offset printing...stl made in Vectorworks

[Nolightforyou]

I'm wondering if any of you have run into this issue.

I was asked to make this VW emblem which I created in Vectorworks.  (I had to run it through NetFabb to cut it in half.)

Everything seemed fine at first, but half way through it started printing offset-like.  Almost as if the entire print head shifted over and then continued to print.  (Hopefully you can see that in the pics.)

I've attached a screenshot so you can see that it looked perfectly normal, and the files if you feel like investigating.  I'm new at creating my own items, so it may be something I did in the file... I'm not sure.

Any thoughts?

[David Celento]

Belt slip? They should twang when you snap them.

[Anne McMills]

One of them certainly twangs. The other feels taught but more of a thud than a twang. Is belt slip a common thing? What causes it? How do you fix it?

Thanks for the advice.

Sent from my iPhone

>

[Eighty]

I don't see how it could be an issue with your STL file.  And provided your belts are pretty tight, not a mechanical problem per se.  Probably a slicing issue - I'm hearing more and more from people who get random slamming when using Makerbot Slicer.  I've had some issues with it too.

 

You can try slicing it at slightly slower feed/travel rates.  If the issue goes away, then you should probably stick with those settings.  What speeds did you use on this? 

[Anne McMills]

I used the standard "low" settings that I've been using for awhile.  (I haven't been brave enough to mess with it too much.) 

while extruding - 80mm/s
while traveling - 150mm/s

Am I understanding that sometimes it travels too fast for it's own good, the belt slips, and it accidentally offsets itself?  Is that right?

As a test, I just printed the chain off the SD card and it printed with absolutely no problem.

Thanks so much,

[Eighty]

Slow the travel down to 120 and try your print again.

[David Celento]

You've got it right. If you haven't installed Sailfish firmware, this may also help. The acceleraration/deceleration seems more forgiving of skipping.

[Anne McMills]

sadly the offset printing happened again.  I tried slowing down the travel to 120 like you suggested.  It started making an awful grinding sound just before it offset this time.  (And it was on a different object than before.)  I assured the grinding wasn't the extruder on the BP.   I've sent the ticket to MB... we'll see if they have anything to add.  It's always something...

[Eighty]

Grinding? That smells like X axis ribbon cable failure. A one-time pop would be lost steps. Grinding... Bad.

[Anne McMills]

yikes!  that doesn't sound like a good thing.  I've attached a short video.  You can hear the sound and see the offset printing.  See if this seems like what you're thinking of.

thanks  :/

On Mon, May 27, 2013 at 5:46 PM, Eighty <adun...@gmail.com> wrote:

Grinding?  That smells like X axis ribbon cable failure. A one-time pop would be lost steps. Grinding... Bad.

--

[Jetguy]

Yes, 100% sure that is the failure. See, what isn't obvious is that
the error happens when Y axis is in certain spots. The cable connects
to the X motor and gantry and flexes each time Y axis moves. If any of
the 4 wires break, then we loose on of the 2 phases to the motor thus
the loud buzzing sound.

You need to go through MakerBot support and get a replacement cable.
While others have done temporary fixes by soldering in new cable, i
don't suggest that route unless you really need to use the machine and
userstand how to solder and fix that problem.

>  IMG_3218.MOV
> 7201KViewDownload

[Anne McMills]

I'm deeply grateful for this insight from both of you.  It will give me a jumping off point to discuss with Makerbot.  I contacted them yesterday but need to wait out the long weekend to see what they say.

Thanks so much!!

[Eighty]

For some reason, I couldn't get the video (audio only).  But the sound that I heard is definitely the X axis cable failure, no doubt about it.  If they can't diagnose it based on the sound alone, then you need to ask for a different tech support guy...