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Niels Ulrik Andersen edited this page Apr 2, 2019 · 17 revisions

This page describes the special considerations you have to take into account when producing an SVG for the PhotonSaw.

  • The recommended program to use is Inkscape, because it produces clean files in a known resolution and that makes everything easier Do not under any circumstances use Adobe Illustrator as it treats SVG as a primitive printer output and that leads to very dirty files where paths are really filled polygons, which is completely useless in a laser cutter.
  • At the moment only the stroke, **fill **and the raster content of the file is being processed, this means that fancier elements, such as stroke-style get ignored
  • Convert text to paths, otherwise the text will be rendered using whatever font happens to be available to the PhotonSaw and it's bound to be another one or in the wrong size compared to the one you wanted.
  • The ordering of operations on the laser is dictated by the element ordering in the SVG file, except that all rasters are performed before any cutting happens, regardless of location in the file. An easy way to make the ordering explicit in Inkscape, and to make it easy to find somewhere to stick the styling, is to use layers. Remember that Inkscape puts the bottom layer first in the SVG , so the stack of layers in Inkscape is cut from the bottom up.
  • Unlike some laser systems that use colors of drawings to indicate a selection of laser parameters, the SVG importer understands, specific CSS style attributes, so no secondary configuration is needed. Values will be forced to be within valid range. You can see the limits in config.yaml
    • photonsaw-speed: The target speed in mm/s when cutting paths. This is generally the only setting you need to adjust, the rest have nice defaults.
    • photonsaw-power: The power at the target speed in Watt (so the maximum for an 80 Watt machine is 80)
    • photonsaw-assistair: Turns the assist air on or off, engraving will generally work better without, while cutting must use assist air
    • photonsaw-passes: The number of passes to make, each path is repeated individually with the same speed and power parameters
    • photonsaw-raster-speed: The speed in mm/s to use when rasterizing fill and graphics.
    • photonsaw-raster-pitch: The distance between lines in rasters, also the default pixel pitch, will be rounded off to whole steps (0.0375 mm with the current hardware)
    • photonsaw-scale-power: true or false, default is true, if it's true then the laser power will be scaled down when slowing down the movement to preserve constant power density.
    • photonsaw-raster-optimization: none, fast, fastest, default is fastest, don't touch this.

The style attributes can be set on a group and thus inherited to all the elements in that group, which makes it easy to only set the parameters once.

Copy-pastable example:

<g style="photonsaw-speed:20;photonsaw-power:80;photonsaw-assistair:true;photonsaw-passes:3">
  <!-- Your layer data here -->

Layers are read from the SVG file (and executed in the PSAW) from the top of the file to the bottom. And inkscape writes the topmost layers at the bottom of the file. This means that the highest layer will be lasered last. Think of an artist painting, the paint at the bottom went on first. It's the same with lasers, only slightly more awesome.

Tip: Make sure you cut inside out. For example if you are cutting a ring, cut the inner circle before the outer circle to avoid movement causing inaccurate cutting.

When the web interface for managing the machine is complete, all the parameters should be configurable through the browser, but for now each SVG must provide its own parameter settings.