Intro: Reusable Acrylic 3D Printing Baseplate
We have an Up! 3D printer where I work and were dissatisfied with the various base options (although this is Instructable was written with the Up! in mind, it applies to all filament depositing consumer 3D printers.) The green paint provided an uneven printing surface, was difficult to clean off the base and looked sloppy. The painter’s tape frequently shifted and had occasional delamination issues. We never got a raft to adhere to Kapton tape (which also happens to be quite expensive.) Moreover, all of these materials are consumables and with the near constant use on our printer, costs can get quite high.
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
A – Setting the Canvas Size - The first step when creating any object to be cut out on a laser cutter is to set the canvas size equal to the raw media size. In Inkscape, this is done by clicking on File:Document Properties (Ctrl-Shift-D shortcut), then filling in new dimensions under “Custom Size.” Most sheets of acrylic are 24”x12”, so these are the dimensions I have entered. Enter the dimensions of your raw sheet and close the window. Click on the “Zoom to Fit Page in Window” button to view your full canvas.
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
All laser cutters have two settings, raster and vector. The raster setting is used for etching surfaces (filling in regions with a bunch of tiny dots.) The vector setting is used for following a line to cut through a material. Similarly, all objects in Inkscape have two settings, fill and stroke. The stroke is the outline of the shape while the fill is the interior fill color. The Epilog Mini 35 will detect an object as a vector object (and thereby cut it) if it is a line that is as thin as the laser beam, which is approximately 0.001”. Similarly, the Epilog Mini 35 will automatically fill in any region larger than 0.001” with raster dots, giving a nice surface roughness to the acrylic.
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
Turn on your laser cutter, air pump and ventilation. Load up your sheet of acrylic, zeroed in the upper left corner of the base.
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
You can print directly on the baseplate, so you simply have to attach them firmly to the base of your Up! and get to work. I use a large binder clip on the front and back of the plate to hold it down. The rear of the base comes extremely close to the upper crossbar of the Up! while printing, so to ensure clearance you should remove the upper handle off of the rear binder clip. The acrylic baseplates hold printed objects tightly without delamination issues, so preheating the base is unnecessary. There is a possibility that you do not need a heated base at all with this setup, but I have not experimented with removing the heater from the Up! yet.
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!