this week i'm gonna use the assignment to prototype and figure out geometry for my "grow a tetrahedron" final
i need the skeleton of the tetrahedron ( 120 degrees? )
I only modeled one of each part
osb is short grain
doesn't have grain direction
orientation of parts on the sheet doesn't matter
i have a bucket of 5/16ths bolts
cad in fusion
0.727" hexagonal intersection
the triple lap joint
• 0.26" dia t-bone holes
• allows 1/4" bit contour
• lap has 0.13" clearance on middle section
layout in illustrator
• make sure Scale Units 1 = 1 Inch
• make your artboard in Illustrator 48x96in, and layout lineart there.
• repeat: open up more .dxf's > scale 1=1 > and copy+paste the lineart to the first .dxf opened.
• lay out your work as you will. grain direction doesn't matter with OSB.
• put holes (tool inside of line) on one layer, and outlines (tool outside of lines) on another layer.
• or different kinds of tools onto their own layer.
• exporting the file as one .dxf will bring all the layers with it to mastercam.
holes and contours on separate layers
test cut - 0.42" for press fit
N51 archshops/chris will generate toolpaths in mastercam
email drawings (.dxf) in advance
• 4x8" board, nominal thickess 7/16"
• 3 tools. corners were remachined with 1/8" drill, and 1/8" sq endmill.
• 1/4in sq endmill for contours.
• 0.015in onion skin.
• 0.008in onion skin for regular plywood
• 0.005in bottom for thru-holes
dust collection system was down, clean after cut
vacuum table couldnt hold down osb, it was cupped.
turn vacuum on, shoot screws away from toolpaths.
(take measurements from drawing/cam)
vacuum (clean) by hand
• feed: 250ipm
• speed: 18000rpm
thnks benjamin for help
vacuum workholding is weak near origin, theres acrylic? sheet to seal that corner
vacuum sensors can be overridden on each quadrant, if P1 error comes on.
utility knife for onion skins
rasp to clean edges
dispose of skeleton
i took the parts home to assemble in my garage.
initially thought the holes were too small, and tried drilling them out.
turns out bolts could be just driven in.
maybe a couple thou bigger would be fine.
unfurl a tetrahedron
geometry seems to work.
notice how each branch can tuck into the triangular region of the preceding branch.
hexagons inside hexagons