3. Computer Controlled Cutting¶
Since this week requires a planned approach, I decided to write my documentation as a guide for the future myself. I am going to refer to myself as “you” here and there in the following text.
This is the assessment for this module:
Group assignment
Characterize your lasercutter’s focus, power, speed, rate, kerf, and joint clearance
document your work (individually or in group)
Individual assignments
- Design, lasercut, and document a parametric press-fit construction kit, which can be assembled in multiple ways.
- Account for the lasercutter kerf.
- Cut something on the vinylcutter.
Group assignment¶
You can find the documentation about the group assignment on this page
Individual assignments¶
Vinyl Cutter¶
Inkscape¶
First step: find a proper image (source: Pinterest)
Then put it into inkscape, obtain a bitmap of it ( so that you’re sure that the black is REAL black) and set the image area as wide as the object. If everything is fine, save it as a png file and open it into the computer that is connected with the Vinyl Cutter.
CutStudio¶
Open CutStudio and trace the contour. The contour will be superimposed on the original image. Remove the original png and take the contour image.
Machine setting¶
Turn on the machine, pull the lever in order to raise the guide-wheels and put the piece of vinyl inside the machine. Be careful to put it at the beginning of the left side of the cutting line. Make sure that the guide-wheels are aligned with the white guide lines. If not, the machine won’t start. Choose wisely the piece to work with, its surface must be regular-ish (no triangles or narrow sides). Then the machine will ask if the object I’m working on is a roll, a piece or an edge. Select the piece option and press enter. The machine then will place the cutter on the corner of the sheet and will measure the whole piece, displaying its size. Once everything is settled, hold the origin button until the machine says that the origin has been set.
Everything is set on both sides, go back to CutStudio and click on the cutting button. Keep the machine settings and go on.
Sticker polishing and application¶
Once the machine has cut the sheet, it is possible to remove it from the cutting area, so that the machine can be turned off (always remember to bring back the tangent knife to its original position). Start peeling the film removing the unnecessary pieces, be careful with small pieces. Remember to use both hands if needed, so that you can hold the small parts while removing the bigger ones around them.
When the sticker has been cut properly, apply the transfer sheet carefully trying to avoid any air bubble between the film and the sticker.
Once the transfer sheet is settled down, peel the sticker away from the original paper film and apply it to the final surface. Always remember to clean the surface and apply the sticker gradually from one side avoiding air bubbles. It’s done, the sticker has been applied properly!
Laser cutter¶
Fusion360¶
For this assignment I decided to create a kit made of 4 different shapes:
- two straight pieces of different length
- one curved piece
- one “hashtag shaped” piece that works as the joint between perpendicular pieces.
Add the parameters clicking on Modify > change parameters
Design your press-fit construction kit through a sketch on the software. If the parameters are set properly, the pieces will change their size if you change the parameters. The basic measures you need for laser cutting are:
- The width of the wood panel (it changes every single time)
- The Kerf (it changes from one side to another of the same panel, so take it as precise as you can).
- The length of each side of your pieces.
I made few fixed parameters (kerf, teeth size and panel width), then the other parameters are simple operations, so that they can change if the basic values are modified.
I started making the “teeth” of every piece, adding (for the male pieces) and subtracting (for the female pieces) the Kerf.
Then I kept doing it from one side to the other end until I got the hashtag shape.
The straight pieces are two teeth connected by straight lines. The curved pieces are two teeth connected by two arches.
The drawing process might take a lot, don’t hurry and be sure that the measures are correct before starting a wrong cutting process. More attention means more spared time and less wasted material.
In order to facilitate the press-fit of the pieces, use the chamfer tool on the corners that will touch other surfaces.
The chamfer can be done manually on the sketch or automatically on the extrusions.
Once the 3D surface has the desired look, create a plain sketch on that surface and save it as a xdf file. This file can be imported in Illustrator.
Vector editor¶
Prepare your image with a vectorial image editor (e.g. Inkscape or Illustrator). The machine’s software will read colours differently so that different settings can be used on the same surface. Red (rgb 255,0,0) means “cut”, other colors (usually black) mean “engrave”. Be careful with the size of the cutting area, the wood is not infinite… The line that is going to be the cutting line (red) must be 0,001mm wide, all the other lines can vary in size.
Once all the colors are set and everything is ready. Go on with the print settings: - Select the “avoid drawing area” option - Click on settings and put the surface’s proper dimensions, check if the color scheme is enabled and apply the settings. - If everything has been set correctly, the cutting area should appear surrounded by a dashed line all around the perimeter. - If not, go back to settings and check if everything is fine, then apply the settings, go back and check again. - When everything is settled, click the print button.
Setting the Machine¶
- Remove all the things from the cutting grid (if the last user didn’t do it before)
- Turn on the machine
- Move the laser pointer along the surface using the x-y axes buttons
- Raise the grid closer to the laser using the z axis buttons
- Adjust the surface if it bends somehow (humidity) with tape all along the area.
- Once the grid is getting closer to the laser, place the little metal piece on the lens and keep raising the grid until the piece falls. That is how the focus is set.
Trotec JobControl¶
This is the software that controls the machine, once Illustrator has sent the printable image. Select the file and drag it to the cutting area. - Check if the file is aligned on the machine’s focus. - Double click on the white area to check the material settings, in this page it is possible to select the material and change the engraving/cutting settings (colors, speed and power). - If everything is fine, click on the button on the bottom right area in order to link the software to the machine. - Once all the checks have been done, the same button will change the icon from a plug to a play icon. - If everything is ready, click on the play button in order to start the cutting process.
Cutting process¶
Before using the wood panel, try your file on a cheaper surface. So that you won’t run out of wood before cutting the actual press-fit kit.
The machine will do what JobControl said. If something goes wrong with the settings, it is possible to stop the machine with the stop button.
This button will stop the machine with a little delay, but it is possible to restart immediately once the settings have been changed.
If the machine must be stopped immediately for safety reasons, there is a red button that interrupts the machine mechanically.
This process will turn the machine off and all the process must restart from Illustrator.
Once the cutting process is over: - Wait before opening the lid, since the machine will vacuum the cutting smoke coming from the cut surface. - Place the laser pointer out of the grid (top left corner). - Lower the grid in order to avoid any accidental damage to the lens. - Remove the piece.
The cutting process is over.
Assembly¶
I cut several pieces and then I tried to pull them together.
The bond is good, the pieces won’t fall but at the same time they can be swapped without breaking them.
I tried combining them in multiple ways, they behave like Lego bricks: the only limit for creativity is the number of pieces available.
The structure is solid, the pieces can be moved quite easily even if the wood is thin. I started building a cylindrical shape with a semi-sphere on top. Then I swapped some pieces and the resulting object is a globe with its docking structure.
The press-fit structure is solid after the second swap, I can consider the building process successful.
The files I made can be downloaded here:
- Hashtag piece
- Curved piece
- Straight short piece
- Straight long piece
- Illustrator ready for cut
- Fusion360 file