Week 02

For this week we had to design and use laser cutting to produce a model using press fit to hold all parts together.

It was great because is the first product we are designing and that makes me happy because this is one of the main reasons I am doing Fab Academy.

Objectives

  • Cut something on the Vinyl-cutter

  • Design, make, and document a parametric press-fit construction kit


  • Weekly Progress >

    First, we had our weekly lecture with Neil Gershenfeld, you can watch it here.



    We also had a Rhinoceros tutorial directly from McNeel Europe. It was great to meet the people that developed one of the most used programs in the world.





    Bruce Mau gave this week’s lecture, he talked about Massive Changes.

    How can we design for a Massive Change? With today's challenges and tools we need more than ever to look deeper to our creations, their meaning and potential for transformation.




    Assingment >

    The first assignment for the week was to make something with the Vinyl Cutter Machine, I decided to cut my logo.

    I used 3 programs for preparing the file, first I made the vector in Illustrator, but for some reason I couldn't open the file in the machine's program, it wasn't recognized in any of the formats I've tried, so Santi (Our tutor) told me to open it in Inkscape and from there the trick is to do a copy/paste directly to Cut Studio (program we are using to send jobs to the machine).

    Process:

  • After you have your vector ready, open Cut Studio. Vector should be lines, no fill.

  • Copy/Paste directly from Inkscape to Cut Studio, if you get distorted lines, resize the vector (make it bigger) in Inkscape before pasting it in Cut Studio, you can resize to the original dimensions there and keep the line quality.

  • Load vinyl piece or roll to the machine. There's a handle (for tight/un-tight the roller) on the back and a tray (for the roll). Un-tight the roller so you can put your piece of vinyl in place, the minimum size of vinyl is determined by the small rods (they hold and move the vinyl), respect the black marks on the roller, those determine the different width you can feed.

  • Then the machine will detect the size of your piece and will auto-set home (X,Y).

  • Now on the program (Cut Studio): Cutting Setup > Properties > Get From Machine (this will auto set our paper size in the program).

  • Resize the vector if needed and send to cut!





  • And this is the result!

    The second project of the week was to design and prototype an object using laser cutting. I decided to do something that I was needing so bad, a laptop computer stand.

    First step, test tolerance. I made a press-fit test kit. I did it in Inkscape.

    If you want to make one, get the files here.

    Then after drawing some sketches by hand, I moved the initial idea to Rhino so I could be accurate with measurements and also to test volumes.

    Then after having the main idea of the mechanics of the object I decided to try it in real life by making a cardboard and toothpicks sketch of the model to test if the mechanics worked, they did, but I had issues in some parts, that's why it is always important to make this kind of tests before defining values in the virtual enviroment, doing this save time at the end.

    And this was the first model that I tried. Later I found some problems, mainly weak points.

    So time for my first try. I prepared the files to send to the machine to cut, DXF format. Remember, you should always export just the object curves and those curves should be closed. Check for double curves also. Be as clean as you can when modeling.

    * When you export DXF select export scheme: 2004 natural, otherwise, in our case, we had bad results.

    Next step send the files to our internal cloud so we can prepare them on the Laser Cutter dedicated computer.

    Our machine a Multicam 2000 uses a program called EnRoute to generate the Gcode.

    Steps for preparing the files:

  • Set the size of the board are you using to cut (stock).

  • Import the DXF file that you uploaded before.

  • Select all the lines and go to draw > close lines, this will prevent open curves.

  • Then go to engrave option and select the kind of work you want to do, engrave or cut

  • And finally you have to define the job parameters (output). Check small parts first > Object Order: Inside Out

  • Finally click on To File button, and that's it, the file is ready to be cutted.

  • Now time for the machining. Steps for setting up the machine:

  • First set home (X,Y): Move the machine to the desired point, that point will become home > When you get there click the blue button with two circles and an "L" shape > click enter (the inverted "L" shaped arrow on the bottom right)

  • The you have to set the material height (Z Axis): Go to the center part of your piece (or if it is a little bit bended go to the highest point, although it is not recommended to use materials in this state.) > then click on the second button on the left, from top down, it has a drill bit shape and one horizontal line > set the height of the material > A little sensor will go down > lower the Z until near the surface > press the "0" button until the tip of the sensor touches the surface > the height is set.

  • Now set the cut parameters: click to menu > then go to parameters 2D > You will mainly need to set two parameters, X,Y Feedrate and Power (it will vary depending on the material you are using. Cut use Pen 1, engrave Pen 2)

  • Test the parameters: Go to Cut Utilities on menu > select the shape you want to try (I usually use square or circle) > click enter and then run (the green button with the filmmaking clapperboard)

  • If everything is correct, time to send the job: Click on the second button located bottom left, bottom up. It has the shape of the machine and a computer connected to each other > navigate trough the files until you find the desired one > click enter > click the green clapperboard button > that's it, the job should start.

  • * There are other parameter that you can set, for example gas pressure, pierce, etc. If you have troubles with this ask your tutor for assistance.

    Parameters I've tried for different materials:

  • Cardboard 2mm: Feedrate: 60 > Power (watts): 250

  • Cardboard 3mm: Feedrate: 50 > Power (watts): 250

  • Cardboard engrave: Feedrate: 80 > Power (watts): 50

  • MDF 5mm: Feedrate: 15 > Power (watts): 200

  • MDF 7mm: Feedrate: 10 > Power (watts): 370

  • MDF engrave: Feedrate: 80 > Power (watts): 70

  • Plexiglass 3mm: Feedrate: 30 > Power (watts): 190

  • Plexiglass engraving: Feedrate: 80 > Power (watts): 70


  • And this was may first try, no problems with the machine, the problem where the measures, be careful, give enough tolerance, depending on the power and height from 0.3 to 1 mm.

    After a small fix, I assembled the first model and tried the mechanics and it worked, but again, an error with the measures pointed out some weak points in the design, this is normal in the process, so be aware if it when planning your project. This meant, redesign again.

    I also did a little test on engraving.





    Then after redesigning and testing, I was ready for the final laser cutting. One advise I can give is to work/try as much materials you can this will give you a better understanding of how laser cutting works.

    And this is the final prototype, there are things that can be improved but overall Im really happy with the result. Also I have to point out that none of the pieces of the structure is glued or screwed, everything is hold in place by press fit.

    If you want to make one, get the files here.