Homebrew PCBs

Can someone please post a couple of photos of a milled PCB and the 
tools used in milling.  I am a tad bit confused by the process but I 
am guessing you simply take a "V" shaped tool and route a small 
channel around each trace or pad.  

TIA
CHris

Chris,

I need to explain that I'm here on this board for reasons other than
PCBs and electronics; I work in the scale model manufacturing field,
creating casting masters with photo-etched parts and also parts cut on
a tabletop CNC mill and lathe.

I say this because I understand very little about what PCBs are and
what it is you all do with them. It's your processes and techniques
that I'm after ;-) But, if I can help with CNC information, please
ask. I'm pretty new at it, but I have a 100 hours-plus or so on the
CNC mill.

(At the moment, because I moved recently, the shop is not in working
order, so I can't immediately go cut a PCB-type pattern to show you.)

Using CAD/CAM software and CNC driver software, I have done lots of
cutting with .005" end mills and also with drill bits as small as a
#97 (.0059" iirc). Some of the file operations have required a couple
of hours and thousands of individual cuts. For my use, the accuracy of
this system has been outstanding (once I discovered how to compensate
for backlash in the software).

I'll try to explain further, if you have questions (and they're not
too tough for me).

-Brian

Brian Chapman
Evansdale, Iowa


---

On Monday 04 July 2005 12:28 am, Brian Chapman wrote:
>
> Using CAD/CAM software and CNC driver software, I have done lots of
> cutting with .005" end mills and also with drill bits as small as a
> #97 (.0059" iirc). Some of the file operations have required a couple
> of hours and thousands of individual cuts. For my use, the accuracy of
> this system has been outstanding (once I discovered how to compensate
> for backlash in the software).

Can you give me a rough idea of what sort of considerations are involved in 
the machine to work at that kind of scale?  I don't think I've ever seen a 
mill that small and my drill bits only go to #80.  :-)

I guess spindle runout is a major factor there?

> Can you give me a rough idea of what sort of considerations are
involved in the machine to work at that kind of scale? I don't think
I've ever seen a  mill that small and my drill bits only go to #80. 
:-) I guess spindle runout is a major factor there? <

Roy, sure, trying to stump me right off the bat, eh? <g

I purchased a Sherline tabletop mill and lathe and later converted
them to CNC using a "turnkey" system from FlashCut. (www.sherline.com)

The Sherline machines, roughly, each are the size of a sewing machine
and are driven with an IBM 600e laptop I purchased used. 

I bought Sherline because, when shopping, all the various reviews I
read were glowing about the quality of the machines. Perhaps as
importantly, I bought Sherline's "ultimate" package that included,
among other things, quality accessories such as Jacobs chucks and also
quality collets. Quality accessories, as I understand it, have much to
do with a machine's cutting accuracy.

I use collets only with miniature cutting tools; I've read that
collets provide greater accuracy than chucks.

I'm a member of the yahoo SherlineCNC list
(http://groups.yahoo.com/group/SherlineCNC/?yguid=225428826), and
spindle runout is seldom mentioned there as a problem. More likely,
threads will deal with problems such as Z axis backlash compensation
and the limitations of leadscrews vs. ballscrews. A number of smart
and talented Sherline owners have documented, and posted at the site,
 machine upgrades that they've developed.

But, I don't think spindle runout is a problem. Let me give you an
example. I have milled a negative mold of the side of a 40-foot long
highway trailer in 1:87 scale (about 5-3/8" x 1-3/16"). Within this
space are about 40 horizontal corrugations (grooves) that I cut, iirc,
with a .012" ball mill. 

In between each corrugation (a space also .012" wide), in vertical
strips, are rivets drilled with a .005" end mill (about 36 vertical
rows, or more than 1400 rivets). Each rivet is precisely placed; none
"slide" into the corrugations. To me, this is the kind of accuracy I
require -- and get -- from this tabeltop unit.

BTW, I've drilled hundreds of holes on this or that workpiece with #97
(.0059") drill bits and have yet to bust. Any sort of runout problem
would probably snap these, but I'm guessing only.

Let me ask you a couple of questions, Roy. What are the narrowest
traces that you would need to mill on a PCB surface (am I thinking of
a copper-clad PCB ready for etching)? In between traces, what are the
narrowest clear areas required; that is, what is the minimum
separation required between traces?

Did I answer your questions?

-Brian

Brian Chapman
Evansdale, Iowa

PS - I'm hoping, once Curt comes back from the holiday, he can advise
me whether or not I can easily adapt the CNC Sherline mill for use as
part of the EDM system I'm intending to assemble. 

The EDM plans I have include a logic board for driving the EDM head,
but I wonder if I can't build the power side of the EDM system only
and use the mill and CNC software for the rest. . . . I'm way over my
head at the moment, but I hope to break the surface and tread water
while I look around and figure out what to do next. <g


---

I have a couple of photos of my milled PC boards at my robot clubs web 
site.  I should post more some day. I've been milling PCBs for years and 
have gotten good results

http://frontrangerobotics.org/UltraSonic/


  - Edward Rupp



Brian Chapman wrote:

>>Can you give me a rough idea of what sort of considerations are
> 
> involved in the machine to work at that kind of scale? I don't think
> I've ever seen a  mill that small and my drill bits only go to #80. 
> :-) I guess spindle runout is a major factor there? <
> 
> Roy, sure, trying to stump me right off the bat, eh? <g
> 
> I purchased a Sherline tabletop mill and lathe and later converted
> them to CNC using a "turnkey" system from FlashCut. (www.sherline.com)
> 
> The Sherline machines, roughly, each are the size of a sewing machine
> and are driven with an IBM 600e laptop I purchased used. 
> 
> I bought Sherline because, when shopping, all the various reviews I
> read were glowing about the quality of the machines. Perhaps as
> importantly, I bought Sherline's "ultimate" package that included,
> among other things, quality accessories such as Jacobs chucks and also
> quality collets. Quality accessories, as I understand it, have much to
> do with a machine's cutting accuracy.
> 
> I use collets only with miniature cutting tools; I've read that
> collets provide greater accuracy than chucks.
> 
> I'm a member of the yahoo SherlineCNC list
> (http://groups.yahoo.com/group/SherlineCNC/?yguid=225428826), and
> spindle runout is seldom mentioned there as a problem. More likely,
> threads will deal with problems such as Z axis backlash compensation
> and the limitations of leadscrews vs. ballscrews. A number of smart
> and talented Sherline owners have documented, and posted at the site,
>  machine upgrades that they've developed.
> 
> But, I don't think spindle runout is a problem. Let me give you an
> example. I have milled a negative mold of the side of a 40-foot long
> highway trailer in 1:87 scale (about 5-3/8" x 1-3/16"). Within this
> space are about 40 horizontal corrugations (grooves) that I cut, iirc,
> with a .012" ball mill. 
> 
> In between each corrugation (a space also .012" wide), in vertical
> strips, are rivets drilled with a .005" end mill (about 36 vertical
> rows, or more than 1400 rivets). Each rivet is precisely placed; none
> "slide" into the corrugations. To me, this is the kind of accuracy I
> require -- and get -- from this tabeltop unit.
> 
> BTW, I've drilled hundreds of holes on this or that workpiece with #97
> (.0059") drill bits and have yet to bust. Any sort of runout problem
> would probably snap these, but I'm guessing only.
> 
> Let me ask you a couple of questions, Roy. What are the narrowest
> traces that you would need to mill on a PCB surface (am I thinking of
> a copper-clad PCB ready for etching)? In between traces, what are the
> narrowest clear areas required; that is, what is the minimum
> separation required between traces?
> 
> Did I answer your questions?
> 
> -Brian
> 
> Brian Chapman
> Evansdale, Iowa
> 
> PS - I'm hoping, once Curt comes back from the holiday, he can advise
> me whether or not I can easily adapt the CNC Sherline mill for use as
> part of the EDM system I'm intending to assemble. 
> 
> The EDM plans I have include a logic board for driving the EDM head,
> but I wonder if I can't build the power side of the EDM system only
> and use the mill and CNC software for the rest. . . . I'm way over my
> head at the moment, but I hope to break the surface and tread water
> while I look around and figure out what to do next. <g
> 
> 
> ---
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
> 
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
>

On Monday 04 July 2005 12:19 pm, Brian Chapman wrote:
> > Can you give me a rough idea of what sort of considerations are
> > involved in the machine to work at that kind of scale? I don't think
> > I've ever seen a  mill that small and my drill bits only go to #80.
> >
> > :-) I guess spindle runout is a major factor there? <
>
> Roy, sure, trying to stump me right off the bat, eh? <g

Nah.  I'm *real* new at a lot of this stuff...

> I purchased a Sherline tabletop mill and lathe and later converted
> them to CNC using a "turnkey" system from FlashCut. (www.sherline.com)

Ok.  I'm still thinking DIY here,  but we'll see where things end up,  
eventually.  I'm in no hurry,  and don't have the money to spend on that 
stuff anyhow.

> The Sherline machines, roughly, each are the size of a sewing machine
> and are driven with an IBM 600e laptop I purchased used.

I think I saw one or two at that Cabin Fever Expo a while back.

> I bought Sherline because, when shopping, all the various reviews I
> read were glowing about the quality of the machines. Perhaps as
> importantly, I bought Sherline's "ultimate" package that included,
> among other things, quality accessories such as Jacobs chucks and also
> quality collets. Quality accessories, as I understand it, have much to
> do with a machine's cutting accuracy.
>
> I use collets only with miniature cutting tools; I've read that
> collets provide greater accuracy than chucks.
>
> I'm a member of the yahoo SherlineCNC list

I carry it here as well,  but don't find much to contribute just yet.  :-)

> (http://groups.yahoo.com/group/SherlineCNC/?yguid=225428826), and
> spindle runout is seldom mentioned there as a problem. More likely,
> threads will deal with problems such as Z axis backlash compensation
> and the limitations of leadscrews vs. ballscrews. A number of smart
> and talented Sherline owners have documented, and posted at the site,
>  machine upgrades that they've developed.
>
> But, I don't think spindle runout is a problem. Let me give you an
> example. I have milled a negative mold of the side of a 40-foot long
> highway trailer in 1:87 scale (about 5-3/8" x 1-3/16"). Within this
> space are about 40 horizontal corrugations (grooves) that I cut, iirc,
> with a .012" ball mill.

That's SMALL!

> In between each corrugation (a space also .012" wide), in vertical
> strips, are rivets drilled with a .005" end mill (about 36 vertical
> rows, or more than 1400 rivets). Each rivet is precisely placed; none
> "slide" into the corrugations. To me, this is the kind of accuracy I
> require -- and get -- from this tabeltop unit.

Cool.

> BTW, I've drilled hundreds of holes on this or that workpiece with #97
> (.0059") drill bits and have yet to bust. Any sort of runout problem
> would probably snap these, but I'm guessing only.

I would think so,  yeah.  What kind of z-axis feed rates are you using there 
for that stuff?

> Let me ask you a couple of questions, Roy. What are the narrowest
> traces that you would need to mill on a PCB surface (am I thinking of
> a copper-clad PCB ready for etching)? In between traces, what are the
> narrowest clear areas required; that is, what is the minimum
> separation required between traces?

I'm not real sure,  to tell you the truth.  A lot of hobbyists are going 
headlong into teeny little surface mount stuff,  and I've decided that 
anything I'm going to build isn't going to involve anything like that.  My 
eyesight just ain't what it used to be,  among other things.  Sometimes 
lately when I'm scavenging parts I think my fingers have gotten bigger,  too.  
So figure 0.1" pin spacing,  and *maybe* a trace would need to run between 
two pads there,  but that's not too likely to be common.  I'm looking at 
fairly simple stuff overall.

> Did I answer your questions?

Sure.

> -Brian
>
> Brian Chapman
> Evansdale, Iowa
>
> PS - I'm hoping, once Curt comes back from the holiday, he can advise
> me whether or not I can easily adapt the CNC Sherline mill for use as
> part of the EDM system I'm intending to assemble.

There's another area I know next to nothing about.  It wasn't until reading 
posts in the past few days or so that I was aware of that stuff being done 
with the work immersed in some kind of fluid...

> The EDM plans I have include a logic board for driving the EDM head,
> but I wonder if I can't build the power side of the EDM system only
> and use the mill and CNC software for the rest. . . . I'm way over my
> head at the moment, but I hope to break the surface and tread water
> while I look around and figure out what to do next. <g

I don't see offhand why that wouldn't work...

Hi Ed,

Thanks, but is there any chance I could persuade you to do a close 
up photo showing a lot of detail.

Thanks!

Much appreciated.

Chris



--- In Homebrew_PCBs@yahoogroups.com, edrupp <edrupp@v...> wrote:
> I have a couple of photos of my milled PC boards at my robot clubs 
web 
> site.  I should post more some day. I've been milling PCBs for 
years and 
> have gotten good results
> 
> http://frontrangerobotics.org/UltraSonic/
> 
> 
>   - Edward Rupp
> 
> 
> 
> Brian Chapman wrote:
> >>Can you give me a rough idea of what sort of considerations are
> > 
> > involved in the machine to work at that kind of scale? I don't 
think
> > I've ever seen a  mill that small and my drill bits only go to 
#80. 
> > :-) I guess spindle runout is a major factor there? <
> > 
> > Roy, sure, trying to stump me right off the bat, eh? <g
> > 
> > I purchased a Sherline tabletop mill and lathe and later 
converted
> > them to CNC using a "turnkey" system from FlashCut. 
(www.sherline.com)
> > 
> > The Sherline machines, roughly, each are the size of a sewing 
machine
> > and are driven with an IBM 600e laptop I purchased used. 
> > 
> > I bought Sherline because, when shopping, all the various 
reviews I
> > read were glowing about the quality of the machines. Perhaps as
> > importantly, I bought Sherline's "ultimate" package that 
included,
> > among other things, quality accessories such as Jacobs chucks 
and also
> > quality collets. Quality accessories, as I understand it, have 
much to
> > do with a machine's cutting accuracy.
> > 
> > I use collets only with miniature cutting tools; I've read that
> > collets provide greater accuracy than chucks.
> > 
> > I'm a member of the yahoo SherlineCNC list
> > (http://groups.yahoo.com/group/SherlineCNC/?yguid=225428826), and
> > spindle runout is seldom mentioned there as a problem. More 
likely,
> > threads will deal with problems such as Z axis backlash 
compensation
> > and the limitations of leadscrews vs. ballscrews. A number of 
smart
> > and talented Sherline owners have documented, and posted at the 
site,
> >  machine upgrades that they've developed.
> > 
> > But, I don't think spindle runout is a problem. Let me give you 
an
> > example. I have milled a negative mold of the side of a 40-foot 
long
> > highway trailer in 1:87 scale (about 5-3/8" x 1-3/16"). Within 
this
> > space are about 40 horizontal corrugations (grooves) that I cut, 
iirc,
> > with a .012" ball mill. 
> > 
> > In between each corrugation (a space also .012" wide), in 
vertical
> > strips, are rivets drilled with a .005" end mill (about 36 
vertical
> > rows, or more than 1400 rivets). Each rivet is precisely placed; 
none
> > "slide" into the corrugations. To me, this is the kind of 
accuracy I
> > require -- and get -- from this tabeltop unit.
> > 
> > BTW, I've drilled hundreds of holes on this or that workpiece 
with #97
> > (.0059") drill bits and have yet to bust. Any sort of runout 
problem
> > would probably snap these, but I'm guessing only.
> > 
> > Let me ask you a couple of questions, Roy. What are the narrowest
> > traces that you would need to mill on a PCB surface (am I 
thinking of
> > a copper-clad PCB ready for etching)? In between traces, what 
are the
> > narrowest clear areas required; that is, what is the minimum
> > separation required between traces?
> > 
> > Did I answer your questions?
> > 
> > -Brian
> > 
> > Brian Chapman
> > Evansdale, Iowa
> > 
> > PS - I'm hoping, once Curt comes back from the holiday, he can 
advise
> > me whether or not I can easily adapt the CNC Sherline mill for 
use as
> > part of the EDM system I'm intending to assemble. 
> > 
> > The EDM plans I have include a logic board for driving the EDM 
head,
> > but I wonder if I can't build the power side of the EDM system 
only
> > and use the mill and CNC software for the rest. . . . I'm way 
over my
> > head at the moment, but I hope to break the surface and tread 
water
> > while I look around and figure out what to do next. <g
> > 
> > 
> > ---
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > Be sure to visit the group home and check for new Links, Files, 
and Photos:

> > http://groups.yahoo.com/group/Homebrew_PCBs
> > 
> > If Files or Photos are running short of space, post them here:
> > http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> > Yahoo! Groups Links
> > 
> > 
> > 
> >  
> > 
> > 
> >