Machsupport Forum

General CNC Chat => Show"N"Tell ( What you have made with your CNC machine.) => Topic started by: Tweakie.CNC on January 28, 2009, 08:16:08 AM

Title: Isolation Routing for PCB's.
Post by: Tweakie.CNC on January 28, 2009, 08:16:08 AM
I had not tried this before, OK it's a very simple circuit but it still needed a circuit board.
Isolation routing is simple, easy and is just like engraving I don't know why I didn't try it sooner - it sure beats ferric chloride for simple one off jobs.

I did not use a dedicated PCB program, instead I created the layout as a bitmap then outlined it as a vector image, exported it as an HPGL plot file then converted it to GCode. Quite easy really.

Tweakie.
Title: Re: Isolation Routing for PCB's.
Post by: Chaoticone on January 28, 2009, 11:02:32 AM
Very Good Tweakie. What is the circuit going to be for?

Brett
Title: Re: Isolation Routing for PCB's.
Post by: Tweakie.CNC on January 28, 2009, 11:27:03 AM
It's a PIC microprocessor based circuit designed as an addition to an existing industrial controller to slightly modify the program sequence and timing.

Tweakie.
Title: Re: Isolation Routing for PCB's.
Post by: Chaoticone on January 28, 2009, 12:20:06 PM
Great, keep us posted on this one. Sounds very interesting.

Brett
Title: Re: Isolation Routing for PCB's.
Post by: Jeff_Birt on January 29, 2009, 09:17:57 AM
I too enjoy PCB milling/drilling...

I have found the combination of Eagle Layout Editor (free addition) + PCBGcode (free, ulp to go from Eagle to GCode), + Mach (an insane value) is pretty hard to beat. You can quickly dray your schematic in Eagle, run the PCBGcode ulp (user language program) to generate GCode for Mach and be ready to go. PCBGcode also supports a cross platform previewer, a drill rack file (will convert all the different drills called for to the set you actually have on hand), and you can selectively include the different layers from Eagle.

http://www.cadsoftusa.com/
http://www.pcbgcode.org/
Title: Re: Isolation Routing for PCB's.
Post by: Tweakie.CNC on January 29, 2009, 10:42:49 AM
Thanks for the info Jeff.

I will certainly have a look at Eagle but it would be contrary to their license to use anything created with the free version commercially - who knows I may buy the licensed version.

Best regards,  Tweakie.
Title: Re: Isolation Routing for PCB's.
Post by: Jeff_Birt on January 29, 2009, 10:50:55 AM
Yes, the free version is for educational or hobby use only. They do have a stepped licensing system with the 'Light' version being really attractive at $50, the Layout+ Schematic version is around $500. I have no connection with them. Just a happy user.

One thing I have been trying to figure out is what drill sizes folks use most often when milling PCBs.
Title: Re: Isolation Routing for PCB's.
Post by: Tweakie.CNC on January 29, 2009, 11:14:00 AM
Hi Jeff,

The smallest hole I drill is 0.77mm but most often I use 0.96mm as this allows for everything. For cutting the tracks I used a 60 degree engraving bit (which is what I assumed everybody else used) but as I said earlier I have not done this before.

Best regards,  Tweakie.
Title: Re: Isolation Routing for PCB's.
Post by: Tweakie.CNC on January 31, 2009, 03:16:45 AM
Thanks to Jeff and by following the links he has given - over the last two days I have learn't a great deal and now have a far better understanding about isolation routing. For those who participate in this process it is far far more than just making circuit boards, their varying techniques, differing cutters used and fineness of detail produced can almost be regarded as an art form in itself.

Because the cutter loadings are extremely small even the most basic and less rigid of the CNC machines have been shown to produce excellent and professional results.

Certainly the Eagle software together with JJ's ulp produces Mach ready routing and drilling files which would be extremely hard to better.

For anyone wishing to make a circuit board or explore a whole new side to CNC I can certainly recommend this method.

Tweakie.
Title: Re: Isolation Routing for PCB's.
Post by: Jeff_Birt on January 31, 2009, 10:14:26 AM
I started out drawing the traces by hand too, in AutoCAD etc before going the Eagle/PCBGCode route. One other tremendously valuable resource is: http://thinktink.com/, this is the parent company of http://precisebits.com. There is a lot of information on the Think & Tinker site, it is well worth reading over several times.

One nice thing they offer is: http://www.thinktink.com/cgi-bin/carbide.cgi?page=drillset&step=20&start=0

These are a sets of solid carbide drills in most common sizes needed for through hole, SMT, and metric equivalent (in that order on page). When I got started milling PCBs I didn't have any idea what the best sizes of drills to have on hand I wanted to save some money by taking advantage of the Qty 10 of a single type bit discount but did not want to buy a bunch of bits that I would wind up not using. So the kits appeal to my 'frugal' side. I was talking to them last night about coming up with a 'starter' set that includes a couple of 60 deg trace isolation bits. I think we figured out what would work in such a kit so I plan to have all the sets including the new starter kit available on my website, www.soigeneris.com, in a few weeks.

Don't read the above as a big sales pitch, it's not. I've learned a lot from my 'Mach' friends here over the years and if I can help a few save some of their hard earned $ then that is great.
Title: Re: Isolation Routing for PCB's.
Post by: Tweakie.CNC on May 08, 2009, 11:33:22 AM
Another small circuit board - this time it is a simple, two position driver for a bipolar stepper motor.

Tweakie.
Title: Re: Isolation Routing for PCB's.
Post by: zarzul on May 26, 2009, 01:11:38 PM
What size of bit are you using?
Title: Re: Isolation Routing for PCB's.
Post by: Tweakie.CNC on May 27, 2009, 01:52:19 AM
I am using a 30 degree engraving point and cutting 0.08mm deep.

Tweakie.
Title: Re: Isolation Routing for PCB's.
Post by: Chris.Botha on May 27, 2009, 02:20:47 AM
nice job man!
Title: Re: Isolation Routing for PCB's.
Post by: Tweakie.CNC on May 27, 2009, 03:38:53 AM
Thanks Chris.

This one is a 'euro card' sized pcb made the same way.

Tweakie.