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III. Milling process

For PCB milling I use a cheap Chinese CNC3018 with the following modifications :

As CAM software I use the Estlcam
It is commercial, but the free version has no technical limitations…
Only when opening and saving longer pauses are inserted with time
I dont’ explain the detailed configuration process of Estclam, combined with the CNC3018, at this point.
Maybe I do it later, but feel free to contact me, if you have questions about that.

preparing the machine

First, I clamped a sheet of acryl on top of my buildplate. It’s just to be safe, that I’ll don’t mill into the aluminum table.
For fixating the PCB, I use double sided adhesive tape and painter’s tape around the PCB.
The painter’s tape is for avoiding vibrations. Vibrations makes terrible noises and could break the mill tool !

After inserting the 0.4mm mill tool, it’s time to open Estlcam.

using Estlcam

open gcode file

Now open the gcode file

If the downloaded file, does not appear in the open dialogue then we have to change the file extension in Estlcam.
Go to Setup - CNC Programs and change File extension to gcode or just rename the file to this :-D

After opening the fts_mini_traces.gcode file, a new window appears and it should look like this

If there is a blinking warning Port not available! check the machine connection and COM port settings.

Go back to the main window and click Setup - CNC Controller and check the COM port.

set home position

Via the Jog buttons, move the machine above the front left corner of the PCB.
This will be our home position. To zero the x / y axis, press the Touch offbutton

With the marked buttons in the picture, the X- and y-axis will be set to -4mm each

z-height measuring

Now I prepare the z-height measuring procedure.
The crocodile clamp goes to the mill tool and the other probe-wire will be fixed at the PCB material.

Now we can start the surface scan

To get a high resolution map, I changed the grid value to 1mm

Now start the scan.

If there’s something going wrong, the procedure can be stopped by pressing the ESC-Key

!!! When it’s finished, remove the probe-clamp and the probe-wire !!! :-D

start the mill-job

Now close the door from the IKEA chamber !!! and then press the play button.

After finish, it should like this......NOT ! :-D

You can see here a nice polish, but not milled traces.

So I prepared the gcode file again in the Fab Modules and raised the values cut depth and max depth to 0.20mm

After that correction, I’ve got a good but not perfect result. (More about that later)

When the mill job finished successfully, don’t change the zero position in Estlcam and don’t touch the PCB !!!

prepare for cutout

Do the following steps :

  • Change the mill tool to the 0.8mm end-mill
  • Place again the Z-probe clamp and wire, as describe above
  • Jog the mill about the PCB, but NOT about the milled traces !
  • lower the z-axis as slow as possible
  • when the end-mill touches the PCB, a blinking warning message appears

Now, go into the Touch off menu and press the button in the middle

Now you have a corrected the Z0 position. It’s necessary, because the mills have different lengths. Press F11 and lift up the z-axis.

!!! Remove the probe-clamp and the probe-wire !!! :-D

start cutting job

Open the fts_mini_cut.gcode
Do NOT change the x/y home position !!! Close the door from the IKEA chamber !!! and press play to start.

After a while, it should look like this

After carefully removing and first cleaning, it’s time to compare with the original FabTinyISP picture

On some points is still copper left and there are shortcuts in the circuit ! I corrected that with a sharp knife and sanded it a little, with a usable result

Let’s go ahead with the soldering session…