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CNC milling

CNC milling

2011-05-12 by kz1927

Hi All,

First thing...my apologies to anyone Not interested.
(I know there are many....;)

I used to make the Fireball CNC machines. That actually
began here on this group back in 2006. Many small desktop
machines were made, but demand was for more cutting space
and larger machines.

The larger a machine became, the more of a "general purpose"
machine it also became.....in order to stay as inexpensive
as possible.

"General purpose" meaning that even the slightest flexibilty
or play in a machine will often translate to limits of what
can be done with the tiny little (brittle) carbide bits often
used for PCB work.

Demand was pretty good for the Fireball V90 machine. It's
capable of doing some very good PCB work and there are many
examples of them on the internet. Demand was enough that I
wasn't able to keep up...as a one person maker of them...so
Fireballcnc was sold to someone better able to produce them.
Probotix.com

But, I was still intensely interested in the small machine that
could do extremely fine work. My purposes were for making jewelry
parts with very, very fine detail in them...I didn't and still
don't use them for PCB work. It's a thing I just never had time for.
But I did need as fine of detail as I could possibly get from
any cnc machine...that'd be anywhere near affordable for me.

I always have liked the smaller, more compact machine sizes and
I find them more practical. So, I'm back to making something as
close to a CNC "PCB machine" as I can get.

Smaller machines aren't as popular as larger ones, so it works
out well enough that I can put more time and attention in each
of the machines I'm making now.

My new machine...called "A4" due to it's cutting area being near the
size of a common sheet of printer paper has very high potential
for very fine trace PCB work with a design intended for rigidity and
strength.

Metal elements are incorporated throughout, but it still keeps
the MDF basic frame, which is very beneficial for damping vibrations
and resonances that can be problematic in all-metal designs....I have
made/tried all-metal machines repeatedly over the years.

A more rigid Z axis is also used. It's capable of handling any trim
router as well as the finer spindles for super fine work such as
the Paul Jones and the Wolfgang Engineering spindles.

As far as an affordable machine that may be excellent for PCB milling
and also handling heavier duty tasks like enclosure work, I believe
it's as good of a machine as can be found. The goal in it's making
has been as fine of work as can be coaxed from any inexpensive
solution for very fine milling.

I will add that it's not an automatic or easy thing to do. It takes
a lot of practice to learn software, feed rates, spindle speeds,
how to choose a "right" cutting bit. But with patience and determination,
the machine can do as fine of milling of many materials as I'm able
to get them to do.

Fireballcnc began right here at Homebrew_PCBs. It's turned out to
be a genuine success. I myself have no more part of it, but I still
love making the smaller...though less popular...machines. I've always
thought they were better suited for the finer work I needed from
a cnc machine. So, I'm starting something new and beginning to
produce some of these machines now that a design has been tested
for a while and "finalized". The machine is called "Microcarve A4"

Anyone interested can see it's progression...a very long thread...
at cnczone....

http://www.cnczone.com/forums/diy-cnc_router_table_machines/109390-my_newest_desktop_machine.html

Also beginning a Yahoo group for the machines...

http://groups.yahoo.com/group/microcarve/

Once again, I apologize to those who aren't interested.
Thanks for your patience....

:)
John Hansford

Re: CNC milling

2011-05-12 by AlienRelics

Nice looking machine! Good to see you back, John.

Steve Greenfield AE7HD

--- In Homebrew_PCBs@yahoogroups.com, "kz1927" <kz1927@...> wrote:
Show quoted textHide quoted text
>
> Hi All,
> 
> First thing...my apologies to anyone Not interested.
> (I know there are many....;)
> 
> I used to make the Fireball CNC machines. That actually
> began here on this group back in 2006. Many small desktop
> machines were made, but demand was for more cutting space
> and larger machines.
> 
> The larger a machine became, the more of a "general purpose"
> machine it also became.....in order to stay as inexpensive
> as possible.
> 
> "General purpose" meaning that even the slightest flexibilty
> or play in a machine will often translate to limits of what
> can be done with the tiny little (brittle) carbide bits often
> used for PCB work.
> 
> Demand was pretty good for the Fireball V90 machine. It's
> capable of doing some very good PCB work and there are many
> examples of them on the internet. Demand was enough that I
> wasn't able to keep up...as a one person maker of them...so
> Fireballcnc was sold to someone better able to produce them.
> Probotix.com
> 
> But, I was still intensely interested in the small machine that
> could do extremely fine work. My purposes were for making jewelry
> parts with very, very fine detail in them...I didn't and still
> don't use them for PCB work. It's a thing I just never had time for.
> But I did need as fine of detail as I could possibly get from
> any cnc machine...that'd be anywhere near affordable for me.
> 
> I always have liked the smaller, more compact machine sizes and
> I find them more practical. So, I'm back to making something as
> close to a CNC "PCB machine" as I can get.
> 
> Smaller machines aren't as popular as larger ones, so it works
> out well enough that I can put more time and attention in each
> of the machines I'm making now.
> 
> My new machine...called "A4" due to it's cutting area being near the
> size of a common sheet of printer paper has very high potential
> for very fine trace PCB work with a design intended for rigidity and
> strength.
> 
> Metal elements are incorporated throughout, but it still keeps
> the MDF basic frame, which is very beneficial for damping vibrations
> and resonances that can be problematic in all-metal designs....I have
> made/tried all-metal machines repeatedly over the years.
> 
> A more rigid Z axis is also used. It's capable of handling any trim
> router as well as the finer spindles for super fine work such as
> the Paul Jones and the Wolfgang Engineering spindles.
> 
> As far as an affordable machine that may be excellent for PCB milling
> and also handling heavier duty tasks like enclosure work, I believe
> it's as good of a machine as can be found. The goal in it's making
> has been as fine of work as can be coaxed from any inexpensive
> solution for very fine milling.
> 
> I will add that it's not an automatic or easy thing to do. It takes
> a lot of practice to learn software, feed rates, spindle speeds,
> how to choose a "right" cutting bit. But with patience and determination,
> the machine can do as fine of milling of many materials as I'm able
> to get them to do.
> 
> Fireballcnc began right here at Homebrew_PCBs. It's turned out to
> be a genuine success. I myself have no more part of it, but I still
> love making the smaller...though less popular...machines. I've always
> thought they were better suited for the finer work I needed from
> a cnc machine. So, I'm starting something new and beginning to
> produce some of these machines now that a design has been tested
> for a while and "finalized". The machine is called "Microcarve A4"
> 
> Anyone interested can see it's progression...a very long thread...
> at cnczone....
> 
> http://www.cnczone.com/forums/diy-cnc_router_table_machines/109390-my_newest_desktop_machine.html
> 
> Also beginning a Yahoo group for the machines...
> 
> http://groups.yahoo.com/group/microcarve/
> 
> Once again, I apologize to those who aren't interested.
> Thanks for your patience....
> 
> :)
> John Hansford
>

Re: CNC milling

2011-05-12 by cnc739

Thanks Steve!

I've spent a lot of time tinkering and refining
those small machines, and I think I've about got it
down pretty good...:)

Here's one all painted up with an extended Z on it....
intended for someone who'll put one of those rep-rap
type extruder heads on it...just to see if it will work...;)

http://www.microcarve.com/personal/johng/jg-015.jpg

Lots of pictures there....

http://www.microcarve.com/personal/

:)
John





--- In Homebrew_PCBs@yahoogroups.com, "AlienRelics" <alienrelics@...> wrote:
Show quoted textHide quoted text
>
> Nice looking machine! Good to see you back, John.
> 
> Steve Greenfield AE7HD
> 
> --- In Homebrew_PCBs@yahoogroups.com, "kz1927" <kz1927@> wrote:
> >
> > Hi All,
> > 
> > First thing...my apologies to anyone Not interested.
> > (I know there are many....;)
> > 
> > I used to make the Fireball CNC machines. That actually
> > began here on this group back in 2006. Many small desktop
> > machines were made, but demand was for more cutting space
> > and larger machines.
> > 
> > The larger a machine became, the more of a "general purpose"
> > machine it also became.....in order to stay as inexpensive
> > as possible.
> > 
> > "General purpose" meaning that even the slightest flexibilty
> > or play in a machine will often translate to limits of what
> > can be done with the tiny little (brittle) carbide bits often
> > used for PCB work.
> > 
> > Demand was pretty good for the Fireball V90 machine. It's
> > capable of doing some very good PCB work and there are many
> > examples of them on the internet. Demand was enough that I
> > wasn't able to keep up...as a one person maker of them...so
> > Fireballcnc was sold to someone better able to produce them.
> > Probotix.com
> > 
> > But, I was still intensely interested in the small machine that
> > could do extremely fine work. My purposes were for making jewelry
> > parts with very, very fine detail in them...I didn't and still
> > don't use them for PCB work. It's a thing I just never had time for.
> > But I did need as fine of detail as I could possibly get from
> > any cnc machine...that'd be anywhere near affordable for me.
> > 
> > I always have liked the smaller, more compact machine sizes and
> > I find them more practical. So, I'm back to making something as
> > close to a CNC "PCB machine" as I can get.
> > 
> > Smaller machines aren't as popular as larger ones, so it works
> > out well enough that I can put more time and attention in each
> > of the machines I'm making now.
> > 
> > My new machine...called "A4" due to it's cutting area being near the
> > size of a common sheet of printer paper has very high potential
> > for very fine trace PCB work with a design intended for rigidity and
> > strength.
> > 
> > Metal elements are incorporated throughout, but it still keeps
> > the MDF basic frame, which is very beneficial for damping vibrations
> > and resonances that can be problematic in all-metal designs....I have
> > made/tried all-metal machines repeatedly over the years.
> > 
> > A more rigid Z axis is also used. It's capable of handling any trim
> > router as well as the finer spindles for super fine work such as
> > the Paul Jones and the Wolfgang Engineering spindles.
> > 
> > As far as an affordable machine that may be excellent for PCB milling
> > and also handling heavier duty tasks like enclosure work, I believe
> > it's as good of a machine as can be found. The goal in it's making
> > has been as fine of work as can be coaxed from any inexpensive
> > solution for very fine milling.
> > 
> > I will add that it's not an automatic or easy thing to do. It takes
> > a lot of practice to learn software, feed rates, spindle speeds,
> > how to choose a "right" cutting bit. But with patience and determination,
> > the machine can do as fine of milling of many materials as I'm able
> > to get them to do.
> > 
> > Fireballcnc began right here at Homebrew_PCBs. It's turned out to
> > be a genuine success. I myself have no more part of it, but I still
> > love making the smaller...though less popular...machines. I've always
> > thought they were better suited for the finer work I needed from
> > a cnc machine. So, I'm starting something new and beginning to
> > produce some of these machines now that a design has been tested
> > for a while and "finalized". The machine is called "Microcarve A4"
> > 
> > Anyone interested can see it's progression...a very long thread...
> > at cnczone....
> > 
> > http://www.cnczone.com/forums/diy-cnc_router_table_machines/109390-my_newest_desktop_machine.html
> > 
> > Also beginning a Yahoo group for the machines...
> > 
> > http://groups.yahoo.com/group/microcarve/
> > 
> > Once again, I apologize to those who aren't interested.
> > Thanks for your patience....
> > 
> > :)
> > John Hansford
> >
>

Re: [Homebrew_PCBs] CNC milling

2011-05-12 by DJ Delorie

Sweet.

I've been pondering CNC recently, and offer some thoughts...

Would it help to have two drive screws per axis, to avoid racking?  My
router lift works that way.  Put them on opposite sides of the load for
the Z axis.

Have you looked at the Harbor Freight 1/8" air-driven grinder, as a
spindle?  I'm wondering if high speed air spindles would have less
runout than, say, a dremel.

Your Y-axis has upper and lower guides, with the load cantilevered off
the side.  Have you considered supporting the Y-axis the same as the X
axis, with a sort of table to mount the load on?

Re: CNC milling

2011-05-12 by cnc739

Thanks!

:)

No racking is possible...fixed bridge/gantry design.
That's one of those details I really like about this
style of machine.

Air spindles...I never bothered, because of the sheer
amount of noise my compressor makes. But the Paul Jones
or the Wolfgang Engineering spindles are quiet...though
low powered..and are really intended for PCB work.

You can bolt on a Bosch Colt for milling enclosures. Pretty
tough router...:)

Several/many designs have been tested, so the way it is now
turned out to be the most practical. They could even have
true linear rails installed, but nothing really is gained
with the relatively small size of the machine.

Here's a high res picture of some ultra fine detail. The
carving in reality is only less than 1" in size.
.003" stepover IIRC....

http://www.microcarve.com/zone12/mib_large/mib2222%20005.jpg

:)
John



--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
Show quoted textHide quoted text
>
> 
> Sweet.
> 
> I've been pondering CNC recently, and offer some thoughts...
> 
> Would it help to have two drive screws per axis, to avoid racking?  My
> router lift works that way.  Put them on opposite sides of the load for
> the Z axis.
> 
> Have you looked at the Harbor Freight 1/8" air-driven grinder, as a
> spindle?  I'm wondering if high speed air spindles would have less
> runout than, say, a dremel.
> 
> Your Y-axis has upper and lower guides, with the load cantilevered off
> the side.  Have you considered supporting the Y-axis the same as the X
> axis, with a sort of table to mount the load on?
>

Re: CNC milling

2011-05-12 by kz1927

Answers are coming up....I'm switching some Yahoo
accounts today to get some things up to date. I made a reply,
but I'm still on moderated status with the new account.

My new account name is cnc739

:)
John



--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
Show quoted textHide quoted text
>
> 
> Sweet.
> 
> I've been pondering CNC recently, and offer some thoughts...
> 
> Would it help to have two drive screws per axis, to avoid racking?  My
> router lift works that way.  Put them on opposite sides of the load for
> the Z axis.
> 
> Have you looked at the Harbor Freight 1/8" air-driven grinder, as a
> spindle?  I'm wondering if high speed air spindles would have less
> runout than, say, a dremel.
> 
> Your Y-axis has upper and lower guides, with the load cantilevered off
> the side.  Have you considered supporting the Y-axis the same as the X
> axis, with a sort of table to mount the load on?
>

Re: [Homebrew_PCBs] CNC milling

2011-05-12 by Mark Lerman

My biggest problem with cnc of pcbs, especially with triangular bits 
is that the pcb material is not even thickness, and more importantly 
does not lie flat. This causes traces to be uneven, areas to be not 
cut at all, and some gouges. The better pcb routers "test" the board 
before cutting and compensate for these things as they cut.

Mark



At 01:10 PM 5/12/2011, you wrote:
Show quoted textHide quoted text
>Hi All,
>
>First thing...my apologies to anyone Not interested.
>(I know there are many....;)
>
>I used to make the Fireball CNC machines. That actually
>began here on this group back in 2006. Many small desktop
>machines were made, but demand was for more cutting space
>and larger machines.
>
>The larger a machine became, the more of a "general purpose"
>machine it also became.....in order to stay as inexpensive
>as possible.
>
>"General purpose" meaning that even the slightest flexibilty
>or play in a machine will often translate to limits of what
>can be done with the tiny little (brittle) carbide bits often
>used for PCB work.
>
>Demand was pretty good for the Fireball V90 machine. It's
>capable of doing some very good PCB work and there are many
>examples of them on the internet. Demand was enough that I
>wasn't able to keep up...as a one person maker of them...so
>Fireballcnc was sold to someone better able to produce them.
>Probotix.com
>
>But, I was still intensely interested in the small machine that
>could do extremely fine work. My purposes were for making jewelry
>parts with very, very fine detail in them...I didn't and still
>don't use them for PCB work. It's a thing I just never had time for.
>But I did need as fine of detail as I could possibly get from
>any cnc machine...that'd be anywhere near affordable for me.
>
>I always have liked the smaller, more compact machine sizes and
>I find them more practical. So, I'm back to making something as
>close to a CNC "PCB machine" as I can get.
>
>Smaller machines aren't as popular as larger ones, so it works
>out well enough that I can put more time and attention in each
>of the machines I'm making now.
>
>My new machine...called "A4" due to it's cutting area being near the
>size of a common sheet of printer paper has very high potential
>for very fine trace PCB work with a design intended for rigidity and
>strength.
>
>Metal elements are incorporated throughout, but it still keeps
>the MDF basic frame, which is very beneficial for damping vibrations
>and resonances that can be problematic in all-metal designs....I have
>made/tried all-metal machines repeatedly over the years.
>
>A more rigid Z axis is also used. It's capable of handling any trim
>router as well as the finer spindles for super fine work such as
>the Paul Jones and the Wolfgang Engineering spindles.
>
>As far as an affordable machine that may be excellent for PCB milling
>and also handling heavier duty tasks like enclosure work, I believe
>it's as good of a machine as can be found. The goal in it's making
>has been as fine of work as can be coaxed from any inexpensive
>solution for very fine milling.
>
>I will add that it's not an automatic or easy thing to do. It takes
>a lot of practice to learn software, feed rates, spindle speeds,
>how to choose a "right" cutting bit. But with patience and determination,
>the machine can do as fine of milling of many materials as I'm able
>to get them to do.
>
>Fireballcnc began right here at Homebrew_PCBs. It's turned out to
>be a genuine success. I myself have no more part of it, but I still
>love making the smaller...though less popular...machines. I've always
>thought they were better suited for the finer work I needed from
>a cnc machine. So, I'm starting something new and beginning to
>produce some of these machines now that a design has been tested
>for a while and "finalized". The machine is called "Microcarve A4"
>
>Anyone interested can see it's progression...a very long thread...
>at cnczone....
>
>http://www.cnczone.com/forums/diy-cnc_router_table_machines/109390-my_newest_desktop_machine.html
>
>Also beginning a Yahoo group for the machines...
>
>http://groups.yahoo.com/group/microcarve/
>
>Once again, I apologize to those who aren't interested.
>Thanks for your patience....
>
>:)
>John Hansford
>
>
>
>
>
>------------------------------------
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

Re: CNC milling

2011-05-12 by cnc739

I agree with you. But those better machines are a bit
more than $439....;)

But again, I haven't milled any circuit board material...
still yet...because of those very concerns. It's a thing
that'll take a good bit of practice to get good at.

I do think, though, that I've come up with a pretty good
fixture idea that should work very well.

Here's the finest example I've seen at cnc milling on
one of my early machines....

http://www.youtube.com/watch?v=lhdqBrciQZU

Phil CA glues the board to the thick aluminum plate. To
be released later with some acetone.

The fixture I have in mind would be a, say, 1/2" thick
aluminum plate, but it'd have a layer of 1" thick cast
urethane on top of it as the work surface.

The aluminum plate would allow repeated fixturing without
distortion of the urethane.

(Castable urethane...similar to acrylic in hardness, but it
doesn't melt like acrylic plastics can. Machines like a dream.

http://www.alumilite.com/ProdDetail.cfm?Category=Casting%20Resins&Name=Alumilite%20Regular

)


The urethane layer would be planed/leveled relative to the
bridge. The board glued in place with a tiny bit of CA
glue...no more than is needed.

The urethane is very chemical resistant, so the board can
be released like in the video....maybe have some grooves cut
into the surface to allow the acetone to flow underneath
the PCB easily.

Reason for the urethane is that it's Much easier to machine
than if it were aluminum. It can be replaced...or even resurfaced
as urethane sticks extremely well to itself.

It can be drilled into with no wear or damage to the cutter/bit.
And can be re-leveled to be perfectly flat relative to the bridge
repeatedly if need be. Even pockets can be made as registration
places for repeated alignment of successive copies of a milled
board.

When I run across someone who's getting good at milling
PCB's, I'll make them one to test and see where it needs to
go from there. I think that's as near perfect of an as needed
dead flat surface as can be inexpensively produced. Until it
gets refined anyways....;)

I'd expect it to work very well.

:)
John
Show quoted textHide quoted text
> My biggest problem with cnc of pcbs, especially with triangular bits 
> is that the pcb material is not even thickness, and more importantly 
> does not lie flat. This causes traces to be uneven, areas to be not 
> cut at all, and some gouges. The better pcb routers "test" the board 
> before cutting and compensate for these things as they cut.
> 
> Mark

Re: [Homebrew_PCBs] CNC milling

2011-05-12 by Simon Gornall

On 12 May 2011, at 14:36, Mark Lerman wrote:

> 
> My biggest problem with cnc of pcbs, especially with triangular bits 
> is that the pcb material is not even thickness, and more importantly 
> does not lie flat. This causes traces to be uneven, areas to be not 
> cut at all, and some gouges. The better pcb routers "test" the board 
> before cutting and compensate for these things as they cut.
> 
> 
> 

I have one of those CNC machines (an EverPrecision EP2002H in fact - see http://everprecision.com/e-epseries-3.html, the EP2002 and EP2006 have the same specs as far as I know), and it really can do 6 mil trace/space accurately (4 is pushing it. It can do that on a good day). Even with the machine running a grid-test before starting the engrave process, though, you can still have a (severely) warped board cause you problems. 

The way the machine tests the depth is to connect a GND wire to the copper surface, then scan a (typically 1cm spacing) grid across the work-area and as the tip of the carve-tool touches the copper, a circuit is completed and the machine records the Z value of the tool at that point on the grid. Most of the time this works great. Sometimes I get copper-plated FR4 that is so warped that this is defeated - we're talking a few mm of deflection in the middle of the board, with the board bowing up, for example. Since the circuit is made at the instant of touch, the bow is never removed, but when you come to engrave, there's more downwards pressure, and the bow deflects and insufficient copper is removed by the tool.

I've always thought another aid would be a vacuum table underneath the PCB - if the PCB is actively being sucked down onto the platform it would remove the bow and make the depth-measurement far more accurate. My suspicion is that a vacuum table would in fact work just as well as the copper-sensing approach I have now, so if you put one of those on a standard CNC, you might end up with a pretty darn accurate surface, and hence a pretty darn accurate PCB.

One of these days, I'll get around to using the K2 CNC machine to mill out a vacuum table for the PCB plotter. One of the side-benefits of the electrical-contact approach is that the tools have their height-above-zero auto-detected, so adding a (thin) vacuum table ought to be feasible.

[warning: Rant mode on]

One thing: DO NOT BUY the EP200x machines - they're absolutely fantastic at what they do, but the service completely sucks. The current dealer won't upgrade my software (even for an additional cost) on the machine I have because I bought it from the previous dealer. Ever-Precision themselves (in China) don't seem to care either. The software I have is buggy (presumably because it's an older version now) and even reporting bugs to them in the hope of a limited fix didn't get me anywhere. I now have a $10k machine that can't be upgraded...

Example of one of the bugs in the software: if you have a pad that is a hexagon rather than a circle/square, the PCAM software will "rub out" the entire hexagon. Looking at the gerbers in gerbview shows the hexagon is fine, and inspecting the gerber file shows that the CAD software (Eagle) uses a different style of macro for hexagons... That style of macro doesn't seem to be supported by PCAM, and since I can't upgrade the software, all I can do is transform hex pads to circles (luckily Eagle can do this automatically. It sucks to be 75% of the way through a two-hour job when you realize you didn't do it this time, though; unluckily, Eagle uses hex pads for pretty much any pin-header so it's something I'm constantly having to remember to do).

[/rant]

There's a couple of other things to consider. You don't get plated-through holes, so your designs for home will probably be different to anything you send out to a PCB - to make sure vias are reachable, and soldering is mainly on the bottom-side of the PCB for example. This isn't any different to etching, but it's worth bearing in mind that this isn't a complete replacement for a PCB house.

On the plus-side, the machine does all the drilling of holes for you as well - and if you have holes that are too big for any drill you have, it can interpolate a router-bit  in a circle to make that hole. It can also route out any shape of PCB, which is occasionally useful to me.

Bottom line: even with the crappy service, and even though I could never in conscience recommend the company, I still love my EP2002. Being able to reliably turn around a 2-sided PCB in an hour or so is, well, brilliant. I never managed to quite get the chemicals method down, so it was still a bit hit & miss with etching for me. The router is worth its weight in gold, it just irks me that the company's attitude spoils it.

Simon



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