Building a 3D-Object Laser Scanner, Part 4

Finally the Parts arrived today.

A first disillusionment came up while we unpacked the parts: some small corners of the planes have broken apart from the parcel-transportation.

These aren't critical parts concerning stability and even though it would work without these broken-off parts, we started to doubt whether we had chosen the right material.

All of the total 136 parts are covered with some protecting film on both sides and the laser-cutting appearently literally welded this protecting film onto the parts.

Several hours of annoying and nit-picking peeling off this film from the variously shaped parts made motivation sinking towards the zero-line.

However, later that day I glued the second on top of the first layer and was positively suprised of the strength and stability the combined parts revealed when the glue had hardened.

Let's think positive and keep on being curious for the final assembly..!

Building a 3D-Object Laser Scanner, Part 3

It turned out that neither 3D-printing, CNC-cutting nor "traditionally" fabricating the assembly frame is an option.

All of these methods would have been too expensive, the latter one as the "cheapest" method still at a cost of more than $1200.

Furthermore one of the goals to achieve also is to spend as less money as possible for our DIY-scanner.

We tried to build the frame by ourselfes as well, but we just didn't manage to get the necessary precision to make all parts fit as planned.

For some days we let the project rest and started focusing on the electronics and software that is another big task yet to come.

I was working on the flowchart that the software-process will follow when I finally found the solution for the fabrication cost-issue: I divided the frame in layers, each with a strength of approximately 6mm or 0.25 inch, extracted like stories of a tall building one by one.

This way the need of a three dimensional cutting or printing could be reduced to a comparatively simple 2D-cutting from several sheets.

During the process of splitting up the model, the weight could be calculated more acurately, what made us switch from the choice of aluminum we first thought we would go for to a much less weighing PETG-Plastic.

Even though we now are one step closer to the final 3D-Scanner construction, we are facing the new challenge of glueing the cut sheets one on top of another which seems not as easy as on the first sight in case of the material used.

Another problem that is yet to be solved.

Building a 3D-object Laser Scanner, Part 2

Here comes the latest update from the building-site of our 3D-Scanner.

During a two hour train journey, I constructed the frame for the whole assembly of the scanner digitally in a piece of software called "Cinema 4D".

It took me quite some time to make the virtual model to become what is called "water-tight" *.

Finally we needed to find a way to turn the virtual CAD-model into an actual physical object.

It seemed that 3D-printing technology, which we already successfully used to build some smaller custom parts, was the way to go. However, the fact that the volume of the object in questions is the critical factor for the fabrication-costs lead us to dismiss the 3D-printing process.

(As it lies in the nature of a frame to occupy a huge geometrical volume even though it's empty on the inside, we ended in a price offer of more that 4500$)

Where do we go from here..?

* To give you a comprehensible example, think of you returning home from a holiday, carrying a souvenir model of one of the pyramids of Gizhe with you. The little souvenir-pyramid has about the size of the palm of your hand and is hollow, meaning it has no bottom covering part and only consists from the side-walls, but for a model this is - of course - perfectly ok.

You might want to place it on the book-shelf but it looks a bit lost there between the books that are slightly taller.

You come up with an idea: you will impose the pyramid over a paper coffee-cup like if it stood on a socle-mounting (the pyramid overlapps the cup a little bit).

The pyramid thrones now suitable on the very top of your shelf!

Yet, your work is not perfect - the pyramid sits very shaky and unstable on the round edge of the paper-cup, the circulating air that results from just opening a window will wave the pyramid from its base.

As you investigate the problem, you will find out, that in fact the inner walls of the pyramid make contact on just 4 single points of the paper-cup, because of the cylindric shape of the latter.

Now in terms of a virtual 3D computer graphics model in a figurative sense making our souvenir-pyramid water-tight would mean to cut the paper-cup into shape so any single point of the cups edge touches the pyramid, all around the full 360 degrees regardless of the two completely different shapes of a round cup and a square pyramid!