Banding problem

I can't remember where I read it, but someone else was having the same issue and it turned out that the printbed was constrained too much and not allowed to expand as it heated. Since it was "bang-bang" temperature controlled, he'd get patterns like that every time the heat would switch on or turn off since the glass would expand and contract upward/downward rather than laterally. After switching to binder clips to hold the printbed in place to allow it to expand outward, and setting PID control on the printbed the problems went away.

appdev007 Wrote:
-------------------------------------------------------
> So yes, it would appear that infill is playing
> into your problem because this cube has neater
> walls. I think you might need to adjust your Z
> steps a bit. I think it's raising the head too
> much and the plastic isn't getting smashed
> together enough. I also think the retraction in
> you slicer might be up too high. I'm going to
> guess that worst side is where it was changing
> layers and therefore doing retraction.
>
> What's your print surface, a glass dinner plate?
> You need something nice true and flat, like window
> pane glass. I recommend hair spray on top of that
> for PLA and school glues stick for ABS. I get my
> glass at the hardware store (lowes) and they even
> cut it to size. (Since I'm in the US I have to
> tell them the size in inches or they look at me
> stupid.)

For z steps, from Triffid Hunter's Guide:

z_steps = motor_steps_per_rev * driver_microstep / thread_pitch

In my case, with acme threaded rods on the Z axis:

z_steps = (200 * 16) / (25.4 / 16)

z_steps = 2015.748031

Does this seem correct?

I have not had a problem with retraction for any other objects, it seems there is something weird with this model. However my retraction settings are as follows:

Length: 1 mm
Lift Z: 0 mm
Speed: 30 mm/s
Extra length on restart: 0 mm
Minimum travel after retraction: 2 mm
Retract on layer change: YES
Wipe before retract: NO

My print surface is the heated bed itself, covered in Kapton tape. This is how the kit came from MakerGear and how it is supposed to be used. However it seems to me that this is not a very good solution and that I should ideally print on a glass plate with the heated bed under it, or some metal plate, in either case I know it must be perfectly flat. However, for most objects I can simply print with the bed turned off completely and work out my banding problem that way. I don't need a working bed to work out the banding problem, since I shouldn't get this banding whether the bed is turned on or not, as far as I can understand this. Printing without the bed does cause some warping though, but that is a different problem.

However, I do plan on getting a glass surface to print on when I have worked out this problem with the banding.

sheck626 Wrote:
-------------------------------------------------------
> I can't remember where I read it, but someone else
> was having the same issue and it turned out that
> the printbed was constrained too much and not
> allowed to expand as it heated. Since it was
> "bang-bang" temperature controlled, he'd get
> patterns like that every time the heat would
> switch on or turn off since the glass would expand
> and contract upward/downward rather than
> laterally. After switching to binder clips to
> hold the printbed in place to allow it to expand
> outward, and setting PID control on the printbed
> the problems went away.


Thank you for your input. However since I have this problem even when the bed is turned completely off, it cannot explain the "banding" problem I am observing.

However what you're suggesting is reasonable, it is not the first time I've heard this conjecture and it might explain why printing with the bed turned on makes it even worse. However it does not seem related to the banding problem.

I have done some more prints now, and a few other things.

1: This thread [forums.reprap.org] talks about a floating point error that can accumulate when the precision is too high on the z steps. This seems highly unlikely to me, but I tried it anyway, it didn't improve the prints at all, as suspected.

2: I have removed the screws from the z motors so that the motors will move instead of the rods if there is wobble. This did not help.

3: I tried printing with "external perimeters first". This gave me almost as good prints as printing without infill.

4: I tried reducing esteps again and printing without "external perimeters first", this gave me bad results again.

Does anyone have some conjecture as to why prints look much better when not printing infill? Should I reduce esteps even more? Any suggestions?

Do you think maybe the nozzle is bumping into the extruded infill and causing the glass print plate to slide slightly on the print bed? Now that you removed the screws on your Z motors, do they move when moving the Z axis? Also from looking at your machine, the Z lead screws appear to be constrained at the bottom. If that's the case, they shouldn't be.

sheck626 Wrote:
-------------------------------------------------------
> Do you think maybe the nozzle is bumping into the
> extruded infill and causing the glass print plate
> to slide slightly on the print bed? Now that you
> removed the screws on your Z motors, do they move
> when moving the Z axis? Also from looking at your
> machine, the Z lead screws appear to be
> constrained at the bottom. If that's the case,
> they shouldn't be.

I am printing directly at a Kapton-tape covered heated bed. But note that I'm printing with the bed turned off (causes warping but prevents low-frequency temperature swings, I need a glass plate or flat metal plate to remedy that problem).

The motors do move slightly when I move down on the Z axis. However there no observable wobble on the ends/tips of the Z threaded rods. The Z lead screws (I am assuming this is the same as threaded rods?) are not constrained. They do enter a printed part which has room for a bearing, but I have removed that bearing so there is room for it to move around without being constrained by anything (the hole is wider than the acme rod).

According to this article [www.evernote.com] which someone on IRC provided a link to, my problem is called "Z ribbing".

I have tried to follow the procedure explained starting at the string "To avoid Z ribbing, you should always choose a layer height that is a multiple of your full-step length."

full-step length for the screws = [pitch of screws] / [number of full-steps per rotation on your motors (usually 200)]

I am using acme Z threaded rods with a pitch of 1.5875 mm.
I am using 1.8 degree Nema 17 stepper motors with 200 full steps per revolution.

Therefore:

full-step length for the screws = 1.5875 / 200
full-step length for the screws = 7.9375*10^(-3) mm
full-step length for the screws = 7.9375 um

so, e.g.: 24 * 7.9375 = 190.5 -> 0.1905 mm layer height
or e.g.: so, e.g.: 32 * 7.9375 = 254 -> 0.254 mm layer height

I tried printing with both 0.1905 mm layer height and 0.254 mm layer height. The banding problem didn't go away.

Have I made some error in how I'm interpreting this article? Has anyone else tried to follow this?

I don't think that is your problem since the banding is too consistant with your prints. We know that you can get decent prints by printing in "spiral vase" mode, so maybe we should look there. Spiral vase mode causes the Z axis motions to be gradual rather than having discrete layer changes. Maybe it has something to do with acceleration or Z feed rate? The Z motors may be missing steps during "quick" layer changes, but not during gradual ones. It could also be a faulty driver, have you tried swapping them?

sheck626 Wrote:
-------------------------------------------------------
> I don't think that is your problem since the
> banding is too consistant with your prints. We
> know that you can get decent prints by printing in
> "spiral vase" mode, so maybe we should look there.
> Spiral vase mode causes the Z axis motions to be
> gradual rather than having discrete layer changes.
> Maybe it has something to do with acceleration or
> Z feed rate? The Z motors may be missing steps
> during "quick" layer changes, but not during
> gradual ones. It could also be a faulty driver,
> have you tried swapping them?

Thanks for the suggestions.

It is probably not related to Z axis motions being too fast:

#define DEFAULT_MAX_FEEDRATE {500, 500, 3, 45}
#define DEFAULT_MAX_ACCELERATION {1000,1000,50,1000}
#define DEFAULT_ACCELERATION 450
#define DEFAULT_RETRACT_ACCELERATION 450
#define DEFAULT_XYJERK 10.0 // (mm/sec)
#define DEFAULT_ZJERK 0.2 // (mm/sec)
#define DEFAULT_EJERK 2.5 // (mm/sec)

I have not tried swapping the drivers. I will try that suggestion.

Sometimes to track down a Z axis issue, I just sit and watch the Z couplers. They should spin only when a layer is fully printed. There should be no twitching or jittering part way through the designated points where things move from one layer to the next. Some software(maybe all?) shows you what layer you are on in real time as it prints.

Maybe I'm stating the obvious! Just wondering if this has been checked.

Swapping drivers is also a good troubleshooting suggestion.

---

Yvan

Singularity Machine

frac, my first thin wall cube print was worse than yours. The layers wouldn't even set on top of each other. It took tweaking just to get it to look like yours. I spend a lot of time moving my axises and measuring. Once I had them all, including the extruder. moving the exact amount they were suppose to my print moved from looking like yours to something more reasonable. The step value I ended up with for my E and Z weren't the exact ones from the calibration. I continued tweaking the E one even after doing the test of watching X length of filament dissapear down the extruder. I kept reprinting the in-filled calibration cube like the one you posted here first and kept looking at it. I would adjust E a little, look at what it did and then make another adjustment until it looked like what I thought it should based on things I had read and pics I was seeing of others prints.

After this, I was left with axis skipping and some other messiness that was taken care of mostly by adding a 2nd supply to take the load of the heat bed off my primary PSU (as we have discussed). The things fixed by the second PSU included overheating of small prints, which I think was due to voltage variations causing misreading of the thermocouple on the hot end. After all this my thin wall cube printed to perfection.

As I'm writing this a 20 mm box is printing with swapped drivers. I swapped Y and Z.

Print settings:

Layer height: 0.254 mm (to avoid Z ribbing, which I hear might be just a myth? Regardless, this should work around that)
Extrusion width: 0.4 mm
Temperature: 185 degrees C
Bed temperature: Off
Cooling: 40 mm and 80 mm fans

Results:

No difference compared to before swapping.

appdev007 Wrote:
-------------------------------------------------------
> frac, my first thin wall cube print was worse than
> yours. The layers wouldn't even set on top of each
> other. It took tweaking just to get it to look
> like yours. I spend a lot of time moving my axises
> and measuring. Once I had them all, including the
> extruder. moving the exact amount they were
> suppose to my print moved from looking like yours
> to something more reasonable. The step value I
> ended up with for my E and Z weren't the exact
> ones from the calibration. I continued tweaking
> the E one even after doing the test of watching X
> length of filament dissapear down the extruder. I
> kept reprinting the in-filled calibration cube
> like the one you posted here first and kept
> looking at it. I would adjust E a little, look at
> what it did and then make another adjustment until
> it looked like what I thought it should based on
> things I had read and pics I was seeing of others
> prints.
>
> After this, I was left with axis skipping and some
> other messiness that was taken care of mostly by
> adding a 2nd supply to take the load of the heat
> bed off my primary PSU (as we have discussed). The
> things fixed by the second PSU included
> overheating of small prints, which I think was due
> to voltage variations causing misreading of the
> thermocouple on the hot end. After all this my
> thin wall cube printed to perfection.

I get what you're saying, it takes a lot of tweaking. But my problem is that it seems like adjusting just one parameter at a time does nothing to improve my primary underlying problem. I have printed more than a hundred 20 mm calibration boxes and done a lot of mechanical tweaking, such as changing from M8 to acme threaded rods and replacing printed pulleys with non-printed ones, I'm not really any closer to a solution.

It seems to me that there must be several things at once that are slightly wrong, and that I need to make several corrections at once (even though I've tried going in that direction on my own, such as adjusting print speeds while adjusting layer height and extrusion width). Or that there is some single underlying cause that has been overlooked so far.

The most interesting to me so far is that when printing with no infill, the prints look a lot better. I want to make my prints with infill look as good as my prints with no infill, or even better, but I have no idea what to adjust to make that happen. As mentioned I've tried (among other things) adjusting layer height, extrusion width, speed and esteps already.

Set your layer height to 0.2 and width over thickness to 2. I'm going for an extrusion width of 0.4. Then print this cube. It's in-filled on bottom and hollow on top. If the in-fill is really the issue, then the bottom should print bad and the top print good right?

appdev007 Wrote:
-------------------------------------------------------
> Set your layer height to 0.2 and width over
> thickness to 2. I'm going for an extrusion width
> of 0.4. Then print this cube. It's in-filled on
> bottom and hollow on top. If the in-fill is really
> the issue, then the bottom should print bad and
> the top print good right?

I am printing this cube now.

However, I printed the standard 20 mm calibration box with no infill at all, just to see if it would get as good results as the spiral vase one, which would determine if the infill alone was a major factor.

The infill is not the factor, it appears that the "double" walls on the 20 mm calibration box is a problem though, observe this result:

[img829.imageshack.us]

This is of a hollow 20 mm box, no infill, but the walls are as thick as they should be (the spiral vase walls are only one extrusion width thick).

appdev007 Wrote:
-------------------------------------------------------
> Set your layer height to 0.2 and width over
> thickness to 2. I'm going for an extrusion width
> of 0.4. Then print this cube. It's in-filled on
> bottom and hollow on top. If the in-fill is really
> the issue, then the bottom should print bad and
> the top print good right?

It appears the object in that file does have infill at half of the height, then the rest half is hollow. Did you want me to set the infill to 0 for this print? Anyway, see my above post.

No, set in fill to like 25% and let it rip. I made that box to have side walls in multiples of 0.4 and asked you to set that just for the reason you were talking about above.

fractal5 Wrote:
-------------------------------------------------------
> appdev007 Wrote:
> --------------------------------------------------
> -----
> > Set your layer height to 0.2 and width over
> > thickness to 2. I'm going for an extrusion
> width
> > of 0.4. Then print this cube. It's in-filled on
> > bottom and hollow on top. If the in-fill is
> really
> > the issue, then the bottom should print bad and
> > the top print good right?
>
> It appears the object in that file does have
> infill at half of the height, then the rest half
> is hollow. Did you want me to set the infill to 0
> for this print? Anyway, see my above post.

I've figured out the problem. Your printer runs too slow. Like it's got to be the slowest one ever made. ; )

fractal5 Wrote:
-------------------------------------------------------
> I am printing this cube now.

Edited 1 time(s). Last edit at 09/05/2013 05:27PM by appdev007.

Your box turns out to be significantly taller than the standard 20 mm box, and it confirms the same problem as before when I print it. Same banding problem.

It was pointed out to me that on the last picture, the spacing is every 6 layers or so, which is 1.524 mm, which is pretty close to my thread pitch, which is 1.5875 mm. Hence this may indeed be simply traditional Z wobble and nothing more fancy than that.

I have tried something new now:

I was given a suggestion that the Z couplers might be tightened at an offset, that is at an askew angle. So I opened them up, and retightened them properly.

Doing this has caused the left side threaded rod to scrape against something on the inside of the end X printed part. There is a space inside that printed part where it is more narrow than the rest, I'm assuming that is where it is scraping. This suggests the Z couplers was indeed tightened at an angle, and this was masking some other problem, which I was given the suggestion that might be bent Z couplers. As a side note I can make the metal-against-plastic scraping sound go away by grabbing the left Z motor with my hand physically and turning/tilting it slightly to the left (my motors are no longer fixed to the plastic mounts).

However I simply tried to print with this configuration, even though is is scraping.

Same problem. I still get the same banding problem with no real difference.

I then added printed Prusa Z isolators: [www.thingiverse.com] to both sides. I tried to print again. and I got a new type of result which is maybe not better, but certainly different. I will post a picture when I have more time to work on this.

appdev007 Wrote:
-------------------------------------------------------
> No, set in fill to like 25% and let it rip. I made
> that box to have side walls in multiples of 0.4
> and asked you to set that just for the reason you
> were talking about above.
>
> fractal5 Wrote:
> --------------------------------------------------
> -----
> > appdev007 Wrote:
> >
> --------------------------------------------------
>
> > -----
> > > Set your layer height to 0.2 and width over
> > > thickness to 2. I'm going for an extrusion
> > width
> > > of 0.4. Then print this cube. It's in-filled
> on
> > > bottom and hollow on top. If the in-fill is
> > really
> > > the issue, then the bottom should print bad
> and
> > > the top print good right?
> >
> > It appears the object in that file does have
> > infill at half of the height, then the rest
> half
> > is hollow. Did you want me to set the infill to
> 0
> > for this print? Anyway, see my above post.

Edited 1 time(s). Last edit at 09/05/2013 07:40PM by fractal5.

fractal5 Wrote:
-------------------------------------------------------
> Your box turns out to be significantly taller than
> the standard 20 mm box, and it confirms the same
> problem as before when I print it. Same banding
> problem.
>
> It was pointed out to me that on the last picture,
> the spacing is every 6 layers or so, which is
> 1.524 mm, which is pretty close to my thread
> pitch, which is 1.5875 mm. Hence this may indeed
> be simply traditional Z wobble and nothing more
> fancy than that.
>
> I have tried something new now:
>
> I was given a suggestion that the Z couplers might
> be tightened at an offset, that is at an askew
> angle. So I opened them up, and retightened them
> properly.
>
> Doing this has caused the left side threaded rod
> to scrape against something on the inside of the
> end X printed part. There is a space inside that
> printed part where it is more narrow than the
> rest, I'm assuming that is where it is scraping.
> This suggests the Z couplers was indeed tightened
> at an angle, and this was masking some other
> problem, which I was given the suggestion that
> might be bent Z couplers. As a side note I can
> make the metal-against-plastic scraping sound go
> away by grabbing the left Z motor with my hand
> physically and turning/tilting it slightly to the
> left (my motors are no longer fixed to the plastic
> mounts).
>
> However I simply tried to print with this
> configuration, even though is is scraping.
>
> Same problem. I still get the same banding problem
> with no real difference.
>
> I then added printed Prusa Z isolators:
> [www.thingiverse.com]
> to both sides. I tried to print again. and I got a
> new type of result which is maybe not better, but
> certainly different. I will post a picture when I
> have more time to work on this.
>

This is the result:

[img829.imageshack.us]

Notice the thick bottom. I don't know why that happens. There appears to be less banding, but is it really gone? Is that what it is supposed to look like?

I also haven't gotten rid of that scraping sound that started after I retightened my Z couplers (sound from the acme Z threaded rod rubbing against the inside of the hole in the X end part, see my post above this one).

It would be great if someone could post a picture of what a 20 mm calibration box is supposed to look like, for reference.

Loading them up now.

Hey, that is a ton better than what you had before!

1. What type of plastic is that?
2. What was the hot end temp?
3. What was the heat bed temp?
4. What layer height was set for that print?

(I'm strongly expecting temperature issues for the bottom of the print.)


fractal5 Wrote:
-------------------------------------------------------
> This is the result:
>
> [img829.imageshack.us]
>
> Notice the thick bottom. I don't know why that
> happens. There appears to be less banding, but is
> it really gone? Is that what it is supposed to
> look like?
>
> I also haven't gotten rid of that scraping sound
> that started after I retightened my Z couplers
> (sound from the acme Z threaded rod rubbing
> against the inside of the hole in the X end part,
> see my post above this one).
>
> It would be great if someone could post a picture
> of what a 20 mm calibration box is supposed to
> look like, for reference.

Prusa i2
0.4 mm j-head (hotends.com)
0.2 mm layer height
0.5 mm layer width
Ultimachine blue ABS
230 deg hot end
110 deg heat bed



[www.flickr.com]

Sorry, only PLA I have on hand is clear and it wouldn't have been very good for this purpose.

Edited 3 time(s). Last edit at 09/07/2013 12:59AM by appdev007.

0.254 mm layer height.
0.4 mm extrusion width.
Same black PLA as before, from MakerGear.
185 degrees C except for 190 degrees C for the first layer.
Bed turned completely off.
Two fans for cooling.

I have printed quite a few boxes with this exact same configuration before. The difference is:

Retightening the Z couplers. This appears to have fixed something, but caused a new problem as I mentioned in my above post: The Z threaded rod scrapes along the inside of the X end plastic part on the left side now.

Also: I'm using Z screw isolators now.

I got the suggestion my Z couplers may be bent. So I'm going to remove them and see if I can figure that out.

appdev007 Wrote:
-------------------------------------------------------
> Hey, that is a ton better than what you had
> before!
>
> 1. What type of plastic is that?
> 2. What was the hot end temp?
> 3. What was the heat bed temp?
> 4. What layer height was set for that print?
>
> (I'm strongly expecting temperature issues for the
> bottom of the print.)
>
>
> fractal5 Wrote:
> --------------------------------------------------
> -----
> > This is the result:
> >
> >
> [img829.imageshack.us]
> >
> > Notice the thick bottom. I don't know why that
> > happens. There appears to be less banding, but
> is
> > it really gone? Is that what it is supposed to
> > look like?
> >
> > I also haven't gotten rid of that scraping
> sound
> > that started after I retightened my Z couplers
> > (sound from the acme Z threaded rod rubbing
> > against the inside of the hole in the X end
> part,
> > see my post above this one).
> >
> > It would be great if someone could post a
> picture
> > of what a 20 mm calibration box is supposed to
> > look like, for reference.

You might try taking a look at this post about z-ribbing on another forum.

[www.printrbottalk.com]

Hope it helps.

I asked about layer height because it looked like your layers weren't smashed together enough. I think your Zs being loose could have been causing some of this. It might be squashed on the bottom now because the tip of the hot end is making better contact with the print and now that 190 deg is just too much down there for it. Notice how the widening shrinks as you go up? That's probably your hot end shedding that extra 5 deg.

If you need 190 to get plastic to stick to bare glass or something, then consider using some hair spray and bring the temp back down to 185 for the first layer. I haven't ever needed to set my first layer temp higher, but of course, this doesn't mean you won't have to.

Still think you might look at adjusting those Z steps.

fractal5 Wrote:
-------------------------------------------------------
> 0.254 mm layer height.
> 0.4 mm extrusion width.
> Same black PLA as before, from MakerGear.
> 185 degrees C except for 190 degrees C for the
> first layer.
> Bed turned completely off.
> Two fans for cooling.
>
> I have printed quite a few boxes with this exact
> same configuration before. The difference is:
>
> Retightening the Z couplers. This appears to have
> fixed something, but caused a new problem
> as I mentioned in my above post: The Z threaded
> rod scrapes along the inside of the X end plastic
> part on the left side now.
>
> Also: I'm using Z screw isolators now.
>
> I got the suggestion my Z couplers may be bent. So
> I'm going to remove them and see if I can figure
> that out.
>

I have now removed my Z threaded rods and examined the Z couplers while they were spinning freely, I examined them very carefully. They appear perfectly straight and not bent in any way.

I have since retightened the Z couplers to the Z rods. I still have the same problem with the sound of the Z threaded rod scraping against the inside of the X end. I have no idea why this suddenly started happening. The rods are not bent.

I removed the Z isolators and adjusted my Z endstop. I now get prints that look like this:

[img834.imageshack.us]
[img541.imageshack.us]

Layer height: 0.254 mm
Extrusion width: 0.4 mm
Extruder temp: 185 degrees C
Bed: 0

So it appears I'm back to my original results now, except that now my Z threaded rod is scraping against the inside of the X end part, even though the rod and the coupler are both straight!

I was given the suggestion I should move to M5 rods instead of 1/4 inch acme. However, this suggestion makes no sense to me. As I understand M5 and M8 rods are manufactured with a lower specification than acme rods, you will almost never get a perfectly straight M5 or M8 rod. So if I bought M5 rods, I would likely end up with even more imperfections in my rods.

appdev007, why do you think I should adjust my z steps?

My z steps:

2015.748031

Which I have arrived at doing the following:

z_steps = (200 * 16) / (25.4 / 16)
z_steps = 2015.748031

In what way should I adjust my z steps?


appdev007 Wrote:
-------------------------------------------------------
> I asked about layer height because it looked like
> your layers weren't smashed together enough. I
> think your Zs being loose could have been causing
> some of this. It might be squashed on the bottom
> now because the tip of the hot end is making
> better contact with the print and now that 190 deg
> is just too much down there for it. Notice how the
> widening shrinks as you go up? That's probably
> your hot end shedding that extra 5 deg.
>
> If you need 190 to get plastic to stick to bare
> glass or something, then consider using some hair
> spray and bring the temp back down to 185 for the
> first layer. I haven't ever needed to set my first
> layer temp higher, but of course, this doesn't
> mean you won't have to.
>
> Still think you might look at adjusting those Z
> steps.
>
> fractal5 Wrote:
> --------------------------------------------------
> -----
> > 0.254 mm layer height.
> > 0.4 mm extrusion width.
> > Same black PLA as before, from MakerGear.
> > 185 degrees C except for 190 degrees C for the
> > first layer.
> > Bed turned completely off.
> > Two fans for cooling.
> >
> > I have printed quite a few boxes with this
> exact
> > same configuration before. The difference is:
> >
> > Retightening the Z couplers. This appears to
> have
> > fixed something, but caused a new
> problem
> > as I mentioned in my above post: The Z threaded
> > rod scrapes along the inside of the X end
> plastic
> > part on the left side now.
> >
> > Also: I'm using Z screw isolators now.
> >
> > I got the suggestion my Z couplers may be bent.
> So
> > I'm going to remove them and see if I can
> figure
> > that out.
> >

KDog Wrote:
-------------------------------------------------------
> You might try taking a look at this post about
> z-ribbing on another forum.
>
> [www.printrbottalk.com]
> =20&t=4596
>
> Hope it helps.

Thanks, I am using a layer height that should deal with the Z ribbing problem though, as explained here: [www.evernote.com] See my earlier post for how I arrived at 0.254 mm which I'm using for my current prints.

Edited 1 time(s). Last edit at 09/08/2013 02:05PM by fractal5.

Just saying the calculated z step value for my machine had to be tweeked. It might be actually moving 0.212 mm when you tell it to move 0.200.

Based on newest pics I would look into feed/temperature issues.

Good luck.

I have measured my z steps with a digital caliper before to translate to accurate real-world Z movement, it is correct. I just did another measurement, it moves exactly as much as it should.

Feed rate or e-steps: I have measured this before and got a good measurement, it is accurate. However I have also tried to increase and decrease e_steps while printing, including having printed several boxes with higher and lower e_steps just to see if this makes any noteworthy difference. It doesn't appear to do so.

Bed temperature issues: Printing with the bed on makes it worse. Kapton tape is enough to make it stick, but I get a little warping. I assume this will sort itself out when I get a glass plate or metal plate so there is not so much heat fluctuations.

Hot-end temperature issues: I don't think I agree that this is the way to go, I have tried other temperatures before, it doesn't appear to really affect the underlying problem (the banding) as much as cause other issues.

If I should tweak the temperature any more, what should I do, e.g. what should the expected results be if I increase or lower the temperature? What should I look for specifically?

I feel like I'm fumbling around blindly, doing experiments without knowing what to look for, what to expect; while constantly having a feeling that tweaking just one thing at a time will never on its own solve the problem.

However, it seems to me this is a mechanical problem. Keep in mind that after I retightened the Z couplers, I got that unwanted sound from the X end and the Z threaded rod and my prints looked different. Doesn't this imply some sort of mechanical problem? I'm just having a hard time figuring out what the mechanical problem is. Everything is straight, everything is tightened down properly. There is no play, slack or anything. But still I get this unwanted sound from the left-hand side.

appdev007 Wrote:
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> Just saying the calculated z step value for my
> machine had to be tweeked. It might be actually
> moving 0.212 mm when you tell it to move 0.200.
>
> Based on newest pics I would look into
> feed/temperature issues.
>
> Good luck.