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:
>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
>
>
>