Strange Zits and Blobs on #3D Benchy

[Brenttnerb 0]

I have an Ender 3 Pro, and have been printing with it successfully for a few years now. I recently started tuning for a new filament, when I noticed some zits on the front of the #3D Benchy. I have never seen this problem before. When I watch it print, It kind of jitters around the corner, causing these extrusion inconsistencies. I can also see some random bulges in the top layer lines, on the width. It is underextruded slightly as well, but I don't think that has anything to do with it. The only changes I have made to my slicer or printer are, calibrating e-steps, making an  encousure, and updating Cura. I doubt that the enclousure has caused these issues, because I tried printing out of the enclousure, with the same results. The E-steps may require a whole number or a multiple of .04 for reliability, but I don't know that for sure. The only thing I can think of would be an acceleration glitch in the newest Cura. Other things I have done are to clean the printer v-slots(rails), tighten belts, and check extruder. Everything appears to be in good condition. I really don't know what is causing this issue. I have printed some other models, and can find little evidence of the same issue, and I have printed the benchy in a different filament, with the same problems. Any insights would be appreciated. 

[Brenttnerb 0]

I solved this problem now, it was simple, and obscure. Stefan from CNC Kitchen had my answer. 

 

[bengalih 2]

On 10/5/2020 at 7:50 PM, Brenttnerb said:

I solved this problem now, it was simple, and obscure. Stefan from CNC Kitchen had my answer. 

 

 Years later, but I wanted to thank you for posting this along with your pics.  I was looking to troubleshoot a very similar looking issue on my old Anet A8 with an 8-bit board.  I couldn't even figure out exactly what search terms to use, so just searched Google Images with "benchy hull problems" looking for something similar.  Found your pic, which led me here.

 

I'd never ever printed a Benchy before and was only doing so because I was planning on switching from Marlin to Klipper and wanted a baseline before.  Below you can see how horribly bumpy the entire front half of the hull was (top).  This was with my current Cura settings printing through Octoprint.  Simply removing Octoprint from the equation made a world of difference, but it still had some pretty rough patches (middle).  After about half a dozen hull prints trying different temps, belt tensions, and placements, nothing made it better.

 

After changing "Maximum Resolution" from 0.05 to 0.5 and "Maximum Deviation" from 0.025 to 0.05, Things improved remarkably.  I don't know how often I was actually seeing these issues on other prints, but it is really like a completely different beast now (bottom pic)

 

 

 

Edited February 25 by bengalih

[gr5 2,330]

Oh this is fantastic information - the video also.  I hadn't seen this topic before and I've seen many CNC videos before but not this one!

 

I use Ultimaker printers and those profiles all seem to have 0.5mm (not 0.05) for max deviation so this explains why SO MANY people get these bumps and I rarely see them.  It's because they have "bad" printer profiles for their printer.