This section describes the different steps we followed to produce a 3.5m long parametric bench at the Fab Lab.
Step 1 : Designing the part using Fusion 360
In order to produce a 3D object you first have to have its virtual design. This is to be done using any Computer Aided Design (CAD) software.
In this example we used fusion 360 to design the different parts. The video below shows the various steps followed to reach the final intended design.
The pieces were designed to be assembled by the help of long threaded rods, using circular spacers between each part, cut from the same material. Parts locks together once all parts are in place.
Step 2: Exporting Sketch to .DXF format
After finalizing the parametric design on Fusion 360, the next step was to extract the Sketch in .DXF format. This file will then be imported to the V-Carve Software.
An Autocad file was then prepared, that contains all the pieces needed to form the parametric bench , fitting them all inside a rectangle that has the same dimensions of the board we are using.
Step 3: Preparing G-Code on V-Carve
After that, the next step was to prepare the g-code based on our design.
The steps to set up V-Carve are as follows:
- Open new page.
- Job Setup: Input Board Dimensions (x, y, & z). Take into consideration the lost area because of the screws used to fix the board.
- Import the DXF file by selecting: “File” > “Import” > “Import Vectors” > Choose the 2D Model
- Move your design to your preferred position of the material you are milling.
- Generate the Path for the inner cuts and then the exterior cuts. To do so the following steps are followed:
- Select the “2D Profile Toolpath” button.
- Select the vector you want to follow for cutting.
- Choose the Start Depth and Cut Depth. In this example we used 18.1mm, as a cut depth, as the board we are using is 18mm thick.
- Select the tool used for outline cutting. In this example, we used a 6mm Diameter End Mill.
- Add tabs to the toolpath to keep the part in position and connected to the main body, to prevent it from moving and getting loose. You can either set them automatically or just press on the cutting path to add a tab in your preferred positions. Those tabs will be removed manually after milling to remove the part.
- Add Ramps if needed, to reduce the load on the tool.
- When everything is set, press “Calculate”, to calculate your toolpath. Select the “Preview Toolpath” button, to visualize the milling job, and make sure the results are as expected. If you notice any problems in the preview, make sure to go back and review all your settings to make sure that everything is running fine.
- Save Toolpath files in your dedicated folder.
Step 4: Preparing the CNC Machine and Zeroing the Tool Position
Next we need to set the zero position for the machine on the board we are using.
To do so, we need to follow those steps.
- Manually move the router to the desired X and Y position, and then zero the X and Y from the control panel
- Zero the Z-Axis using the automatic zeroing option on the Shopbot software. The plate is positioned under the router on the surface of the board, and the “Z-zero” button is selected. The process is fully automated
Step 5: Performing the Milling Job
Next we perform the milling job. Just import the G-code to the Shopbot software and launch the job. The video illustrates the milling job.
Step 6: Remove the Milled Parts and Prepare for Assembly
Once the parts are ready, cut all tabs using a Wood Chisel. When the parts are cut, clean all wood chips at the edges using sand paper, so that you have clean smooth finished edges.
Step 7: Assembling the pieces
The final step is to assemble all the pieces. Enjoy your new Parametric bench.