Top ten frequently asked questions for CandyFab.
How does it work?
Pretty well, actually! =D
For the big overview, take a look at the main article about the CandyFab 4000.
How do you add the next layer?
Manually, with a scoop of sugar. The machine spreads the pile of sugar uniformly over the build region, and then lowers the piston slightly-- to clear the spreader bar -- before the next layer is melted.
Why isn't adding the next layer fully automated?
Adding a sugar handler would double the size of the machine, and wouldn't really save us much time or effort (since the sugar would still have to be lifted up manually or with a very complex system). Also, it wouldn't increase the precision because the vertical axis is already computer controlled. Add into that mixture that the machine is *not* whatsoever designed for unattended operation, and the last good argument for an automatic dispenser goes away. We had originally planned to automate it, but when we realized how easy and reliable it was to add the sugar by hand, we simply lost interest.
When the machine performance gets fast enough that adding the next layer gets to be a significant time sink-- or at least very annoying --we'll obviously get around to building a great big sugar hopper that sits on top of the existing machine. :)
How does it taste?
Pretty damn good.
While our process has incredible potential for making interesting food, we are still prototyping and we have only just begun to work with the sugar under conditions that could be construed as proper food handling procedures. The early versions (like the CandyFab 4000) were primarily interested in treating the sugar as a relatively safe (but not edible) industrial chemical and prototyping medium.
There is no fundamental obstacle to food-safe 3D fabrication, and the CandyFab 6000 is designed with food handling in mind. We fully expect that food production will be one of the important things that folks do with CandyFab. You know those ice sculptures that show up at fancy buffets? We're coming for them!
Will you sell me one?
Yes; patience please. ;)
The first version, the CandyFab 4000, is a DIY project that anyone can build-- but you need to start by scrounging some old components to recycle. We are presently releasing the new design, the CandyFab 6000, that is easier to build by using new, off-the-shelf components. Our plans will be fully open source and freely available online. We will also gather up the components as full and partial kits to take some of the hassle out of purchasing individual parts. If you'd like to get a notification when kits are announced, sign up here.
Full turn-key systems are also under consideration for the future.
Why don't you use powdered sugar?
Our resolution is limited by other factors (mostly air flow rate) at a much higher level than the grain size of even granulated sugar, so it wouldn't actually help anything. It would however be much messier and (possibly) harder to contain with the canvas sack. Also, powdered sugar tends to not be pure sugar, but instead have a small amount of corn starch added. We do not know how that would affect the build, rigiditiy, clarity, or color of sugar sculptures built with that mixture. At some point we will try it, but there is not any urgency to do so.
Have you considered using a laser?
If you want a 3D fabrication system that works by using a multi-kilodollar laser, you can go out and buy one right now: this is the basis of selective laser sintering and selective laser melting fabricators. The whole point of CandyFab is to advance low-cost alternatives to these expensive fabrication systems.
While people often ask if a cheap "DVD player" laser would work, the fact is that we are not aware of any laser systems under $1000 that would do the job well; we expect that 2-5 W of laser power would slow but effective, and that 20-50 W of laser power would be needed for high performance.
If we were to pursue the use of laser systems in CandyFab, we would run into a number of issues. First, the economics are not favorable for what would otherwise be a low-cost fabrication technology. Second, any laser with power above 100 mW is a serious safety hazard. The magic of the modern laser engravers (e.g., Epilog) isn't what they do, but that they have made it safe. Any powerful invisible laser really needs to be operated in a sealed, interlocked box with *tested* IR-blocking viewports. Third, there are possible patent issues with developing new systems based on laser sintering and melting.
That said, and the drawbacks pointed out, we do plan to investigate a number of DIY alternative printing technologies that could be adapted to work with the base CandyFab system, even if not made part of the main CandyFab development thrust.
How long does it take to print?
CandyFab currently takes about half a second to print a pixel, but we have reason to expect that things can be sped up in a few different ways. The heater design has not made much progress since the early versions-- the CandyFab team has been concentrating on redesigning the electrical and mechanical parts of the machine-- but heater redesign is now a top priority.
What kind of files does it take?
You may be asking the wrong question. This isn't a plug-and-play thing you got at the big box store. It isn't a software package, it's a machine. It does what you tell it to, and *you* have to tell it what to do. Our first take at software takes a bitmap file (e.g.) PNG to tell it which dots to color in (er, melt) and which not to on each plane of printing, and it's up to you to slice the file in your choice of 3D programs. We've already demonstrated how to do that for POV-Ray, and how to convert STL files and use those. Are there other file types that can be used? Absolutely. If you want to suggest file types that we should be looking at, please do. If you want to help add capabilities, please do.
Can you print other things besides sugar?
Dude, just wait 'til we get started! If you can melt it in your oven, CandyFab can sculpt it. The basic requirement is that the media have a fairly low melting point and are available in granular form. Some obvious things that we're planning to try: Various plastics, chocolate chips, glass, and low-melting-point metals.
We have successfully printed in HDPE plastic, but it was smelly. Melting sugar smells better.