http://clock.bonsignore.com/post/49837495031/2d-design-with-solidworks-and-inkscape-mit
2D Design with Solidworks and Inkscape
MIT Technology Review recently published an article that argued “a lack of accessible design tools is holding back 3-D printing”. I have to agree, and the same applies to 2D laser cut design. I have access to Solidworks at work, and I wish that I could avoid using it for open hardware projects like this. While it’s expensive and bloated, it is an excellent tool for designing and developing engineered structures. So I’ve downloaded or created Solidworks versions of the clock’s innards, used it to design the pieces of the enclosures, and put everything together in an assembly to check the fit and tweak dimensions and features before laser cutting anything.
Ponoko requires an .SVG file for laser cutting, and they recommend using Adobe Illustrator, CorelDRAW, or Inkscape to create the file. Inkscape is open-source, but there isn’t a Mac native version readily available. I found a suspicious looking link tohttp://rapidshare.com/files/2591591009/Inkscape-r-10.7%2B-x86_64_RC5.dmg on an Inkscape forum. I was surprised to find that it works fine. Here’s are some notes on my workflow:
- I created some basic T-slot box templates in Inkscape using Justin Shaw’s http://wyolum.com/t-slot-boxmaker/
- From Inkscape, “Save as…” a DXF file, and select “mm” as the base unit, with “LWPOLYLINE type of line output” checked.
- Opened the DXF file in Solidworks as a 2D sketch. I used the template as a reference for slot and tab sizes, hole placements, etc, and created my new geometry using dimensions, constraints, and all the other usual Solidworks methods.
- I created all of the components as separate bodies in a single “parent” .SLDPRT file. This makes it easier to line up mating components, and reference feature dimensions between components. After everything was complete, I used “Insert > Feature > Save Bodies” to create separate new part files for each component. Then I created an assembly with each of the children, plus additional .SLDPRT’s for the electronics and other components. From here, I checked the fit and alignment of everything, and made changes in the original parent .SLDPRT file. The children and assembly update automatically when they are regenerated.
- Once everything checked out OK, I created a Solidworks drawing (.SLDDRW) from the parent .SLDPRT with all the enclosure components (File > Make drawing from part). When prompted to select a sheet format, choose “cancel” because we don’t want any decorations — only geometry. Make sure the scale for the view is 1:1 (I also set the sheet scale to 1:1). Then save as a .DXF, an in the “options” dialog, choose version R13 and select the checkbox for “scale output 1:1 – enable”
- Back in Inkscape, open the .DXF file. When prompted, make sure that the check box for “automatic scaling” is not checked, and that a manual scale factor of 1.0 is selected.
- Now, make sure Inkscape is using “mm” units on its grid. Preferences > Grid > Rectangular grid > Grid units > “mm”. Select a feature and check the height and width dimensions displayed near the grid at the top of the window, and confirm that the scale is correct!
- Select everything, and change the object properties for the line stroke to “0.010 mm” and color to 0/0/255 per Ponoko’s instructions.
- Copy everything, and paste into a Ponoko template. I like to create groups for each part (box-select the features, then command-G) before moving them around to arrange them on the sheet.