4. Computer controlled cutting¶
1. Weekly Brief Summary¶
We gathered at FabLab Kamakura to set up the laser cutter. I was puzzled by the data conversion, but I understood the output flow from InkScape. We also learned how to control 3D data with parameters.
2. Weekly Assignment Requirement¶
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Group assignment
- characterize your lasercutter’s focus, power, speed, rate, kerf, and joint clearance
- document your work (individually or in group)
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Individual assignments
- Design, lasercut, and document a parametric press-fit construction kit, which can be assembled in multiple ways. Account for the lasercutter kerf.
- cut something on the vinylcutter
3. Group Assignment¶
FabLab KAMAKURA 2021 Lab site / Computer-Controlled Cutting
4. Laser Cutter¶
Make Parametric model by FreeCAD¶
In FreeCAD, I can use “SpreadSheet” workbench. Parameters can be stored in association with their names, and their values can be referenced during modeling. To recall it, right-click on a cell and select Alias to Name.
When you draw a sketch or make it three-dimensional, you can call up the value of SpreadSheet from the formula editor by typing Spreadsheet.<ALIAS NAME>.
In this case, I set the thickness of the cardboard and the alignment so that it can be adjusted by kerf.
Make SVG file from FreeCAD¶
I added grooves where the blocks could be inserted, and adapted the parameters there as well; after extruding into 3D, I used the “TechDraw” workbench to export SVG files according to the orientation.
Laser Cut¶
FabLab Kamakura has TROTEC Speedy 100 CO2 laser cutter, with a max. work area of 605 x 310mm.
Basic work flow is as below, more detail is written in our group assignment.
- Setting material on honeycomb stage.
- Adjust focus by using jig.
- Open path data in Inkscape.
- Edit path data, its color and thickness for TROTEC control panel can recognize.
- Send data for TROTEC control panel via
printmenu. - Set power and speed parameters.
- Run print.
The parts were cut with a laser cutter. The parameters were Power 85, Speed 2.0, and alignment was 2.5 mm each.
5. Grasshopper / Construction Kit¶
I use Rhinoceros/grasshopper for making press-fit construction kit. Grasshopper is a plugin of Rhinoceros, kind of parametric design tool. It can define parameters and geometries as Rhinoceros objects.
I set 4 parameters, Circle Radius, Board Thickness, Kerf and Depth. Num Slider is good components for changing parameters Intuitively.
After making 3D objects, I use make2D to get vector lines. Also cut it by lasercutter.
This is my press-fit construction kit. I can change circle radius, notch depth and width. You can combine them and construct objects.
6. Vinyl Cutter¶
For create types and numbers by vinyl/laser cutter without falling extra parts, FabLab Japan made FabFont. It shared under by CC-BY-SA 3.0 licence, and can download from here.
I used ScanNCut DX / SDX1200 for create some stickers, like pinball game decoration.
We need to choose proper cutter, brown one is for cloth, black one is for paper and cutting sheet, so I set the second one.
I need to attach material to the adhesive sheet. Push buttons to set them, and need to change settings to cut. In this time, I set Cut Speed = 3, Cut Pressure = 9 and half cut is on.
Also I made some test piece for checking machine’s accuracy by Illustrator and FabFont. After making vector data, I need to save it as svg file and export it for USB memory stick. Presentetaion, not Style. If not, scanNCut cannnot read SVG data. Finally I adjust size and made point marks.
7. Learning Outcome¶
- FreeCAD SpreadSheet workbench is easy to use.
- Grassshopper is very intuitive to use.
