Simple isolation routing software

I've tried several different pieces of software to convert PCB layouts to G-Code. I have stumbled upon a piece of software called FlatCam. This will read Gerber and simply generate G-code. 

I had some example Gerber from the web but it didn't load (the FlatCam screen was blank). I opened the Gerber with gerbv and it showed some spurious lines that I deleted - FlatCam then opened it and a few clicks later, I had g-code cutting a piece of copper clad FR4. 

Long live Enthusiastic developers and smart students. Well done JP at FlatCam.org

The obligatory test circuit

Well, it had to be done really :) what else could I choose but an NE555 LED flasher.

A few tips: 

1) don't use 20year old PCB material. The board was warped, copper filthy, copper soft and difficult to mill. 

2) don't try to use 25year old resistors that you've found in a box.

3) put on your glasses before drilling the holes in the board (I thought I'd save time and not CNC the holes....)

Strangely enough, all of this combines to make a bit of a mess. Almost impossible to solder. I've never seen better examples of dry joints. Oh well, I got there in the end. Toggling LEDs.

It's running on 3xAA batteries in the pack under the PCB. 

(Ignore the fragments of text on the board - nothing to do with this test!)

Disaster and slow recovery

For the first time everything is really running perfectly. Mach3 is all setup correctly. Really happy - and then...

Yesterday XP died. I mean really really stuffed! Even my Linux live cd won't see the hard disk. I think it is physically stuffed. 

Talking to a neighbour yesterday i told him "My data should all be backed up but I've lost all my Mach3 settings."

He calmly turned to me and said "but program settings are data". 

Of course he is right. Why hadn't I backed these up or written them down or etc etc etc???

Reluctantly I now have to start building all this stuff up again. 

12 hours later and XP is installed again, all updates, patches etc run. 

Mach3, Cambam and Eagle back on again. 

After a good load of adjusting, I have enough settings in Mach3 to make the motors run again. 

The distance calibration seems a bit off at the moment but I'm happy to see it moving again. I think the old hard disk is destined to become a novelty door stop. 

Was the new bit worth it? Oh yes!

Clearly my attempts to save money were a waste of money. I finally gave in and bought a real 30degree isolation router bit on line. 

This may sound stupid but the first observation was how sharp it is - I mean REALLY sharp - this has to be a good thing!

I wound up Mach3, adjusted the z axis zero and went for it. 

Awesome! Perfect cut, no jagged lines as it catches rather the cutting. I wonder if I can reduce the track size ??????

Amazing. The only wobbly piece was in the middle at the top. I had the feedrate set way too high and also the board wasn't stuck down well enough. 

Ok so this needs a little more fine tuning but this is seriously impressive. 

PCB Isolation routing

I first saw isolation routing at an electronics trade show years ago. For anyone reading this who does not know, instead of etching a PCB by disolving unwanted copper in an acid bath, isolation routing cuts out the tracks you want by milling a cut in the copper around the track. This is something I have wanted to try since the first day I saw a YouTube video of someone making their own PCBs with a CNC machine. 

Of course it isn't that easy. I tried KiCad -> gerber -> g-code but it didn't work. I then went back to the (apparently more common) Eagle -> PCB2Gcode approach. It took a few tries but eventually (after turning off the checkboxes for the comments) Mach3 read in the file. 

I tried with my Ferm(cheap Dremmel) plus Dremmel sharp pointed bit (30 degree??? Pointy bit). 

I've tried three runs so far. 

It's very difficult to get it to cut through all of the copper evenly without ripping off sections. You can also see jagged lines where it digs in rather than cutting smoothly. 

Ummmm... Track width too small and setting for router bit width too small... Try increasing both....

Less bad but its still really difficult to get it to cut the copper. Try again this time going lower and lower and lower on the z axis. Oh yes, the tape holding the board became loose so it wobbled by a couple of mm. 

I also tried an engraving bit but this is really meant to grind on the side not the end - it didn't work. 

I think I need a new real router bit. 

A little light engraving

To see how accurate the beast is now, I opted for a light weight task and mounted my low cost multi-tool with a sharp point bit. 

I then grabbed an offcut of plastic  ( a block of Delrin that I bought a while ago) and tried engraving a little.

(I also experimented with spraying some white paint on the black Delrin and then sanding it off again to improve contrast... mixed results...more experiments needed)

The multi-tool is clamped by a block that I attach to the main tool support. The main tool support is made for my Blank&Decker router. 

Very impressed!

Looking at this, I should also be able to do PCB isolation milling as well which I've always wanted to try. 

Eureca!

Big deep breaths.....

I disconnected the link to the x dive so that I could slide the z assembly across. 

Yuck!!! It is grinding and not right at all. 

Suspicious of the top rail, I gently slid the rail out so the the z assembly was just on the bottom rail - still binding. 

Put the top rail back in and remove the bottom rail..... Smooth as silk!!! 

I removed the z assembly and could see that one of the bearing blocks was just slightly off centre - maybe 0.5mm too low. nothing wrong with the block, i had drilled the holes in the wood in the wrong place. Ok time to be bold!

I removed the offending bearing block and the thing is wobble free with two bearing blocks at the top and one at the bottom. 

Reassemble (including strengthening the attachment to the drive on the x axis) and... Oh my... It trundles smoothly back and forwards. 

Quick grab a router!