It seems like over time my print quality is degrading and I would like some opinions on the image attached. The top print was done months ago and it is pretty smooth to the touch and looks good. The lower print was just done and it is rough and feels like harsh sandpaper.

Now this is important: These are from the exact same Gcode file, no changes were made to it.

Some prints are fine looking on one side (Left Front) while harsh looking on the other side (Right Rear) and the top.

After this started I changed out my smooth rods (they had groves from the bearings) and the bearings to higher quality ones. I also check my belt tension it's good, I tried lower temps (ABS I print normally at 235c) I tried down to 220c, I tested my feed length and when I extruded 100mm of filament it was like 99.5mm (should be close enough). I also tried several different colors of ABS. Since the Gcode can be ruled out as the cause and I tried different filaments this in theory only leaves the printer itself at fault.

I just can't find anything wrong with the printer, belts tight, X/Y carriage slide smooth, everything is tight (no loose hotend, bed or anything else I can think of. It's a mystery to me and I need help. I sell some printed parts and need them to be good quality.

Machine: AirWolf 3D V5 (based on Prusa Air) Gen6 board with Repetier firmware and Repetier host to print. ABS with heated bed at 95C and Budaschnozzle 2.0.

Tightening the belts and changing out the smooth rods and bearings did make a little better but not nearly enough.

Any ideas?

Thanks in advance.

Attached another image (white rocket) that shows just the sides bad, the sides away from camera look good.

Edited 1 time(s). Last edit at 04/28/2014 09:12PM by tmorris9.

I would say you are over extruding.

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Thanks but that's why I tested and when I extruded 100mm it came up at 99.5mm (so if anything it's a hair short)

It could be the filament diameter is greater now which is causing the over extrusion since you say it is an old gcode file. Maybe you had 2.8mm filament and now you have 3mm.

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I am pretty sure the black filament is from the same roll. But lets assume it's not, how would I test this? Can I change something in Slic3r like extrusion multiplier and see if I get better results?

Just checked and in Slic3r my filament is set at 2.84, I measured it at 2.86, Enough to cause a problem?

Quote
tmorris9
I am pretty sure the black filament is from the same roll. But lets assume it's not, how would I test this? Can I change something in Slic3r like extrusion multiplier and see if I get better results?

You could use a live flow modifier to change it on the fly to get it perfect. If you have an LCD you can follow the instructions that say "fine tuning the flow" [www.tantillus.org] . If you do not have an LCD you can still do it live from the host software with M221 S100 (change the 100 to a percentage you want) if it is over extruding I would try 95, 90, 85 etc until you find the point where it under extrudes and then go up from there.

There is also the possibility that it used to under extrude due to filament slippage, weak idler springs or some other drive issue you have now fixed.

Also does the gcode file you have still have the comments? It would be good to confirm you had the filament diameter correct for the current size as well as check if the flow modifier was at 1 when sliced and not increased to account for under extruding as hypothesized above.

Edited 1 time(s). Last edit at 04/28/2014 09:42PM by Sublime.

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Quote
tmorris9
Just checked and in Slic3r my filament is set at 2.84, I measured it at 2.86, Enough to cause a problem?

Doubtful, but it would result in a small over extrusion.

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More info.

So I took a 50x pic from each with my microscope. Scale is the same on both. Maybe it will give more information.

Under the microscope it looks more like under extruding which is what your steps per mm indicate. But at the same time the extrusion is rough not just too skinny. You say you are using the same role of filament and that the first print was from months ago. That makes me think that roll of filament has been sitting around for a while and could have absorbed moisture which can result in bad extrusion similar to this.

Other things I would try since it is black filament would be to clean the hotend out, increase the temperature and of course a different roll of natural filament as a base line.

Also is this happening with all slicers? I know you have recently tried Cura or Kisslicer for the rocket and had better prints.

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OK, I see what you are saying about moisture. I actually put on a new clean nozzle a few days ago to test that and it made no difference. I am printing right now at 240 (can't go higher with Budascnozzle.) I will see if I have any unopened filament and try that.

New filament did not help (was sealed with desiccant) but I may have found it. I noticed a bit of filament on the outside of the extruder and I think the aluminum threaded extension may have a hole in it. I have to disassemble the whole thing to be sure.

Do you think that would cause the problem?

If it is leaking it would cause under extrusion and oxidation. The oxidation would cause the nozzle to build up crude in the tip really fast which would result in high back pressure, slipping filament drive and blotchy extrusion. I would take it apart, burn out the old material with a torch from the barrel and tip and then do a full rebuild.

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Well,

Trying to take my hotend apart basically destroyed it. Aluminum heater block with an aluminum core screwed into it is just not a good idea, they basically fuse together permanently (Budaschnozzle) I went ahead and replaced the hotend but I ordered an E3D as well.

So, fresh hotend, fresh ABS, and I still had bad prints. Checked the temperature of the hotend with a Fluke meter and it's within 3c of accurate (close enough). I noticed that my thin vertical walled items where stronger than normal (layer adhesion is better) so I got to thinking maybe I am printing too hot for either this hotend or this filament.

I printed my ABS at 235c for 2.5 years. So I did some tests and it turns out I get very good prints at 210c now. I don't know if my old hotend was a bit cold (never measured it) or if this particular ABS (same vendor as always Lulzbot) wants lower temps.

Need to test other older filament in stock to see.

But the good news is I am printing good again.