Export Laser Cutter GCODE From SketchUp

I've written a plugin to export GCODE from SketchUp. The plugin is designed for laser cutters that switch the beam on during G1 moves, and off during G0 moves. The .zip file contains the .rbz plugin file, and a SketchUp file, test_teeth.skp, containing the test pattern shown in the video.

You will need:

• Laser cutter, with the beam focused correctly for the material you want to cut
• A computer running SketchUp, and a program to send Gcode to the laser cutter
• Sheet material that is safe to cut on a laser cutter

How to install my plugin

(not shown in the video) - unzip the .zip file attached to this Instructable.

1:20 Explanation of the way the plugin compensates for the width of the cut path.

How to calibrate my plugin for your laser cutter

2:21 Install the nb_skptolaser.rbz extension / plugin in SketchUp.

2:58 Open test_teeth.skp in SketchUp.

3:43 Click Tools -> Export Gcode from 2d drawing.

4:20 The Cutting Parameters window will appear. The default 'beam diameter', ie the diameter of the hole the laser makes in the material, is 0.14mm, and the cut speed is 2mm/s. Passes over each path allows you to run the laser over the sheet material several times - I find this makes neater edges, and lets me cut thicker material than I would otherwise. You can set various other cut parameters, but beam diameter, cut speed, and number of passes are probably the ones you will change most often.

My plugin doesn't allow you to set laser strength. I use the analog dial on the laser cutter control panel, and I find that a fairly weak beam combined with multiple passes with the laser creates the best edges.

The default parameters work best for me with 3mm acrylic sheet, on my 40W laser. If you want to change them, you can. Otherwise, just..

8:50 Click OK

9:16 Choose a name for your Gcode file, and a location to save it. Then click Save.

11:55 Open the program you use to send Gcode to your laser cutter. I use Printrun / Pronterface because my machine runs on and Arduino with the Marlin firmware.

11:58 Load the Gcode file you saved from SketchUp.

12:05 Cut the test shapes on your laser cutter.

You may need to play around with the cut speed, beam power, and number of passes, before the two shapes are cut out successfully.

12:26 Remove the two shapes from the laser cutter, and try to fit the two sets of teeth together. If they fit very loosely, your beam diameter parameter is set too high. If the teeth don't fit together at all, your beam diameter is set too low - ie/ the software thinks the beam is thinner than it actually is.

13:02 If the teeth weren't a perfect fit, adjust the beam diameter parameter, export the Gcode again, and cut the pieces out again.

Work through the last steps, cutting test pieces, and adjusting the beam diameter, until the teeth fit together perfectly.

Congratulations - you can now cut out any 2d shape from SketchUp on your laser cutter. You may need to work through the calibration steps again if you want to cut different sorts of sheet material, but if you do, don't forget to make a note of the various parameters you use for each material.

3D Parts - second video

My plugin also has a feature that can convert 3d shapes which are organised into components representing pieces of sheet material, into 2d shapes. Those 2d shapes can be converted into Gcode using the steps described above. That feature runs when you select 'Create cut sheet as SketchUp file' from the Tools menu. It's a bit hit and miss for complex shapes, and I tend to flatten my 3D models manually using cut and paste.