Head printing too low

[Bonce]

Hi guys, I’m having a strange problem. I’ve calibrated my steps on all 3 axis and extruder but when it’s printing the head is slightly too low causing the head to push a small amount out the sides which is causing bulging on the sides. Any ideas what might be causing this?

[Joecool3]

See if you can or can’t tweak your Z axis limiter switch. It’s a physical switch which tells the program when it’s reached 0,0,0,XYZ. If you can adjust the switch, raise your printer head up an inch or two, to get it out of the way.

Then what I did on my Z switch was to loosen the bolts holding it in place just enough to where I can force it higher or lower, but tight enough to where it won’t move unless you push it. Make sense?

Then, (I used a long stick to act as slow leverage) just raise the Z switch up by a hair. It might take a bit of fiddling with, but that should help.

Furthermore, make certain that your printer bed is flat relative to the nozzle. (Move the nozzle a millimeter or so above the bed, and (while the printer is off), slide the x axis from one side to the other, making sure that the nozzle is the same distance the whole way across. Do the same on the y axis, and double check, too. You should know how to adjust the height of the bed.)

Tell me if this helps,

-Jonathan

[Bonce]

Thanks for this Jonathon.

I’m using a CTC Prusa I3, the z limiter switch is mounted on the base and the x gantry has a bolt that is settable for the height, so I’m getting a really good first layer (not too thick, not too thin, perfect piece of paper to test the various points on the bed to make sure it’s level).

What I’m seeing is that the printer knows where 0x/0y/0z is, and when I measure out 100x/100y/100z its at 100/100/100 so I’m fairly confident I’ve gotten my steps right, I’ve also similarly gotten my E Steps configured correctly (if anything I think it’s actually under extruding a smidge, but that’s future me’s problem).

However, when I’m printing a test piece I use the head seems to be lower than it should be for the current layer, at first imperceptibly but this seems to get worse as the piece gets printed higher and higher, so it seems like the Z axis steps are too low, so as it progresses up the print height its pushing the previous layers (only a couple of layers, but enough to deform the print) around.

It’s been most noticeable with slic3r as that tends to fill this piece 100%, I’m now running a print using cura as a slicer and where cura will fill with air as much as possible it’s happening a lot less, although still a bit.

…this printer is so close to being configed up to usable standards, it’s making me itch

Cheers,

Chris

[Joecool3]

Ah, I understand. The same thing happened to me, only much worse, in the opposite way. The layers were too far apart and over a short time the layers weren’t sticking, and overall, the print was basically string.

So this problem is in the slicing configuration. I started by using Slic3r and I still use it now, so I’m not experienced at all with cura; hopefully the two are similar enough.

Before you slice an object, click on the configuration box in the slicer tab. Under the “Layers” settings tab, you’re going to need to adjust the layer thickness. The reason each layer is slightly too close is because the slicer software told each layer to be shorter than the actual thickness of the filament, i.e, the nozzle could be 0.35mm in diameter, and the software says to make each layer 0.30mm high. This should make sense now.

So experiment with the layer thickness. My nozzle is .3mm; yours should be somewhere around that diameter as well.

Happy prints,

-Jonathan

[Joecool3]

I assume you’re using the repetier-host software

[Bonce]

That is inspired! Perfect, I shall have a go at that tonight, makes a huge amount of sense!

[Bonce]

As is always the case, ‘life’ got in the way

Still, probably a good thing as had a bit of time to think about it, if I adjust the layer height, that will just programmatically adjust the gcode that’s generated, either increasing or decreasing z definition on the print (it would still be over extruding), whereas if I set a different diameter for the nozzle (mine is .4 so I tried .45) that should then account directly for the configuration issues as this is the cause of the over extrusion.

So, set it to .45 dia for the nozzle and tested against the corner bracket piece, and although there is still bulging at the sides and the upright holes are slumping I’m confident this is caused simply by the plastic mass being so warm its causing it to slump , (so I need a nozzle fan, fair enough, thought that anyway).

So I’ve printed the companion cube from portal (it’s my 'if this is a good print, the printer is ready for use).

It’s perfect

So, thank you so much for this, was getting really depressing because I thought I’d tried everything and now because of your help it’s now ready to start doing the cool stuff (REAL optimisations).

Only thing I’d say for yours is you might want to change your conf adjustment from layer height to nozzle diameter, should mean your slicer (I’m also back to using slic3r again now ) is able to gen up some pretty perfect gcode for you.

Thanks again

[Joecool3]

Ah, yes; you’re very correct. I guess I originally meant the nozzle diameter, but didn’t make that clear, so I’m glad you were able to figure it out on your own!

Awesome that your prints are turning out perfect! That’s cute having that lovely box to accompany you

You ought to try printing out Lego parts. I’ve printed a couple gears and I’m working on setting up a whole automatic lego transmission. I’m seriously impressed with how much you can do with one of these machines.