How do you add additional layers to the candy fab, and maintain thickness? is it a manual process?

> How do you add additional layers to the candy fab, and maintain thickness? is it a manual process?

The process of adding sugar is manual, but the layer thickness is computer controlled.

Additional sugar needs to be added each time that a layer finishes, which can be from several minutes to several hours, depending on the amount of 2D area that is printed on a given layer. After a layer finishes, the computer tells the vertical axis servo motor to lower the sugar bed by a fixed increment. The sugar bed is inside a box with four fixed walls and a moveable floor, so when the sugar bed lowers, the top surface of the sugar is now slightly below the top edges of the box. We then manually add a couple of scoops of sugar to the top of the sugar bed and slide a straight edge across the top of the box to leave behind a flat surface of sugar that is of uniform thickness above the last (fused) layer.

We had originally planned to build a large hopper above the unit that would sprinkle down the correct amount of sugar and then run the carriage back and forth with a squeegee to flatten it out. That's not necessarily an easy task, so we decided to put it off until everything else was working. As a temporary measure, we instituted the procedure above. However, it has turned out that this procedure is so easy and reliable that we simply lost interest in trying to make an automated system.

Here's some food for thought: Adding any automatic filling system to an additive 3d fabricator will necessarily require storage space (at least) equal to the print volume plus the machinery required for the filling action. In most cases, this will approximately double the size of the apparatus. For our machine (in our kitchen) doubling height would be acceptable, but not width, and it would be (at least) as much work to lift buckets of sugar up to fill the hopper as it would to put in a scoop after each layer.

Thanks for the information, a while ago I built a hot air gun, using a radio shack desoldering iron (the kind with a bulb) and an air line from an air compressor. I tested it earlier today, and it fuses sugar quite well...now I am looking towards building a carriage.

3d fab has been a project I have wanted to do for a long time, but the costs are very difficult for anyone with a small budget. This seems very much more within the range of something that can be done by almost anyone. Thank you for publishing the idea to the masses.