12. Mechanical design, Machine design¶

In my Mechanical Design Week work I attended the egg painter machine project. I designed some laser cutted parts for the project.

See my contribution for the project below

Here is the link to the Group Work Web page.

In the Machine Design part I attended the Group Work. That project had a great idea of Pointing machine to display values in the help of the stepper motor. The project has not been completed yet because of the distruptions to the schedule caused by COVID-19.

Egg-Painter project¶

The following document contains the description how the frame of the machine was cut.

Isolating the Laser-cut Parts.¶

The Design File was opened in Fusion 360. The project was copied for creating the frame in order to avoid breaking the original desing. Then the process described in the Fab Lab Oulu Wiki was followed. The parts requiring laser cutting were saved, the rest were removed from the bodies list. In the delete phase, the removal of referenced parts was accepted even if deletion caused downstream feature failures. Some extra parts was still remaining but they were deleted, therefore the process was repeated one more time, until there was only necessary parts left.

Then the tool library file (https://gitlab.com/fab-lab-oulu/Fab-Lab-Oulu-Documentation/-/wikis/uploads/fusion360_laser/tool_library/fablab_laser.hsmlib) and post processor file (https://gitlab.com/fab-lab-oulu/Fab-Lab-Oulu-Documentation/-/wikis/uploads/fusion360_laser/post_processor/svg_laser.cps) were downloaded and installed in Manufacture mode according to the instructions given in the Fab Lab Oulu Wiki instructions step 2. The import libraries icon was hidden under Local tag. That change was because of version change of Fusion 360 and it was not mentioned in the instructions.

After selecting the downloaded file and opening it, the new tool was installed.

The installation of the post-processor file was more straight-forward. It required pressing the post processor icon (marked with G) close to the tool icon, then pressing the import icon and selecting the downloaded post-processor file.

After the required files were installed, it was time to continue the process. We went to SETUP and selected Create Manufacturing Model.

Then we selected Edit Manufacturing Model.

Then we selected Create -> New Component, From Bodies and painted all the bodies in order to change all the bodies to individual components for the next phase.

Arrange The Components¶

We arranged all the component to a plane by using Arrange tool.

We selected all the bodies.

Then we selected XY-plane.

We changed then the cut area to 200 mm x 250 mm and set the placement clearance to 1 mm. Then we hid the origin and finished editing the manufacturing model.

Creation of the Toolpaths¶

We created a new setup.

We selected cutting and selected the components.

Then we selected Cutting and Selected the tool.

We chose the laser cutting tool we just installed.

Then it was time to select the faces to cut. We selected one face and checked select all faces on the same plane.

Then we selected Keep Sharp Corner.

Then we deselected lead in, lead out and zeroed the piercing value.

Fusion 360 calculated the toolpaths.

Exporting the Desing to the Laser cutter¶

We selected export and chose the post processing file installed earlier.

After clicking post, the file was created.

Converting SVG file to PDF file in Inkscape¶

The conversion of the filetype was straightforward and follows the normal procedure.

The .svg file created was opened in Inkscape. The whole document was selected (Control-A), the width of the line was changed to the width of 0.02 mm and continuous line required by the laser cutter and the color of the line was changed to black, 000000FF in Inkscape hexadecimal format. After that, the file was saved as PDF for cutting.

Using the Laser¶

Then the parts were cut in the laser cutter following the normal procedure. 3mm acryl cut profile was selected and the cutter was calibrated for the acryl. The cut was run twice in order to make the cut go thru. Two of the parts were re-cut in order to fix the design. At that round we decreased the speed of the cutter slightly and managed to do the cutting at one phase for those parts. The protective surfacing was then removed and the frame cut was succesfully assembled.