Care and feeding of the laser cutter

Laser Cutter 101

Overview

• What is it and what can it do?
• Toolchain
• Settings That Matter
• Materials Selection
• Operation of the Laser Cutter
• Basics of 2D Design Tools
• Preparation of Design Files

What is a Laser Cutter?

• computer-controlled CO2 laser
• combination printer and plotter
  • draws with light not ink
• effectively it burns the material

What Can It Do?

• cut/engrave many organic materials
• cut/engrave some plastics
• engrave some glass and stone
• engrave anodized aluminum
• mark metals using Thermark
• cut/engrave ceramics (possibly)

What Can't It Do?

• cannot cut metals (power/wavelength issues)
• cannot cut glass, stone
• will not cut due to danger:
  • vinyl, ABS, some foams

Why Use a Laser Cutter?

• quickly prototype designs
• create complex cuts with tight angles
• scale a design to fit needs
• complex engraving on variety of materials

Toolchain

Toolchain

• 2D design software
• 3D design software
• laser cutter control

but first some

Terminology

• Raster - draw pixels
• Vector - draw lines
• Point - typographic measure
  • now 1/72 inch
• SVG - Scalable Vector Graphics

Raster and Vector

Scaling gives different results

2D Design Tools

• Inkscape
• CorelDraw
• Adobe Illustrator
• Gimp/Photoshop

2D File Formats

• Open Vector Formats
  • SVG, PDF, PostScript (PS), EPS
• Vendor Vector Formats
  • AI, CDW
• Open Raster Formats
  • JPEG, TIFF, GIF, BMP

Other Formats

Inkscape Installation

https://inkscape.org

• Windows
• Mac
• Linux

Settings

Lasering Modes

• vector
• raster

Laser Settings

Common to both modes

• power
• speed

Vector-only Settings

• Assigned by color

  • order of cutting
  • number of passes

• vector current - global

Raster-only Settings

• threshold - filters out colors
• DPI - global

Color Assignment

• Design Colors -> Laser Settings
• work from the inside out
• black for raster mixed with vector
• lighter colors for vector if combined

Materials

Material Safety

• approved materials only
  • wood, MDF, plexiglass, natural fiber
• some glass with testing
• stone requires careful testing
• anything else requires approval
  • find the MSDS
• banned materials include:
  • vinyl - generates chlorine gas
  • ABS, polystyrene

Material Size

• 20 x 11.5 in (508 x 292 mm) work area
• 1/8" - 3/8" (3 - 9.5 mm) thickness is typical
• removable bottom allows flexibility
  • except we may need longer lens

Material Tests

Each material and effect requires different settings.

• vector mode has tests built-in
• raster mode requires custom test
• Remember to focus on material
• Take note of power vs speed
• limit vector current if lightweight

Operations

Safety Protocols

• big red button
• fire extinguisher
• work area clear
• water pump, air pump on
• exhaust fan ready
• never leave unattended while running

Job Preparation

Things you do with every job

• ensure pumps and fans are working
• clear workarea and add material
• focus laser manually
• make sure laser is connected and homed
• adjust settings to design colors
• run job

Startup Procedure

• exhaust fan/vent prepared
• water and air pumps on
• laser power on
• launch RetinaEngrave3D and ‘connect’
• press ‘Home’ on panel or in software

Shutdown Procedure

• power off exhaust fan
• power off laser & pumps
• remove fan from window and relock
• exit RetinaEngrave3D application
• vacuum out work area at end of day

Front Panel Controls

• fast/slow/align/load/reset
• lock/unlock
• home
• return/test-fire
• perimeter check
• start/cancel
• jog buttons

2D Graphics Basics

Shapes

• Rectangles
• Ellipses
• Lines
• Polygons
• Paths - the general case, nodes and curves
  • all shapes can be converted to paths

Shape Properties

Shapes have many properties including:

• fill - paint-mode and color
• stroke - paint-mode and color
• stroke-style - width, joins, caps

Objects

objects also have

• width
• height
• angle
• location

Text

is a special case, with own properties

• font, size
• transformations can apply

Transformations

apply to single or multiple shapes

• scaled
• rotated
• translated
• skewed

Group Operations

apply to multiple shapes

• group/ungroup
• align

Design Preparation

Workflow

• set document units and size
• load/create design
• verify each path’s attributes
• transform to match desired size
• apply customization
• assign colors to each shape/path
• save file as SVG on USB key or file

Inkscape Main Window

Document Settings

Key Properties

• Fill
• Stroke
• Width
• Color

Fill

Used only for shapes to be rastered

• no fill for vector shapes
• maybe fill for raster shapes

Selecting Fill

Stroke

Used for shapes to be vectored

• width - small, 0.5 points
• color - explained later
• style - solid or dashed lines

Stroke Paint

Stroke Style

Color

Used to assign laser settings

• black,red,green,blue,magenta,cyan, yellow
• black - use for raster (if any)
• others as needed for different settings
• yellow typically for bounding box if any

Interface Walkthrough

• document settings
• pan/zoom
• guides
• shapes
• selection
• transforms
• alignment
• group/ungroup