CNC Pancake Printer #DIY

Printing Pancakes With A Camera Dolly?

My kids are enthused by 3D printing, casually remarking about things they could ‘just print’.  Recently they asked to build a pancake printer – what a cool idea!

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I thought about how to build a simple batter extruder and gantry.  It didn’t take long to realize that IREnE, my new DIY camera dolly, is the perfect platform to use as a ‘theta-style‘ gantry!  So I set about adding pancake printing functionality to the camera dolly.

Extruder

The other pancake printers I’ve seen online (like Mexican Viking’s) use compressed air to push batter from a reservoir through a nozzle.  I did it a little differently and used a syringe as the extruder.  IREnE already has a motor driver set up for the Secondary Rotator.  Simple to swap this component for the extruder.

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Pancake Design

The makers of the Pancake Bot provide Pancake CAD/CAM software for free on their website.  Perfect!   The current version is 1.2.0 beta.  Hopefully is remains free…

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It’s December, and my wife demands more Christmas

Unfortunately the workspace dimensions cannot be adjusted.  Maybe the setting is buried in the software?  I couldn’t find it.

The output gcode is optimized for their printing platform.  I wanted to optimize it for my printer, so I wrote a vbscript gcode processor.  Just drop the original *.gcode file onto the script, and it spits out a modified copy (*_e.gocde).  It removes pauses (G4) and homes (G28 & G0 X0 Y0), adds an extrusion factor (M221), splits the moves into travel (G0) and print (G1) with appropriate feed rates – and a few other things.  You can find it in the project file repository.

CNC Parser

Much of the required code was already in the dolly.  Since I intended to send the print gcode to the controller using Repetier Host, I needed to add a compatible gcode parser.  Here’s a HUGE shout-out to Dan Royer of marginallyclever.com for providing an awesome how-to guide on writing a gcode parser.

I didn’t want to modify the original IREnE firmware.  So the parser is discrete and can be removed from the firmware with a simple switch (commenting out #define CNC_PANCAKE).  The parser doesn’t do anything until it recieves a command over the UART interface (by a USB connected to a computer).

Only a handful of commands are recognized: G0, G1, G4, G90, G91, G92, M3/M76, M5/M75, and M221.

Recipe

Gather up some flour (3 cups), eggs (2), butter (90 mL), sugar (1 tablespoon), baking powder 2.3 tablespoons) , salt (0.7 tablespoons), and milk (~2.6 cups).  Mix!  Add more milk to thin the batter

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Got the camera dolly mixin’ up another batch

The first go-around, I didn’t mix the batter long enough.  There were enough chunkies that the syringe kept getting plugged.  Make sure it’s mixed VERY WELL.

Results

The extruder works, but I can see why other printers use larger reservoirs.  There’s enough batter in the syringe for one decent pancake.  I found runny batter tends to make very thick lines, while thick batter doesn’t extrude consistently.  Further experimentation required to find the right consistency.

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I probably won’t use the syringe again.  A large reservoir requires a valve to control flow.  Probably a valve at the nozzle would work best – A motorized plug / stopper, or maybe a sphincter… I MEAN A FLUID-REGULATING VARIABLE APERTURE.  Yeah, that’s a much better word for it!

Merry Christmas!

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