thats extremely interesting. ive never really heard of this. what do you personally use babystepping for? what advantages are there for manually moving the z-axis while its printing?

 

Interesting: @sheffdog had done something similar, where he actually wrote his own M-code in marlin to do something similar:
Fine tune bed height in Marlin while you are printing | Mason 3D
I asked him why, and I think he said he found it advantageous when printing with a smaller than .4mm nozzle, and really high resolution, during the first few layers. Can't remember exactly, maybe he'll chime in

 

It's in Marlin 1.0.2 as well.

I've used it mostly when I had a glass build plate directly on a heated PCB. The glass would warp as it heated, didn't seem to matter the source of the glass. Because of this, I would adjust the Z height during the perimeter extrusion. Easier to do that, that to set Z offset, test, set again, etc... Same goes for having to move the Z endstop for the same reason.

Since my switch to a aluminum plate I've never had to adjust the Z height.

Babystepping might also useful if you happen to have a step skip. This is a band aid of course, but still useful.

Forgot to mention, I am using babystepping on the prusa i3, not the C Bot, which I'm still building.

 

I have asked a number of times and I guess the developers have no clue if it works. They kept telling me it did not.
BUT it only does not work for CoreXY for the XY axis. Apparently none of them have a corexy.

I will use it instead of killing the print to readjust my zero point. It seems to want to be different for PLA vs ABS and when I just mess it up to begin with.

 

just had my heated bed mk2b setup on my existing printer few days ago.. big thanks to ppl who advice on the wiring and relay etc.

just wanted to share on printing directly on glass on top of the heated bed. It is amazing to see how glossy the bottom layer can turn out to be.

the printed part is the bottom plate from Carl's rework. thanks Carl, the 5.4mm fitting looks good with M5 bolts.

 

Can anyone shed some light on this??
I have 2 prints of similar objects. 1 has default settings for accel.- 1 has accel of 6000.
The 1 with 6000 shows a more pronounced overshoot on the corner where Slic3r starts.
Actually, it isn't overshoot b/c the head was moving toward the upper edge (leading edge) -
there is a VERY slight trace of actual overshoot on the other 3 corner trailing edges (lower edge).


U can see the top 2mm doesn't show the anomaly b/c slic3r decided to chg the start point on those layers The anomaly on the other piece is about 1/2 of this one.

So how would this be corrected? Is it an over extrusion at the start point?

 

Why don't you just put each part in its own file and have the filename say how many you need? Most slicers can probably add and arrange multiple items wile splitting is not always easy.

Having similar parts in one big file just makes me wonder if they are actually the same or just very similar looking. Knowing that I need Part 1 three times would make it easier. I could print it three times or make the slicer multiply it and arrange it on the bed (which is only 8x8 cm on my current printer, so usually it's only one for me anyway... )

 

Hi folks,

I've managed to assemble the printer and electronics (picture forthcoming tonight) and have managed to get a couple test prints done after a lot of frustrating tweaking of the stepper drivers, endstops, and firmware settings. The cube tests have pretty decent tolerances as it is although the could use some tweaking to get better than the +/- 0.25mm observed currently.

Carl, great job on the design! Quick question, do the extrusion lengths change in the BOM calculator with the new design?

I also have a question regarding firmware. It seems that 0,0,0 is at the back left of my machine instead of front left. Homing occurs with X at the (back) left, Y at the back. Should I change:

#define INVERT_X_DIR false
#define INVERT_Y_DIR true
#define INVERT_Z_DIR false

to

#define INVERT_X_DIR true
#define INVERT_Y_DIR true
#define INVERT_Z_DIR false

and then flip:

#define X_HOME_DIR -1

to

#define X_HOME_DIR 1

which would allow continued homing of the x at the rear of the machine?

THANKS!

 

this is what mine is
// Invert the stepper direction. Change (or reverse the motor connector) if an axis goes the wrong way.
#define INVERT_X_DIR false
#define INVERT_Y_DIR false
#define INVERT_Z_DIR true

I rotated my unit so the motors are on the rear - I didn't like them sticking out in front.
If your motors are on the front then X= false will move it to your back
and Y=true will move it to your left
So my home is front left which would be your rear right

#define INVERT_X_DIR false
#define INVERT_Y_DIR true

I have no idea what
#define X_HOME_DIR -1
does, but my guess is that 1 will home to MAX endstops, which u probably don't have.

I would stick with the INVERT to get it right.

 

What about grouping the individual files into subdirectories? You can just zip up the whole directory tree to distribute.

 

The issue is it won't 0 to the endstop if the INVERT is set to the wrong state.
So, yes, leave the home_dir as it is but make the INVERT run it toward the endstop - wherever it is - you built it - it is trial and error.
That is why ppl pay big bucks for inferior printers - so mfg can configure it for them.

 

Looking for some guidance on my xy gantry. I've assmebled the gantry and run the belts, but the gantry is not running even. I suspect the belts are too tight, but before I start tearing everything apart, wanted to check with you folks and see if any of you have run into the same issue.

Also Carl, in order to use a carriage mounted X endstop I created a little bumper that is added to the gantry mount. Giving you a heads to see if it makes sense to modify your design to remove the need for the little bumper or not, as it also changes the length of the screw and is only needed if you want to use a carriage mounted X endstop. The bumper adds 3 mm of material to the top portion of the area between the braces on the right side. You can see the X endstop switch below in the first photo, it's on the back of the carriage. Look to the right and you can see where it meets up with the bumper, the corner of it sticks out just a bit. For now I am just using one on the min endstop, but the code can add one for the max as well.

 

Carl, you sir are a scholar and a gentleman. Thanks! Your assumption that I tightened one belt at a time was correct. I followed your instructions to the T and everything is dead on even now.

As for the bumper I was describing, I added a better photo of it below. Will look over Adam's design as well to see if I can adopt it. I can modify the depth the switch sits at. The current design only sinks the switch into the carriage by 1 mm, this is to leave some material between the nut trap and switch. When I mounted it up last night, the switch was not making reliable contact with the XY bar mount, which is why I added the bumper.

Excuse the stringy print, I printed this in petg and printed it very hot to ensure good inter layer bonding. Guess I didn't clean it up as well as I thought...

 

side note, as im buying parts and preparing to print and assemble this thing, these types of close up and detailed photos are like gold! so thank you chris, and everyone else that posts tons of pics of their printers...i love em!

 

I have only an 8x8 cm printbed at the moment, so for me every piece broken out would help - especially since I have to ask a friend for the bigger parts .
But it would still help if it weren't such big "collections".

For easier downloads, the files could be structured into archives as others suggested.

I still have a lot of decisions to make and I wonder if I should start a new build to discuss these. Or is it better to keep everything inside this thread?

 

It'll be more or less a standard build I guess. Me asking shows that I'm not sure myself if I should do that . My idea was to document the thought process, why I decided to build a C-Bot and not a different frame, what electronics to go for, what kind of heated bed, what control board, etc. and some discussion on those elements.

For someone who builds his first printer, there are a lot of questions open besides the basic build. I know a lot of it has been discussed in this thread, but it's difficult to piece everything together still, especially since there are so many interesting ideas popping up it can be quite confusing.

But I also don't want to split the discussion into different sections. So I'm guessing I'll just discuss with you guys in here .

 

This one used 6000 in slic3r for everything except first layer which is 4000.
Slic3r changed start point to another corner on the top 2mm for some unknown reason.
Watching it, it appears that the head is actually moved behind the edge when it starts another line resulting in what looks like overshoot.
Now thinking about it..............if it were set to RANDOM start I guess it would produce blobs - That is an indication my jerk is set too low. But jerk is a fct of Marlin.........OK.I'll try that.

 

Oh, BTW, I reworked my Marlin. I now have Babystep_Z set so I can use it without actively printing - to test it, and I have it set so it shows on the menu with 2 clks of the select button so I can get to it fast when it does start to print.
Nice - now I have to get used to turning the knob in the correct direction.

 

Carl - I modified my plate long ago but never posted it b/c I couldn't figure out why it wasn't this way originally. Since it is still that way, maybe u can tell me. What I did was to make a cut out so the belt could go around the back side of the plate and have the teeth rest in the teeth of the plate instead of the smooth side of the belt on the teeth of the plate..

This makes clamping much more secure and I am not tempted to screw so tight that I separate the part (which is why I had to reprint it.). It also lets the belt lie more in the rail groove instead of outside it.
OH!, I just realized -- my unit is turned around so that the motors are in the rear, so for most ppl the mod would have to be implemented on the back piece.
Do u want to add the belt clamps to these files also?
I haven't followed all the chgs to these parts. What I just noticed is that the adj hole was moved to the bottom. What advantage is this? What other chgs have u made?
thx