Homebrew PCBs

Hello Art,

Another quick question, What feed rate did you use?

Thanks and Sorry for the bother,
Joe

On Thu, Dec 13, 2012 at 10:37 AM, joe M <joe9mail@...> wrote:

> Hello Art,
>
> Thanks for your advice.
>
> How did you end up using the 30 degree V-bit? Have you tried the other
> v-bits such as 45, 60 and 90? I am trying to understand how you went about
> the process. Whether you bought all the v-bits and just tried them all to
> figure out which one was best or if you were recommended that particular
> v-bit by someone.
>
> About the CEM board, I read that it is easier on the drill and mill bits.
> But, I also read that it emits a weird smell when being cut. Did you notice
> something like that? BTW, do you know if the fumes from cutting the CEM
> boards are carcinogenic? I have been told this "there are a zillion
> carcinogenic phenolic compounds...pentachlorophenol for example." Just
> curious, if you gave this any thought.
>
> Thanks again,
> Joe
>
>
>
>
> On Thu, Dec 13, 2012 at 9:25 AM, Art Eckstein <
> art.eckstein@wirelesshometown.com> wrote:
>
>> **
>>
>>
>> Joe,
>> Yep, you have run into a couple of problems with
>> boards being level. It has been found the boards
>> will "bow" up in the middle when clamped on the
>> edges and FR$ has (I think) a 10% tolerance for
>> board thickness. The best way to hold down the board is by vacuum.
>>
>> As for the "paper" board, you want CEM type as
>> opposed to the FR4. I get mine from a seller on
>> Ebay
>> (<http://stores.ebay.com/PCB-Laminates-Copper-Clad?_trksid=p2047675.l2563
>> >).
>> There are a few "autoleveling" packages that
>> probe the board height before doing the isolation
>> milling and these seem to work quite well. I use
>> Eagle and a ULP called pcb-gcode.ulp with autoleveling to make my boards.
>> For fine work, I use a 30� V bit, and for general
>> non critical stuff, a 60� one from <http://www.drewtronics.net/>.
>>
>> HTH
>> Art
>> Country Bubba
>>
>>
>> At 09:01 AM 12/13/2012, you wrote:
>> >Hello,
>> >
>> >I am trying to mill the pcb (FR4) with a taig.
>> >
>> >I did not have much luck with a uniform trace isolation even when I hold
>> >the board flat down by clamping down on the board edges. It appears that
>> >the pcb surface might not be uniform and that might be the reason why I
>> >cannot remove/mill out the copper layer consistently. I read about using
>> a
>> >foot (http://hackaday.com/2011/04/22/pcb-milling-tutorial/) to push the
>> pcb
>> >down while milling, but, that was a bit too much for my skill level.
>> >
>> >I read somewhere that it is easier to just paint the whole circuit board
>> >with some paint and then remove/scribe the paint off wherever the traces
>> >were being milled. This process is described here:
>> >http://reprap.org/wiki/Scratch_n%27_Etch_PCBs . Just wanted to check if
>> >anyone has experience with this?
>> >
>> >On a different note, I read that "paper phenolic" boards are
>> better/easier
>> >on the mill and drill bits. I checked digikey and mouser and could not
>> come
>> >up with any "paper phenolic" boards. Wondering if anyone knows of a
>> >supplier for "paper phenolic" boards?
>> >
>> >I used the EM2E8-0625-90VC bit from
>> >http://www.precisebits.com/products/carbidebits/scoreengrave.asp to mill
>> >the board. Maybe, I need to use a 45 degree bit as noted in this article:
>> >
>> http://millpcbs.com/index.php?option=com_content&view=article&id=23&Itemid=47
>> >
>> >Any thoughts or advice, please?
>> >
>> >Thanks
>> >Joe
>>
>>  
>>
>
>


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