A 3D printed gingerbread house
The Christmas season for me is characterised by some very distinct sensory inputs. The sparkly Christmas lights that illuminate every bustling shopping street, or the ever-present tunes of Wham! and Chris Rea. December is also characterised by the inevitable smell of ginger, cinnamon and cloves. Mixed together with flour, sugar and eggs, these ingredients form the basis of gingerbread, arguably one of the most important Christmas symbols. Walk into any shop, school or office space, and the chances are high that you will find a little red box on the counter, or in the reception area, filled with these sweet, figurative biscuits.
While many of us eat gingerbread biscuits to ease ourselves into a merry Christmas mood, others take a more crafty approach to making gingerbread houses and scenes. Some stick to rolling pins, while others use laser-cutters and CNC mills. I decided to supplement this by creating a process for additive gingerbread making, using existing desktop 3D printing tools. I’m sure any expert gingerbread house artist will agree that his crafting of gingerbread houses is a skilful art. This tool sets out to complement that great tradition.
As a design researcher at the Oslo School of Architecture and Design, I am continuously exploring new materials and processes for digital fabrication. While experimenting with clay as a 3D printing material, I was challenged by some of my students with the following challenge: What would happen if we replaced stoneware clay with gingerbread dough?
While the initial thought seemed simple enough, there first trials with gingerbread printing uncovered some immediate problems. Firstly, gravity is not your friend. Secondly, materials usually become softer as they get hotter. If you have ever made a gingerbread house, you will probably know that baking flat pieces and glueing them together later is the way to go. This, however, is not how I wanted my gingerbread house to be made. So I needed to develop my own process.
The dough: starting off with an ordinary gingerbread dough recipe, I modified its consistency to be significantly harder, adding more flour and corn starch. Then, to make it flow more easily, I added some alcohol. The idea is that as the alcohol evaporates the deposited layers of dough get harder. To find the right consistency is of great importance – too soft and the structure will deflate. Too hard and the material will not be deposited correctly.
The tool: The tool in use is in fact a commercially available WASP 2040 3D printer, modified with a Liquid Deposition Modeling (LDM) extruder, that allowed me to contain and deposit the liquid material. However, in the initial experiments extruding the gingerbread, the structure would collapse under its own pressure. I therefore added a custom extruder nozzle with a heater, which allowed me to print the material at a set temperature. The heater would help evaporate the alcohol and hopefully make the dough harder.
The Design: The design of the gingerbread house is loosely based on Borgund kirke, a traditional Norwegian wooden stave church. The structure has relatively few overhangs (apart from at the top) which makes it an ideal structure to 3D print. While the earlier, smaller structures (see the picture above) were made hollow on the inside, the later versions were larger, and required significant internal structures. And as more material is displaced, the more gravity takes its tolls. The design, in addition to preparing an optimal batch of dough, and getting the process parameters right, was a continuous compromise. If you are curious to see how the digital blueprint looks like, have a look at the open-source model on thingiverse.
The printed structure is just less than 22cm tall, and it shrinks slightly when baked in the oven. And although the principle structure is digitally fabricated, the icing is done by hand (for now). It is now still in a nascent, experimental stage, and perhaps future gingerbread enthusiasts will want to print their own wonderland of gingerbread architecture, people and untold imaginary creations while decorating with icing and candies manually. Maybe someone else will devise a 3D printing icing and candy-placing robot. This is an open call to further develop the wonders of creating holiday treats and other awesome edibles.