Thursday, June 11, 2015

Microscopic pictures of the PCB ink coating that was laser etched

Hello.

I’m posting here the latest microscopic pictures of a PCB that was covered with black spray ink and illuminated by the 808nm 0.5W laser diode that was installed on my ShapeOko2 CNC. The focal point was moved by the machine to draw an insulating trace around the tracks.

As can be seen, the focal area is not round and the result is not good. I’m trying to find a laser diode with a circular profile to fix this.

 

 

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Tuesday, June 9, 2015

Latest results

I’m posting the latest results, after disassembling the ShapeOko2 and reassembling it due to a change from one country to another.

A few things have changed:

1- I found an easy way to place and hold limit switches in the machine. See the pictures below for more info.

2 - The YetAnotherGCodeSender program was advanced and now it can be compiled in a Raspberry Pi and in a Mac. Probably on Linux too. The program uses a very crude text based interface and controls quite well the TinyG planner queue, sending commands to the controller only when it is able to process them;

3 - I installed a 808nm laser diode on the machine as I said I would. I tested it against black ink covered PCBs and it could remove the ink where the laser beam hit. Pictures below too;

4 - Instead of using a specific program for generating GCode from GERBER files, I decided to follow the following workflow:

a – Draw the board then export the layers to GERBER format;

b – Open gerbv, installed on a Mac through MacPorts, load the GERBER layer and export it to PNG;

c – Open MeshCAM, load the PNG layer, set the Z thickness to 0.1mm and set black to +Z. Follow the normal procedure and generate a toolpath only with the pencil pass. Save the G-Code to a file;

d – Send the GCode file to your CNC machine. I’ve used my own software here and made it translate the negative z movements to Laser ON and the positive ones to Laser OFF. Incredibly, it worked. The first result can be seen on the last picture below.

 

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