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Monday, July 28 2014 @ 07:26 AM PDT

Fabricating complex shapes: A sugar chain

Sugar Chain
One of the hallmarks of rapid prototyping technologies is that they are additive processes, where material is incrementally added to a form. This makes it practical to make complex shapes that cannot be efficiently manufactured by traditional subtractive processes, such as CNC milling, where material is cut away from a block to make an object.

Consider, for example, a chain of connected links. While skilled whittlers can indeed carve a chain out of a single piece of wood, it's a labor intensive process that requires accessing the part from many different angles. In contrast, in an additive process it is no more difficult to make a connected chain than it is to make any other shape. To prove the point, we constructed this chain of 12 links-- using about a pound of sugar per link. (Yow!) Read on for a few build photos.

We began with the design for the completed chain, drawn in POV-Ray. Each chain link consists of two tori, cut in half, and connected by two cylinders. This gives the appearance of a stretched chain, but with a proper circuilar cross-section at every point. The twelve links are arrange with six lying flat and six arranged vertically.

The next step is to slice the object into a set of 2D images. We have previously detailed the method that we are using, which essentially consists of computing the intersection of our object with a thin horizontal box, the thickness of which is matched to the thickness of our printing layers. For this large object, the layers are 1/8" (3.2 mm) thick.

Chain model

The animation here shows what a representative set of the slices look like, as we build up the object. (Not all layers are shown).

Chain Layer 4
When we first start to build up the chain, we are only printing the lowest part of the six chain links that are vertically oriented; it's hard to see from the pattern of melted sugar alone how this will turn into a chain.

Chain Layer 1
In the middle section of the chain, where we are printing parts of all twelve links, it is a little more obvious what we are printing.

One thing to note is that the loose "horizontal" links are suspended by the loose print medium (sugar) in the print bed. This is in contrast to some other fabrication technologies which require a separate support matrix to be built alongside the actual desired obect.

Sugar Chain And there we have it!

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Fabricating complex shapes: A sugar chain | 8 comments | Create New Account
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Authored by: schorhr on Tuesday, July 31 2007 @ 04:58 AM PDT
This is amazing, it really looks great; Especialy the photos of the work in progress are really great.
I know the resolution is rather low, but how small would you be able to print a chain before it becomes to brittle?
  • Wow. - Authored by: Windell on Tuesday, July 31 2007 @ 10:25 AM PDT
  • Wow. - Authored by: Anonymous on Friday, August 03 2007 @ 07:11 AM PDT
  • Wow. - Authored by: Windell on Friday, August 03 2007 @ 10:02 AM PDT
Fabricating complex shapes: A sugar chain
Authored by: Anonymous on Monday, August 06 2007 @ 03:59 PM PDT
It looks to me like the links of the chain are more smooth then some of the earlier fabs, did you change the thickness of the layers of sugar that you melted with each pass?
Fabricating complex shapes: A sugar chain
Authored by: Anonymous on Wednesday, March 19 2008 @ 07:03 PM PDT
You could build a chain mail suit to protect yourself from people with diabetes!