Need help improving print quality

[vpconway]

I've been struggling getting good quality prints out of my RostockMax. I was printing pretty well a few months ago but seem to have lost the recipe. Just as I was printing well my Steve's extruder died. I now have an EZStruder. It is a lot easier. I've got that working pretty well although I do seem to have occasional issues with it under extruding. The photos attached show where I stand now. This is the right facing owl at 1/2 scale. I stopped it to examine the infill which looks good but it doesn't look like 25% to me. I'm not really worried about that though. I'm also pleased with the connection between the infill and the perimeters.

I've printed this owl with this spool of filament much better before. The two issues I need help with are the blobs on the feet and the poor printing with the overhanging feathers. The feathers on this sample are a slight improvement from my last print. The loop of filament on the one feather is smaller on this print than others but it is ALWAYS on the same feather. This is my first print since changing my old arms with the new ones - which are much nicer. I also noticed slop in the pivots where the arms connect so I added rubber bands at the top and bottom of the arms.

I've played with all sorts of slicing parameters. The parameters for this print are after the photos. One parameter I know I've changed since printing well is the extra length on retraction.

Any advice would be appreciated. Thanks in advance.

infill view

feet and feathers

bottom - looks good to me save for a little warping

back - good but more blobs than I've had before

This was sliced with slic3r 1.0.0RC2
0.5 mm nozzle
0.2 mm layer height, 0.35 first layer
3 perimeters
all quality items selected
randomize starting points
infill 0.25
only retract when crossing
speed: infill at 40mm/s others 30mm/s, external perimeters 70%, first layer 30%
default width 0, first layer 150%, perimeters 0.6, all others 0. (my best prints have been with default of 0)
temp: first layer 225, others 223
retraction: 7mm, z lift 0, speed 50, min travel 3mm
extra length 0.07 (I think I'll try this at 0, my best prints were at 0)

Vance

[mhackney]

Vance, a couple of things come to mind. Firstly, I've also experienced a lot more blobbing with slicer 1.0.0RC2. I still have a few previous releases and KissSlicer. In almost all cases, I see more artifacts like this with slicer 1.0.0RC2. Secondly, looking at your 2nd photo with the "droop loop" - it really looks like all the layers are a bit droopy. I think this might be symptomatic of too high extrusion temperature. Try lowering your extrusion temp by 10°C and testing it by heating the hot end and extruding 50mm or so into air. If it extrudes with no EZStruder hiccups, then try a print at this temp. If it hiccups, increase the temp by 3° and try again. AND/OR check your extruder current setting - in firmware if using a RAMBo. I had to tweak up the current when I switched from Steve's to EZstruder.

cheers,
Michael

[vpconway]

Thanks. I've been struggling with the droop for a while. The blobs are new and I recently switched to 1.0.0RC2. That fits. I was anxious to use the new quality features. I'll go back to an earlier version.

When I went to a lower temp the infill gets sparse. How high did you raise the current?

Vance

[ccavanaugh]

Vance,

In addition to what Michael has suggested,

Check your drive gear on the EZStruder and make sure you did not grind filament and get some build-up. Ground filament in the teeth will also cause inconsistent extrusion. If you are getting grinding, one adjustment to look at beside current adjustment is to reduce your extruder acceleration. I've found that some filaments are a bit more brittle than others and are more susceptible to grinding under hard accelerations even when print temperature is correct.

[vpconway]

I'm printing an owl right now. I went back to repetierhost 0.9C and the blobs appear to be gone.

I also dropped the temp by 3 degrees. Unfortunately I can't get a good look at the feathers while it's printing due to where the printer is. The infill is poor and you called it: It's grinding. I can't find an acceleration control for the extruder in slic3r. The print accelerations are all 0. Specifically what parameter(s) are you referring to?

Thanks,
Vance

[vpconway]

I aborted the print. Too much grinding and the extruder was slipping.

Far less blobbing. The feathers are marginally better. It would seem I should lower the temp a more but I clearly can't go lower in temp and extrude. I thought the speeds I had were actually slow. I really don't want to slow down more. The half size owl with 25% infill takes a little over 3 hours.

I haven't upped the current yet. I think I need to solve the grinding first.

Thanks,
Vance

[ccavanaugh]

Extruder acceleration is a firmware configuration. I think the default is 3500, but I dropped down to 2000. You can change it using your LCD control panel... just remember to store the eeprom values

AND, if your temps are not high enough, you will grind filament regardless of acceleration settings. I would trying pushing filament by hand at various temperature ranges and see if you notice anything.

Have you verified your temperate extruder temperature accuracy using a meter?

[mhackney]

My current is set to 200 for the EZStruder. And yes, turn down the acelleration also. And, when you do get grinding, do check the extruder cog to make sure it has not built up plastic, causing it to slip more. ccavanaugh's suggestion to push by hand is a good one too.

[vpconway]

Thanks.

I haven't verified the temp but I'm not worried about. From the print it appeared I needed to lower the temp so I did. Running 3 degrees cooler led me to extruder problems. BTW, Yes, the extruder is full of plastic. The print was doing OK when there was a little plastic but when enough collected it was done.

I intend to change the acceleration and leave the temp at 230 for now. If I get rid of the grinding I'll change the current.

I may not get to it until Saturday though so please don't think I'm ignoring your advice. I appreciate it.

Vance

[vpconway]

Well I went to make these changes this morning and I'm treading carefully. I have one of the first machines and have a Rambo 1.0 (1/8 stepping) board. Of course, when I got it I had the Steve's extruder. I know the firmware has changed for the 1/16 stepping Rambo. I have not yet upgraded. It seems the firmware also changed for the ezstruder. At least configuration.h has. The acceleration is set to 6500 in mine. 3500 in the current release.

I'm going to update my firmware but I need to be sure I've covered everything I need to for the version of Rambo board I have.

Vance

[vpconway]

My prints are now improving. It's no longer grinding so I can lower the temp some more. And raise the current.

Thanks for the help.

Vance

[mhackney]

Great!

And making the few changes to Configuration.h for 8 vs 16 micro steps and/or Steve's vs EZStruder are all simple and documented on this forum. The Repetier upgrade post I made a few weeks ago has a well commented Configuraiton.h. Just start from the top and read each of the comments, you shouldn't need to muck with anything else.