This call for prior art is part of the EFF's effort to keep 3D printing open. Read about the initiative here, and check out Google Patents or the USPTO for full details about this particular application.

Additive manufacturing system and method for printing customized chocolate confections "Additive Manufacturing System and Method for Printing Customized Chocolate Confections"

This application claims that 3D printing with chocolate is sufficiently inventive to receive a patent, paving the way for every thermoplastic material to be covered by its own patent when used for 3D printing.


  • App Number: 13/432424
  • Publication Number: US20120251688 A1
  • Assignee: Stratasys, Inc.
  • Prior Art Cutoff Date: Prior Art predating March 30, 2011
  • Availability for Challenge: Open Until At Least April 4, 2013

APPLICATION OVERVIEW: This application claims the use of chocolate in extrusion-based 3D printing. The chocolate is held in a heated reservoir. When printing begins, the chocolate is pumped from the reservoir to the print head, while still being heated to maintain its temperature and tempered state. The print head then extrudes the chocolate material to build the 3D object. Unused chocolate in the print head is then sent back to the reservoir and heated again.

Claim 1 requires, among other things:

  1. An additive manufacturing system for printing a chocolate confection, the additive manufacturing system comprising:

    at least one controller configured to receive instructions for printing the chocolate confection, and further configured to relay commands relating to the received instructions;

    a platen;

    a recirculation loop configured to circulate a flow of a chocolate material, and further configured to maintain a temper of the chocolate material; and

    a print head in signal communication with the at least one controller, the print head being configured to receive at least a portion of the chocolate material from the recirculation loop, and further configured to extrude and deposit the chocolate material onto the platen to print at least a portion of the chocolate confection based on the commands from the at least one controller.

WHY IT MATTERS: Printing with chocolate is wonderful, but this isn’t just about chocolate. There is a vast array of thermoplastic materials that can be used in 3D printing, and it should not be possible to get an exclusive patent on each new material that is used in conjunction with well-known technology. The use of a recirculation loop (sending unused print material back to the reservoir) is also an obvious idea.

Are you familiar with technology similar to that described in this patent application?

If so, please submit evidence of that prior art as an answer below. Please submit only one piece of prior art per answer below. We welcome multiple prior art proposals from the same individual; please create separate answers for each one. This is so the community can vet each individual piece of prior art independently.

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  • From halfbackery.com "Sp.: profiterole. I'm actually developing a microfluidic device which create micron-diameter profiteroles at a rate of approximately 5000 per second. The main problem is the high viscosity of the cream and the tendency of the chocolate to set in mid-flow. — MaxwellBuchanan, Jan 10 2011" (not a tag but part of the quoted material)
    – George White
    Mar 15, 2013 at 1:33

13 Answers 13


Please people understand Patent Terminology in this space. All of this stuff is described as solid freeform fabrication...housed under Class 425 Subclass 174 at the USPTO. I used to examine this entire spectrum of technology for years!


http://www.google.com/patents/US6280785 (Base 103 Reference) Teaches everything including Chocolate

http://www.google.com/patents/US6280784 (Base 103 Reference)Teaches everything including Chocolate

http://www.google.com/patents/US6902246 (Secondary 103 Reference) Teaches Recirculation Loop

Obvious to one having ordinary skill in the art at the time of the present invention because the teachings of '246 tout benefits as well would enable for reuse of build materials to avoid wastage and improve apparatus and methodology efficiency. There's case law to that touts that benefit as indicative for a satisfactory 103 (a) rejection.

  • Is the MIT paper primarily for background? If it does have something important in it do you have a way to get a date on it, I didn't see one. A very quick word search didn't find circulate or loop in the '246 document.
    – George White
    Mar 19, 2013 at 3:27
  • Always nice to run into a former Examiner. Welcome.
    – Yorick
    Mar 19, 2013 at 15:03

"Temper" is a technical term referring to the structure of the chocolate. If you overheat it at any point in the loop, and then cool it again, it will harden with a bad texture and an oily feel. You then have to do a recrystallization ("tempering") protocol to get it back into good shape.

So they appear to be claiming keeping the chocolate in temper around the loop. They do not mean "temperature" except that temperature is important to retaining temper.

Obviously every material has to be kept within some temperature range or be damaged, so that's not novel by itself. And maintaining temper is a very basic principle of chocolate handling, so that wouldn't be novel. There are automated machines to put chocolate into temper and hold it at the right temperature; they hover just above the "home cook" level of kitchen instrument. Those chocolate fountains you see around are specifically designed to recirculate melted chocolate while holding it in temper.

I don't know about recirculating 3D printing media. Chocolate is relatively hard to melt properly, because the melting temperature is relatively close to the losing-temper temperature, so you have to heat the bulk very evenly. You might want to look at other 3D printing media with similarly narrow temperature requirements. That may mean something relatively exotic. I suspect most of the popular FDM media are specifically chosen because they're not too finicky about having the outside of the mass overheated a little in the melting process. So it may not be common to have to play tricks like recirculating the medium.

But anyway I imagine the novelty they're claiming is for the combination of the recirculator with other elements, like maybe hooking it up to the extruder. I suggest you post the whole claim.

  • 1
    I edited the question (I'm not the OP) to include part of claim 1 because I thought the question made light of what was involved in the invention. Thanks for explaining temper. I removed the "SIC"s and edited the question again to include all of claim 1.
    – George White
    Mar 15, 2013 at 21:20

stumbled onto this from searching 3D printing. Any curtain coating process will likely be recirculating the product, and confectionary producer curtain coating with chocolate will be recirculating the chocolate. Hence documents such as http://patents.justia.com/patent/4032667

  • I didn't find "circulate" in that document with a quick search.
    – George White
    Mar 22, 2013 at 1:31

The key to this claim is the recirculation of material however it is broad. Not sure where to find prior art on this subject specific to chocolate. There should be more specifics on the recirculation claim since other 3d printers recirculate material.

http://alumni.media.mit.edu/~saul/masters/masters_s.pdf Page 23 - Describing Chocolate through extrusion means



http://www.zcorp.com/documents/218_2008-0201-Cadalyst-Low%20Cost%20RP.pdf Under section: The Players

http://www.ennex.com/~fabbers/RP-ML/food.asp Past discussions of 3d printing chocolate(not much info for claim busting)


Why yes, I am knowledgeable about prior art for Chocolate printing. I mention it in my provisional patent application for mass-customization online in a 2006 patent filing.

Provisional 60/747,601 Filed May 18th, 2006. The patent was concerted to an actual Patent in May 2007 and has 5 co-pending Continuation-In-Part Applications pertaining to Chocolate and many other things.

I'd say 2006 pre-dates March 2012!


  • Nice. Searching by your user name and "chocolate," I did not see a corresponding published application in the PTO database. Providing the serial numbers of the applications would probably be helpful for a citation analysis for the individual looking for prior art.
    – Yorick
    Mar 22, 2013 at 0:43
  • That provisional was filed by a "Bryan C. Norman". I skimmed through it (48 pages) and didn't see any detailed dissuasion of any 3d printing technology. If chocolate printing is there it is a very short passage. Application 20110313878 is about to become a patent. "Chocolate" does seem to appear in it.
    – George White
    Mar 22, 2013 at 1:21

Chocolate Extruder (February 28, 2011): http://www.thingiverse.com/thing:6756 http://www.youtube.com/watch?v=qIFkw5RNXqQ

Chocolate Extruder (July 23, 2011): http://www.thingiverse.com/thing:10278

Chocolate Extruder (October 8, 2011): http://www.thingiverse.com/thing:14421

Chocolate Extruder (October 11, 2011): http://www.thingiverse.com/thing:12430

Chocolate Extruder (February 7, 2012): http://www.thingiverse.com/thing:17216

Chocolate Cooler for 3D printed Chocolate: http://www.thingiverse.com/thing:19354

Chocolate Pump for 3d Printing: http://www.thingiverse.com/thing:18933

I could keep going...

  • I did not see anything about keeping the temper of the chocolate by a recirculating flow. Or that issue addressed at all. Just printing with chocolate isn't enough.
    – George White
    Mar 27, 2013 at 6:18

Printing with chocolate is described on this wiki page: http://reprap.org/wiki/Chocolate_Extrusion . According to the history view of that page it is older than a year.

  • 1
    To to be considered as prior art a reference needs to predate the application. Also, this page says that if the chocolate is at the right temperature it can work. The patent is about a specific way to accomplish that.
    – George White
    Mar 25, 2013 at 1:43

The Fab@Home group had a Wiki which had pictures dated in the range of Spring 2007. The Wiki is gone. Perhaps someone could contact the Fab@home group and ask.


There is nothing new about recirculating chocolate in a tempered state, the concept is a standard part of tempering machines that are used to hand fill moulds.

All the electronics and print head stuff sounds like basic extrusion printing, nothing new here.

  • Sometimes putting two old things together makes a new thing. In fact almost everything new is made from old things.
    – George White
    Mar 28, 2013 at 22:43

There might be some information / photos on the chocolate printer built at Fotango (now defunct) in 2004 using lego bricks with various additional tubing / syringes. It was successfully demonstrated by James A. Duncan at O'Reilly Foo Camp in 2004.

It did manage to get slashdotted in '04, there may still be the original videos / photos / design around ...

See http://hardware.slashdot.org/story/04/09/10/1221251/3d-chocolate-printer-made-from-legos See http://ibiblio.org/pjones/blog/make-the-mookbagazine/


It might be worth contacting the University of Exeter (and Cornell, mentioned here) to see if they dealt with recirculation and whether they published it. http://m.bbc.co.uk/news/technology-14030720


Looking at claim 1's parts, 1a and 1b are taught by existing 3d printer technology, 1c is taught by existing chocolate fountains, but 1d is the issue - how to extract the recirculating flow as printable material. For anyone versed in chocolate, keeping the temperature and viscosity stable by moving the chocolate is well known and there should be prior art for 1d in fluid movement. Crude oil is similar - it can't be allowed to bake or solidify. It seems that it would be obvious to a competent engineer to divert part of the flow from a chocolate recirculation loop (say http://www.dairyeng.com/acrobat/chocolat.pdf) to the extruder for printing once the University of Exeter or anyone preceeding that taught that chocolate could be 3d printed?

Also Hans Fouche since 1993: http://3digitalcooks.com/2014/01/interview-hans-fouche/

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