Introducing A Different Approach to 3D Printing
Kevin is at his desk, looking at a computer screen. He explains that he is "test driving" a new 3D printer, one that is very different than the Cubex he got about a year ago. The loaner 3D printer he has behind him, which is a Cerberus 250, is much smaller than the one being built for him by Steve and Jacob Graber, but it's enabling him to learn the software and wrap his mind around this style of printer.
The Cerberus style, with its three tall struts and carriages on each strut that go up and down, looks like a triangle, which is why some people call it a "delta" style.
Kevin's Cubex printer uses the "XY" approach - fore and aft, left and right - in which the table goes up and down. In the delta style, the table is fixed, and the head goes up and down. The head also seems to have more range than the XY printer. To Caron, it seems more precise.
He's printed a couple of pieces with the Cerebus 3D printer and, as he shows a piece he printed the night before, he says the printer is amazingly fast. The trefoil knot he is showing took about 3 hours to print. With the Cubex, it would have taken about 18.
And, says, Kevin, the Cerberus was only printing at half speed, which improves the detail of the printed item. His new machine, will print up to 60" tall and 34" in diameter. "That's the size of the Voice!" Kevin says. The printer itself will be 40" in diameter and 8 feet tall. It will print up to 300 milimeters a minute, which is about 2 feet a minute. The Grabers are going to put doors on it so that no one puts a hand into it and gets smacked.
Next, Kevin shows some of the features of the printer. He shows the extruded aluminum struts and the corner pieces, the latter of which are actually printed on another 3D printer. (On the new printer, they will be cut with a CNC machine out of aluminum.)
All of the electronics are buried in the bottom. Also, the tray is heated, which is great when using ABS plastic, as opposed to cornstarch-based PLA plastic, as it likes to keep everything about the same warm temperature. Kevin's Cubex does not have a heated tray, and if the piece being printed on it gets cold, it sometimes shrink and pulls up off of the print tray.
Kevin then shows a can of hairspray, which he assures viewers isn't product placement (the Cerberus 250 isn't, either). That's what the Cerberus uses to adhere the item being printed to the print tray. The Cubex uses what looks like a glue stick with material in it similar to Elmer's glue mixed with water. It's a little runny, and you just smear it onto the printer's plastic tray. With the Cerberus's glass print tray, a light dusting of hairspray holds the piece on the tray. Caron has already made three prints and only applied the hairspray once thus far. It just sticks right on there.
Next he shows the drive roller that feeds the filament off the spool, down through the Bowden tube and into the print head itself. In the Cubex, the drive roller is buried in the top of the machine - just a little different.
The software for the Cerberus is very different than that used by the Cubex. He can pause the print, change colors or, if he runs out of filament, put new filament in, feed it through, and resume printing. With the Cubex, if there isn't enough filament, the printer won't even start. The computer looks at a chip in the cartridge and says it won't even do the job, and you can't even begin.
The delta machine is all open source - you can find the plans and all the parts on the Internet. You can also contact the Grabers at https://plus.google.com/+SteveGraber. They sell kits or will build the machine for you.
After about 3 hours of printing - maybe a quarter of the time it would have taken the Cubex to print this piece - it's done. Kevin clicks on the home button to lift the print head out of the way, then breaks the sculpture loose from the print tray using a pair of flush cutters to lift the edge of the support web that printed along with the sculpture to hold up any overhanging aread while the hot plastic cools. (Anything over about 45 degrees needs to be supported.)
That will give Kevin a finished maquette, or model, that will help him assess the proportions and practicality of the piece - will it actually stand up on its own once the support is removed? If the sculpture isn't self-supporting, he can go back into the CAD file where he created it and adjust the design.
The support web pops right off. Lo and behold, the sculpture does stand up on its own. It's a great proof-of-concept: the design is right, the balance is right, the proportions are right, it stands up on its own. Making it out of steel, well ....
(And don't miss the behind-the-scenes commentary at the end.)
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