The fabrication team took turns to design tool paths, watch over the shop bot and troubleshoot errors throughout the assembly process. We encountered the following issues and solutions while cutting:
Tool Path Design and File Prep
Initially, the design team was having issues with the flat pack plug in, since they were mostly working on OS platform. They were able to flat pack some of it, but for the most part each piece was manually imported into the V-carve file. That took some time to figure out and laying it out in the most efficient way possible. Following the online tutorial we were able to get most of the settings right but we did encounter some issues. We believe the strange translation between programs and operating systems was causing some issues with joining vectors even after we did the Join/Close vector command. We went back and forth between the tool path calculations to make sure all the vectors were closed, so we had to do that manually as well. Selecting each individual circle for pecking tool path was a pain in the butt, but we found the most efficient way is to drag the mouse in the circle pattern and collect all around it while holding shift button. Someone please invent a plug in or function to detect circle vectors in V-Carve. Something that helped optimize the cutting was to separate inner cuts from outside cuts, so we had 3 tool paths total (in order) Pecking, Inner path, Outer path.
Cutting:
We hadnt done pecking on the Shopbot before so we werent aware that the pecking depth didnt need to be more than 1 or 2 per hole. Our initial setting for the peck depth was .75 mm which for a 12 mm cut depth was around 16 pecks per hole. That took about 4 hours of cutting. For the later cutting we set it to be 6 mm per peck and that helped significantly.
We had several pieces that did not survive the first run, due to faulty tab settings and some dog bone errors. They werent appearing on the tool path at all since the material is 9mm thick, while our cut depth is 12. We had initially set them to 1 mm, which did not appear to make a difference at all. Then 3 mm, which only appeared on a few of the pieces. 4 mm seemed to be the ideal since it left Just enough material for the pieces to not move, but also snap out very easily without the need of external tools. Basically for tabs it would be:
Cut depth (12mm) - Materal thickness (9mm) + 1 or 2 mm.
Several pieces of web started to wobble due to tension form the machine and the very narrow amount of material between them did not provide enough support. This is the resulting cut in the web:
This also created some warping in the sheet which caused some of the outside and inside cuts in the smaller pieces to not be deep enough. We fixed this by doubling the spacing between the webs in V-Carve which provided enough support and adding the tabs correctly.
Re- Cutting:
A useful way to keep track of Re-cutting on the same sheet is to save several versions of the VCarve file. Each new version contains all the previously cut vectors, for reference, but you delete the existing tool paths every new version. Just remember to delete them under the toolpath settings and start fresh so there wont be any confusion or doubling of tool paths during the cutting process. Ideally this is all done in the same session so that you dont lose your Z-axis if the shop bot is turned off.
3D prints:
In addition to milling the board, some of the parts needed to be 3D printed. We initially tried to print them all together on the same 3DWOX, but having a lot of small parts printing at the same time caused the nozzle to push everything around on the bed. We successfully printed two parts per machine.
ASSEMBLY
ASSEMBLY WAS A MARATHON, FOR THE MOST PART IT WAS FUN TO DO, ASIDE FROM THE CONSTANT NEED TO DISASSEMBLE PIECES TO FLIP OR LET OTHER PIECES GO UNDER BECAUSE WE HAD NO INSTRUCTIONS. ON THE GROUP DOC PAGE WE DECIDED TO WRITE OUT A STEP BY STEP GUIDE TO MINIMIZE THIS WASTED TIME IN THE FUTURE.
