Fab Academy 2022

@ Opendot, Milan

Interface and application programming

For the Group assignment, we had to characterize the design rules for our PCB production process: document feeds, speeds, plunge rate, depth of cut (traces and outline) and tooling.

1. MILLING MACHINE AT FABLAB OPENDOT:

In the Fablab Opendot we can work with 2 differents milling machines:

We were introduced to these machine by our Local Instructor. We were told about basic operation for the maintenance which included, how to work in a safe way, how to clean the machine, how to set up the job. At first we started working on the Roland MDX-40A but, for technical issues, we switch to the Shopbot before starting the milling operation.

2. MILLING A PCB

PCB milling is the process of removing areas of copper from a sheet of printed circuit board material to recreate the pads, signal traces and structures according to patterns from a digital circuit board plan known as a layout file (say thanks to Wikipedia for this clear definition).

We can produce an high quality PCB using the right endmills and setting the mill with the best parameters for the kind of job we are going to do (speeds,rotation, jog, z-axis height, depth of cut…).

3. SETTING THE SHOPBOT PRSALPHA

We decided to mount the “sacrifical layer” of the Roland MDX-40A on the Shopbot workplate using some clamps with screws then we proceed in this way:





Once the PCB is firmly set-in position, we mount the drill bit, size 1/64”, for the trace cut.




The process of setting / mounting the drill bit (every drill bit) is as follows:

!ATTENTION: when you remove the endmill always put something on the surface of the copper plate to avoid to scratch it accidentally!

Now you can set the coordinates for the “home position” (the point from where the CNC will start its work) for the X and Y axis, and the height for the Z axis (the bit should touch the surface of the copper plate).

4. GENERATING TOOL PATH USING MODS



5. PCB MIILING (TRACES AND OUTLINE)

Look closely (but not to much!) while the CNC is working. If you want a coffee…I’m sorry ‘cause you can’t leave the CNC unattended while is on.

When the machine finish, check the work, if you’re not satisfied by the “engraving” you can re-do it changing the height of the z-axis (but don’t change the position of x and y axis) If you’re satisfied, instead, you can change the endmill, change the collet chuck, change the endmill with the proper one, produce the path for the outline (with Fabmodules), upload it on the program and cut it (as usual, change the height of z-axis but don’t move the x/y axis)

6. FINAL RESULT

7. CONCLUSIONS

8. SETTINGS

Instructor

Contacts