Bizarre printing issue

Up until yesterday my printer was working pretty well. Then all of a sudden my extruder wasn't level with the bed, so I set about leveling it, and redoing the steps/mm calibration for X,Y,Z, as well as adjusting voltage on the stepper drivers.

Although now when I print, it seems to printthe first 5-10 layers just fine. Then it starts smearing the layers as it gets taller, it drags the tip of the extruder over the printed surface, and pushes down on the piece it's printing.
My Z-home height is fine when homing and went starting my print.

Any advice on to what would cause such a thing?


Here is an image of the result:

what may be happening is your extruder hardware is falling apart, hopefully at the cheaper extruder, and not internally to the hot end. if z axis is draggin then something is sinking further down, possibly being pushed by the force of the feedstock right?

it is hard to know for sure, without seeing the printer extruder as well.

Edited 1 time(s). Last edit at 08/16/2013 08:30PM by jamesdanielv.

I think it's a software problem. Did you recently change your layer height settings?

Could your extruder and/or x carriage be deforming because of heat? I had that happen when I was trying to print ABS and my extruder/carriage were made of PLA. Lesson learned for me was that these two components should NOT be made of PLA. Maybe that's what's happening to you???

I've checked the extruder and hot end(E3D hot end, been working great so far), no deforming going on here.
My layer height was set to 0.20mm

can you show us an image of your extruder setup including the hot end and the x carriage that it is mounted on?


the other thing that could be possible is the z rods are sliding out of the z motor couplers. i had this happen, and finally blue taped the motors and glued it as well as tightened down the couplers. so far it keeps working, even with z height change during retract.

Maybe you should try a larger layer height. .25+ is generally recomended, but maybe your issue lies elsewhere. Did you change the steps/mm on your z axis before these issues occured?

Can't see why you should need to re-calibrate X and Y?
Anyway, the first 5-10 layers look poor not just the upper ones. A better idea would be to post a video if you can?

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Waitaki 3D Printer

I'm not sure if it would be the couplers slipping, as it does manage to get as high as it does during its failed print. And it also moves up and down with no binding occurring along z-axis.

I'll try to upload a photo of everything (extruder+hot end) tonight or tomorrow morning.

I'll also try my same print with a larger layer height to see if I get any success. I did not change my steps/mm before it started going bad.

The first 5-10 layer may be poor, but they are consistent height. After that the layers just start getting pushed down on as if the extruder is not lifting and it just smears the layer it already completed, while still laying down a bead of plastic.

lubricate your z threaded rods and maybe also the bearings

Here is an image of my extruder and hot end as requested

It might be warpage due to the cooling fan.

ohioplastics Wrote:
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> It might be warpage due to the cooling fan.

I had thought about that, but it's ducted and only passes through the fins on the hotend.
It also never affected any of my previous prints.

warm the hot end up, and wait 30min, then with a Popsicle stick try to bend it back and forth. perhaps where it is mounted has melted, and the hot end has some slop.

Even with a duct it will affect the ambient temperature. The further away you get from the heated bed, the cooler it gets.

I tested to hotend to see if there was any wobble, and there is none, it is solid. The top part of the hot end that is bolted to the extruder doesn't get past 40 degrees Celsius.


So I've figured out the large part of the issue, it was related to the custom G-Code in Slic3r. The one that tells the Z axis to retract at the start of a print, the feed rate was set to 5000, and this was causing my steppers to make a weird noise at the start of each print after homing the Z-Axis.
I watched it actually screw up the level of my Z-Axis(one motor turned more than the other), by about 3mm's from one side of the glass table to the other!!

So I dropped this feed rate down to 40, and it eliminated the weird noise and throwing the Z out of level. I tested it about 30 times, of starting a print, pausing it, raise the Z 20mm's then restart a print, and it kept it's level after all those up and downs.

Now I'm just working on getting the corners to look good. One corner always looks messed up compared to the other 3

yes, i had same problem too...but not that obvious...its like extruder is start extruding too late...

and this is only visible in single layer wall, correct?

smaller retract could help, also unckeck "retract during layer change" if i remember correct.

this changes helped a lot.

another thing, with wich i have played yestrday is extruder. check for backlash in gears.... if they have play, then you set higher retract value, but when starting to print in next spot then eytruding have delay for that value. this is logically more sensitive in 3.0mm fillament.

...and so on...

Edited 2 time(s). Last edit at 08/19/2013 06:06AM by woo.

a good z axis speed is 3mm/s or 180mm/m

I've got the same corner issue on my prints, and it has been explained to me that this is caused by steppers decelerating. Aside from slowing down, I'm told, there's little to be done about it.

If you find otherwise, please let us know.