Banding problem

I'm certain I have at least one mechanical problem now. I'm not sure if I've always had this/these specific problem(s) or not, but now I have this problem:

After some more mechanical adjustments (removing rods, inserting them again, trying to square the machine more properly) I noticed that when I lower the X carriage assembly on the Z axis (home) that the right hand side nut pulls itself free from the X end.

I also made another observation. When the X carriage assembly is at the top on the Z axis, the left hand Z threaded rod points to the left in the lower end Z part (where there would usually be a bearing). As I lower the X carriage assembly on the Z axis, the rod slowly centers itself.

What does this indicate mechanically? That the nut and/or the X end printed part are askew? Or that the rod is bent? That the machine is not square? It also makes a slight circle at the bottom.

Is there any guide or tutorial paper that would be helpful for me in this current situation?

Quote
I also made another observation. When the X carriage assembly is at the top on the Z axis, the left hand Z threaded rod points to the left in the lower end Z part (where there would usually be a bearing). As I lower the X carriage assembly on the Z axis, the rod slowly centers itself

The Z motor is out of line with the carriage.

Quote
Is there any guide or tutorial paper that would be helpful for me in this current situation?

This is for a different machine but it's basically the same design, you are welcome to use it if you like. Near the bottom of the page it shows how to align the threaded rods.

http://forum.eckertech.com/viewtopic.php?f=7&t=117

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Bruce Wrote:
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>

Quote
I also made another observation. When the
> X carriage assembly is at the top on the Z axis,
> the left hand Z threaded rod points to the left in
> the lower end Z part (where there would usually be
> a bearing). As I lower the X carriage assembly on
> the Z axis, the rod slowly centers
> itself

>
> The Z motor is out of line with the carriage.
>
>

Quote
Is there any guide or tutorial paper that
> would be helpful for me in this current
> situation?

>
> This is for a different machine but it's basically
> the same design, you are welcome to use it if you
> like. Near the bottom of the page it shows how to
> align the threaded rods.
>
> [url=http://forum.eckertech.com/viewtopic.php?f=7&
> t=117]http://forum.eckertech.com/viewtopic.php?f=7
> &t=117[/url]

Okay, that was just a slip on my part. I forgot to level the X carriage. That solved the problem quoted above.

However now the left side of the Z rods is stuttering as it moves down. Is this also related to squaring, or something else? I also have that unwanted sound of "scraping" that seems to come from the Z threaded rod (still left side) scraping against the inside of the X end printed part.

The stuttering and scraping noise is because something is binding in the X end. Does that thing use tensioning springs for the threaded rods?

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Bruce Wrote:
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> The stuttering and scraping noise is because
> something is binding in the X end. Does that thing
> use tensioning springs for the threaded rods?

I just managed to correct it. Now the bad sound is gone and everything looks very good. I undid the M8 nuts holding the left hand side together at the bottom and moved it around while it was jogging up and down.

Edit: It does not have tensioning springs for the threaded rods. I had that before, but removed them.

However, just as I was about to adjust my Z endstop to print a new 20 mm test box, the printed part for the Z stop broke.

Edited 1 time(s). Last edit at 09/10/2013 07:18PM by fractal5.

That sucks... crazy glue?

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Bruce Wrote:
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> That sucks... crazy glue?

It was a complicated fracture. I printed a new one by just manually clicking the endstop, to my surprise that actually worked on the first attempt.

I'm printing a new 20 mm box now, to see if there are any improvements.

Sadly I still (after squaring the machine better) have the exact same problems.

I have now made some changes:

I printed a new endstop by clicking the endstop manually.

I removed the longest threaded rod on the X axis at the bottom of the machine. Inserted it again and redid all the squaring of the machine. I used a caliper and a weight on a string to do this squaring.

I got some suggestions on IRC to print with 0.37 mm extrusion width and 0.2 mm layer height and 174 degress C for PLA.

This is the result:



Edited 1 time(s). Last edit at 09/14/2013 11:17PM by fractal5.

Hey, those look better squished together than the previous prints. I do notice that the layer offset occurs every 3rd layer. I finally dealt with the last of my wobble issues by printing a set of these (they hold the z smooth rods tight) and buying a set of these. I think this took the play out from in-between my linear bearing and my x ends and dealt with the never straight z threaded rods.

appdev007 Wrote:
-------------------------------------------------------
> Hey, those look better squished together than the
> previous prints. I do notice that the layer offset
> occurs every 3rd layer. I finally dealt with the
> last of my wobble issues by printing a
> set of
> these (they hold the z smooth rods tight)
> and buying a set of
> [url=http://www.makerfarm.com/index.php/hardware/z
> -coupler.html]these[/url]. I think this took the
> play out from in-between my linear bearing and my
> x ends and dealt with the never straight z
> threaded rods.

Thanks for the advice. However I already am using similar Z couplers on my setup:



As for the improved X ends, that is a suggestion I have gotten on IRC as well. The i2 has an improved design over the i1 and I have planned to print those. Are these better than the original i2 parts? Or are they inferior, but require a lot less work to install on an i1 machine?

as far as I can tell it just makes your Z axis a little more difficult to remove. It does constrain it rather well eliminating wobble. I have them on my paper now

New results:

With the help of two friends I have gotten a new bed made of an aluminium plate, it is a 5052-H32 plate, 1/4" x 10" x 10". It has been drilled and mounted directly on top of the heated bed with a conductive compound between the two plates to provide good heat conduction. The plate itself is covered in Kapton tape and has a hole drilled into the side of it (depicted in one of the pictures below), the temperature sensor is placed inside this hole together with conductive compound.

I have also redone the squaring, again. However, I have yet to print the improved i2/GregFrost X end parts. So my current setup has at least one problem, and that is that the X belt bends the smooth rods when it gets tightened. I believe printing the improved parts will solve that.

This is the setup:

New setup, picture 1
New setup, picture 2

When I print with this setup, I get the following results:

Face 1
Face 2
Face 3
Face 4
Three faces

I believe this is an improvement. However, note that some of the faces look better than others. Why is that? I have a fan both in front and in the back, as before.

Edit: Most importantly, the banding problem is still there, just less severe.

Edited 1 time(s). Last edit at 09/24/2013 06:53PM by fractal5.