SD Card > PIC24 > Route PCB

RepRap developments

I thought it high time I posted some information about recent development work I have been doing using parts from the RepRap project.

The original idea started late last year, I wanted to put together a simple CNC router for producing PCB

A few notes about the test PCB attached to my first post.

Looking at the picture gives you no impression of the scale. The whole board here is about 45mm square, the lines round the outside step in 1mm at a time, the last one 0.5mm. The pads round the outside are 2.54 pitch, on the TQFP chip 0.7 pitch with 0.2mm between pads.

This is as far as I have managed to go with small surface mount, the tracks at 0.5mm are fine but to get the tool between the pins of the TQFP 44 at 0.2mm with (2 passes!) is a struggle. The photo shows most of the tracks are good but others have run together scrapping the board. I show this failed attempt because it details where I am with the PCB Milling. Through hole boards are generally wider tracks and wider pitch on the pins, this breakout board is a real test of accuracy and is about the limit I have seen produced on a commercial Aluminium built router.

Going back and checking my PCB Gerber I see that all the tracks are not exactly lined up with the pads, fixing this should tidy things up a little plus I am going to stiffen up the X-axis a little more and test the results.

Any feedback from others doing PCB routing would be welcome, what machine you are using and how fine a track is feasible.
I will post progress as things move on.

Tony.

Hi Tony,

... good job!

So the reprap can make his own PCB's too

With some more development the point of 100-percent-reprappability of the mechanical and electrical components could be reached this year - and then aim fabbing the electronics too ...

Viktor

There's still having it mine the raw materials and fab the IC's ;-}>

As far as I'm concerned the point at which given one I can make another using only commodity parts was when it reached as self replicating as I need. From here on it is making it more useful and the replication easier/cheaper. PCB Milling covers both nicely.

tofletcher:
What tool-chain are you using to build the firmware?

The firmware is developed in the free edition of the Microchip MPLAB C30 C complier, in conjunction with the ICD 2. All standard issue to keep things simple and accessible.

Tony

Tony,

Great job!
What software are you using to create your PCboard layouts? How do you like it; is it freeware or something commercial?

Thanks,

Larry Pfeffer
ursine at gm4il d0t c0m

Larry,
You can use any PCB software as long as it will output a Gerber file, then use Eagle power tools to convert it to an Eagle script.

The PCB software is Eagle 4.16r2 Light.
Have a look at the link below, this will tell you all you need to know about Gerber to G-code.

www.brusselsprout.org/PCB-Routing/

Tony

Hum wonder if it would work to paint a thin coating of plastic paint on a pcb.

Then use the repap mill to scratch away the paint with a fine needle or so.

The toolhead would be much lighter, make less noise and less litter. Also the tool could rest on the surface, making it less sensitive to misalignment!

Then one could just etch the thing and eliminate the expensive photo-resist of common technologies. You wouldn't need the nasty NaOH nor the UV-light exposure box. Also you would get away from laser printing on soon-to-be-history expensive Overhead plastic film!

Etching a PCB in an old plastic ice-cream box using Ferrum Chloride is really not that difficult comparing to what goes on otherwise in this forum ;-)

Drilling the holes at the same time would be nice too!

... it's not easy to find a paint, which stick perfectly to the copper without breaking out around the carved traces.

Maybe it's easier to use normal PCB's with the photosensitive coating and simply carve the coating instead of UV-curing?

Viktor

Wow!

Definitely worthy of a blog post on builders.reprap.org or blog.reprap.org... but then again. Let's do that once the design is available and people can play with it. No need to tease everyone THAT hard...

---

Regards,

Erik de Bruijn
[Ultimaker.com] - [blog.erikdebruijn.nl]

Hi Erik,
Thanks for the comments, the whole design will be posted in full and the idea is to keep on developing it as far as it is practical.

I deliberately dumped a description of the whole project into this forum to see if it was of interest to a wider audience. It contains a fair bit of info to digest and thought if people wanted it

...Now doing basic printing
See builders blog