blobby rough surface (Page 1 of 2)

picture needed

looks like your extruder steps per mm isn't calibrated quite right or your Z steps per mm is way off. The blobs are excess plastic that had no where else to go but out. Coupled with the fact that you are getting a lot of filament dust (seen in another post) you are definitely over extruding.

http://www.soliwiki.com/Main_Page#Calibrations Try these

I just crossed the bridge of figuring out how to dial in my steps per mm for the extruder. I marked a line at the top of my acrylic extruder block (just even with it). Than i used calipers and measured up 100mm and made another line. Manually extrude 100mm (i hit the extrude 10mm button, ten times). Now compare where the line you drew landed compared to the top of the acrylic block. did it extrude to much or to little? If the line is above the top of the block, you didn't extrude enough. if the line fell below the block, you extruded more than 100mm. If the line is above measure from the top of the block to the line and subtract that from 100mm. If the line fell below, draw a new line even with the top and back out the filament manually. than measure the difference from line to line, and add that to 100mm. once you get this number take that number divided by your programmed number of 100mm and it will give you a ratio which can be turned to a percentage. say it went 75mm, and it was suppose to go 100mm, than thats 75%. So you need to add 25% more steps to your eeprom. if you look at your extruder steps, example being 2200 steps per mm, take 2200x.25=550 steps. Now add that to your 2200+500=2700 steps per mm. Enter this new number in your eeprom settings for the extruder. Now start this test all over again until your dialed in. Took me about 4 trial runs to really get it right on the dime!

hope i said that correctly, its 4 in the morning.. haha good luck.

I calibrated everything using PLA, and it works great.  Do I have to recalibrate for ABS?

As I watch the extrusion, the ABS seems to expand a little just after the extrusion and the print had has passed.  Is this normal?  Could it be the result of too much water in the ABS?

That might explain the problems.  I'll check tonight and report back.

Many thanks.

GWFAMI

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The bad filament I have seen basically won't adhere to itself causing the layers to flake apart.

There are so many good suppliers out there. I have used Maker Geeks and Octave with good success. The best way to ensure quality is to make it yourself. Check out http://Filastruder.com and http://osprintingllc.com/ . It will also save you a bundle of cash if you plan on printing a lot.

ok, well apologizes for getting in the details on this topic.

Ok, I understand some of what is going on on that page. He's not talking about the volume change at the pinching of the filament with the hobbed gear, but rather in the actual part you produce. I guess this also makes the most difference in parts with a large surface area to the volume ratio. Interestingly it means my method of relying on a 0.42 or 0.5mm one-wall object for calibration can be a little flawed.

But to un-derail,

gwfami, where are you right now? Has calibrating helped?

Won't be able to recalibrate until after work tonight.  Will report back then.

Recalibrated the feed, was off by quite a bit.  Trying a print now.

The Z steps should be fine, that is based on the thread pitch and doesn't vary.  Your height could be short from the first layer being squished, and the height being rounded down because the overall height doesn't divide evenly by the layer height.

No calibration on this machine can survive a bouncy trip on UPS trucks for vast distances. It should come with a note saying that :-).