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
This week we will be using the machines from the FabLab for our assignments.
I decided to start with the vinylcutter assigment. Because I always think of the use of the things I do, I decided to make a cool laptop sticker which I will place on my computer.
I checked some pictures online for already existing stickers, and got inspired to make my own. I decided to make BEAST MODE inscription, and a picture below the text. Very simple, easy to design, and at the same time cool and attractive!
In the DraftSignt environment, on the left panel, I choose
Note tool, to make a text. These are the settings I am using:
The font I am using is
Kristen ITC, mode
Bold, font size is
Next step is to make a picture below it. I decided to add a button, which will represent ON mode. On the left panel, I choose to draw a rectangle with the following dimensions:
width: 90mm, and
After I have my rectangle, I type in the command line
Fillet. By the way, the command line is a great feature, which makes DraftSight a very useful and convenient tool. After I typed the Fillet command, the software will give an option to choose the radius by pressing
r. In my case, I choose the radius to be
Next thing is to make the button more beautiful. I use the
Offset command to make an offset of the existing button. The software will ask to choose the line for which I want to make an offset, as well as the direction and the dimensions. I decided to make two offsets, one with
2.5mm, and another one with
1.5mminside the existing button.
This is only the shape of the button. I want it to look like an iPhone button, which is a little bit rounded and has kind of a round slider inside. So now I want to do the inner button/slider whatever it is called.
On the left panel, I choose the
Elipse tool, to make the button oval along the existing shape. The dimensions of my elipse are
width: 28.56mm and
height: 17.97mm, which perfectly fits inside the shape that I created.
On the left side of the button, I will write ON. To do this, I choose again the
Note tool on the left menu, and type my text with the following settings: the font is
Bold, font size is
Now I want to give my sticker the final appearence. I want to separate the parts that will be removed from those that should be fixed. I use the
Hatch command, and press on
Fill, and choose the color which I want to use, making sure that the box
one color is clicked. After I chose the color, white in my case, I click on
specify entities. This will allow me to choose the enteties where I want to use the Hatch/Fill. I will use it on the offsets which I created earlier.
This is how the final design looks like:
The electronic cutting machine available in our FabLab is Silhouette Portrait. It uses a small blade to cut paper, cardstock, vinyl, fabric, and other material up to 8 inches wide and 10 feet long.
After I imported my design into the Silhuette software, it had some little deviations from the original design. The scaling was disturbed, as well as some aligments. After I fixed this, and aligned it to the right corner, it looks like this:
I also have to draw a rectangle around my design in order to save some material, otherwise, when I finish the cut and remove the unnecessary parts, I will have to remove the whole page with it.
Before printing, I have to set up some parameters. I set the
Page size - A4, orintation
Portrait, choose the material, in my case is
Vinyl. Before printing, the software gives an option to make a test cut. After I double checked everything, and made a test cut, I can launch the print.
After the cut was done, I had to remove all the unnecessary parts. This is how it looks after I removed everything:
And now, I had to stick it to my laptop, where it should right in the middle, and aligned. I think it was the most complicated part of the whole assigment :D
But gues whaat??? Here it is!
The next task will be to find the kerf of the lasercutting machine available in our FabLab Kamp-Lintfort.
The kerf is the amount of material removed by the laser cutter as it burns through it. Since the laser cuts down the center of line given by the computer it will leave 1/2 kerf on each side of the slot to account for, or one total kerf per slot. The kerf depends on the material and its thickness, but also differs for each lasercutter. That is why, the kerf test should be done for every type of material and thickness in order to have accurate results.
The Laser Cutter that we are using here in FabLab is Epilog Fusion 60Watt, a CO2 lasercutter with a working area of 1016 x 711 mm. It can cut and ingrave materials like wood, cardboard, acrylic or other engineered plastics.
Because this assigment is a group task, each of us chose a material to make tests on. I chose to play with cardboard.
First of all, I measured the thickness of the sheet which is
Searching online on different kerf tests, I found a very nice template design which can be downloaded HERE and modified it using
When I open the file, I select the lines that represent slots, and set their
stroke thickness according to my caliper readings, which is
6.5mm. Because the Illustrator asks for a value in
pt units, which means points, I have to convert first 6.5mm into points. I used the old friend Google for this.
Now I insert the value into the stroke
Then I go to the top menu, choose
Object and then click on
Expand. This will turn my lines into blocks.
After I select the blocks and the other pattern lines, I go to
Pathfinder and then use
Subtract to make the boolean substraction from area shape. This is what I get:
Now its time to cut.
I had to make several cuts to find the right settings. And the ones I used for my final cut are:
After the cut, I can measure with the caliper the real size of the joint. And I can notice that there is a slight deviation from what it was at the beginnig
In my design it was
6.5mm and now it is
7mm. And if we apply
(7mm - 6.5mm) / 2 cuts = 0.25mm kerf. But this would not be the precise value. One cut cannot say much. For getting more accurate values, I need to make more cuts, and take the average.
I decided to replicate a common kerf test which I found on internet. I draw a rectangle, and devided it equally into 19 smaller rectangles. The dimension does not really matter, the important thing is to make them equal.
In order to cut the blocks, I use the same settings as before:
Speed - 20; Power - 100; Frequency - 15. When I finished the cut, I should get 19 equal rectangles inside a bigger rectangle. I have to push all the blocks to the left and measure the gap created on the right with the caliper.
I measured the gap to be
4 mm. To find the kerf, I devide the gap measurement by the number of cuts (20), so we have
4mm / 20 = 0.2mm kerf.
And this is the kerf! 0.2mm for a 6.5mm cardboard, using the following lasercutter settings: Speed = 20; Power = 100; Frequency = 15
Now when I know the kerf for the material I am planning to use, I can make something more interesting out of it.
We have to design and make a press-fit construction kit, that can be assembled in multiple ways. I had several ideas, but the realization was a little bit different than what I expected.
My first idea was to design a chair. In order not to use too much material, I wanted to make a small model. For designing the 3D model, I used the best in my opinion 3D software . It was during the previous week of Fab Academy when I tried this software for the first time, and its really GREAT!
When I open Fusion 360, I press on
Create new Sketch and then choose the axis which I want to work on. On the tom menu, under the sketch arrow, I choose the
spline tool, and draw something like this:
This is gonna be the draft shape of my future chair. Then, I go again to the top menu under the sketch arrow, and choose the
offset tool, and make an offset of
5mm. After I made the offset, I connect the lines to have a closed shape.
And now I want to give my sketch a dimension. I go to the
create tool bar, and click on
extrude. This will transform the 2D model into 3D. I decided to make it
Let's say that I am satisfied with this model, now lets slice it. I go first to the left corner of the Fusion 360, and press on
show data panel, then choose my model and press on the little
i button, and then
open details on web. Next, I download my model in the
.stl format. The file should come on the email registered in AutoDesk.
For the slicing software I am using which is also from AutoDesk. After I import my .stl file into the 123D Make software, I have to add in the
manufacturing settings the dimensions of my sheet, in my case cardboard, and also specify the kerf.
Next, in the
construction technique I choose
Interlocked slices. This will output a visual result. I noticed that the slicing parts are not very well done due to the poor design, so I decided to change it a little bit. I made a more solid and stable base, by adding one more round curve. And when I was done, I generated a .dxf file, which I imported in in order to laser cut the generated parts. After I organized everything in a more efficient way, this is how it looks:
Unfortunately, I did not notice the mistake marked on th picture before I cut:) but only after the cut was done, the weak part of the construction just broke immediately. I still decided to continue to assemble the chair, maybe some other issues will appear for which I should be prepared in the future.
Does not look bad right? But actually it does. The weak point that I mentioned above broke. And now I have two parts of a broken chair :D
Conclusion: It was a failure, but I learned from it!
Getting even more motivated, under the time pressure, I still decided to give it another try. I will design a table this time :D
I will start with Fusion 360 again. Open a new sketch, and
I used the following dimensions:
width = 100mm; height = 50mm
Then I go to the top menu, under the sketch arrow, and opn
fillet tool to round the corners of my table.I used
radius = 10mm
Trim tool, I delete one edge of the rectangle.
Now I will do an offset of
5mm and then connect the lines to close the shape.
Next step is to
extrude the 2D design. I gave it
65 mm dimension
To download the file and import it into the 123D Make software, I use the steps mentioned above
I used the same parameters for the cardboar sheet dimensions, and kerf as I used before
Playing a little bit with the dimensions, nr. of parts on the 1st axis and 2nd axis, I came up with the following configuration:
And now let's export the file. The format is
.dxf, a recognizable format for Rhino software.
Here I also get a preview of all the parts and their arrangement on the sheet. When I import the generated file into Rhino, I arrange the parts again by myself in an efficient way, in order to save material. And now I am ready to cut!
The assembling process was pretty easy. I just followed th steps recommended by the 123D Make software. And this is what I get!