Machines where introduced this week. The machines we used this week where
My first encounter with a vinyl cutter was a couple of years ago when i made the
number plate for my bike.
The guy at the shop was printing the number on a plastic kind of sheet and i found that after the so
called printing the letters where
cut off leaving holes in there place. This sheet was used as a stencil to paint the numbers to the
number plate.
Now i find the same machine here. The model we have is Roland CAMM-1Servo.
After our instructor Yadhu gave us a demo i got really curious about how precise the
blade cut the sheets, just the top layer leaving the bottom layer intact.
Vinyl Cutter with its parts
For vinyl cutting i had choose what to cut. First i picked a photo of myself to create
a sticker.
The major constrain in printing some thing like a photo is that you need to convert is
properly to a binary image(black and white only).
I used photoshop for the purpose. First i converted the image to a grayscale image and then used the
treshold function in photoshop to adjust the values of white and
black. I had to later do a bit of cleaning up to get an image as follows
Convert the image into grayscale
Tresholding the image
Saving as png
Later i used the same process to make a sticker of the logo of our company.
This machine needs a .camm file as input. The FAB team has a large set of tools to
convert images in different format to .camm.
This is called as a FAB MODULE. The program can be launched by running "fab" in the terminal. It is a
simple program which can first let you choose the input and output
file types.Next we can resize the image if needed and then you can vizualize the path; here we can fine
tune the
settings such are error pixel or power. Remember not to set the error pixel value to
very small values, if so the cutting will be worn out
Launching the fab module
Resizing, fine tuning
Generate and send the .camm file
In the machine there are just a few controls and adjustments. The primary thing is to load the sheet.
Sheets can be either a piece of a roll. There are wheels which pull the sheet in while cutting. The
placement of
these rollers are restricted to certain regions marked with white. Take care to always place the wheels
on these places.
If you are using a piece, then the machine measures the length of the piece before you cut. There is a
sensor in the
machine which lets it do that. So while using piece make sure that you place it above the sensor also so
that the
machine can measure it.
Once you have properly loaded the sheet you need to choose the type( piece or
roll) from the machine hard
control
after which you can place the blade where you want to start cutting and click and hold the origin button
to save the
position. With that done you can send in the file from the fab modules and get it done.
Final sticker sticked on to a table
Original file
Once in between someone else was using the machine and his cutting has already started. I opened up another file in the fab modules and suddenly the printing was haulted. So we realized that even after sending the .camm files we cant load another work in the fab module, we need to wait till the cutting is complete.
Lasers always fascinated me; the technology, the applications and the way it has
chained the things around us.
Few links about laser tech
laser tech
explained
video explanation
With laser cutting i was exploring more uses of laser. Our machine is Trotec Speedy
100. Our instructor Vishnu thaught me how to use
inkscape designed files in the laser cutter. He showed me some demo of cutting and engraving. I was
inpressed the way the machine engraves fine details into
craft wood.
The machine we are having in our lab is 'Tortac Speedy 100'. It has a bed size of 610 x 305 mm
and a height of 170 mm. It works at 12 -60 watts power depending on the settings. This machine does not have
auto focus and we have to manually set the focus.
Laser cutter,Speedy100
1. Make sure that the document size fits your drawing, you can make the document size
little bit larger that the
drawing size.
2. The document size should all be in mm
3. If in the job control software you find larger sized rectangles than the actual size you expect,
that
probable means you have set the size wrong in the properties session
This weeks group assignment was to find the kerf of our laser cutter
While cutting with a laser cutter, unlike cutting with a blade due to the thickness of the laser beam, the cut formed had a thickness, this is called as kerf. Kerf depend on the material, and the specificaitons of the laser beam and the focal length of the lens. Finding the kerf is important if you are making a pressfit with a rigid material such as wood or acrylic.
Finding kerf is simple, You need to cut a small square on the material you want to find the kerf.
With a venier caliper, measure the inner diamension of the hole and the outer diamention of the
piece.
Substract
and divide by two, this is the kerf of the material.
Here we made a kerf gig as shown in the figure below.
Kerg gig
Cut out piece for kerf
photo courtsey: Ajith Kumar
Kerf of the laser printer which was found to be 0.325 for craftwood, 0.24 for acrylic.
This weeks assignment was to make a press fit kit.
Initial concept
Parametric design is the kind of design pattern in which you make a model based on parameters. The simplest
example is a circle.
You can crate a circle by considering many point in the circle or by defining a function which takes radius
as the
parameter. Parametric design is more like the second way, we define shapes as function with there parameters
acting like controls.
The greatest advantage of parametric modeling is that if you want to bring about some change in the model
you need not recreate the entire
model , instead changing the corresponding parameter is enough and the software automatically updates
everything.
Fussion 360 has a powerful parametric modeling environment. Fussion's model environment is based on sketches
and these sketches are
parametric my default. You can even store these parameter in variables for quick modification. You can
access this menu from
Modify >> Change parameter
Change parameter section in fussion
Now you can click on the plus button and enter the variable name and the value in the field and save it.
Saving parameters
Now while drawing the shape make sure to use this parameter. After making the full design you can change the
value corresponding to any
parameter and the shapes automatically gets updated.
Drawing shapes parametrically
Its time to make the parametric model of my press fit kit. I am making a hexagonal shape with
a connector which can be connected in different ways to form different shapes. I create variable for
dimensions for every part of the shape and
use constrains to make the model parametric. Thus when i change the parameter the whole model get updated
automatically. Here in this model i can change radius, wing length
with fussion automatically updating the design for me. This is show in steps 2, 3,4 and 5.
1. Creating the hexagon shape
Final hexagon
2. Testing the parameters
3. Testing the wing width parameter
4. Testing the slot width parameter
5. Testing the slot depth
6. Applying fillets
7. Extruded into 3d model
8. Finally exported the sketch as dxf and opened in rhino, cleaned it up and
gave it to print
Original fussion file
Original rhino file
Everything worked well expect that the wings which i
needed to be folded and pinned
was not cut properly. I want the machine to cut everything leaving
the bottom layer of the cardboard so that i can bend it across and clip it. That was a real
challenge to
find the right value of power and speed of the machine engraving.
I cut using different parameters but it was not working.
Testing with bends, here the bend is not forming properly
Testing out different parameters for the bend
Later Yadhu came up with the idea of double dotted cutting lines and it worked. I have already compensated
for the laser kerf in the design so everything fitted well in the first go.
The double dotted cutting lines
Folding and fitting the hexagons
This error was due to the fact that the machine we are having has a maximum print size of 300x600 mm. Anything you try to print beyond this diamension will give you this error.