Assignment:
design, make, and document a parametric press-fit construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways.
Laser Cutting
Computer-controlled Cutting
do you want to play chess game?
What is cutting kerf?
Kerf = Width Kerf is defined as the width of material that is removed by a cutting process. It was originally used to describe how much wood was removed by a saw, because the teeth on a saw are bent to the side, so that they remove more material than the width of the saw blade itself, preventing the blade from getting stuck in the wood.
Why kerf width is important
When
cutting
parts
on
a
CNC
plasma
or
laser
machine,
you
want
to
produce
accurate
cut
parts,
with
final
dimensions
as
close
as
possible
to
the
programmed
shape.
So
if
you
program
a
6”
by
6”
square,
and
the
plasma
arc
removes
0.200”
of
material,
as
it
cuts,
then
the
resulting
part
is
going
to be 5.8” by 5.8”. So the actual tool path has to be compensated by 0.100” to the side of the programmed path, all the way around the part.
Rather
than
re-program
the
part
at
a
different
dimension,
the
CNC
will
take
care
of
this
automatically
just
by
telling
it
which
direction
to
offset,
and
by
how
much.
Most
modern
CNCs
take
the
actual
kerf
amount
and
automatically
offset
the
tool
path
by
1/2
of
that
amount,
so
that
the
finished
part comes out very close to the programmed dimensions. That is why the kerf value is often referred to as “kerf offset”.
My personal test
to find Kerf,power and speed , I made a square pieces to cut with laser.After the cuts, with the calibre I can been compare designed measures to jobs result.The vector file requires precise settings, for example the color method must be rgb, the cut color is conventionally set to red, then the color of the lines must be R = 255 G = 0 B = 0, while the thickness of the line must be 0.001 mm. the initial value is 10 mm that resulting from the cut is 9.78 then the difference of 0.22 kerf = 0.22 / 2 = 0.11.Kerf for every process is different
Each cutting process removes a different amount of material, or kerf. The more precise processes, like waterjet and laser, remove a smaller amount of kerf, which is one of the reasons they can be more precise! A typical example shown here is for 1/2” thick mild steel. Typical Kerf Width for 1/2” thick C.S.: Plasma: 0.150” Oxy-Fuel: 0.045” Waterjet: 0.035” Laser: 0.025”
The Laser cutter machine
The model of laser cutter machine we have in ours Fablas is named Speedy 400 by trotec production. The job is sent to the machine through a virtual printer driver that redirects data to the management software of the laser cutter machineThe Chess
My idea for this assignment is to realize the pieces and chessboard of the chess game, obviously with press-fit technique.With the help of google I found a good image of chess pieces, at this point I have to process the image to make a vector version that is editable.To prepare the processing file, I use the inkscape and adobe illustrator software.
before
executing
the
cut
it
is
necessary
to
calibrate
the
z
axis
by
means
of
a
spacer
to
be
placed
on
the
side
of
the
laser
head.
Slowly
raise
the
plane
with
the
control
buttons
and
when
the
focus
tool
touches
the
floor
it
releases
itself
falling
on
the
plane
and
therefore
the
height
work
is
set.
The
last
step
is
the
setting
of
the
cutting
settings,
it
is
about
adjusting
the
power
and
speed
of
the
laser,
I
will
use
the
values
I
got
from
my
initial
test.
At
this
point
everything
is ready to cut the pieces chess.
Original Files and Useful Links
Parametric objects: TETRIS!!!
To complete this week's commitment it is necessary that I create a parametric project, my idea is to reproduce the famous “TETRIS” game, as material I chose the plexiglass. First I have to find the right value of the kerf, for this I do cutting tests. using the adobe illustrator software, I have drawn squares of different sizes, then I will join the squares to find the best combination of values. The game of tetris consists in fitting the pieces to complete a line, and then move on to the upper one.
Kerf: 0.1 mm
The best result was : the square of 10.2x10.2 (male that reduces and becomes 10x10 mm) the square 9.8x9.8 (female that widens and becomes 10x10 mm) we have two cuts …. then 10.2mm - 10 mm = 0.2 / 2 (two cuts)= 0.1 mm kerf .
Draw the pieces of tetris: Fusion 360 Software
To draw the pieces of the tetris I chose to use the software "fusion 360", I start to draw using the tool "line", and in a second time I add the dimensions.
Sketch Dimension
With this tool I can insert the value or expression that defined before in the dedicated tool.Insert the parameters
By defining the parameters, you can create a design that changes automatically when the geometry values are changed. First of all I define the variable "KERF" that from the tests I have determined to be 0.1 mm. Next, I define 4 basic dimensions for the sides. KERF = 0.1 mm SIDE1 = 10 mm SIDE2 = 20 mm SIDE3 = 30 mm SIDE4 = 50 mm BY CLICKING ON THE SIGN "+" YOU CAN ADD A VARIABLETo use the parameters
Is very simple to use the parameters created before, you have to click on the dimension and insert the expression , for example, I used this expression :" SIDE1+KERF*2", the result is that :the value of total KERF is added to the value of SIDE automaticly.
In this way I complete all pieces in the “TETRIS”project…
Go to cut the pieces…
With the same settings used for the test, I proceed to cut the plexiglass to complete the work and verify that everything is correct. The cut is performed slowly but with a single pass and the result is a very precise joint.
Cutting the pieces….
the result: perfect joint!
