Designing the 3D Model
My idea was to create a 3d model based on a 2D model drawn on Draftsight and then import it to FreeCad to transform it into a 3D object.
2D Drawing
Commands used:
I used the same commands I always use which are mentioned in previous projects.
3D Modeling
After having the 2D sketch I imported it to FreeCad and because I joined everything into one polyline in Draftsight FreeCad recognizes it as a srurface.
This is how it looks:
Next step was to extrude the polyline. This can be done by changing the option at the drop list from Start to Part then the extrude button should appear.
Now I have to add the cuboid of material under my design and join them using Boolean union. This can be done by pressing on the cube icon and selecting the dimensions(Length 70mm , Width 100, height 40 mm) from the combo view box.
To join the 2 objects together select them and then press on the icon of Boolean union (the 2 blue spheres joined together).
After This I subtracted 3 cylinders from the object.
Finally I exported the object into an .stl file to open it in Fusion 360 to set the milling settings.
Milling the 3D Model
For this assignment I used Fusion 360 software and Roland CNC machine.
First of all I imported the .stl file to fusion 360. To do this click on upload (Cloud icon) and choose your file.
Sometimes it happens that when you import the file it is not in the correct orientation so you might need to rotate it. To do this click on modify choose move and add the rotation angle around the correct axis and press ok.
I wanted to check the dimensions to make sure everything is okay. To do this click on inspect and choose measure. I found that my design is scaled by a factor of 10. Probably it is an import problem so I had to scale everything by a factor of 0.1 to get my desired dimensions.
To scale down select the object, click on modify select scale enter the scaling factor and then press ok.
Now the object is ready to be setup for milling
First thing to do is to choose a milling strategy. For this assignment I will just be using a roughing milling strategy because the quality of the output is not critical. For better quality a finishing milling strategy should be choosing after the roughing one.
To do this click on 3D and choose adaptive cleaning.
Time to set the settings.
Tool: 3mm flat
Speed: 10000
Coolant: Disabled
Now go to passes
Z distance: 0.6mm
Tolerance: 0.1mm
Maximum roughing step down: 6mm
Fine step down: 0.6mm
Passes
Before starting milling you need to simulate the process to make sure it will be successful.
I found that I have 1 collisions.
I changed the Fine step down: 0.3mm and now I have no collisions
To export the file as G code for the CNC click on actions choose post process. Choose the destination to save the file and then press ok.
After exporting the G code it is highly recommended to open it to make sure there are no errors in the beginning, it should be a quite long file.
Finally you need to set the origin of the machine as the origin you selected for the object. Open RolandVPannel, click on set and choose xyz origin. Now move the head of the machine using the arrows until the tool reaches the origin point and then go slightly inside the material using the low speed z axis movement. Keep an eye on the machine and switch between high and low while moving in order not to crash the tool into the material.
Click on cut, delete any old jobs existing, choose your G-code click add and click on cut.
Final product
Conclusion
I believe the settings used for the cut were good enough for the assignment because the quality of the product is not very critical. But generally it could have been better because the cylindrical sections' surfaces were not very clean and all the details of the model were not very defined and this is because the tool used is 3mm in diameter which is big compared to the size of the model.
Downloads
3D Model