As we narrow down where our challenges are with the Cerberus 3D Gigante printer – we’ve wrestled with software, hardware and filament issues – we’ve at least found one way to deal with the dreaded filament bulge.

How filament can be anything but a consistent size from beginning to end eludes me, but as we covered in a previous post, we’ve had a couple of bulges that stThis is supposed to be 3 mm filament - Kevin Caronopped the extruder cold. But then, what could you expect when 3 millimeter filament is more than 3.47 millimeters wide? In fact, the filament is supposed to be under 3 millimeter – about 2.95 mm – but  in places this filament wasn’t even close and the extruder couldn’t handle it.

While Ultimachine figures out what went wrong, I had to come up with some sort of solution on this end to finish printing this 30″ tall pedestal. So I came up with what I call an FCD, a Fiendishly Clever Device, so I could keep printing ….

It’s pretty simple, really. And fortunately, it works pretty fast. So when I got the new filament Ultimachine rushed me overnight so I didn’t have to pause the print, I took it out to my garage, where I’d set up a temporary FiBDeR (Filament Bulge Detector and Remover).

I had made one down at my studio, too, but I needed every moment I could muster so that I didn’t have to pause the print to change the filament.

As for my 3D printing filament bulge detector and removerFCD, on each end, there’s a holder for a 5 pound filament spool made of PVC pipe.


Between them, I put a piece of metal with a 3 millimeter hole drilled into it. Yes, exactly 3 millimeters – the point is to get the filament to feed through the extruder, and to do that, it needs to be 3 millimeters or slightly less.

part of my 3D printing filament bulge detector and removal device - Kevin Caron

I screwed the  piece of metal to my workbench to make sure that it is exactly level and at the right location.

Then I simply transferred the filament from the spool it came on, through the hole in the metal, to an empty spool I had on the other side.

The whole process took about 15 minutes – I finished in time to slow down the print and be able to feed the new filament into the extruder without even stopping the print.

Fortunately, this time there were no bulges in this spool (that means I’m batting .500), but if there had been, my Fiendishly Clever Device would have scraped off the excess material to reduce the entire reel of filament to 3 millimeters in diameter.

I know it works because I’ve removed bulges from two other spools.

I’m now so gun-shy that I’ll probably use this tool on every spool from this particular manufacturer – it’s definitely worth the 15 minutes it takes.