Week07
group assignment • do your lab’s safety training • test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for your machine
# Group Assignment: CNC Machine Characterization
Machine Description¶
The machine used in this assignment is a Scientific Forest CNC Router located at Fab Lab Winam. The machine is a 3-axis CNC router used for machining sheet materials such as plywood, MDF, acrylic, and other non-ferrous materials.
Specifications¶
Machine Type: 3-Axis CNC Router Model: MakerFab 4×8 CNC Router Working Area: 2438 mm × 1219 mm (4 ft × 8 ft) Control Software: Velocity CNC Control Toolpath Software: Velocity CNC Tool Used: 1/4 inch (6.35 mm) Astrolite Coated End Mill Maximum Spindle Speed: Up to 24,000 RPM Collet Type: ER20/ER25 Power Supply: 220V AC
Safety Features¶
- Emergency stop button Kick the emergency button incase of any danger
Ensure you remove dust using vacuum cleaner before using the machine
Safety Training¶
Before operating the machine, I received safety training covering:
- Emergency stop procedures
- Proper use of eye protection
- Hearing protection during machining
- Dust protection using masks
- Safe tool changing procedures
- Material securing methods
- Safe machine startup and shutdown
For testing ,
For these test i must at least cut something from the machine.
I designed a 100mmX150mm rectangle.
Desing process
I normally select hybrid since it comes with additional features such as bodies.
2D Contour¶
2D contour determins how you want to mill, for my case it was a throuh hole and thats the reason i went for 2D contour. Under it i did the tool selction where ,
Spind
And** 1/4 inch ** tool diameter
I chose the flat end mill
Stocks¶
stocks are… now to set my stock, i selected **from solid **
since i wanted to use the whole solid, now i have to select the body as my solid,
## Tool Path generation
Under manufucture i go to milling then under ** setup** i click new setup.
Before i sketch, i selected the pane according to orientation of my bed, ensuring the y and x axis ressembles how my bed is physically alligned. so i selected x,y,z plane.
I sketched the 150mm X 100mm, which am going to cut on a 18mm plywood.
During extrution i extrude to the thickness of my board which is 18mm
Setting home was important as it let me go the the bed position when i click home, so i had to set it by right clicking then i chose set as top, and fron t and home.. after i have set the position correclly
Runout Test¶
Runout was evaluated by installing a 6 mm endmill and rotating the spindle manually while observing tool movement.
Observation¶
The tool showed minimal visible wobble, indicating acceptable spindle alignment for woodworking applications.
Conclusion¶
No significant spindle runout was observed that would negatively affect machining accuracy.
Alignment Test¶
Machine alignment was evaluated by comparing the dimensions of machined parts against the original CAD design.
| Feature | Designed Dimension | Measured Dimension |
|---|---|---|
| Slot Width | 18 mm | 18.2 mm |
| Tab Width | 18 mm | 17.9 mm |
| Panel Length | 500 mm | 499.8 mm |
Fixturing Test¶
The workpiece was secured using wood screws attached to the spoilboard.
Advantages¶
- Strong workholding
- No material movement during machining
- Suitable for large sheet materials
### Disadvantages
- Leaves holes in waste areas
- Requires careful placement to avoid toolpath collisions
Speeds and Feeds Evaluation¶
The machine was tested while machining plywood using a 6 mm flat endmill.
| Parameter | Value |
|---|---|
| Tool Diameter | 6 mm |
| Spindle Speed | 18,000 RPM |
| Feed Rate | 3000 mm/min |
| Plunge Rate | 1000 mm/min |
| Depth per Pass | 3 mm |
Observations¶
- Smooth cutting action
- No excessive vibration
- Minimal burning
- Good edge finish
Material Evaluation¶
Material tested:
- 18 mm Plywood
Results¶
- Easy to machine
- Good structural strength
- Minor edge tear-out
- Suitable for press-fit assemblies
Toolpath Evaluation¶
Profile Toolpath¶
Used for cutting external geometry.
Advantages:
- Accurate dimensions
- Fast machining
Pocket Toolpath¶
Used for internal material removal.
Advantages:
- Clean internal features
- Consistent depth
Dogbone Features¶
Used to compensate for round cutter geometry in press-fit joints.
Advantages:
- Improved assembly fit
- Reduced post-processing
Group Learning Outcomes¶
- Learned CNC machine safety procedures.
- Learned the relationship between feed rate, spindle speed, and cutting quality.
- Observed how tooling parameters affect machining performance.
- Gained experience in collaborative problem solving during CNC machine setup.
- Improved understanding of the complete digital fabrication workflow.
Conclusions¶
The Scientific Forest CNC router demonstrated good performance for large-scale fabrication. The machine maintained dimensional accuracy within acceptable tolerances and produced clean cuts in plywood using a 6 mm endmill. Screw fixturing proved reliable, while profile and pocket toolpaths produced accurate parts suitable for press-fit construction.
The characterization process improved our understanding of machine capabilities and provided machining parameters that were later applied during individual assignments.