Printing in the trough of disillusionment

[hubrigant]

Man, I wish I knew what I was doing wrong. I got a couple of great prints, and a bunch of tolerable ones, off my first spool (black PLA from MatterHackers), but with the second spool (white ABS Pro from MatterHackers), I'm struggling.

The first big problem was bed adhesion. I tried glue stick. I tried hairspray. I tried Kapton. I added a copper heat spreader. I replaced the chipped borosilicate plate with a new mirror. I repeated the additives on the mirror. I raised the bed temperature (up to 100°C), but the prints seemed to stay soft/squishy for too long, so I lowered it. Lowering it enough to reduce squishyness (70°) lost adhesion, but 75° went back to squishy.

The hot-end temp's also been problematic. I seem to get decent consistency at around 180°, but the extruder skips. At 185°, the skipping stopped, but I'm back to drooling nozzle and squishy prints with distorted, gloppy seams.

The plane from the attached picture printed about as well as anything I've printed with the ABS, but it's clearly got issues: front-end curled off plate, gloppy distortion on the nose and tail, I had to set the print rate down to 25% for the last inch or so due to the squishy layer problem, and the raft peeled off the on the left side (relative to picture) during the first layer, almost screwing up the print.

What am I doing wrong???

[gchristopher]

You said you switched from PLA to ABS? 180C extruder temp seems way too low, I thought the standard print profile for ABS called for 235-238C?

I started out printing primarily with Black ABS from MatterHackers with my stock hotend and got pretty nice results.

[jram]

Have you tried purple glue stick in combination with hair spray? An enclosure is also a huge help when printing with abs. Since getting an enclosure and printing and the skirt 0.01 from the part, I haven't had a single problem. I usually do a 4 or 5 loop skirt

[hubrigant]

@gchristopher: my very first two prints (PEEK and layer fan shrouds) were essentially successful, and both were printed in ABS. I don't remember what temps I had set back then (January timeframe), but I suspect they were the defaults from the print profiles I loaded in the assembly manual. 180C seems WAY too low to me, but as I said, even at 180C, the filament drools out of the nozzle. At 225C, it's a goopy mess!

@jram: I've tried purple stick and hair spray, but not both yet. I've got 5 loops on the skirt 10mm from the object, and have a 5mm brim in my current Slic3r settings, which helped keep my test cube stuck down but was insufficient for a larger print. I did build an enclosure (clear acrylic in wooden frame), but actually have overheating problems, both with regards to having the electronics inside the enclosure and also with regards to PLA glass point, so there are now several vent holes in the top.

I'm wondering if I'm not having a couple extruder problems. First, the nozzle had gotten clogged around the time my PLA ran out. The drool coming out of the nozzle is curling around, so maybe I didn't get the nozzle cleaned enough, resulting in uneven extrusion pressure. Second, in all my futzing about clearing the nozzle, could I have damaged the thermistor and/or the heating elements such that they're really cranking out 200C+ but the thermistor's underreporting?

As for the rough printing, looking at the test cubes and the plane I printed, the bad spots are mostly on the "back" of the print, in line with the Z tower. Perhaps the belt tension's off there, compounding my other problems?

[gchristopher]

@gchristopher: my very first two prints (PEEK and layer fan shrouds) were essentially successful, and both were printed in ABS. I don't remember what temps I had set back then (January timeframe), but I suspect they were the defaults from the print profiles I loaded in the assembly manual. 180C seems WAY too low to me, but as I said, even at 180C, the filament drools out of the nozzle. At 225C, it's a goopy mess!

Yeah, when my extruder reaches temp, whatever filament is in it comes dripping out. The main problem I get from that is that the extruder isn't fully primed when the print starts. The print quality is still great, though.

For a while I added a few extra skirt lines to prime the printer, but now I just manually extrude 10mm of extra filament immediately before hitting start on the print. I use tweezers to pull the initial bit of extra plastic away before the print head drops to start the print. I should figure out gcode to do that automatically!

If you're getting globs during the print, maybe increase the retraction distances when the head lifts in your slicer settings?

[Captain Starfish]

Have you calibrated your hot end against a thermocouple?

180º seems pretty low for it to be oozing, I don't see it until about 220º or more usually.

Also: have you got a fan running over your RAMBo electronics? Mine used to skip all the time, it was the stepper driver overheating and shutting down. Added a spare fan blowing edge-on to the PCB and that all just stopped.

Biggest killer I've found for bed adhesion has always been too much height off the bed at z=0.

[hubrigant]

Have you calibrated your hot end against a thermocouple?

I don't have a thermocouple, but I checked the temp using a digital meat thermometer that tested within 1°F for water boiling temp at my altitude and with a Harbor Freight infrared thermometer, and both showed similar temps in the 170°C range when the RAMBo was holding at 180°C, so it looks as if the thermistor's not WILDLY off.

Biggest killer I've found for bed adhesion has always been too much height off the bed at z=0.

I went through last night and re-zero'd Z height as well as recalibrated the towers. They're all now within roughly a half of a thickness of a sheet of printer paper of each other. I haven't printed anything, though, as I'm also going through and redoing the belt tension with my new tensioning devices (derived from this threadhttp://forum.seemecnc.com/viewtopic.php?f=35&t=1169). Once I'm done with tensioning, I'll re-check Z height and give it another go.

[hubrigant]

After spending a huge amount of time futzing around with calibrations, etc., I finally got everything set up as well as I think I can manage. Based on my dial indicator, the geometry's now flat to within 0.02mm across the build surface. The belt tensioners are working great. I re-zeroed the Z axis. I tried printing the test cube again, and the first layer STILL wouldn't stick!

Frustrated, I pulled the ABS spool off the printer and put the nearly-empty PLA spool on. Lo and behold, it printed almost perfectly!

Is it possible that the adhesion problems, the gloopy prints, etc. were all the result of a bad spool of ABS? It seems as if that could explain why the ABS was drooling from the nozzle at only 180°C.

[Eaglezsoar]

After spending a huge amount of time futzing around with calibrations, etc., I finally got everything set up as well as I think I can manage. Based on my dial indicator, the geometry's now flat to within 0.02mm across the build surface. The belt tensioners are working great. I re-zeroed the Z axis. I tried printing the test cube again, and the first layer STILL wouldn't stick!

Frustrated, I pulled the ABS spool off the printer and put the nearly-empty PLA spool on. Lo and behold, it printed almost perfectly!

Is it possible that the adhesion problems, the gloopy prints, etc. were all the result of a bad spool of ABS? It seems as if that could explain why the ABS was drooling from the nozzle at only 180°C.

A bad roll is indeed possible. This forum contains many stories from users who got a bad roll.
The sad part is that the only way to determine a bad roll is to replace it with a roll from a well known manufacturer.
Please let us know what you discover.

[hubrigant]

So, I finally bit the bullet and got a new roll of filament (Hatchbox PLA), and it sticks just fine to the bed.

I've had the ABS in a sealed box with silica gel for a week or so. Once I get my new nozzle (original one's in bad shape from many, many mistakes of mine that have clogged it badly), I'll try one more time with the ABS before throwing in the towel on it.

[rehabmax]

Adjust your bed temperature to 70º C for PLA for better adhesion. The default is 60º C but I found that PLA was sliding all over the place. I use 210º C for PLA at the extruder head. i like the matter hackers filament. One spool of Black PLA was very brittle and kept breaking in the Bowden tube. I stopped using it.

Another thing was that i tried to print multiple items if they would fit on the bed, since it is pretty large. Bad idea. Just because you can position 4 or 5 small items on the bed it usually will not work out well. Don't give the printer too much to do at one time.

Edit the part to make sure it is flush with the bed. You can manipulate X,Y,Z axis rotation in Matter Control.

Check the "Raft" box when needed if you think the print will be wobbly. There is also a box for :support material" if there is going to be an overhang.

Try to print horizontal prints as much as possible, flat against the bed.

For ABS I use the Blue Painter tape.

The best thing i did was increase the bed temperature to 70ºC for PLA and melt it at 210º C.

A word of caution about items you download to print from Thingiverse or other sites. There are often files that have major errors in them and will not print properly. Most are pretty good but you have to be careful.

Have you adjusted the X,Y,Z, and bed travel accurately. Have you done the notebook paper test for all 4 and saved it to EEPROM? i have had to run the adjustments more than once when my prints were not coming out well.

Are the cheepskates running up and down smoothly and the rollers making the right level of contact?

I put my Rostock Max v2 together myself and I am not an engineer. it took me several months, doing it at night. I had to practice soldering to get my technique down.

This machine requires close monitoring and fine tuning .I have learned some lessons along the way. I got the machine up and running in October i think. Now I am very pleased with it. it is very accurate. The print quality is very good. Start out with some simple shapes and designs. Don't go for super complex pieces in the beginning.

Keep you hot end clean with a wire brush occasionally to dislodge any stuck filament. Make sure the Kapton tape stays around the hot end and wires. One time I looked up and it was all gone. Maybe it burned up. Anyway i took the assembly apart and added several more layers of Kapton tape.

I have more than one thing in the trash can that did not print properly. Don't be discouraged.

[geneb]

If you're printing PLA at 210, you're either printing REALLY fast, your thermistor is reading high, or you've got crap filament.

55C is a sweet spot for bed temp - I've been using that setting for 3 years, zero issues.

g.

[bot]

PLA varies wildly. So do the components that make up a 3d printer. 210 is too cold for some PLA, using an e3d with the built-in Rambo thermistor table.

[rehabmax]

When the bed temperature was 60º C the glass was practically a skating rink for my PLA filament. Nothing would stick and it would be all over the place after a few layers. Does that mean its bad filament? 210º C extruder temperature also gives me decent layer adhesion. Prints come out well for me. I guess i could lower the melting temperature a bit but I have had problems with brittle prints that broke apart. when the filament was too cool. i get my filament from Matter Hackers. I don't splurge for their premium stuff usually. My Rostock max seems to work well with these settings. If there is a risk of damaging components I'll make adjustments but it seems like the temperatures i am using are within the system's safety zones.

i think temperature varies by filaments and even batches. i am not a filament connoisseur, i just want decent prints. This works for me, it was only a suggestion from my experience.

[626Pilot]

I print PLA on a 50C bed with Elmer's School Glue sticks. It adheres just fine. I once tried 60C (printing with PLA and HIPS) and it still adhered fine. The trick is to give the school glue about 30-45 seconds to partially dry before starting the print. If I don't do this, it is like a "skating rink." The filament will just drag around and not stick anywhere.

[hubrigant]

I've been running my bed hotter, 70C at the moment, because I'm using a 1/8" copper plate heat spreader between the heater and the glass. The temp the thermistor measures is higher than the temp at the printing surface, so I adjust to compensate.