Make Plastic 3D Models From CAD Designs Using an Automated "milling Machine"

A good way to make 3D plastic models easily.

you'll need:

-- an EGX-300 engraver machine (we will use it for milling)
(http://www.rolanddga.com/products/engravers/EGX-300/) I saw it on ebay for $2000 at some point. If you buy from Roland, costs $5000 unless you're using it for educational purposes (then it's cheaper)

-- a 3D CAD program that can make .3dm files (I use Rhino 3D)

-- VisualMill software program (http://www.mecsoft.com/Mec/)

-- a computer with a serial or parallel port (to send instructions to the EGX-300)

-- a vacum cleaner

-- milling bits (and drill bits if you need to drill holes too)

-- delrin plastic

-- a hacksaw to slightly modify a piece of the EGX-300

-- mechanical timer

-- glue gun

cut off the bottom part of the vacuum hose adapter so that it does not extend down any further than the top of the mill bit.

duct tape the vacuum hose to the EGX hose.
Plug the vacuum into the mechanical timer.

use your CAD program to design what you want to mill out. Remember, the EGX can only mill from top down. Your design can still have concavities on the top and bottom side, you're just going to have to flip it over so the EGx can mill both sides.
I usually split my design into pieces which I melt together with a soldering iron after the EGX has milled them out.
Make sure there is no piece of your design taller than what can fit below the mill bit of the EGX.

After you're done with your design, make a wall around it which is the height of the pladtic material you will be milling. If the material it taller than the workable length of your mill bit, make a lower ledge within this wall (see my CAD design below).

make sure that all spaces are wider than the whatever mill bit diameter you use!

make thin arms to hold yor design as it's being milled.

open visual mill, and follow the instructions in the .doc file (visual mill instructions.doc)

you'll need to mount you plastic in a stable way so that it doesn't shift during milling. The EGX comes with clamps to help do this.

The way I did it is:
I stuck plastic slabs to the EGX bed using mounting tape. I made a .3dm CAD file which had two 1mm diameter holes, one on each side of a large slab. I send these to visual mill and the EGX which drilled holes into the plastic taped to the EGX bed.

I used these holes to put dowel pins in, so all future plastic that I mill with the EGX gets mounted on these pins (have to drill 1mm holes into each plastic slab that I want to mill). (use the same .3dm file I used for the original bed drilling)

After mounting my project plastic onto the dowel pins, I also put melted glue with a glue gun all around the piece to keep it even more stable. This isn't very necessary.

-- set EGX spindle speed to max (turn knob)
-- mount plastic.
-- put bit into EGx.
-- set Z0 way above your mounted plastic (see EGX manual for how to set z0)
-- open 'roland print' program (comes with the EGX), click open, click your prn file, click open.
-- watch to make sure EGX is doing what you expect.
-- stop the EGX
-- move EGX down so the bit is barely above the mounted plastic, set it as the Z0 (see EGX manual)
-- use 'roland print' to reopen your project
-- start the vacuum cleaner, set the timer to stop the vacuum approximately when you think the EGX will be done.
-- watch your project get milled, wheee!