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					Introduction to
 Laser Cutting


   Brygg Ullmer
   Brygg Ullmer
  October 2, 2000
  October 2, 2000


                Brygg Ullmer, MIT Media Lab, 1999
Overview

•Motivation
•Motivation
•Underlying science, technology
•Underlying science, technology
•Getting started
•Getting started
•Design tools and tips
•Design tools and tips
•Workshop
•Workshop




                            Brygg Ullmer, MIT Media Lab, 1999
What is the laser cutter?

•High-power pulsed laser oriented through
•High-power pulsed laser oriented through
  motion control system (e.g., X-Y plotter)
  motion control system (e.g., X-Y plotter)

•Vector, raster cutting and etching capabilities
•Vector, raster cutting and etching capabilities
  over a range of materials
  over a range of materials




                                Brygg Ullmer, MIT Media Lab, 1999
What makes the laser cutter special?
•Remarkably tight pathway between
•Remarkably tight pathway between
  software description and physical fabrication
  software description and physical fabrication
•Applicability of mature design tools,
•Applicability of mature design tools,
  common skills and competencies
  common skills and competencies
•Minimal fixturing + high execution speed
•Minimal fixturing + high execution speed
•Modest learning curve, “danger factor;”
•Modest learning curve, “danger factor;”
 “semi-domesticated” machine tool
 “semi-domesticated” machine tool
•Support for broad range of quality, structural,
•Support for broad range of quality, structural,
  aesthetic, functional materials
  aesthetic, functional materials

                                    Brygg Ullmer, MIT Media Lab, 1999
Range of materials
Cuttable:
Cuttable:
 •Acrylic
 •Acrylic       •Food
                •Food      •Metal*
                           •Metal*
 •Cardboard
 •Cardboard     •Stone
                •Stone     •Living tissue
                           •Living tissue
 •Wood
 •Wood          •Rubber
                •Rubber    •Semiconductors
                           •Semiconductors
 •Paper
 •Paper         •Leather
                •Leather   •[insert most materials here]
                           •[insert most materials here]
 •Fabric
 •Fabric        •Glass*
                •Glass*
Non-cuttable:
Non-cuttable:
 •PVC et al.
  •PVC et al.
 •Glass*
  •Glass*
 •Metal*
  •Metal*
                            Brygg Ullmer, MIT Media Lab, 1999
Orders of magnitude: power

•Laser pointer:
•Laser pointer:             ~3 mW (E-3)
                            ~3 mW (E-3)
•Entry-level laser cutter: ~15 W
•Entry-level laser cutter: ~15 W   (E 1)
                                    (E 1)
•Our laser cutter:
•Our laser cutter:         100 W
                           100 W   (E 2)
                                   (E 2)
•High-end laser cutter:
•High-end laser cutter:      6 kW (E 3)
                             6 kW (E 3)
   ALS Express 6000 Watt CO2 Laser Cutter
   Capable of holding 5' x 10' sheets
   Cuts up to 1 1/4" thick on mild steel

•Fusion, defense lasers:
•Fusion, defense lasers:                     GW..PW (E 9..E 15)
                                             GW..PW (E 9..E 15)
   In May 1996, a record-setting laser shot produced pulses of more than 1300 trillion
   watts, or 1.3 petawatts of peak power, more than 1300 times the entire electrical
   generating capacity of the United States. The laser pulse lasted less than one-half
   a trillionth of a second, more than a thousand times shorter than that typically
   produced by the Nova laser

                                                   Brygg Ullmer, MIT Media Lab, 1999
Physical scale

•Excimer microengraving:
•Excimer microengraving:




•CO2 kilowatt systems:
•CO2 kilowatt systems:




                           Brygg Ullmer, MIT Media Lab, 1999
Laser technologies

•CO2: IR. Gaussian beams; highly focusable.
•CO2: IR. Gaussian beams; highly focusable.
•YAG: Near-visible. Gaussian beams;
•YAG: Near-visible. Gaussian beams;
        less focusable, but redirected with
        less focusable, but redirected with
        visible-light optics (e.g., glass fibers).
        visible-light optics (e.g., glass fibers).
•Excimer: UV. Non-Gaussian beam;
•Excimer: UV. Non-Gaussian beam;
  hard to focus, but good for masked usage.
  hard to focus, but good for masked usage.
  High photon energy.
  High photon energy.
•Semiconductor: Arrayed ganging of diode lasers.
•Semiconductor: Arrayed ganging of diode lasers.
  High power achievable, but not coherent.
  High power achievable, but not coherent.
  Least focusable.
  Least focusable.

                                   Brygg Ullmer, MIT Media Lab, 1999
Cutting mechanisms




                     Brygg Ullmer, MIT Media Lab, 1999
 ML LC gurus
•Brygg Ullmer (TMG)
•Brygg Ullmer (TMG)
  layered structures
  layered structures

•Egon Pasteur ((Vismod)
•Egon Pasteur Vismod)
  complex structures
  complex structures

•Joe Pompei (BVG)
•Joe Pompei (BVG)
  audible structures
  audible structures
•Saul Griffith ((Nanomedia)
•Saul Griffith Nanomedia)
  mobile structures
  mobile structures


                              Brygg Ullmer, MIT Media Lab, 1999