WEEK7 Computer-controlled machining
WEEK7 Computer-controlled machining
Group Assignment
test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for your machine
Group assignment Page
Individual Assignment
make (design+mill+assemble) something big (~meter-scale)
Conditions
CNC router : ZN1325@Fablab Hamamatsu
Tool Diameter: 6mm
Material: Block board
Material Thickness: typically 12mm
Material Size: 910x1,820mm x2(max)
Design
I want to make a bench with storage compartments spaces under the seat. I used Fusion 360 for the design, and Slice for Fusion360 for creating the slice data.
Exporting to STL file for Slicer app.
Importing stl file to SLICE for Fusion360.
Adjusts setting to change size,constructions, and model output. I decided to slightly reduce the size to keep it within the material quantity limits.
The parameters related with materials can be set in the "Manufacturing Settings" screen.
Before exporting to a DXF file, you can check if the assembly is possible based on the slice data using the "Assembly Steps" feature.
Exporting to DXF file.
CAM settings
CAM toolpath is made by "Cut2D".
Here are the steps to import a DXF file into CUT2D and generate a G-code file for CAM:
Import DXF File:
Open the DXF file in CUT2D. Go to File → Open and select the DXF file.
Edit Paths:
The imported DXF data will be displayed as path objects. Edit the paths as needed. You can combine objects, split them, and edit nodes.
I have added tool paths for holes needed to secure screws to hold down the material.
Export G-Code:
Go to File → Export G-Code to open the export dialog. Select the G-Code output format and enter the output file name.
CNC Preparetions
Setting the material on the CNC.
Ensure that no chips or debris remain on the cutting bed, and place the material parallel to the bed.
Use the up, down, left, and right arrow keys on the PC keyboard to move the CNC spindle to the optimal position. Set the XYZ zero coordinates in Mach3.
Start milling
To drill holes for securing the material first, load the G-code for the hole drilling by pressing the "Load G-Code" button. Press the "Cycle Start" button to begin milling.
Once the hole drilling is complete, secure the material with screws through the holes.
Import into CAM Software:
Press "Load G-Code" button to import the G-Code file of the assignment into Mach3. Press "Cycle Start" buttion to start milling.
Precautions:
Do not leave the CNC machine during cutting operations.
If an abnormality occurs, press the STOP button in the software as much as possible.
Wear eye protection to prevent flying debris from entering your eyes.
When I checked the estimated completion time on Cut2D, I realized it would take a considerably long time. Following the instructor's advice, I decided to increase the spindle travel speed.
According to Mach3, the travel speed can be increased up to around 200%. It was recommended to gradually increase the speed while monitoring the cutting conditions. By incrementally raising the speed, I was eventually able to perform the cutting operation at 200% speed.
Sanding
Milling completed. After lightly sanding, I tried joining the materials together.
The width of the cut section is narrow, and I couldn't fit it in all the way like in the photo.
Measuring the sizes
Since the material thickness is 12.0mm (actually measured at 12.2mm), I naturally designed the width of the "Cut Section" to be 12mm.
I measured several spots with calipers, but it seems the width is a bit too narrow.
It's the beginning of a long period of sanding to match the width of the Cut Section to the thickness of the material.( ;ㅿ; )
Sanding for 12.0mm
In order to widen the width evenly, it is necessary to file both the left and right sides equally.
To achieve this, I decided to wrap sandpaper around a 12mm-high eraser and use it for sanding. This provides the right amount of flexibility and allows me to sand both sides evenly.
The eraser method worked surprisingly well, and the assembly was successfully completed.
Varnishing
I used Kinuka (a Japanese wood finish/coating product) for the final finish. Kinuka is an eco-friendly wood finish made primarily from rice bran, a byproduct from polishing rice grains. It is derived from renewable plant-based materials like rice bran, rather than petroleum-based ingredients. It is free of harsh solvents and toxic chemicals, making it safer for humans and the environment.
The rice bran gives it natural anti-bacterial and anti-fungal properties. It allows the natural look and feel of the wood to shine through after application. It is a traditional Japanese wood finishing technique that has been used for centuries.
So in summary, Kinuka is a natural, plant-derived wood finish that is gentle on the environment and human health, while still providing protection and enhancing the beauty of woodwork projects. Its rice bran base makes it an eco-conscious choice compared to conventional solvent-based finishes.
