presented by:
John Canny

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Design Realization
Last Time
 More on kinematics and IK.
 Some concepts from dynamics.
This time: Manufacturing & Materials
 Manufacturing is undergoing a revolution:
 Traditional methods:
 Casting, molding, fusing, slumping
 Milling, lathing (non CNC-versions)
 Stamping
 Rolling, extrusion
 Shape is “write-once” (not programmable) in these methods
Next-wave Manufacturing
 Reprogramming shape:
 CNC machining:
A computer outputs a path for a cutting tool to create a specified surface.
 Not new, but now inexpensive, PC-based.
 Plastics, wood, metal, glass.
Milling
 Milling involves a moving XYZ head that cuts into the workpiece:
 Bits can achieve different finishes.
Lathing
 Lathes cut circularly symmetric parts.
 Shafts, furniture, fasteners,… lenses.
 Can also do grinding and polishing.
Milling Example
 CNC milling example (Deskproto web site)
 Finish is quite smooth
 ballnose cutting tool.
 Lots of waste, but can be recycled!
Next-wave Manufacturing
 PC-boards:
 Created with CAD tools.
 Photographic reproduction:
• Low cost in volume.
• High complexity possible.
 Multi-step process, BUT:
 Web-based services have 24-hour turnaround, low cost.
Next-wave Manufacturing
 CNC Laser cutter:
 X-Y axes control a powerful laser.
 Fine line (0.007” or better).
 Positioning to 1000 dpi,
 Some control of depth:
• Engraving as well as cutting.
 Moderate cost: $10,000 Versalaser 16x12” workspace
Laser Cutter Capabilities
 Precision is good enough to make smooth sliding surfaces (gears).
 Layering can be used to make 3D surfaces (very popular for architectural models).
 Can even make PCBs by etching metal from clear plastic!
Other 2D Cutting Technologies
 Lasers can cut metal, but not easily
 Power limits, need to deal with material removal.
 Plasma cutters use an electrically-generated plasma jet to cut
 Sweeps away material.
Plasma Cutters
 Thin shapes in a variety of metals.
 Torchmate 3 machine is $10,000 for 4x8’ workspace.
Water Cutters
 Similar idea to plasma but based on high-pressure waterjet.
 Cleaner method: water plus metal can be collected.
 Cost??
3D printers
 A variety of 3D printing techniques have appeared in the last few years.
 SLA: Stereolithography: laser curing of liquid plastic.
 SLS: Selective Laser Sintering: similar, laser fuses powder.
 LOM: Layered Object Modeling: laser cuts paper one layer at a time.
 FDM: Fused Deposition Modeling: a thread of plastic is melted through a moving head.