Crane Quad from M3D – Part 2

Part 1 of this review is easily summarized: Good controller, weak mechanics, all supporting a color mixing head.

Let’s talk about that head.

Ever heard of the subreddit ATBGE? Awful Taste But Great Execution? This is sort of the opposite. GCBAE. Great Concept But Awful Implementation.

The concept behind color mixing is great, and when you get the thing loaded and working and it continues to work through one whole print, the results can be stunning. Here are a few pics from their web site:

The head itself has four small geared extruder motors that drive filament into a common heat block / mixing chamber. This cutaway gives you some idea:

The nozzle fits the heatblock so well that you might think it is all one piece; in reality, the nozzle IS replaceable (with their proprietary part only).

Any mixing printhead has an interesting limit: All the inputs MUST have filament in them, or feeding filament will force melt back out that empty input. M3D publishes good instructions to help avoid this. Nonetheless, I managed to jam an input in the first few minutes of trying to load the printer.

That led to about two hours of disassembly, understanding the head, and trying to clear the block. The documentation here is severely lacking. There is some information on changing a nozzle, and I used this to get the nozzle and heat block assembly out. Clearing the block ultimately required heating that assembly, holding it in pliers, and jamming a hex tool that just happens to almost exactly fit a 1.75 hole. With four holes, there is a certain amount of “whack a mole” to get everything cleared at once. A lot of working with this eventually got all four holes where they would pass filament.

This is NOT FOR THE FAINT OF HEART. This thing is going to require advanced 3D printing skills and/or mechanical skills to get it to work at all. I came very close to damaging the white plastic insert, very close to the first print not happening at all.

With the printer now loaded and able to feed all four filaments, I started their sample print, the spiral vase. Getting layer 1 going on the manual leveled bed took a couple of tries, but nothing too serious.

Once I could see that the print was proceeding I left it to finish over the next several hours (NEVER leave a brand new printer completely alone… my phrase ‘left it’ means that I turned my attention to other things in the Bat Cave; I was always in the same room and within about 20 feet of the printer).

Result? Fairly OK-Ish for most of the print, the top 1/2 inch or so was completely de-bonded for unknown reasons. Their filament, their printer, their sample pre-sliced file.

And… the print stuck to the black print surface quite firmly. I finally chiseled it off to get the print itself free. I still have not gotten the circle of plastic, THICK circle of plastic, off the bed. Again, their filament, bed, and temperatures. This is completely unacceptable, to ruin the bed on the very first print.

Summary: Head is VERY finicky to get loaded, didn’t even make it through the sample print without jamming, and requires mad skills to unclog. Bed material grabs supplied filament so well it ruins itself.

Ick.

I’m glad I didn’t pay a lot for this thing. I’m trying to decide now how much more time to invest. I may be hard headed enough to print the fish, because my wife thinks it is cute. After that, the idea of spending all the loading/unjamming time on a regular basis… no thanks.

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