Week 7 - Making something BIG

I made a test of a structure to hold the moving machines for the final project.

CAD design

First job was to design the parts in CAD program. I used Fusion 360. Here is a picture of design. This design consist of two side walls and top part. On the side walls there is a place for motor that will move the stage back and forth. On the top part, there is a hole to give some room for the up/down moving structure, but that will be designed later on.


After making the 3D design, I took the parts that will be made and arranged them in one plane next to each other so that I can mill them at one go. Dimensions of the blank material are 1197mm x 2440mm x 11mm. The material is called obs3. It wil not be suitable for long duration use at the target aplication but it works fine for testing the parts and initial testing.

Parts must be in X/Y-plane, positive axis and Z-axis pointing up from the parts. Origo can be seen on this picture right bottom corner. There is a secondary origo that came with the top part, but I could not get rid of it. At the end it did not affect the process.

To get the parts in same plane I copied the design and rotated all pieces so that they were on the same plane. Then I made sure all parts were at same altitude from the plane. On this case at zero height. So the parts were on X/Y-plane and bottom of the parts at the zero level on Z-azis.


Making the milling files for milling machine

Files for the milling machine could be done in the Fusion 360 with specific setting file for the g-code that would work with our machine. Here I will descripe the process in pictures.


















Finally this is what the g-code looks like.



Operating the milling machine and milling

Here is the milling machine and its controls.


First turn the machine on from the main switch (3 in upper picture) and power switch (1 on upper picture). Vacuum pump can be switched on at this point if stock is on the table. Turn the Vacuum on from the table as well, use the areas of the table that the stock covers. If stock covers whole table, use all areas. At the moment vacuum pumps are not powerfull enought to keep the stock well in place, so use clamps or so, to secure stock to the table.




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Turn on the computer and start the program to control milling machine. Program is called NCstudio. First origo must be set. Generally origo is in left front corner of the machine. It might be good to leave some space between the stock edge and origo. For example I used 2-3 cm fom stock corner to set the x/y-origo point. To set the x/y-origo, move the spindle head to correct position. It can be moved on software from the right hand side on the GUI or using the hand held controller.







To calibrate the z-axis you need to use the calibrating head. Set the hand held calibrator piece below the mill bit. Hold it there and from the software select operation -> mobile calibrator. Software asks if to continue. When you have the calibrator head in place, click yes and z-azis is calibrated to the calibrator. Calibrator must be held at place during the operation.



After setting machine up and material is on place it is time to load the g-code to the machine. This is simply do be File -> Open command. The new g-code will not show on the screen before simulation or actual milling has been done. It is good habit to run the Simulation before running the actual milling. Simulation start from Simulate icon on the top row of the commands on screen.

While the milling is in progress the g-code is shown on the right of the software screen. In case you need to pause or stop milling process it is good to notice the line g-code is on. This way it is easy to return to the right spot if needed.

Finally I milled the pieces. It worked really nice. Only issue is the material edges need to be sanded or filed to make them clean.


The cutting dept was pretty well optimized, milling went almost through as can be seen on the picture.


Cutting made the edges quite rough as seen on the picture, it needed some filing and sanding to get them good. Here is an another picture of before and after sanding the edges.


I also needed to file a bit of material of the joining parts to fit them well. But it was really close to fit right in.


Here is a final product at the place. It fit well on the spot.



I used there structures on my final project as well. I had to manually re-model them a bit for it but otherwise worked well.

Files used with this weeks assignment

Roof .stl file
Left wall .stl file
Right wall .stl file
Cutting the holes
Cutting the rest
Extra cutting, single run for final cutting if needed - holes.
Extra cutting, single run for final cutting if needed - rest.

.Stm file exported from Fusion 360