Suddenly blobby prints with smaller areas

I'm certain I've seen others have this problem numerous times with any given 3D printer, and I overlooked it because it's never happened to me. Now that I'm experiencing this error and trying to find any threads about it, I'm coming up totally empty. Take a look at this, printed in PLA:

The little blue column on the right is a print I did months ago. The clear white column on the left is a print I did tonight. Larger areas are printing just fine, but anything with a smaller perimeter results in a big blobby mess, and I have not the slightest clue as to why. I've adjusted the infill amount, the perimeter speeds, etc. The thing is, it always occurs whenever the perimeter is under a certain amount it seems... like printing a pyramid, the base prints just fine, and as you go up and the pyramid tapers narrower, it looks fine up to a certain layer. And then BAM, when the perimeter is under a certain size, you can visibly see where it just all of a sudden it begins to blob and mess up. Every single time. Here's the pyramid (ignore the fact that it looks the base is warped - the base printed fine, just bent when I went to remove it from the bed):

At a certain layer, it happens. I never used to have this problem, what could possibly be wrong? Thanks in advance for any suggestions!

Edit: Just wanted to reiterate - it only happens when printing smaller areas. Larger items/areas print just fine, and that's what's confusing me...

 

Do you have a parts cooling fan?

 

I don't believe so. Pardon my ignorance This is the first Robo 3D version, from the Kickstarter, and I haven't added any external fans or anything. The part that confuses me is it used to print just fine before. I stepped away from my Robo 3D for months, set it up on my new laptop,now I'm suddenly encountering this problem. I tried the default settings supplied on the get started guide with no luck.

I can't quite figure out if the error is software or hardware related, hmmm...

 

Thanks for the replies! The material difference definitely sounds like it could be the culprit, and what you described (the layers not solidifying quickly enough causing the hot to push it around) does sound about right. The blue PLA that shipped with my ROBO 3D worked fine, and I just started using some transparent PLA I bought off of Amazon. I might have a little bit of the blue PLA lying around somewhere, maybe I'll try swapping it out to that and see if it makes a difference.

I'll look into a fan. For now, I have a huge powerful standing fan. So let's see... I'll try:

-Using a fan
-Adjusting temperature settings for this transparent PLA
-Seeing if using some of the original blue PLA makes a difference

And if neither of those make a difference, I'll take another very careful look at Slic3r's settings.

Thanks for the suggestions, greatly appreciated! I'll let you guys know how it goes tomorrow!

 

Just wanted to respond with an update real quick. First off, thanks so much for the suggestions - it solved my problem! The layers weren't solidifying quickly enough. I tried a couple of different approaches. Enabling "auto cooling" in Slic3r definitely helped, so that each layer was given ample time to solidify a bit. 15 seconds minimum for each layer helped some. But blasting the entire print with my huge standing fan worked wonders - I could do smaller layers (perimeter and infill) in about 6 seconds with no problem of it remaining goopy or getting dragged around. I quickly modeled and printed a basic female figure, something with a curvy and defined shape, to see if it worked well.

So I think the best bet at this point would be to install a parts cooling fan. A couple questions concerning that though...

Would I just need to purchase something like this http://www.ebay.com/itm/3D-Printer-...d-Nozzle-/161230858378?_trksid=p2054897.l4275 , create or find and print a mount for it, and attach it to the extruder? And then I'd wire it into the Arduino board? I'm not finding much info specific to the Robo 3D on installing a parts cooling fan, but I'm guessing that's the approach, huh?

 

You could contact the Robo guys and they may just send you one with the mount since all later units are being shipped with them by default.