Computer Controlled Machining¶
Scheduling¶
After last weeks hectic schedule, I decided to make some alterations to my plan, and I’ll have to spend more time documenting my work 😭 School has now properly started, and we’re still working out how to balance out our time. So I started off this week by creating my schedule.
Individual Assignment¶
For this week, we had to design and then machine a design (something big). I decided to create a table that someone could use while sitting down, and one that’s tall enough to promote good posture.
I used Fusion360 to design this project because it’s what I’m most familiar with, and I’ve already tried and documented most other 3D CAD software. So here’s what I did during the design process, and you can follow along if you’d like.
Fusion360¶
If you haven’t already downloaded Fusion360, you can visit this page to learn more.
I started off by creating the user parameters for my design. This is because not all of the boards at our Fab Lab are the same sizes, so you have to be flexible with your dimensions.
Then, I used the circle tool and the line tool to create 2 circles along a 1 meter line.
Then, I used the control point spline tool to draw 2 curves, which I’ll explain below.
Control Point Spline¶
The control point spline enables users to create smooth and customizable curves by adjusting control points along the spline path, providing precise control over shape and curvature.
Here’s how the tool works:
Once the tool is active, use your cursor to create different points along your path.
Then, adjust the points to manipulate your path to whatever you’d like. You get used to the movements after a bit of practice
Then, I extruded the sketch that I made by the material thickness parameter (which I renamed to “Plyboard”)
I then created a new sketch on the extruded face like so:
Afer negatively extruding this new sketch (in order to cut into the body), I copy-pasted this sketch information onto a new sketch.
I extruded this new sketch and then make ANOTHER sketch on top of that using the rectangle tool.
I extruded this new sketch as shown, and then needed to make the legs a bit more prominent.
So, I created a sketch using the spline tool from earlier, and then extruded that using the cut settings.
After that, I added a support at the bottom using the rectangle tool, and we’re done !!!
Here’s the render incase you’d like to downnload it !
Dogbones !!!¶
The rounded geometry of the drill bit used in a CNC machine prevents the creation of sharp corners in materials. This limitation means that you need design considerations such as dogbone joints to make sure your pieces fit and your creation has structural integrity. So I needed to add dogbone joints to my design.
I started off by going to this page, and downloading the add-in by tapnair. The instructions are pretty self explanatory.
Once I had the add-in installed, I gave it a shortcut by pressing the 3 dots next to the option, and then entering the shortcut I wanted (ctrl + d).
Once you’ve pressed your own shortcut, click on all the joint slot edges, and then set the tool diameter to 6mm. Your joints should look like this:
Follow this step for all the other parts of your design.
DXF Export¶
Now, you’ll have to export your design as a DXF. To do so, you’re going to have to click on CTRL+P to open the project menu, and then click on the face that you’d like to save.
Then, open your sketch list, and right-click on the newest sketch. A tab should open up, with the option save as DXF. Once you click on this and ave your file path, you should be good to go !!!
The CNC Machine¶
The Shopbot CNC Router (PRS Standard)¶
The Shopbot CNC router is capable of slicing through various materials such as wood, plastics, foam, and even lightweight metals like aluminum. It’s versatile enough to craft a range of items including signs, furniture, cabinets, intricate carvings, props for theater productions, and even customized jigs and fixtures for industrial use.
Information/Specifications
| Specification | Value |
|---|---|
| Cutting/Movement Area | 266.7 x 124.5 x 20.3 cm |
| File Types | .EPS, .SVG, .DXF, .DWG, .STL |
| Mechanical Resolution | 0.015 mm |
| Position Accuracy | +/- 0.127 mm |
Safety Rules !!!¶
The CNC Machine is the most dangerous machine for it’s user !!! So here are some rules to follow around the CNC machine AT ALL TIMES !!!
- Always wear safety glasses and hearing protection when the machine is in operation.
- Never leave the machine unattended while it’s running.
- Keep hands, hair, and clothing away from moving parts.
- Always use the appropriate feed rates and spindle speeds for the material being cut.
- Ensure the workpiece is securely clamped or drilled before starting the machine.
- Regularly check and maintain the machine for loose components and wear.
- Never wear loss cloths that might get caught while you are cutting. Also if you have lond hair always remember to tie it up!
- Remember always to have the emergency stop button right beside you so that if anything happens… You can immediately stop it.
- If any debris and dust is left over, always ensure that you have cleaned it before using it.(If you have a dustcollector, you dont need to clean but still check if any dust is being leftover!)
CNC Machine Software¶
Now that I’ve exported my files, it’s time to set up the CNC machine.
VCarve¶
I’m using VCarve to set up my components.
I started off by setting my workspace dimensions, and then importing my files.
Once I imported my files, I adjusted the layout using the “Move Selected Objects” setting.
You can also rotate your shapes using the Pviot Point option, and then entering how much you’d like to rotate your objects by.
Then under the “toolpath” panel, click on “profile toolpath”
Here’s a visualization of what your toolpath will look like, and make sure to set your origin axis!
Also remember to add tabs so that your component doesn’t move around when it’s being cut out (very important) 😨
Finally, save your toolpath and then start cutting.
Here’s a video of the cutting process !!!
Assembly¶
This is how I assembled all the pieces at the end !!!
hero shot !
Reflection¶
I had a lot of fun this week !!! It was a bit scary because this was my first time using the CNC machine, and I’ve always heard about how dangerous it can get. But, I’ve overcome my fear of this machine (although I’m still staying cautious), and I’m confident when I use it !!! I’m excited to see how I can incorporate this machine into my final project !
-wozer
The Mentioned Files¶
This website was created using a template provided by Mr. Anith Ghalley and was used with his permission.*