Milling a Circuit

Project by Jeremy Fryer-Biggs

printed bracket with precision milled holes!

One of the truly unique capabilities of the microfactory is the ability to print and mill the same part. We are going to devote several posts to the special capability but first up - printing a custom bracket and then precision milling in screw holes. Have you ever noticed that when you print parts the screw holes never go where you want them? This project will demonstrate how to use a microfactory to make this a thing of the past!

project parts list

  • mebotics spoil-board
  • acetone
  • scrap abs
  • glass
required bits

you will need a 1/8th endmill for milling the plastic bracket.

Eagle Speaker Circuit Layout Image By Jeremy Fryer-Biggs

printing the bracket

first we designed the part we want to make in CAD

CAD rendering of bracket by Jeremy Fryer-Biggs

then we remove the holes so that they WON'T be printed in and export to .stl

CAD rendering of bracket by Jeremy Fryer-Biggs

We use Slic3r to create a g-code tool path of the general shape

Image by Jeremy Fryer-Biggs

then we allow the machine to get up to temperature. we recommend using a mebotics spoil-board for this operation because they are designed to be optimal surfaces for printing AND milling operations. ALSO for the best results we recommend mixing a small quantity of acetone with scrap abs in a glass and spreading the slurry directly over where you intend to print. This will minimize warping and improve adhesion (which is particularly crucial during the milling step).

Photo By Rachel Tine

print the part!

Photo By Rachel Tine

(watch a video of the part printing)

milling the precision holes

Next we export a .dxf version of our part file from our CAD program and use CamBam to make a tool path. You can write a combined file and put a "tool change" into the program but for simplicity's sake we prefer making two separate programs to run

Image by Jeremy Fryer-Biggs

when the printing has stopped, raise the gantry and put in the 1/8th endmill. Perform a touch off to the table to re-zero the tool then run the milling program

Photo By Rachel Tine

(see video of the milling program running)

and voila a printed bracket with precision screw holes!!

Photo By Rachel Tine

special thanks to

Rachel Tine - for doing the cool photography