Bridging tests, the good and the ugly

Bridging tests, the good and the ugly

Anyone who has spent more than a few passing seconds with a 3d printer knows that prints fail. Sure, we love to celebrate how well 3D printers can do, but failures are just part of the process. There are a multitude of reasons that a print might fail. Some are predictable, like the models above that were specifically designed to be difficult for our printers so that we could clearly see which ones did a better job at handling certain tasks. Some are completely unpredictable, a random occurrence that couldn’t be replicated if we tried. Typically, those failures are simply discarded, adjustments made, and the printer restarted.

Since we were testing 26 of the leading commercially available 3d printers for our big 3D printer review, you might imagine there were plenty of failures to be seen. I walked around and snapped a few pictures. Many were unremarkable, simply a tweaked setting or a tiny bit of misfortune.  Keep in mind that these are very knowledgeable people who spend much of their time printing.

Then, there are the failures that have some kind of a story.

Lets start with this poor little guy.

IMG_0016 (Small)

The testers plugged in this printer, dropped a file on there to see how it would perform out of the box and this happened. At this same point the print would begin to shift off to the side, ruining the model. Again, these testers are very experienced. They immediately launch into checking the most common reasons that might happen (belt skipping, set screws loose, etc). None of these were the issue. The print would shift slowly to one side after a while, even though everything was mechanically set.

After a while, some of the testers say that someone on a forum thought maybe the driver chips for the motors could be overheating. So we quickly ripped the case open and literally just set a fan next to it blowing across the board.

IMG_0025 (Small)

This solved the problem immediately. Prints came out surprisingly well after this point. We’ll have to make sure the manufacturer is shown this so that they can add some cooling to their machine. From what we understand, this isn’t a common problem but we just happened to have the perfect environment to cause the failure.

And finally, the most bizarre failure of the weekend. We had a printer that is rather nicely built and prints, in my personal opinion (you’ll have to wait for the empirical data), quite well. Early in the weekend we set it to print a test file and went to eat some food. When we returned, there was a 1.75mm thick slinky stretched out across the room.

IMG_0008 (Small)

What had happened was that somehow the filament had broken immediately before it enters the extruder, but after the gear that pushes it through. We have no idea why this happened, but the result is very interesting. The printer has no way to know that material isn’t passing through the nozzle. It just kept right on going, feeding more filament through as though it were printing normally. The confined space and pressure from the gear caused the filament to kink up like this, similar to raking scissors across a strip of ribbon.

Sadly, this also resulted in incredibly poor performance from this printer after this. The extruder was jamming and we had a very hard time clearing all the plastic from it. I’m not positive exactly how they resolved the issue, since multiple attempts at cleaning the hot end didn’t work, but toward the end of the weekend I did witness this printer putting out some pretty nice prints again.

At this point you’re probably wondering what printed well. You may be hoping I might divulge the results of some of our testing. Sorry, that just isn’t going to happen! You’re going to have to wait till November 25th when we release the reviews to the newsstands.

However, if you want some reading to hold you over, you can go back and read who stood out from last year’s review.