Random banding issue. Layers don't line up perfectly.

Attachment 8449Attachment 8450Attachment 8451Attachment 8452Attachment 8453Hi. I was wondering what causes the layers not to line up in the pictures. I thought it was z banding but my layers not lining up is random. Also, the layers that don't line up seem a bit underextruded on all sides of the 20mm calibration cube eliminating a loose x or y axis both of which i have tightened multiple times. Also, in the one picture it looks like my bottom layer was extruded inconsistently, which I thought might be connected. I initially thought underextrusion was the problem and while extruding more does help minimize the banding (see right block in pic of two black blocks), it creates overextrusion issues in other places. It seems that a high temp also helps the problem. But the temp was 235 Celsius which seems a bit high for black PLA. Any ideas what might cause this random banding? Thanks

Is there some play in your nozzle? This could happen if the nozzle could move about a little bit. Make sure everything is rock solid.

I just tightened all the axes. Probably a little to much. There was a fair amount of resistance to movement. Anyways, it helped a little bit, but the issue is definitely still there. I'll post pictures when the next print is done.

Attachment 8454Attachment 8455Attachment 8456Attachment 8457Here are a few pics of my new print. Looks a bit under extruded on the sides but maybe over extruded on the top. Or maybe that's just because of the slicer. I guess this thread has just turned into a critique my print thread. I notice that the filament occasionally makes a faint crackly sound when being retracted. My retraction is at 3mm. Also, I printed at 100% flow and my e-steps are calibrated so my extruder is pushing the right amount of filament through (I measured). I am trying 110% flow just to see what happens. I appreciate any advice. Thanks. Here's some print info:
Print speed: 30mm/s
Nozzle Temp: 230 Celsius (high temp explained in first post)
Bed Temp: 60 Celsius
Filament: MakerFarm Black PLA
Layer height: 0.1mm (0.3 mm first layer)

Hi,
I think that the way you approach this is not systematic enough.

If the e-steps are calibrated OK, don't play with it, you'll just mess the situation for the filled layers (and notably the first ones). Unless of course your filament is not perfectly 1,75mm.
By the way, why do you print a very thick 1st layer ? Are we talking raft here or real first layer ? If the esteps are not set properly, you will overflow your layer and that will mess the following ones. Same if the Z-offset is not set properly.

The temp is way too high for PLA. This seems suspicious in itself.

Try printing slower and see if that brings you to a cleaner print for at least a temporary solution.
Is the movement smooth on all axis ?
Have you lubricated the rods ?
Is your extruder knobbeed bolt / gear / whatever clean ?
Do you have a cooling fan on the print while printing PLA ? That ALWAYS helps.

yeah 210 and a cooling fan.

That doesn't look like 0.1 to me either :-)

try 0.2 - 0.1 might just be too little plastic coming out.

Thanks for all the reply guys. I'd been going at it systematically for two weeks but ran out of ideas to be honest. Temp and flow rate seemed to help but I think they just masked the real issue. I will go back to the settings suggested above and let you guys know how it goes. Maybe from there you can give me a suggestion as to what to fix. I will recalibrate e-steps and check my z-offset again too.

Oh and my first layer was thick because cura said it provided better bed adherence and I just went with the default. Should I match it to the rest of the layers? I'll do that for my baseline test. Thankss.

Attachment 8481Attachment 8482Attachment 8483Attachment 8484Attachment 8485Here's a print I did going back to my basic settings.

Print temp - 210 Celsius
bed temp - 70 celsius
print speed - 30mm/s
layer height - 0.2mm
initial layer height - 0.2mm
retraction - 4mm
retraction speed - 30mm/s
infill - 15%
shell width - 0.8mm (0.4mm nozzle)
flow - 100%
makerfarm black PLA
cooling fan enabled on full speed
e-step calibration was good
bed leveling was good
z offset was good

honeslty im just glad I can print objects this cool. But I would like to improve it. Two thoughts I had were that maybe my Hobbed bolt isn't tightened right causing inconsistent extrusion or maybe my PLA has absorbed water because it's hydroscopic. I know I can put the PLA in an oven to dry it out but I don't know how tight my honbed bolt should be. Could someone let me know? And other ideas. Thanks! I really appreciate it.

I run PLA with about the exact same settings except for retraction speeds.

I'm using 1mm retraction and 20mm/s for the speed. YMMV

-moyes

I'm trying it out now. Best lead I've got. Thanks!

My retraction seems a bit better now but the print still looks pretty much the same. Unfortunately it didn't solve my original issue. I'll just keep trying new things one at a time. Any other ideas? Thanks!

Check the bottoms of your Z threaded rods. If they're not flat, and the uneven edge is in contact with the motor shaft, artifacts like this can occur. You can just file them flat or better yet, file them flat and then drop a BB into the tube so it provides a single point of contact on the bottom of the screw.

Another thing to check is to be sure your filament is unrolling freely into the extruder. I saw something similar to this once when my filament was tangled and it spent the night pulling against a half-hitch tied around the spool.

Someone also suggested making sure your hot end wasn't loose, and I didn't see you respond to that, specifically. You said your axes were all tight, but is the hot end tight in the carriage? Is there any wiggle in the way the hot end is mounted to the extruder?

Thanks for the reply. I checked the Z-rods and tried a BB. No luck. The filament thing made sense but alas watching it/ making sure it was loose through a whole print didn't help. The hot end is tight too. I can move it but its only due to the flex in the wood. I've made sure all the connections are as tight as possible. One interesting thing is that my prints are significantly better in Slic3r. I've been with Cura because I liked how it sliced objects better but I figured I'd give Slic3r another chance. There is still some banding but its much less severe. Any idea why the slicer might have such a big impact. Possibly a clue to solving the issue. I'll just keep at it one variable at a time. If anyone has any more ideas I'd love to hear them. Thanks

Quote:

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Originally Posted by pjfossee

Thanks for the reply. I checked the Z-rods and tried a BB. No luck. The filament thing made sense but alas watching it/ making sure it was loose through a whole print didn't help. The hot end is tight too. I can move it but its only due to the flex in the wood. I've made sure all the connections are as tight as possible. One interesting thing is that my prints are significantly better in Slic3r. I've been with Cura because I liked how it sliced objects better but I figured I'd give Slic3r another chance. There is still some banding but its much less severe. Any idea why the slicer might have such a big impact. Possibly a clue to solving the issue. I'll just keep at it one variable at a time. If anyone has any more ideas I'd love to hear them. Thanks

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Maybe different print speeds?

Ah I wish it were that easy. I've tried 10mm/s - 75mm/s. Faster seemed a bit better but I think it's just masking the issue more than solving it.

Is the Death Star from your pics this one?

http://www.thingiverse.com/thing:245922

If so, I'll take a stab at printing tonight and see what mine looks like.

-moyes

FYI, 9/10 times I end up going back to Slic3r. Never really liked what Cura or MatterControl was giving me.

Yep, that's the same one. I couldn't thank you enough for doing that! I'll print one out again with my slic3r settings to compare. Thanks!

I solved the problem. It was just the fluctuation in the heated bed temperature causing the issue. I feel like an idiot for not realizing it. Especially because I did think of it two weeks ago but after a print came loose with the heated bed off I trashed the idea. I just read a forum post talking about different types of relays and mentioning that mechanical ones like mine sometimes cause too much temperature fluctuation. I noticed my temperature varied between 69 and 72 Celsius but just considered it normal. I know better now! I seem to be able to print fine if I turn the bed off after a few layers. I don't think that should present too many issues would it? Thanks for all the help guys - I solved about a dozen other issues I didn't even know I had thank to your help.

Attachment 8510If anyone's curious. I'm sure you can tell which one is the better one. Same layer height.

Any tips on getting my prints to stick better now that I can't use my bed for the whole print? Or possibly a better replacement for the relay? Or a fix for the bed? I'm researching it now but figured I'd ask. Thanks.

I quit using 70C for my bed temp with PLA due to adhesion issues.

Currently using 50C and hairspray with pretty good results.

-moyes

A cold bed and 3M blue painters tape cleaned with alcohol provides me with great PLA adhesion. I've broken multiple prints and pieces of glass with this approach. If I have a delicate part or a very large print, I'll cut back on the alcohol swabbing so that wax on the tape limits the adhesion.

Make sure your clips are close to the bed corners. The farther they are from the corners, the less degree that the glass is mechanically tied to the bed mounts in the corners.

It's not the mechanical relay that is the problem here. The root issue is that the (glass + heat bed) flexes as heat is turned on and off. A mechanical relay requires the heat to be turned on and off fairly slow, leading to the flex being detectable in some prints. Swapping out the mechanical relay with a Solid State Relay (SSR) allows you to then migrate to PID, a smarter control method built into Marlin that turns heat on and off far faster. The faster cycling both provides a more stable temperature and won't lead to as much noticeable flex. It takes the combination to reap the benefits. Just swapping out the relay alone won't solve the problem.

For more info, you can search the MakerFarm subforum for Solid State Relay. Here's one recent thread - 3dprintboard.com/showthread.php?15818-How-I-fixed-Z-banding-on-my-12-quot-i3v-AL-Y-bed-and-solid-state-heat-bed-relay-PID

Looks like bed warping issues to me, try a print with blue tape and the heat bed off and see if it looks better.

If it does you need to get an aluminum bed if you haven't already and get a solid state relay and setup PID control on your heat bed. There is a thread somewhere in the forums that I did when I setup PID on my heatbed that has some info on how to do it.


"EDIT" I somehow replied to a cached version of this thread before you realized it was your bed as I mention above"

Here is what I did to fix my bed warping and Z banding.


http://3dprintboard.com/showthread.p...ighlight=fixed

I've never succeeded with a hot bed and PLA. I've had my best success with blue tape and a cold bed. Cleaning the tape with alcohol or acetone caused the print to bond permanently to the tape. It worked great for me just on the tape, skin oil and all.

James

Quote:

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Originally Posted by clough42

I've never succeeded with a hot bed and PLA. I've had my best success with blue tape and a cold bed. Cleaning the tape with alcohol or acetone caused the print to bond permanently to the tape. It worked great for me just on the tape, skin oil and all.

James

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On the makerfarm for PLA I use glue stick and keep the bed at around 60°C and have good adhesion, on the Daughters Da'vinci JR without a heated bed I use blue painters tape and as you mention if I clean it with alcohol the parts can't be removed from the tape without pulling the tape off the bed surface.

What I don't like about the painters tape is the rough texture of the printed surface that was in contact with the tape. The other issue with tape is that sometimes the part will still warp and pull the tape away from the glass print surface even though the PLA is still stuck to the tape.

For me glue stick and heat seems to work the best

Thanks for all the replies. I'll definetly be moving to blue painters tape for the time being it looks like. And Chadd, it was actually your thread that gave me the answer. Thanks! I'll be ordering a solid state relay soon. If I have these issues with PLA and a heated bed can I assume I will have them with ABS as well? If so hopefully a SSR will solve that. I'll probably build am enclosure while I'm at it.

Quote:

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Originally Posted by pjfossee

Thanks for all the replies. I'll definetly be moving to blue painters tape for the time being it looks like. And Chadd, it was actually your thread that gave me the answer. Thanks! I'll be ordering a solid state relay soon. If I have these issues with PLA and a heated bed can I assume I will have them with ABS as well? If so hopefully a SSR will solve that. I'll probably build am enclosure while I'm at it.

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The higher the bed temp the worse the warping will be because the heat bed has to kick on and off so much, so yes you will likely have more issues with ABS than PLA. But both will look like crap until you get the bed warping taken care of.

Once you get it fixed the difference is literally unbelievable, it not only fixes appearance but also will fix things like layer delamination, first layer issues, nozzle dragging, strings, etc etc..

Quote:

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Originally Posted by clough42

I've never succeeded with a hot bed and PLA. I've had my best success with blue tape and a cold bed. Cleaning the tape with alcohol or acetone caused the print to bond permanently to the tape. It worked great for me just on the tape, skin oil and all.

James

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I have always used hot bed (70C) with PLA and its been brilliant. But with the hair spray tip. You are the pro however :-). The hair spray wears off after a couple of prints so needs to be reapplied. It works amazingly well.

Well im definetly looking forward to installing the SSR. If my heated bed came preinstalled with the mechanical relay, do you think I can just jumper it so that it is always in the closed state thus bypassing it? And then add in a SSR and hooking it up to the RAMPS board and heated bed. I've looked at the circuit diagrams for it. Seems pretty simple.

Quote:

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Originally Posted by pjfossee

Well im definetly looking forward to installing the SSR. If my heated bed came preinstalled with the mechanical relay, do you think I can just jumper it so that it is always in the closed state thus bypassing it? And then add in a SSR and hooking it up to the RAMPS board and heated bed. I've looked at the circuit diagrams for it. Seems pretty simple.

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I am not familiar with the new on board relay so I can't help you much there. I would assume that it has solder points on the heat bed where the power is applied from the relay to the board, you could probably attach the new wiring from the SSR to those points.

Well it's been a little while but I finally got the relay and installed it. The prints are a thousand times better. Also got a PEI sheet while I was at it and I'm now printing ABS wonderfully too. Thanks for the help everyone!

Quote:

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Originally Posted by pjfossee

Well it's been a little while but I finally got the relay and installed it. The prints are a thousand times better. Also got a PEI sheet while I was at it and I'm now printing ABS wonderfully too. Thanks for the help everyone!

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No problem, glad it helped.