Crane Quad from M3D – Part 1

I kickstarted (or whatever it was) an M3D Crane Quad a couple of years ago. Received it a couple of years later, which was about three weeks before this post.

This is marketed as a color-mixing printer. It uses Cyan, Magenta, Yellow, and Clear filaments, all going into one head with one melt chamber. Some of you will recognize those as “Process” colors (except clear is usually black in process printing).

By mixing these at print time, the Crane Quad should be able to print thousands and thousands of colors. And it (sort of, occasionally) does.

Before we discuss the print head and color mixing, a few other pros and cons. First, the cons.

This printer is flimsy and poorly implemented in every way. Were I a decision maker at M3D, I’d be embarrassed to ship my (supposedly) fantastic print head atop such a poor platform. It is a bedslinger in the traditional RepRap/Prusa/CR10/… format. Nothing wrong with those, in fact some variant produce fantastic quality. Not this one. Cheap wheels, poorly spaced thin metal shapes, everything as flimsy as possible. Very infirm feeling printer when you handle it.

I realize that every dollar spent or saved on the internal cost of a consumer item that will ship 10,000 units is 10,000 dollars of pure profit. However, there are plenty of places in this particular printer where starving that last little bit of cost makes the usability and quality very questionable. Balancing cost and quality, this printer would benefit from just ‘a few dollars more’ (hey, wouldn’t that be a great title for a movie?). In turn, this would do wonders for the customer/consumer. Here are a few examples:

The bed came out of the box begging to create a short and damage the controller board. I used liquid tape to prevent future problems.

There is no bracing anywhere, just 2020 profile pulled against each other with bolts. Even the fundamental design gets into the act, with the spacing on the wheels being such that, even if the stamped steel were thick (hint: it’s not), the geometry still wouldn’t be stable or rigid.

The bed itself is aluminum, and a fiberglass sheet and a sheet of black ?PEI? (or similar) is provided, along with four small binder clips to hold all that together. Worst combination I’ve ever seen. Bed leveling is completely manual, and the thumbwheels provided are the smallest possible that still fit the bolt. These small bolts are hard to turn; given the incredibly weak brackets and wheel assembly that slides the bed, turning a bolt causes the bed to move all over the place. Leveling is quite frustrating.

OK, I’ve probably clearly communicated: The printer itself is the poorest of the poor.

In addition to being cheaply made, there were plain QC issues. The carriage holder was so bent the wheels would not engage the 2020 profile at all. And this holder shipped in a VERY protected part of the shipping box. There is no way this was shipping damage; this thing got packed like this. Ick.

The bed subframe was not bent, but it was off the rails… (just like the rest of the printer).

On the Pro side, they did choose a Duet Maestro controller. These are the lowest end controller in the Duet lineup, and that entire lineup represents some of the premier controllers in the 3D print industry. Network attach (Ethernet only, in this case), Web interface for upload, print, monitor, manage the printer. All configuration is done via commands and/or files, never a need to recompile the firmware. Moment to moment operation via a screen, knob, clicker on the front of the printer. Full 32 bit controller. Very active developer and support organization. Overall an excellent choice by M3D.

Summary: Good controller, weak mechanics, all supporting a color mixing head. More about that head in Part II, here.

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.