Week 4 : Computer-Controlled Cutting

• make lasercutter test part(s), varying slot dimensions using parametric functions, testing your laser kerf & cutting settings (group project)
• cut something on the vinylcutter
• design, make, and document a parametric press-fit construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways

Vinyl Cutting

There is no specific project that is focussed on this very useful tool. There are a range of ways you might utilise it throughout the programme, or your local instructor may set a specific project. You might make:

• stickers
• flexible circuit boards
• a textured surface/relief pattern
• screenprint resists/stencils

Ensure that you have used it in some way during this time and met the objectives below.

Group assignment

Characterize your lasercutter

Tbricks

For my press-fit construction kit, I thought about a triangular module with different holes inside to let the light go through.
As I needed a geometric design, I started to work on libreCAD wich is very powerful to design parallel, tangent, rotation, fillet and different lines with geometric properties.
In a second time, I imported my libreCAD design (dxf file) on Inkscape to use clones to make holes and connecting parts I would be able to adjust on material thickness.
For my prototype, I took MDF 3mm. As we have measured that float due to a cut is around 0.1mm and I wanted the pieces to be fixed a bit strongly, I designed a curve extra material 0.1mm thick.
I cut it on Trotec speedy 100 lasercutter with 100% power and 1.30% speed and play with those bricks and connectors with my daughter all the evening.

Tbricks modules and connectors on Inkscape

I like clones very much because you can easily change size of all parts but cloning is not strictly parametric.
So I also made a parametric 3D model on Freecad.
On Freecad, you can create a spreadsheet where you can store your design parameters. On A column you can type data_name, data value on column B. Then, right click on data value and add an alias (better is data_name).
When you add length constraints on your sketch, click on f(x) bullet and enter spreadsheet.data_name instead of a value.
Then, when you change data value on spreadsheet, your design changes. By this way, your design become parametric.

Tbricks on Freecad

Vinyl

At home, my children always forgot to close the toilet cover. Rather than repeat again, I decided, this week, to make a sticker. Cover lid will ask my children to close it. First, I think about the message. I want it to be more a wink than an order just for my kids to remember to close the cover.
I have chosen : Close me, I am shy and a shy smiley.

I designed my logo with Inkscape. On this 2D vector open source software, you can design geometric shapes, add text (it's better to transform text in path before using vynil cutter computer to avoid font missing problems) and even vectorize bitmap pictures. Then paths can be used as cutting paths.

I cut my sticker on Roland CAMM-1 GX-24 24" Vinyl Cutter.
I first tried 120gf, but vinyl hasn't been cut well, mostly in corners.
130gf was better but some parts were not well cut.
I found that cutting force equal to 140gf is a good value for my material. This value depends on material thickness and maybe resistance.
It's not so easy to peel extra material so I made extra cuts to divide the job in several parts so I peeled in 6 parts. It was easier to peel.
I used a tape to keep position of each character and fixed my sticker under my toilet cover. After three days, the result is a hundred percent success.

referme moi, je suis pudique

Animated gif

To insert photos in my documentation, I decide to create animated gif.
With Gimp, I resize all my photos at the same size 378x408.
On the first photo, I add a new layer and copy paste the second photo on this layer. I repeat it for each photo.
When all photos are ordered in layers, I used a filter/animation/optimize (for Gif).
Then I Export with gif extension and check As an animation, fix the delay to 2000 milliseconds and also check use delay for all pictures.