User:Mct/shopbot auth 1 notes

• 3-axis routing with 2.5d designs
  • can't cut overhangs
  • continuous xy movements with discrete z steps
  • shopbot's axes:
    • x: long side of the table - to the right, when sitting at the control computer
    • y: short wide of the table - forward, when sitting at the control computer
    • z: vertical
• shopbot can handle continuous z, but the toolchain taught here won't go over how to do that

• workflow: design (CAD) -> layout, tooling, speed (CAM) -> machine (CNC code)
  • CAD just concerned with the shape to be machined
  • CAM concerned with the interface between the design, the materials, and the machine
• vcarve: handles CAD & CAM (& can import CAD stuff from other programs)

• CNC code, 'toolpath':
  • gcode
  • openbsp (used on shopbot routers)

• main toolpaths - all have depth parameters:
  • profile
    • remove material along a shape
  • pocket
    • remove material over an area
  • drill
    • just plunge at a point

• securing material (sheet wood) to table: plastic nails
  • still should be careful about nail placement

• end mill (router bit) properties
  • cutting diameter
    • small tools generally take longer than big ones, but can do finer cuts
  • shank diameter
  • nose shape
    • square
    • v
    • ball
  • flute count
  • flute shape
    • up/down
    • spiral
    • straight
    • roughing

• CAM cut variables - affect time and quality of resultant cut:
  • cut depth - depth of the final cut
  • pass depth - depth of each pass
    • should not be greater than cutting diameter
  • stepover - horizontal thickness of each pass
    • only relevant for pocket cuts
    • 40% of cutting diameter (rule of thumb)

• rate variables:
  • spindle speed - RPM of tool
    • 12k to 16k generally, max 18k
  • feed rate - tool speed in plane (x-y)
    • deterimined using chip load calculator
      • feed rate = chip load * flute count * spindle speed
        • chip load (in)- material removed per flute cut
          • function of material & cutting diameter
        • flute count (flutes/rotation)
        • spindle speed (rotations/min)
        • feed rate (in/min)
      • can also generally be looked up in a chart
    • under 200 in/min, but not too slow
      • machine can be kept within appropriate operating parameters by changing input variables (i.e. varying tool, spindle speed)
    • max on shopbot: ~360 in/min
  • plunge rate - tool speed in z
    • 50% of feed rate (rule of thumb)

• vcarve
  • workflow
    • enter material parameters
    • create or import design
    • enter toolpaths mode, assign toolpaths to portions of the design
  • material dimensions
    • 'job size' establishes material shape in plane
    • 'material' establishes material thickness
      • nominal thickness should not be trusted - rather, should be measured with calipers by shopbot station
    • 'xy datum' positions origin
  • design modes
    • drawing modes have to be explicitly exited to switch
    • transform - click to select, then click again to enter mode
  • toolpaths
    • select shape(s), then set toolpaths
    • profile
      • add 0.05 to depth
    • tool parameters
      • use tool number to order multiple tools in a single job
        • have to change them manually