Homebrew PCBs

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


[Non-text portions of this message have been removed]

hey Joe - I milled a pcb using my homemade CNC machine - I actually used
double sided tape to hold it down and probably went a little too deep with
the bit (although it all worked)

http://www.backyardworkshop.com/blog-posts/most-recent/176-milling-a-circuit-board.html

Jamie

Jamie
Check out my CNC projects (and more) at http://www.backyardworkshop.com



On Thu, Dec 13, 2012 at 9:01 AM, joe M <joe9mail@...> 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
>
> [Non-text portions of this message have been removed]
>
>  
>


[Non-text portions of this message have been removed]

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

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@...> 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
>
>  
>


[Non-text portions of this message have been removed]

Hello Jamie,

Those are some good looking pens.

That seems to be a pretty sharp bit. What bits did you use?

Thanks
Joe

On Thu, Dec 13, 2012 at 9:15 AM, Jamie Cunningham
<jamie@...> wrote:

> hey Joe - I milled a pcb using my homemade CNC machine - I actually used
> double sided tape to hold it down and probably went a little too deep with
> the bit (although it all worked)
>
> http://www.backyardworkshop.com/blog-posts/most-recent/176-milling-a-circuit-board.html
>
> Jamie
>
> Jamie
> Check out my CNC projects (and more) at http://www.backyardworkshop.com
>
>
>
> On Thu, Dec 13, 2012 at 9:01 AM, joe M <joe9mail@...> 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
>>
>> [Non-text portions of this message have been removed]
>>
>>
>>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

I have had very good results with 90 degree cutters.





PCB cut with 90 degree bit
<http://xa.yimg.com/kq/groups/4505361/sn/588202274/name/pcb_3.jpg>















[Non-text portions of this message have been removed]

Joe,
Reading in the pcb-gcode group, I learned that 
you needed to "calibrate" your bit to find out 
exactly what size it was actually cutting based 
on depth of cut as not all bits are made 
equal.  I have a project coming up that will use 
Tssop14 footprint chips and the pin spacing is 
.65 mm with a pin width of .35 mm which leaves an 
isolation width of .3mm (~.012"). So I bought a 
pack of various sizes and started to play with 
width of cut vs depth of cut. I am trying to 
perfect my equipment to be able to RELIABLY cut a 
good isolation at a depth of .002". Still playing 
with that one. Just finished my vacuum chuck but 
have not tried it yet.  Was getting decent cuts 
using the double sided tape routine, but got 
tired of the sticky mess on the back of the board.

I have not noticed any particular smell to the 
cutting process, but there is always some risk 
with ANYTHING. I still think it is better than 
the risks with chemicals! (My personal opinion)

Art
Country Bubba


   At 10:37 AM 12/13/2012, you 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@...> 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
> >

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
>>
>>  
>>
>
>


[Non-text portions of this message have been removed]

Thanks Joe!

I believe that's a 30 degree engraving bit (I only have 30 and 60 degree
bits atm)

Jamie
Check out my CNC projects (and more) at http://www.backyardworkshop.com



On Thu, Dec 13, 2012 at 10:39 AM, joe M <joe9mail@...> wrote:

> **
>
>
> Hello Jamie,
>
> Those are some good looking pens.
>
> That seems to be a pretty sharp bit. What bits did you use?
>
> Thanks
> Joe
>
>
> On Thu, Dec 13, 2012 at 9:15 AM, Jamie Cunningham
> <jamie@...> wrote:
> > hey Joe - I milled a pcb using my homemade CNC machine - I actually used
> > double sided tape to hold it down and probably went a little too deep
> with
> > the bit (although it all worked)
> >
> >
> http://www.backyardworkshop.com/blog-posts/most-recent/176-milling-a-circuit-board.html
> >
> > Jamie
> >
> > Jamie
> > Check out my CNC projects (and more) at http://www.backyardworkshop.com
> >
> >
> >
> > On Thu, Dec 13, 2012 at 9:01 AM, joe M <joe9mail@...> 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
> >>
> >> [Non-text portions of this message have been removed]
> >>
> >>
> >>
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> > ------------------------------------
>
> >
> > Be sure to visit the group home and check for new Links, Files, and
> Photos:
> > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
>
>  
>


[Non-text portions of this message have been removed]

Hello Buckeyes1997,

90 degree cutter cut was very smooth without any burr. But, it did not
provide much leeway when the pcb is not very smooth. Even a mil difference
was leaving small islands of Cu.

Did you use the 90 degree cutter from here?
http://www.precisebits.com/products/carbidebits/scoreengrave.asp

Is that an FR-4 board or a paper phenolic board? btw, What is the size of
the smallest trace on that pcb in the photo?

Have you tried other bits before deciding on the 90 degree cutter bit?

Thanks
Joe



On Thu, Dec 13, 2012 at 10:55 AM, buckeyes1997 <buckeyes1997@...>wrote:

> **
>
>
>
> I have had very good results with 90 degree cutters.
>
> PCB cut with 90 degree bit
> <http://xa.yimg.com/kq/groups/4505361/sn/588202274/name/pcb_3.jpg>
>
>
> [Non-text portions of this message have been removed]
>
>  
>


[Non-text portions of this message have been removed]

Joe,
I use 30 IPM and 30,000 rpm
No bother either as I am glad to give back to the system that has 
given me so much.


Art
Country Bubba


At 11:01 AM 12/13/2012, you wrote:

>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@...> wrote:
> >

Hello Art,

Is there any algorithm to figure out the feed rate? I am using a mill feed
of 6 inches per min at 10,000 rpm and it seems to be working well (in my
amateurish opinion). I am not sure what to look for (burrs, etc) to ensure
that it is actually working fine. Any thoughts, please?

I will just order the different degree bits and try them on to figure out
which is better.

BTW, I read that the CEM boards have a problem with small traces. The
traces supposedly cannot glue as well to CEM as to FR-4. Wondering if you
encountered that issue.

Thanks
Joe



On Thu, Dec 13, 2012 at 11:05 AM, Art Eckstein <
art.eckstein@...> wrote:

> **
>
>
> Joe,
> I use 30 IPM and 30,000 rpm
> No bother either as I am glad to give back to the system that has
> given me so much.
>
> Art
> Country Bubba
>
>
> At 11:01 AM 12/13/2012, you wrote:
> >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@...> wrote:
> > >
>
>  
>


[Non-text portions of this message have been removed]

Joe,
I forget where I saw it, but one rule of thumb is 1IPM per 1000rpm of 
the spindle. It seems to be a good starting place and of course might 
need tweaking depending on your exact setup.

In the bit calibration program, yes I do have some problems with 
trace width less than .005" and I have not yet tried it in FR4. By 
the way, if your interested in the bit calibration as developed by 
Poul-Henning Kamp, you can find the information here 
<http://phk.freebsd.dk/CncPcb/calibrate.html>

Art
Country Bubba



At 11:17 AM 12/13/2012, you wrote:

>Hello Art,
>
>Is there any algorithm to figure out the feed rate? I am using a mill feed
>of 6 inches per min at 10,000 rpm and it seems to be working well (in my
>amateurish opinion). I am not sure what to look for (burrs, etc) to ensure
>that it is actually working fine. Any thoughts, please?
>
>I will just order the different degree bits and try them on to figure out
>which is better.




>BTW, I read that the CEM boards have a problem with small traces. The
>traces supposedly cannot glue as well to CEM as to FR-4. Wondering if you
>encountered that issue.
>
>Thanks
>Joe
>
>
>
>On Thu, Dec 13, 2012 at 11:05 AM, Art Eckstein <
>art.eckstein@...> wrote:

On Thu, Dec 13, 2012 at 11:41 AM, Art Eckstein <
art.eckstein@...> wrote:

> **
>
>
> Joe,
> I forget where I saw it, but one rule of thumb is 1IPM per 1000rpm of
> the spindle. It seems to be a good starting place and of course might
> need tweaking depending on your exact setup.
>
> In the bit calibration program, yes I do have some problems with
> trace width less than .005" and I have not yet tried it in FR4. By
> the way, if your interested in the bit calibration as developed by
> Poul-Henning Kamp, you can find the information here
> <http://phk.freebsd.dk/CncPcb/calibrate.html>
>
> Art
> Country Bubba
>

Hello Art,

Quick question, How often do you run the above calibration to check if the
bits have dulled or if the cnc machines' runout is above tolerance? Or, is
there some method that you use to figure out the dulled bits?

Thanks
Joe


[Non-text portions of this message have been removed]

Joe,
So far, most has been just tying to make things 
work properly. Calibration needs to be done 
initially to find out how wide a path your 
actually cutting. If you are cutting wider than 
you think you are, your making thinner traces! 
Bit wear usually shows up as excessive burrs or 
if you have damaged the tip (easy to do if your 
using small angle bits (30° or less) the quality 
of the cut will show that you need to do something.

Art
Country Bubba



At 12:29 PM 12/13/2012, you wrote:

>On Thu, Dec 13, 2012 at 11:41 AM, Art Eckstein <
>art.eckstein@...> wrote:
>
> > **
> >
> >
> > Joe,
> > I forget where I saw it, but one rule of thumb is 1IPM per 1000rpm of
> > the spindle. It seems to be a good starting place and of course might
> > need tweaking depending on your exact setup.
> >
> > In the bit calibration program, yes I do have some problems with
> > trace width less than .005" and I have not yet tried it in FR4. By
> > the way, if your interested in the bit calibration as developed by
> > Poul-Henning Kamp, you can find the information here
> > <http://phk.freebsd.dk/CncPcb/calibrate.html>
> >
> > Art
> > Country Bubba
> >
>
>Hello Art,
>
>Quick question, How often do you run the above calibration to check if the
>bits have dulled or if the cnc machines' runout is above tolerance? Or, is
>there some method that you use to figure out the dulled bits?
>
>Thanks
>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
>
Hello Art,

I use this tool path (gEDA/pcb -> gerber and excellon -> pcb2gcode ->
G-code -> EMC2/Axis -> tabletop CNC as detailed at
http://reprap.org/wiki/PCB_Milling#gEDA.2Fpcb_-.3E_gerber_and_excellon_-.3E_pcb2gcode_-.3E_G-code_-.3E_EMC2.2FAxis_-.3E_tabletop_CNC)
and am trying to figure out if there is an "autoleveling" package with
linuxcnc (emc^2).

I read up on the autolevelling package at
http://phk.freebsd.dk/CncPcb/index.html and it appears to be exactly what I
need.

I believe it makes a crude 3-D map of the Cu surface and adjusts the z in
the gcode accordingly.

Thanks
Joe


[Non-text portions of this message have been removed]

Joe,
Just a question, why not use Eagle>pcbgcode>board?
A gentleman just posted how he got Eagle 6.3? and 
pcbgcode.ulp to work on Unbuntu.
And it has auto leveling capability.

Art
Country bubba




At 05:32 PM 12/13/2012, you wrote:

>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
> >
>Hello Art,
>
>I use this tool path (gEDA/pcb -> gerber and excellon -> pcb2gcode ->
>G-code -> EMC2/Axis -> tabletop CNC as detailed at
>http://reprap.org/wiki/PCB_Milling#gEDA.2Fpcb_-.3E_gerber_and_excellon_-.3E_pcb2gcode_-.3E_G-code_-.3E_EMC2.2FAxis_-.3E_tabletop_CNC)
>and am trying to figure out if there is an "autoleveling" package with
>linuxcnc (emc^2).
>
>I read up on the autolevelling package at
>http://phk.freebsd.dk/CncPcb/index.html and it appears to be exactly what I
>need.
>
>I believe it makes a crude 3-D map of the Cu surface and adjusts the z in
>the gcode accordingly.
>
>Thanks
>Joe

On Thu, Dec 13, 2012 at 5:43 PM, Art Eckstein <
art.eckstein@...> wrote:

> **
>
>
> Joe,
> Just a question, why not use Eagle>pcbgcode>board?
> A gentleman just posted how he got Eagle 6.3? and
> pcbgcode.ulp to work on Unbuntu.
> And it has auto leveling capability.
>
> Art
> Country bubba
>

Hello Art,

Good point. Let me check out getting Eagle installed on linux.

Thanks again,
Joe


[Non-text portions of this message have been removed]

Hello
Yes that is the same 90 bit I used.  I have tried some 60 degree bits and maybe a 30 degree.  I thought the 30 cut too deep to make it useful.  The 60 was okay but again cut deep to get trace spacing.  The 90 cuts shallow to get good spacing.

The trick here is to measure the board and compensate for the board not laying flat or being tipped.  If you cut the board and one section is lighter cut than the other then the board is not flat or aligned properly.  You can either manually align it better or comp in software.  I chose to comp in software.

Matt



--- In Homebrew_PCBs@yahoogroups.com, joe M <joe9mail@...> wrote:

>
> Hello Buckeyes1997,
> 
> 90 degree cutter cut was very smooth without any burr. But, it did not
> provide much leeway when the pcb is not very smooth. Even a mil difference
> was leaving small islands of Cu.
> 
> Did you use the 90 degree cutter from here?
> http://www.precisebits.com/products/carbidebits/scoreengrave.asp
> 
> Is that an FR-4 board or a paper phenolic board? btw, What is the size of
> the smallest trace on that pcb in the photo?
> 
> Have you tried other bits before deciding on the 90 degree cutter bit?
> 
> Thanks
> Joe
> 
> 
> 
> On Thu, Dec 13, 2012 at 10:55 AM, buckeyes1997 <buckeyes1997@...>wrote:
> 
> > **
> >
> >
> >
> > I have had very good results with 90 degree cutters.
> >
> > PCB cut with 90 degree bit
> > <http://xa.yimg.com/kq/groups/4505361/sn/588202274/name/pcb_3.jpg>
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >  
> >
> 
> 
> [Non-text portions of this message have been removed]
>

oops..

Yes its FR4 from radioshack. I found their board has much smoother surface than the junk I got on ebay.  The smallest trace is probably around 8/9 mil.  The board didnt come out perfect but it was a good test to see how well my system was working. I'm not sure I would mill a board this fine and expect it to work but it looks like it could be done.
matt


--- In Homebrew_PCBs@yahoogroups.com, "buckeyes1997" <buckeyes1997@...> wrote:

>
> Hello
> Yes that is the same 90 bit I used.  I have tried some 60 degree bits and maybe a 30 degree.  I thought the 30 cut too deep to make it useful.  The 60 was okay but again cut deep to get trace spacing.  The 90 cuts shallow to get good spacing.
> 
> The trick here is to measure the board and compensate for the board not laying flat or being tipped.  If you cut the board and one section is lighter cut than the other then the board is not flat or aligned properly.  You can either manually align it better or comp in software.  I chose to comp in software.
> 
> Matt
> 
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, joe M <joe9mail@> wrote:
> >
> > Hello Buckeyes1997,
> > 
> > 90 degree cutter cut was very smooth without any burr. But, it did not
> > provide much leeway when the pcb is not very smooth. Even a mil difference
> > was leaving small islands of Cu.
> > 
> > Did you use the 90 degree cutter from here?
> > http://www.precisebits.com/products/carbidebits/scoreengrave.asp
> > 
> > Is that an FR-4 board or a paper phenolic board? btw, What is the size of
> > the smallest trace on that pcb in the photo?
> > 
> > Have you tried other bits before deciding on the 90 degree cutter bit?
> > 
> > Thanks
> > Joe
> > 
> > 
> > 
> > On Thu, Dec 13, 2012 at 10:55 AM, buckeyes1997 <buckeyes1997@>wrote:
> > 
> > > **
> > >
> > >
> > >
> > > I have had very good results with 90 degree cutters.
> > >
> > > PCB cut with 90 degree bit
> > > <http://xa.yimg.com/kq/groups/4505361/sn/588202274/name/pcb_3.jpg>
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >  
> > >
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
>