First time (yes, again) with laser cutting. Luckily a local guru gave us basic tips and info to have a smooth first approch which I am of course sharing for future generations below (not so shure how many generations will reach and use this...)
Laser cutting machine basically works the same way a magnifier works when light is casted over its lens at a certain angle. The lens concentrates the radiation into a point and depending in the intensity it burns, and in this case, cuts.
So yes, since the scheme is the one showed above is what happens you need to make shure to set the cutting surface (foco) at the top face of your material. In our local machine this is done with an accesory you hang in the lens while you move the workplane up until the "accesory"
This must be done to tell the machine where the workplane will be. Once this is achieved and the machine is turned on etc etc the laser will indicate the origin of the laser cut.
Stupit and accurate note: the laser is not the light that burns and cuts materials, it's just a replicated light that has the same parcours of the "cutting light".
Once the hardware part was tackled we move to the sofware that makes this cutter machine works. Bad news: you will need to use corel no matter what. So first the vectorial drawing needs to be imported into core (any corel allowded format) and lines must be turned into the laser cut colors: red (cutting) black (graving). This is how it's coded in our local machine, you can code your own colors and parameters.
Once you're done getting your drawing ready you need to select the template (accroding to the material you're goig to use), drag and position your drawing into the laser cutting software.
I wont' dig much into templates, if your'e familiar with autocad or revit parameters are like ctb files or view templates. You need to do several printing tests to achieve the look you're looking for. Well, this is teh same and it works with basicaly three parameters: speed, power and location in z axis. Speed is inversaly propotional to the cutting result and power directly. Z is the distance in vertical this parameter can blur slightly the engraving.
First part of the assignment was do some basic cuts to try our local machine and to get the right measure of profiles to joint pieces. We tryed basis templates, speeds and powers for both, cutting and engraving.
I did a massive marathon of tests, first only in my computer. From the typical boring layered object (yes, that is a chesspiece of a horse for the chessboard I am not doing)
up to joint pieces that first fit and then rotate to fit in another position.
Assembling pieces and rotating them did caught my attention
I saw somewhere that type of joint is called a key joint which sounds logic. There's not that many examples online of key joints (which made me of course want to know even more), I did found however this lovely low quality example on this website Enrico Bassi did.
Sneak peak of my rotation tests on model:
I wanted to create a joint that works as a joint. (and took a table as basic piece to show how the joint works)
The main Challenge was to be able to joint in three different axis, tanking into account that lasercut can only cut perpendicular to the material plane.
First attempt was kind of basic with cad 2d drawing and a basic 3d modelto get familliar with pieces shape:
But, getting back to the rotation idea my intention was to get a more complex and developed joint.
Achieving the key joint after lots of model tests and adjustments:
Here my joint was too far from the border, meaning it would not fit the table since the countertop would have remained unleashed.
So the implementation of the idea would be something like this:
Rotating the 3dmodel also counts as test since pathh of pieces can easily be seen. However fitting and dimensions won't escape laser cutting tests.
Once happy 3d model tests were over i jumped into laser cutting macines tests. Below the first one where my firts piece did fit but did not turn. It neeed to be wider to turn.
What I point with my pinkie at the end it a change I will make in those edges sepatation since the piece is not tight enough.
I forgot I have no table at home so I decided to do a more "testable" object using the same key joint.
I draw everything on cad since I am familiar with it and was faster to get a general idea of the geometry. Then used freecad for making my pieces parametric.
I've tried several options for making the geometry parametric, from a 2d drawing than can be afterwords extruded to a 3d model that can be chaped through both, constraints and bollean operations.
Since piece #2 has an axial symmetry axis what's best is parametrizing only half and then use the parametric mirror command to euqal that
I developed mi final project model in grasshopper since I was already familiar with that sofware.
I tryed a basic lettering vinyl cut and did two options of the same sticker. I just wanted to be able to invert mass and voids with the same profile. Here's a quick guide of our machine for future FabLab's oompa loompa in montevideo:
I finally did a text inside a circle so two possible outcomes were possible: (a) Whether using the text profile and using each separate as a sticker.
This is the most difficult part since you gotta trasfer every letter into a layer of transparent vinyl and it sometimes gets kind of tricky.
(b)whether a round plain vinyl with carved letters I sticked in my gear:
When I tryed to upload my progress to the MIT website using GIT I experiences this issue:
and quickly sort it out with this LINK
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