I was tasked with creating a more efficient, reusable base setup and came up with a laser engraved ¼” thick acrylic sheet. We wanted a certain amount of surface roughness for the raft to adhere to, but a dissimilar material so the ABS would not weld to the base. I experimented a little with simply sanding the surface, but could not get quite the right amount of roughness. A laser cutter not only gives the perfect surface texture for the bases, but also will automatically cut out the exact dimensions for the full base plate. I also tried both 1/8” sheet, but it warps a little due to the heat from the base and the nozzle while ¼” stays much flatter. Finally, the acrylic bases are infinitely reusable. Once it has been well used and is marked up from all of the rafts, you can simply put the plate back in the laser cutter, re-engrave the surface and it will be back to good as new.
This Instructable was written for Inkscape on Windows 7 and Epilog Mini 35 laser cutters, but a similar procedure could be followed for any vector graphics suite and laser cutter.
Step 1: Draw the Plates in Inkscape
B – Drawing the Baseplate’s Outline – Draw a rectangle by clicking on the “Create rectangles and squares” tool on the left toolbar, then clicking and dragging across your canvas (Do not worry about the size, placement, color or outline of your rectangle; we will modify all of those parameters.) Switch from the “Create rectangles and squares” tool to the “Select and transform objects” tool. The horizontal toolbar directly above your canvas will switch from “Change: W [#] H [#]….” to A series of icons and four numerical input fields labeled “X,” “Y,” “W,” and “H.” X and Y dictate the location of the object while W and H dictate the width and height of the object. A dropdown box indicating units sits to the right of the H field, by default this is set to “px” (pixels.) Change it to “in,” (inches) then set both the width and height of your rectangle to 5.50 (the Up! has a 5.5" square base.)
Step 2: Creating the Etched Fill and the Cut Outline
With your square selected, open the Fill and Stroke dialog under the “Object” menu. The Fill and Stroke dialog includes 3 tabs “Fill,” “Stroke Paint,” and “Stroke Style.” Under the Fill tab, select the Flat Color option and move the R, G and B sliders to approximately 100 to create a solid grey fill inside your rectangle. Also, make sure the A (alpha/transparency) is set to 255 for a fully opaque fill.
Under the Stroke Paint tab, select Flat Color and move the R, G and B sliders to 0 and A to 255 to make the outline solid black.
Under the Stroke Style tab, change the units from px to in and set the width to 0.001, this will vectorize the outline and make the laser cut the outline.
Your square should now look something like this. If you want multiple baseplates (suggested if you print often, so you can always have an empty plate), select your initial square, hit Ctrl-D to duplicate it, then drag the new square to a different region of your canvas. A 24”x12” sheet of acrylic can hold up to 8 plates.
I am also including the original files as both svg files and as a pdf if you do not want to go through the trouble of making them again.
Step 3: Cutting Out the Baseplates
As of this writing, Inkscape’s printer drivers don’t play particularly nicely with Epilog last cutters, so you have to save your drawing as a pdf, then open it in Adobe Reader when you are ready to print. When you attempt to save as a pdf in Inkscape, there will be a variety of options for saving. The default options create a laserable file, so do not change anything.
Open your pdf in Adobe Reader, click on Print, select your laser cutter from the drop-down menu then click on properties If you have already saved settings for various materials, select the quarter inch acrylic setting. If not, the Epilog suggested settings are Raster Speed: 100, Raster Power: 60, Vector Speed: 3, Vector Power 100, Vector Frequency: 5000Hz, Resolution 600DPI. Click OK to return to the print dialog, check the box saying “Actual Size” under “Size Options:” to match the print area to the size of the acrylic sheet and then click print. Click “Go” on your laser cutter and watch it get to work making your baseplates. Each plate takes about 8 minutes to complete, so be sure to allot enough time for the laser to cut out the plates. When the cutter is finished, wipe the plates off with a damp paper towel to remove all of the acrylic dust and let them dry.
Step 4: Using Your Baseplates
To remove the printed object, first take the plate off of the Up! then pull the object off of the baseplate. Sometimes this is difficult as the baseplate holds onto the object very securely, so you can use a small woodcarving knife to separate the object from the base.
Reuse the baseplate until it starts looking too dirty, then re-etch the surface with the same flat fill (an outline is unnecessary.)
Enjoy your new reusable baseplate!