1 Topic by stein.inge

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Topic: Print changing position in the middle of the print

Hi all

I have a 2nd generation printer connected to a Win7 Enterprise, 32 bit system with the Repetier-Host Solidoodle V0.85b

I'm trying to print a piece downloaded from Thingiverse that takes 3 hours and 13 minutes to print. I have done about 10 trail runs and only one came out correct. All the rest have the coordinates shifted in the middle of the print. Se the attached picture. The only program running on the system is the repetier on a clean Win7 system.

Every time the print goes wrong, I drop the print, reload the file and slice it again.

Do anyone know where the problem could be? Is it the printer itself, the slicer or something that I don't understand? All help would be greatly appreciated as right now I'm bleeding filament......

Best regards Stein

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2 Reply by Manx

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Re: Print changing position in the middle of the print

that sounds similar to the problem i've been having  in the thread about repeating errors.

3 Reply by mburns

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Re: Print changing position in the middle of the print

Not sure if this'll work for you but I had that problem a long time ago on my SD3. It turned out to be the microcontroller overheating so I wound up mounting two small computer fans over the board and that completely solved the problem. Try pointing a desk fan or something at the controller during a print and see if that clears it up.

4 Reply by grob

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Re: Print changing position in the middle of the print

Manx wrote:

that sounds similar to the problem i've been having  in the thread about repeating errors.

I agree - see my answer there, might apply to you too! smile

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

5 Reply by accusedmonk

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Re: Print changing position in the middle of the print

My printer started doing this after I upgraded to the Rumba board.  I added a fan to no avail.  I am utilizing the LCD screen so I had to relocate the board location near the front so I had to increase the length of all wiring.  None of it was twisted so I was apparently getting bad interference.  What solved my issue was drawing up a nice little wire twister, printing it out, and after twisting the new lengths of wire my problem went away.

Bowden SD3, Rumba, E3D hotend, Mk5 with RtRyder changes, Direct drive Y axis and bearings, GT2 pulleys and braided fishing line, Lawsy linear bearing conversion, M3 Z screw.

6 Reply by stein.inge (edited by stein.inge 2015-03-26 03:15:32)

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Re: Print changing position in the middle of the print

This is the latest update. I decided to stay up late yesterday waiting for 3 hours printing the same item one more time while putting a home fan pointing on the board mounted on the back of the printer. It worked fine for 2 hours and then it started a hickup. As you can see from the print, it moved 4 times before I just turned it off and went to bed.

Next step wold be to mount a pc cabinet fan very close to the board and try again.

So problem still not solved......

regards Stein

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7 Reply by stein.inge

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Re: Print changing position in the middle of the print

accusedmonk wrote:

What solved my issue was drawing up a nice little wire twister, printing it out, and after twisting the new lengths of wire my problem went away.

Hi 5accusedmonk
What is a "wire twister". Are you able to upload a picture?

Regards Stein

8 Reply by grob

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Re: Print changing position in the middle of the print

stein.inge wrote:

It worked fine for 2 hours and then it started a hickup.

2 hours delay suggests this could be either overheating stepper driver, or nozzle crashing due to warping. Your fan on the control board probably rules out overheating.

Did the print come up at the corner about the time it failed? Or did the section of the print change at that layer (e.g. big change in area, or started on several "islands" after a big flat bit? If it is because the nozzle is dragging on the print, I'd guess the only solution is to either wind up Vref a bit (which would make cooling the steppers all the more important) or reduce the friction in the drive system (lubrication, check alignment, linear bearings, bearings on the drive shaft, direct-drive, etc.) - the idea being to increase the force on the nozzle required before skipping happens.

accused, I'd love to see that wire-twister too... I did mine by hand, taped to the back of a chair!

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

9 Reply by stein.inge

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Re: Print changing position in the middle of the print

Hei grob

I will check when I get home tonight. One question -  what does it mean to "wind up Vref"

Regards Stein

10 Reply by accusedmonk

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Re: Print changing position in the middle of the print

Keep in mind, I'm not sure what you have done to your printer and I'm sure your wires aren't your issue, but I was just pointing out crosstalk can cause this same problem as it did with me.

I uploaded my wire twister to thingiverse.  It's very simple but it works well for my needs.
http://www.thingiverse.com/thing:743679

http://i.imgur.com/szwYc6t.jpg?1

Bowden SD3, Rumba, E3D hotend, Mk5 with RtRyder changes, Direct drive Y axis and bearings, GT2 pulleys and braided fishing line, Lawsy linear bearing conversion, M3 Z screw.

11 Reply by grob

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Re: Print changing position in the middle of the print

stein.inge wrote:

Hei grob

I will check when I get home tonight. One question -  what does it mean to "wind up Vref"

Regards Stein

Sorry Stein!
I mean to increase the motor current by increasing the stepper driver reference voltage ('Vref') very slightly. Here's some more information:
http://www.soliforum.com/topic/9975/adj … tion-mode/

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

12 Reply by stein.inge

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Re: Print changing position in the middle of the print

Hi folks
First, thank you for good feedback. Here is the latest status update after a weekend of printing. Yes, Im actually printing now and not only producing plastic garbage :-)

All I have done is to remove the plastic cover for the electronics on the back of the box and put a fairly powerful table/floor mounted fan to cool it down. I have printed a 3 hour piece and some smaller items, and there is no problems. The next step will be to print another large item without the fan and see if I can repeat the error. And then see if I again can rectify it adding the fan again.

More info will come

regards Stein