I started the assigment studying and searching for some good references. I found this and this pages with the modular machines made by Nadya Peek and James Coleman at the MIT.
Then I had a look to the past machines made here in Opendot during Fab Academy 2016 at this page.
Below one example:
We dismantled an older machine in oreder to reuse some mechanical parts, in particular some rods and some stepper motor with endless screws plus bolts and other mechanical parts.
I take measures of that mechanical parts.
I did some sketches of the mechanical layout of the machine with 2 linear axes.
And some detail about connections and parts in 3D printing.
At the beginning of this week I realized that my knoledge of 3D modelling was to weak to model a complex machine. During the past assigments I already tried several softwares and the one I liked the most had been Onshape and I decided to deepen my knowledge in this software.
I searched for video tutorials and I watched as many as I could. I found them in the Onshape official page for tutorials. I understood better some key concepts of Onshape and of 3D parametric modelling such as: part modelling starting from a sketch, parametric design with quotes and constrains to sketches, assemblies of parts, output drawings, export of faces and parts, sharing of the model, versioning, etc..
I started from the translating element which is moving along a linear axe. Everything I did was parametric so I could change overall dimensions and even small details and everything automatically was rescaled. I found that very usefull along the modelling process.
Here below one example, I scaled the height of the box from 50mm to 40mm and everything was automatically scaled.
Finally I found very easy to share the model with my group with Onshape.
I found very easy to export the faces of my model to dwg file ready to be cutted.
Then I imported the drawings in Rhino.
I put everything to be cutted in one unique layer in Rhino.
I set 3,4 of speed in the settings for 4mm sheet of playwood.
During my first cut I did a mistake: I chose a 5 mm sheet of playwood instead of 4. My pieces obviously were not matching with each other. So I did a second cutting with the right material: 4 mm playwood.
The result of the second cut was well cutted but I had some troubles with the small pins that falled inside the net of the laser cutter. I did more than it was needed but still I lost lot of them. I should put some tabs in the drawing to keep them linked to the wood sheet.
When I did the assembly I figured out that there were some mistakes.
I completed the 3D model with the goal to do something that was modular. In this way I could use the same design to build a machine with 2 linear axes.
During the design process I did several modifications to the 3D model. Everything was easy because the model was completly parametric and almost every part and component was hierarchically depending to each other.
I exported the surfaces in .dxf format and I opened them in Inkscape.
In document propetries I re-sized the folio depending on the surface of the piece of playwood.
To each line the red color.
In the printing preferenes I set the dimensions of the folio so they matched the dimensions in the document propetries.
First I cut the 4mm playwood folio to the working area of the Trotec that is 300mm x 600mm.
In the software of the Trotec laser machine I moved the printable area to the place where the wooden folio was placed. I did the focus and I started the filter of the machine.
In the material database I set these parameters for 4mm playwood:
I did a second cutting following slightly different options suggested by Tiziano:
Finally it was time to do the assmbly of all the mechanical parts.
I collected all the screws, bolts, rods, etc. that I needed.
I started the assembly of the first linear mechanical axe.
I cut the rods that will be the guides for the sliding element.