1. Characterize your lasercutter's focus, power, speed, rate, kerf, joint clearance and types
   1. Cut something on the vinylcutter
   2. Design, lasercut, and document a parametric construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways, and for extra credit include elements that aren't flat

Plan for  the week



This week is our computer controlled cutting week where we are creating compatile design files, knowing about the devices like laser machine and vinyl cutter, controlling them by communicating via Mods and controlling the parameters like cutting force,speed in case of vinyl cutter and kerf, speed, intensity in case of laser machine. Staring the week we began to work with vinyl cutter then to laser machine.

Working with Mods

Mods is software tool developed by MIT's Center for Bits and Atoms (CBA) to help build digital fabrication workflows in a modular way. It takes a design in one format, process through its algorithm consisting different modules calculating and analyzing the file and finally generate code that machine can understand and send it to the machine. Best part of it is that we can visualize all the process and know about the flow of the process. And secondly, it can be used for operating multiple digital fabrication devices like vinyl cutter, laser cutter and CNC mills in Fablab.

Vinyl Cutter

About the machine


Vinyl cutter is a 2-Axis cutting machine which can move the fine point blade to perform a cut in a thin sheet of material like vinyl, paint mask, reflective vinyls, twill, heat transfer, circuit making material and sandblast material. We need to first choose the material we need to cut and the blade as well. For loading and unloading material there is a load/unload lever on the left side of the machine. Please refer the manual. Then, choosing the blade, you must consider the thickness of the material you are going to cut. There are normally blades with three angles 30, 45 and 60 degrees. Lesser angles are for lesser thickness and vice versa. Now while loading them please note that the protruded length of the blade is he sum of media portion and half of carrier portion as mentioned in the link mentioned above. 


I will just give you the basics while setting up while using the vinyl cutter.

  1. Load Material:
    a. Make sure the loading lever is lowered
    b. Pass the test-use material through the machine
    c. Move the pinch rollers so that they are positioned at the edges of the material and also inside the areas of the pinch-roller position-verification marks
    d. Align the left edge of the material so that it lies parallel to the guide lines
  2. Set the machine up:
    a. Press the power button. 
    b. Choose "PIECE" inside "SELECT SHEET"
    c. Press ENTER and the cutting carriage moves to the left edge and the material moves forward and backward. Then, the cuttable width and length appear on the display.
    d. Make sure that material feed was
    performed correctly, then press 
  3. Install the Blade
    a. Turn the blade-holder cap to tighten completely (tighten until the cap cannot be turned further)
    b. Insert the pin.
    c. Insert the blade.
    d. Adjust the amount of blade extension to match the material.
    e. Loosen the screw of the cutting carriage
    f. Support the screw from below and insert the blade holder
    g. Tighten the screw
  4. Optimizing the Cutting Quality for the Material
    a. Make sure the [PEN FORCE] slider is centered (at "0" on the scale)
    b. Hold down "TEST" for one second or longer
    c. Press forward to feed the material toward the front, then use the included tweezers to peel  off the cut shapes and check the cutting quality.
  5. Peel off circle
    Case A: if the circle peels off alone, check if there is any faint traces on the material's backing paper, if it is OK move to another step, and if the blade trace is indistinct, increase the cutting force and again test until its OK.
    Case B: Rectangle 2 also peels off, increase the cutting force and again test until its OK.
    Case C: The blade trace is too deep and cuts into the backing paper, decrease the cutting force and again test until its OK.
  6. Set the Origin Point:
    a. Use arrow keys to move the cutting carriage to preferred location
    b. Hold down "ORIGIN" for one second or longer
  7. Now you machine is ready to take the data for cutting.

 After material is loaded, you need to clamp it in the marked location in the machine which has a grip to hold it. Enter whether it is a roll or a sheet. If you mistakenly enter sheet in case of roll, the machine will pull all material of the roll to measure the total length, so remain cautious, Then following are the main parameters that you need to control eitherin mods or the machine:

  1. Cutting speed: Though the maximum cutting speed is 500 mm/s for Roland GX-24, we have to adjust it according to the quality of the cut. This parameter should be adjusted in such a way that the blade does not skip the cut and the edges does not lift off while cutting is in process.
  2. Cutting force: This parameter is adjusted in such a way that it cuts the material smoothly and does not leave a score mark in the the lower side of the carrier material. High cutting force and/or speed may decrease your tool life.
  3. Blade offset: Please set it according to specification fo the blade.
  4. Setting up the origin: Use side buttons to move the cutting blade and set the machine at the bottom left extreme of your intended cut shape. Press and hold the origin button one second or more for setting the origin to zero.
  5. Test the cut: Press test on the machine which should cut a square inside a circle. You should be able to take off the part between circle and square easily without peeling square. If not tune the parameters to have a perfect cut.

For the current cut, i used, 60 degrees blade with diameter 0.254mm, cutting speed of 2mm/s, and cutting force of 110gf.

Loading file and pushing to the Machine

1. Making a vector file: First, I downloaded an image to convert into vector which is used as an input to the vinyl cutter via Mods Then I used Adobe Illustrator to convert the raster file to vector file. Download here

Vector file for 2D cutting

2. Then on the computer, the folder where mods main file are saved, terminal is started from that folder using following code
        bash start-server


3. This will open up the landing page where you can select between different operations. Select cut under Roland GX-GS 24 vinyl cutter.


4. Now, you can either enter a svg file or a png file as an imput. I selected the png file. Enter the tool diamater and hit calculate. As soon as you hit calculate you can see all the process in the flow and final tool path can be seen.


5. Next, check whether the tool path is ok or not. Some times, if the image is too small or if there is any image procesing problem, if tool path may not be as per our expectation so please make sure it is ok before starting the cut. Then select the cutting speed and the cutting force for the machine. Open the web socket and click on the "send file to device" which should start the cut.


Please install artivive in android or iOS and hover it over the image below to see the cutting process.


Applying vinyl to the product

Now, after the vinyl is cut, remove the material and use the tweezers to remove the excess material leaving only text and apply the application tape to maintain the position of all the characters. Then affix the material together with the joined application tape to the target object.


Now cautiously remove the application tape.


Finally the result for vinyl cutter


Parameteric Design

What is Parameteric Design? Why do we need it?

Parametric design is like a spreadsheet that is set up to make calculations; you choose which math function will be performed, input the different numbers, and your result depends on what those variables are. This is basically the parametric design process. Parametric design is a very useful tool to any designers. It lets you modify the final product based on the parameters you enter. It may be time consuming to do parametric design, but, once you do it, you know its value during modification or for alterations of your design.

For parametric design there are basically three steps:

  1. You must decide your parameters which you want to vary like thickness, length, breadth, etc which have have possibility of modification. (Do not try to apply parameter to each and every dimension, it will confuse you)
  2. Then you can add those parameters with base value and a short name for identity in the CAD you are using.
  3. Link the parameters to the dimension in your 2D and/or 3D. You can also do mathematical operations while applying parameters.
  4. Change the parameters and see how the final product changes according to your input.


For the laser cutter, I was just thinking about the products that i could make. While showing other how to do parametric design in CATIA, my instructor asked why don't you design a rocket out of fun. And I thought, WHY NOT? Then I followed following process:

1. First I have to make a construction kit so first i thought of a platform for the rocket as a launcher

2. Then I tried the whole design of platform with rocket and first focused in platform at first.

Modular designed Platform

1. Designed modular platform for the rocket using 3 main shapes.


2. Separating the design only for the platform, first what I did and should be done while modeling as well as designing is finding the basic element of your design which can be a base element for mirror or boolean operation making the while body. I will give you one example of what I have done.


3. Then Time for deciding the parameters and the open CAD software. or me I have selected diameter, thickness, kerf, overlap and chamfer as parameters.

4. I am assuming that you have already installed CATIA V5 and know basic modeling skills in CATIA. Open CATIA V5, then File >> New >> Part

5. If you have not used parametric design previously in CATIA, your parameters and relations might be hidden so first you have to change settings to show on the tree. GoTo Tools >> Options >> Infrastructure >> Part Infrastructure, Then click on Display tab and check parameters and relations and hit OK.


6. Now modeling begins. Please follow following process to complete model in CATIA

  • Open Tools >> Formula and select Length Inside on the dropdown list on left side of New parameter of type and click it. Press OK which should give you the parameter in the tree.
  • Now double click the parameter in the tree and edit according to your requirement. You can now add other parameter in a similar way or use Ctrl+C and Ctrl+V to paste parameter and change it according to your need.
  • After you set all the parameters then click on positioned sketch and select the plane (yz-plane) and hit OK. (positioned sketch have feature like editing the sketch place or origin or axes which comes handy if you want to modify. Use this and later if you want to modify you will thank me later)
  • Select profile tool and start making profile starting from origin. Make a tentative shape where vertical and horizontal and be snapped and shown in blue if followed. 
  • Then time to make it parametric. Click on constraint tool and select the line for dimension, in the entry box right click and press edit formula.
  • Inside formula you can select form the tree and mathematical operations also can be done like above and hit OK.
  • Use parameters likewise for other dimensions and each line should be turned into green which signifies fully constrained.
  • Exit from the sketch and to create solid GoTo Insert >> Body 
  • Click on pad and as previously add parameter to the thickness.
  • Add chamfer in the edge where the other part fits in and also make it parametric as before.
  • Then click on mirror, select xy-plane as mirroring element and hit OK.
  • Now for boolean operation click on dropdown of rectangular pattern and select circular pattern. Select Parameters: complete crown, Reference element: X-axis (right click on entry box and select) and press OK
  • Your shape is now ready. Similarly add other elements until all are included and continue for generating dxf.
  • For generating dxf you have to make a drawing out of the shape. Click on File >> New >> Drawing select A4 ISO, landscape and hit OK.
  • Click on front view and change the window by clicking window >> ****.CATPart select on the face you want to take front view as (i.e. the flat side of the shape) and which should show you preview when you hover and take you to drawing sheet when you click it. Then click outside and delete unnecessary things like view names.
  • Click on File >> Save As and select dxf and save it for using it for laser cutting.

The Rendered image is as shown below.


Then I planned to make a rocket body as follows:

  1. First I thought about the basic size i want to
  2. make and decided to make it 250 mm.
  3. Then i thought how to lock them and thought of vertical sections and horizontal sections.
  4. Though about different sized parts I have to make, for vertical, I had to make 2 different shapes and for horizontal, it varies upon the number of section.

Then i thought what would I want as a variable which i would change later. Following parameters were selected:

  • Height of the Rocket
  • Width of the section I want to cut
  • Thickness of the material
  • Number of vertical sections
  • Number of horizontal sections
  • kerf of the laser

Results after modeling


Download CAD file

Different parameters

  • Height of the Rocket= 250mm, 350mm, 200mm 
  • Width of the section I want to cut= 20mm , 15mm, 10mm
  • Thickness of the material= 2mm
  • Number of vertical sections= 9
  • Number of horizontal sections= 10
  • kerf of the laser=0.1mm

Height of the Rocket= 250 mm
Width of the section = 20 mm
Thickness= 2 mm
No. of vertical sections= 9
No. of horizontal sections= 10
kerf of the laser=0.1 mm

Densely packed

Height of the Rocket= 350 mm
Width of the section = 15 mm
Thickness= 5 mm
No. of vertical sections= 15
No. of horizontal sections= 20
kerf of the laser=0.1 mm

Loose packed

Height of the Rocket= 200 mm
Width of the section = 10 mm
Thickness= 3 mm
No. of vertical sections= 6
No. of horizontal sections= 5 
kerf of the laser=0.1 mm

Modular platform


Both when set together should look like below.


Download CAD file

Laser Cutting


Laser cutting is one of the most used machine in Fablab. The one we are using is Trotec speedy 100. It is a machine with CO2 laser which can process wide variety of materials such as rubber, acrylic, coated metal, tin, special steel, anodized aluminum, cork, cardboard, glass, leather, marble, several plastics and wood. Materials PLA, ABS must not be cut from the machine which will release poisonous gases.Also metals except mentioned above cannot be processed which may damage the lens. Normally, we should not cut any material whose property is unknown. This is also a 2 axis machine which bed remains constant over which material to be cut or engraved is placed and there is a x-axis movement and y axis movement of the laser pointer head though which it is engraved and cut. Laser generator, is at the back of the machine and mirrors placed in exact corner positions to reflect to laser thought the head and to the material concentrating by a lens to perform the operation. The specific laser machine that we are using had a working area of 610 x 305 mm with honeycomb style bed. You can get to know about the machine from this manual. We also have Trotec Atmos exhaust system with activated carbon which will filter the harmful gas that comes out during the operation of the laser machine. It must be turned on when the laser machine is operating. The laser cutting machine should be placed near ventilation or make a good airflow with chimney and exhaust fan fumes will flow out of the room.


Laser machine is very sensitive machine and dangerous at the same time if the user is not present when operating. Hence You must be in front of the machine observing the operation as there is a chance of fire while the laser cuts though the material. In Fablab, we have a mark with yellow tape outside which a user cannot go when laser cutting or engraving is in operation.

Now, in order to perform a job, we must know few things like setting x and y positions and focusing the laser by adjusting the z position. There is a keypad on the lower right corner at the top face of the machine which is used to navigate the machine.


 Steps before performing cut or engrave

  1. Turn on the machine.
  2. Place the material on the bed.
  3. Move x and y axis using navigation keys above the material.
  4. Focusing the laser: We will be focusing the laser manually using the focus tool that comes with the machine.
    a. Place the focus tool on the laser head as shown in the picture below. 
    b. Move the bed in z direction unless it reaches near to the bottom of the focus tool. 
    c. Now, carefully move the z axis up with one click at a time unless the focus tool automatically falls down. The laser now should be in focus.
  5. Move X and Y position from where you want to start the job which will be the reference position in the software as well.

Here is a link to some tips and tricks which you can use during laser cutting and engraving.

Group assignment

In order to have a best result from the machine, we need to first find out the parameters of the laser for the given material as it differs from material to material and also with the thickness. following are the parameters that we have to find out to have a smooth cut.

  1. Power
  2. Speed
  3. Number of passes
  4. Kerf
  5. frequency
  6. joint clearance/overlap

Now in order start cutting, you need to send the file to laser via Job control.We can send the file from different softwares like inskscape, rhino etc to the job control but for now we will be using rhino.

As Laser is a 2 axis device it needs 2D file. It does not matter if it is a vector or a scalar. Since we are designing to test the kerf, we need the shape accurate so I am using CAD to make a dxg file. After you have exported dxf file, import it in rhino.


After you import it in rhino, since you want to cut the profile, select all the lines by clicking and dragging the point over all the shape. and on the toolbar enter following as a parameter.

  1. Display color = red
  2. Linetype = continuous
  3. Print color = red
  4. Print width = hairline

The line is kept red because later in the job control, you will see what is red assigned for in the process. You can select other colors if you want to do process like engraving and controlling the depth according to power, velocity and frequency of the laser cut.

Then click print from the toolbar menu or simply press Ctrl+P and select Trotec as the printer. Make sure the ratio is 1:1 and all the shape falls in the print area. You can slect different materials in this platform or also can use Job control to set the material and parameters. After you click print, it should take you to the Job Control which sends the data to the printer.

Turn on your laser cutter and after it auto levels make sure the XY is positioned and laser is focused as explained earlier. You can turn on the Exhaust filter just before the job starts.

After the job control is opened press ready on the lower right corner of the job control. It should give you the cross point where the laser head is located. Simply drag the file to the reference start point.


Now set the material as per your requirement in the following material darabase and inspect your cut.


We tested on 4mm balsa wood and 4mm acrylic for the cutting parameters. A square cut of 20 x 20 mm inside a square cut of 40 x 40 mm was taken for the reference and following were the results

  1. For balsa wood,
       i. Power=100
       ii. Speed=0.5cm/sec
       iii. Number of passes=1
       iv. Frequency=1000
  2. For acrylic,
       i. Power=1000
       ii. Speed=1cm/sec
       iii. Number of passes=1
       iv. Frequency=1000

Now after the part is cut, two things had to be found out, one is kerf and another is to find out fitting size.



Kerf by definition is the width of material that is removed by a cutting process. For Laser, it is the material removed by laser while cutting. Normally it is the diameter of the tool i.e laser beam in laser cutter. For every material, it is different. For this, as mentioned before we calculated it by subtracting inner dimension from the outer followed by dividing it by 2.


By following the process, the Kerf for 4mm balsa wood was found to be 0.15 whereas for acrylic it was 0.2

Joint Clearance/overlap

Joint clearance is the clearance between the mating parts two connecting bodies. There are three types of fits which care clearance, transition and interference fit. You can choose according to your requirement. Please refer this reference to know about different types of fit.

Then keeping the standard thickness of 4 mm, jig with slots starting from 3.4mm to 4 mm with 0.1 increment is parametrically designed and made with the same laser cutting setting used while making kerf jig.

Specifically for the solar panels installed in streets, no one is cleaning them and though they are installed, they are not working properly due to the dust.


The the fit was ok with 3.5mm slot but was rigid with 3.4mm slot which means if we want to keep a rigid fit, we need to keep overlap of 0.45 mm total and 0.225mm for one side. So the dimension of the hole should be (thickness-kerf-overlap=4-0.15-0.45 = 3.4mm). This will be used to design the parts.

Individual Assignment

As per individual assignment, we have to use cardboard with thickness 3.45 mm thickness was used.For this first we need to find kerf as well as overlap needed for the rigit fit. Hence same process was repeated.


The kerf was fouind to be 0.23 mm and the overlap to be 0.87 mm, i.e the slot should be (3.45-0.23-0.87)mm = 2.35 mm

The parametric model was then converted according to the kerf and overlap and as shown earlier was first converted to 2D layout with proper nesting and transferred to dxf Then the file is imported to rhino.


Next selecting all the line properties are changed according to the requirement, i.e. cutting, with following parameter.

  1. Display color = red
  2. Linetype = continuous
  3. Print color = red
  4. Print width = hairline

Keeping the selection in the top view press print. Make sure that the ratio is 1:1 and the shape fits in the displayed box and click on print which should take you to the Job Control.


Then the Laser cutter was turned on, the material was placed which is sufficient to cut the design. Then laser head was kept above the material and focusing was done.


X/Y position is set and then the file that is shown in the Jobname is dragged on to the working space such that the top left edge if the job lies on the reference cross of the laser pointer.


Then the material was set as cardboard with the following setting.

  1. Power=100
  2. Speed=1cm/sec
  3. Number of passes=1
  4. frequency=2800
  5. Air assist=ON

Then make sure that the lid of the laser is closed and the exhaust system is turned on and press ready which should start the job in laser cutter. Make sure that you are fully present when the process is going on and make sure there is no fire in the chamber. And in no time, your job will be ready to be taken out. Leave it for some time for gases to go out through the exhaust system and take out the parts.


Now assemble it and the product should be ready.


Modular design for the platform

Now for the modular design same process had been followed and is shown in the following images.


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