3. Computer-Controlled Cutting

Procedure:
0. Assignment Go
1. Vinyl Cutting - .SVG and .PNG Go
2. Creating My Parametric Pieces in AutoCad Go
3. Group Assignment's Conclusions Go
4. Lasercut Go
5. Building press-fit kit. Go
6. Download Files Go
Group Assignment: Lasercut Machine Tests

0. Assignment

Laser 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

Learning outcomes:

Demonstrate and describe parametric 2D modelling processes

Identify and explain processes involved in using the laser cutter.

Develop, evaluate and construct the final prototype

Have you...

Explained how you parametrically designed your files

Shown how you made your press-fit kit

Included your design files and photos of your finished project

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.

Learning outcomes:

Identify and explain processes involved in using this machine.

Design and create the final object

Have you...

Explained how you drew your files

Shown how you made your vinyl project

Included your design files and photos of your finished project



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1. Vinyl Cutting

With the vinyl cutting machine, you can both cut with a .SVG file image or a .PNG file image. I am going to use both to see the differences.

Using a .SVG file

A .SVG file is an image made out of vectors. What I did was to take an image from the internet, from a website called 'Animalia Life' (boton con DIRECCION:_ http://animalia-life.club/other/jaguar-face-black-and-white.html __), go into the gallery and pick the one that I like.

The file that I have downloaded from the internet is a JPG file, and I need to convert it into .SVG file. Therefore, I open Adobe Illustrator and import the image:



The tool I have used to convert the pixel to vector is called 'Trace Image' and select the 'Black and White Logo'. What it does is, it takes all the black pixels, converts them in a group that on its perimeter is closed with a vector. As there are lots of black spots, there are lots of closed vectors that are filled with black. Here is the image after being traced:



In red, all the red vectors that create the leopard figure.

Now I have my modified image and it's time to export it to SVG file and import it in fabmodules.

Turning the machine and the computer on. Open the cmd and enter './fabl modules' to start the connection between the machine and fabmodules. The next message appeared:

'listening to connections 127.0.0.1 on 12345'. --> Everything ready to start using the computer!

The next step is to import file in fabmodules in firefox:



Input file: svg
output format: Roland vinyl
Process: cut vinyl

Properties:

-size of the image: 1417x1417 px with 300 dpi.
output:
-force: 70
-velocity: 2 cm/s
-origin: left bot right
-process:
-tool diameter: 0.25mm
-number of offsets: 1
-no offset overlap

Before calculating the image, I need to adjust the force needed as always a test is needed before cutting.

The Vinyl Cutting Machine

When turned on, I need to select what type of vinyl am I cutting: a piece or a roll.

I select a roll (as it is a pink roll), and there are two options: select 'roll' or select 'edge'. I select edge, the one that cuts your file on the edge of the paper.



I align the vinyl and tighten it with the small rollers the machine has.

Now, I need to make some tests to make sure the machine uses the correct force to cut. On the control panel, select force and try different forces. First try with a 70g of force.



The machine cuts a square inside a circle. If the vinyl comes out easily, without having the white base being cut, then it is the correct force to use. Done! 70g is perfect.

Going back to fab modules, change the force needed and calculate.



Once everything is ok, send.

Result:

The Process Of Taking The Extra Vinyl Off

Then, I took a special paper named 'transfer paper' that is sticky on one side and put it on top of the piece that has not been separated. Put pressure to make sure all the little parts get stuck to the transfer paper and then, separate it from the white base.

Now, I have the final piece on the transfer paper and place inside my book. Carefully, separate the transfer paper from the vinyl little pieces, making sure they do not move.

On the .PNG file process, there is an image of this transfer paper I am talking about.

Final Result



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Using a .PNG file

Again, to go through the whole process, I went to a friend's piano school website 'Escuela Piano Toccata' and took its logo: http://escueladepianotoccata.com/

Now, I have to modify the image. Import to Adobe Photoshop and make it have 1000dpi:



Now I have the image ready to import it to fabmodules.

I turn on the computer and the machine as I did for the .SVG image entering what is needed. Then, open fabmodules:
-input file: png
-output format: roland vinyl
-Process: cut vinyl



Again, as I cut the images in two different days, I needed to adjust the force by testing the machine:



force: 80 g



Test done and correct! Let's start!





After fabmodules has calculated the image. It's ready!



Done!

The final piece that came out from the machine had several problems as I had very thin lines. The material had not stuck together with the white base having the following problems:



I carefully take all the different parts I do not need:



As done before, I take the transfer paper. I place it on top of my piano, and separated it from the white base. This is the transfer paper:



Final Result:




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2. Creating My Parametric Pieces in AutoCad

What I wanted to make for my press-fit building kit is a sculptural puzzle game. My idea was to create 2 or 3 different pieces where they fit perfectly together. Then, cut them on the lasercutter machine and try them out to see what sculpture I could make.

Before creating my new pieces, I needed to know the conclusions that were done before on the group's assignment.
Group Assignment: Lasercut Machine Tests

As I am going to use a 3mm cardboard, I know that the kerf I will be probably using is of 0.25mm, but it was done with a 6mm cardboard.

What I did was create a parametric desing where I can change the dimensions that I need while I do the different tests.

The two parametric pieces that I have are:



The idea behind this parametric design is to have the option to modify two dimensions:
-the kerf
-the width

With those two parameters, the piece changes without modifying its essence, making it possible to have changes according to the design. These two parameters are:

-a1: changing kerf's dimensions
-d1: changing the length of the sides (as it is squared, width and height are the same).

Creating My Squared Shape

To create my parametric design, I have used AutoCad 2010 to do it. First I am going to draw the geometry of the piece, then add geometry restrictions and at last, dynamic parametric restrictions that I will be able to modify once its finished.

First, I need the piece drawn on the design program:



It is a simple shape: a square that has 3 longitudinal holes that slice with another piece. To start with the geometric restrictions, I am going to snap together vertices, so when the piece is modified, they stay together.



The next step is to make sure the horizontal and vertical lines stay as they are: being horizontal or vertical. They can be larger, they can move, but always staying at the angle.



What is left now is to make sure the chamfers stay perpendicular between one and another so they do not mess up the geometry of the hole. This part is needed so when the other piece is introduced to this one, that cardboard fits correctly.



Plus, as now they are perpendicular between one another, I need to make sure they are exactly the same in length. I activate the 'equal' geometry restriction, so when the piece varies, this magnitude does not vary. Just a reminder, it does not matter if the piece becomes bigger, these lengths do not need to be bigger.



Now I have to create my first dynamic restriction: the global length of the piece. I have named this two parameters as d1 and d2 (being d2 the same as d1). Now, I have d1 = 38.40 mm, and if I change that, it changes automatically d2.



On the other hand, I need to create my dynamic restriction number 2, where I can vary the hole where the other pieces slide into. These dynamic restrictions are named a1, a2 and a3. As it can be seen on the picture, a2 and a3 are the same as a1. It has a dimension of 5.75mm.



For the material left between the holes and one side of the piece, that part needs to have a minimum amount of material to operate correctly when manipulating the piece. Therefore, another 3 dynamic restrictions have been used (1 per each hole), with the same width as the hole. These have been named as s1, s2 and s3, having the same value as a1.

Making Sure It Works

Now, I have changed d1's and a1's values. From being 38.40mm and 5.75mm to 45mm and 6.5mm. On the image, the piece has been changed successfully: the horizontal and vertical lines have stayed as they are and the chamfers have not enlarged nor positioned in different angles, there is enough material so the side do not break.



Let's try with other dimensions: d1= 40mm, a1=7.5mm. Let's see what happens if I reduce the size of the piece but enlarge the holes.



Everything is correct! Now I can cut!

Creating My Triangular Shape

Here is my second piece. The strategy I need to use is slightly different from the piece above. As before, I will create my geometric restrictions first and then the dynamic restrictions to later modify the design. Let's go for it!



Each vertices need to stay together when modifying the piece. I will start by adding this type of restriction.



As done before, I will continue with the horizontal and vertical lines. The big difference from the previous shape is that it does not have that many horizontal lines. Instead, there are diagonal lines placed at 60 and -60 degrees. This just adds some difficulty to the parametric process. I will assign the horizontal and vertical lines that need to stay as they are, allowing to modify its length.



The next step is to make sure all diagonal lines stay diagonal when modifying the piece. Therefore, I will use an angle restriction between two lines: the base horizontal line and the 60 degree line at one side. I will do thie 6 times with all the piece.



In order for the previous step to work, I need to make sure that the vertices where two lines come together are perpendicular. I added a new perpendicular restriction:



Now, one of the lengths I will be able to modify is the dotted line on the picture below. Plus, all the other lines that are the same as this one I will add a geometry restriction of equality, meaning that when I modify this first length, all the other will change as well.



More geometric restriction of same corresponding lengths all around the shape.



Now, first dynamic restriction that later on will be able to be modified: d1. D1 is the hole's length.



Erasing the middle hole. No need to have it.



h3, Making Sure It Has Been Done Correctly

-For a1 (the hole's width) = 6.6mm, for d1=4.7mm.
-First modification done: a1= 5.5mm, d1= 7.5mm.
-All the piece has changed as it is suppose to.

Let's try another one:

-a1=9mm
-d1=7mm
-Perfect!



Once I have the pieces I am going to use, export my files and ready to go to the lasercutter machine.

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3. Group Assignments Conclusions:

The tests we have done as a group in the laser cutter machine have been with different kinds of materials:


-Medium Density Wood - 3mm
-Cardboard - 6mm
-Foam Core Board - 5mm
-Methacrylate
-Engraving with different adjustments

These tests have had both successes and failures, until arriving to a well engraved and cut piece in order to calculate their corresponding kerfs.

As a conclusion , each material has its own kerf that later on I will be using to create my own stuff. Here is the list of the different kerfs:


-Medium Density Wood's kerf: 0.55mm
-Cardboard's kerf: 0.25mm
-Foam Core Board's kerf: 0.3mm
-Methacrylate's kerf: 0.15mm

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4. LaserCut

Using The Lasercutter's Program 'Lasercut5.3'.

As the machine is connected to a computer, I need to copy the files in the desktop so there are no connection problems with the pendrive.



I open the program and import my file.



Now I need to:
-organise the top layer (the first one will be cut first, then the second one, the third and so on).
-open the 'Cut Options' and enter the parameters for my material
-free the memory from previous cuts for my file
-download



Next to the machine, there is a printed paper where all the parameters needed for each material. For my material: cardboard 5mm has:

The kerf I have used has been tested before in the 'Group Assignment's Website'. In that assignment, we have made different tests with different materials. The kerf I have used comes from those we have done.

For the cardboard I am going to use, I have a kerf of 0.25mm. This means, if I want a 6mm width hole to slide my pieces into one another, I need to design a piece with 5.50mm width hole. The 0.50mm is done by the laser, cutting 0.25mm on one side and 0.25 on the other.

Please check the test we have done previously: Group Assignment's Website

Cutting Options Used

-Speed: 20
-Power: 25
-Corner Power: 20
-Setting each layer to 'Cut Mode'



At the right hand side of the menu, there is a column named 'Output', where you can download only certain files either to make test or cut each layer or pair of layers separately.



Once all adjustments are done, 'Download' and a new window pops up with the previous file that has been stored the machine's memory. Delete the previous file and 'Download Current', to make sure only my file is on the machine's memory.

The Machine's Workspace

Machine Controls and Cutting

Turning on:
-the lasercutter machine
-the fan (make sure it is at 20-25 degrees Celsius)

Placing The Material and The Height of The Focal Height

The laser tube needs to be at a certain height, so the lens inside diffract the laser at its maximum power for the adjustments previously introduced. Therefore, the height for the lasercutter machine I have used is 6mm. There is a MD wood to used at the exact point where the tube needs to be in relation to the material:



Once it is on its place, used the top screw to fix its positions and close the machine.

Control Panel

General view of the control panel



Each button on the panel correspond to a specific function. The most important are (in order)

-datum: goes home position.
-laser: when pressed, it lasercut to see where is going to start cutting.
-test: when pressed, the lasertube moves all around the perimeter of the object that is going to be cut.
-start/pause: when pressed without workind, starts cutting. When pressed during the cutting process, pauses.
-stop: stops cutting.
-left/right: left - right for the control panel and to position the laser tube.
-yellow: escape button.
-longest button: enter
-menu

In order, the pictures are (datum, laser, test, start, stop, left/right):





While the machine is cutting, the user has the option to manually increase the power. Unless you have enough experience to do so, is better for the machine to cut automatically.

The red button is the emergency button. When any problem appears, press this button to stop the machine right away. The Power Panel that shows the quantity of current used for the laser must always be below 30 mA. It should work under 20 mA, and sometimes between 20-25.





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5. Final Result: Press Fit Construction Kit

Playing around with the pieces

1st system (only squared shapes used):



2nd system (using my two parametric design and a new piece):

Sculpting with my designs

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Download Files

Download Leopard Files: svg, ai, psd.
Download Kit Files: dwg, dxf.
Download Piano Files: png, psd**.

**This last link to PSD and PNG files is linked to the FabLab Madrid Ceu's folder. As I have heavy files, my instructor decided it was best to link it to the fablab's folder (51mb).

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