1

Hi,

I am having a couple of problems with my Prusa i3 MK2. It appears that most prints have some weird lines. I printed the rectangle at 200 microns, about 15mm/s or less with PLA and 100% fan speed, hot end at 190C. Marvin had the same problem but it has been printed with the file from the included SD card (marvin printed at 100 microns).

I already contacted support but this was their message:

Hello Max,

Since you’re using S3D, which is a problem child for us at PRUSA and not a fully supported slicer, I’d like to know if you’ve had similar issues with the factory prints (and if you can share photos of these for reference. Since you were able to calibrate I assume they are somewhat more successful?

To which I replied: (on the 5th Jan)

Hi Greyson

I had the exact same problems with the Marvin on the SD card. Also had problems with the dragon supplied on there but that was for the print not finishing.

I attached the image of marvin.

No response up until now…

If you can help me with this it would be really appreciated.

Thank you in advance

Max Moors

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img_20170102_195632.jpg4032×3024 1.34 MB
img_20161221_112510.jpg
img_20161221_112510.jpg4032×3024 1.21 MB

2

Did You assemble it or You got assembled?

3

It looks a bit over extruded, maybe try print at a lower extrusion Multiplier? And calibrate the extruder following toms guide for example: 3D printing guides - Calibrating your extruder - YouTube

another tip is to join the Prusa i3 MK2 slack group which can be joined here: http://codehemi.com/

We are like 130 users there and at least 20 really active users helping out!

4

Hello Max,

Just to make sure, you have calibrated your printer, and Marvin is printed at 100 microns, right?

From what I can see, I think possibly the z-axis is slightly tilted because the first layer on the left and right feet of Marvin seems different.
Maybe you should also check the belt tension on the x and y-axis.

5

I got it preassembled. I have rechecked the belts and calibrated the extrusion multiplier. But still the same problems. I have checked the z axis lead screws, it does look like they are bent. Here are the pictures

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img_20170108_211153_1.jpg4032×3024 2.36 MB
img_20170108_211140.jpg
img_20170108_211140.jpg3024×4032 2.56 MB

6

Thats normal! They are not 100% centered in that hole and are meant to be able to move around some.

Try print the Marwin GCode again, but reduce flow to 95 on the LCD and see how that looks.
What filament are you using?

7

Not surprising the response (or non response) from Prusa. The SD card reader on mine isn’t functioning correctly and even though I told them I meticulously checked everything including running a continuity tester on every line of the two LCD cables, responded back a week later with " have you checked the LCD cables?"

I gave up and just accepted that my SD card won’t function, but it doesn’t matter much since I use Octoprint exclusively.

It’s very sad that they are immediately trying to point a finger at simplify 3-D, but again, not unexpected.

I suspect your problem is related to your build as there are layer shifts. Check that everything is tight including your belts and the x rod tensioners.

8

OK thanks! I’ll do that. I am using colorfabb PLA/PHA, Josef prusa’s PLA and MakerPoint PLA (All have the same problem.

9

You do have some surface imperfections that may elude to a mild extrusion issue but the odd lines on the prints are from Z-banding/Z-wobble… Since the long rectangle has the most surface area hold it against your Z screws… You will notice that the lines are exactly the same space as your threads on your Z rods. There are a lot of documents and posts out there covering these issues with some possible fixes… Not all things are fixable the same way and part of it could be resolution vs setup related meaning your layer resolution is even recognized by the printer and falls into your machines particular microstepping capability. I apologize for not having more answers but Search google for those terms and it will show you a ton of results for possible fixes

10

I have checked before the job started if the belts and screws where tight. (which they where).

I now ordered the E3D silicone Sock and try to take a look if it is from the temperature deviation (my deviation is about 5ºC from the set temp).

BTW. The printer does also make a lot of noise. Here is a sample: https://goo.gl/photos/Za7WF63Ricu4Je8f9

11

The next thing I would try in that situation is I would move the Z axis up and down repeatedly (using the control panel) and watch carefully for any kind of wobble anywhere. The movement should be very smooth. I would ensure all belts are tight (plucking them should sound a note in the bass range) and I would verify the heater block is not wobbling inside the extruder.

BTW, the problems with the LCD and SD card communication are caused by electronic interference due to lack of shielding on the cables. I suspect that running the cables through some kind of grounded and insulated metal tube would solve those problems. It might even be possible to cobble together a metal tube using aluminum foil and duct tape.

12

I listened to your video. The Y axis sounds wrong, like something is broken. I would temporarily take the belt off the Y axis and listen to the motor as it moves without anything attached. If the motor sounds OK, I would then apply some tension to the motor using my fingers and see if it still sounds OK. I would also try moving the bed, again without the motor attached; if that movement is not smooth, then the problem might be with the 3 linear bearings below the bed.

If the problem is with the bearings, you might be able to do what I did a few months back and just lubricate the 2 Y bars using a spray containing Teflon from the hardware store.

13

Thanks I’ll also try that. I’ll give you feedback when done.

14

I guess that it is the stepper:

15

I printed marvin at the lower flow but I got severe under extrusion… So probably it is not that.

16

So the left side of mine also looks like that, and it vibrates and makes this terrible sound with certain y-axis movements. Suggestions?

17

Sounds like your hotbed is not screwed down properly, or has vibrated loose, my suggestion to you is to flip the unit over, and check every screw nut bolt, belt, make sure everything is snug, not reefed down, but snug., belts are tight, but should be able to be squeezed to touch each other in center of axis., check the gears on the x, y, and extruder, they should be tight, the extruder is brass and soft , check if it’s stripped, I had to tap mine to next larger size , m4 x 70 thread, very easy job, and use next larger grub screw., once yo do all this, then the two z axis screws are not centered, to the left end of the axis there are two screws that hit the end of the two horizontal smooth rods, they push on the ends to help fine tune the level of your x axis by loosening one and tightening the other, you can level it, thereby centering the rods., I only wrote this for others searching the issues normal., I would guess this is a mechanical problem vs software…