20. Project development¶
I’ll summarize here the several steps done during the assignments to work on my final project…
This was the starting point of my project, after discussion with colleagues of the Applied Arts department… First sketch of the project
This assignment gave me the basis to work with websites and version control with git repositories. This will be useful to create a website to promote my project and to keep the upcoming versions of web data, designs data, software, users guide, etc.
CAD will be an important tool to create the design of the different pieces of my structure: motor support, frames…
Laser cutting will probably be THE tool to create the working surface and seat of my alcove office. And also cutting the felt of the booth structure…
Week 05, 07, 09, 11 and 12, 14 and 16¶
With my project in mind and my experience in electronics, this is the core part of my structure: A microcontroller and its extension for input (environmental data sensor; temperature, humidity), output ( motor control to deploy the booth), user interface and communication will be required to automate and ease the booth use.
3D print will be useful to create the motor support as a minimum, probably the articulation of the deployable structure.
Computer controlled machining will be used to create the seat, and planar working surface of the office.
Molding and casting is probably the less visible but still essential part of the job, to create a box to protect all the electronics parts…
This was the starting point to see the different aspects to look at when designing something new. But I’m not able yet to evaluate costs and answer complex questions as long as the prototype is not functioning…But this is a good preparation exercise to ask questions…
Week 15, 17¶
mechanical design questions will probably arise while making the prototype, but I don’t have clear ideas about it yet…
Wild card week: this was a good opportunity to start working with deployable structure, but the lack of time and material delivery will delay experimentation with those materials.
Again, to soon to elaborate the dissemination plan, but I’ll definitely take some time to answer them ASAP.
Here we are, far from done.. An extra month will be needed to complete my project, second full time job…
And final sketch, from week20:
UPDATE -JULY 2019¶
Having decided to present the final project in next cycle, I’ll develop here in details the different steps I follow(ed) to finalize the project.
Mechanical design - Unfolded structure¶
The first step is to design the geometry of the deployable structure.
Typical dimensions of office tables are minimum 60 x 120cm, to 80 x 160cm as a maximum. We will use the minimum dimensions as a basis for our first prototype.
The minimum height of the booth should be about 60cm, to allow the user to seat comfortably in front of it.
This will define the geometry of the structure, as given in the sketch below:
Plane surface with folding pattern:
Proof of concept on paper:¶
Half of the folding pattern is drawn on scale 9/60 and two similar planes are drawn. This to ease the folding process.
Paper is slightly cut on top side of the edges (other side of the sheet for the hollows)
Folding process starts from one end towards the other end, ensuring the construction 3D structure:
Two similar structures are built following hte same process:
Both structures are linked after folding and fixed on table with adhesive paper:
And here is the resulting structure:
Preliminary tests on the felt structure¶
A first test is performed with a felt of less than one millimeter thickness.
A thicker felt reinforcement could be glued on the thin support, cut following the folding pattern:
Folding the thin felt tissue is done easily, ironing does definitely help keeping the pattern, even flat!
Before going on with this first structure, we perform a second test with a 3mm felt support, without additional reinforcement.
Folding the thicker felt is, as expected, more difficult,ironing doesn’t help, but slightly cutting the edges on a half millimeter depth helps keeping the pattern.
In addition, the use of a heat press helps also keeping the folding pattern, as illustrated below:
Full scale felt structure¶
Given the results of the tests, and the limitations of the available laser cutting machine, it has been decided to use 3mm thick felt panels, of size 30cm x 60cm, laser cut on one millimeter depth, set in the heat press, stitching separate pieces after use of heat-sealable fabric on the joint limit.
Fixation to support¶
Thin metal or plastic rod need to be fixed on the felt (through a tubular slide sewn onto the felt) to fix the whole structure on the support and to enable the motor controlled opening/closing.
Typical dimensions are:
2mm x 0.6mm or 2.5mm x 1.4 mm sold at 0.6€/m
5mm x 0.40mm
6mm x 0.60mm
11mm x 0.40mm
11mm x 0.50mm
13mm x 0.80mm
15mm x 0.60mm
25mm x 0.50mm
25mm x 0.70mm, sold at 1.25€/m
Mechanical design - Storage case¶
The idea is to have a case in an U form, that can be fixed on the table (60x120cm) - without damaging it, and that supports the felt structure when it is not in use, as well as the controlling electronics.
The original idea is to have a light laser cut wood case, to be fixed on the table.
After some (long) reflexion and looking through the internet, it has been decided to design 3D printed parts that will also allow to fix the motors at both ends to control the deployment of the felt structure. A vice is probably the best suited way to do it, in order to account for the variable table thickness, without damaging it.
Should we make a complete box (with or without top cover) or just a horizontal support?
Answer: Simple support
How to fix the folded structure on its support?
Material choosen: 3mm thick MDF wood (medium density fiberboard) (available size: 60x30 cm for the laser cutting machine)
(DESIGN of 3D parts and wood structure)
A unique PCB is designed to hold the electronic part of the system: microcontroller, motors control, temperature sensor, user interface. Design of previous assignments are reused.
A case will be made to protect the electronic parts. (laser cut MDF or molded box)