[geneb]

Is the hot end whip or ptfe tubing putting any strain on the effector as it moves? For giggles, try printing on a cold bed and see if the same artifacts are present.

g.

[caseydanger]

Is the hot end whip or ptfe tubing putting any strain on the effector as it moves? For giggles, try printing on a cold bed and see if the same artifacts are present.

g.

Hey geneb! Thanks for replying. Here's what my whip and ptfe tube look like while printing:

I'll try printing the same file again with a cold bed. If this turns out to be a heated bed issue I do have a tricklaser heatspreader on the way!

A couple of extra thoughts since I've had time to reflect more:

• I have done the measurement where you remove the ptfe tube from the hotend, cut off the filament with a razor right at the end, and then extrude 100mm of filament to check your esteps and that appears to be right on the money as well.
• When I print a single-wall, open-top calibration cube for testing my line width, it moves very slow and methodical and this artifact I'm seeing does NOT present itself.

[caseydanger]

Hey everyone! Wanted to update this post for future folks that might come across it.

I'm going to tentatively say I fixed it! I printed a 20mm cube and this was my result:

Previously the sides of a calibration cube looked similar to the tiny crate in my original post, with the same random layer artifact. The solution? My belts were too tight! I spent some more time researching, like I should have in the first place, and came across an answer in a thread by none other than geneb describing what the belt tension should feel like! Something along the lines of pressing your middle finger and thumbs together and feeling the muscle right underneath your thumb.

I'm currently printing another item that has displayed this artifact and I'll update the post one more time. Fingers crossed!

[geneb]

\o/