PC board milling?

[Rob Seastrom]

Yeah, what Martin said...

I can *maybe* see doing this if I had "free" access to someone else's
expensive machine that had the accuracy *and* repeatability to exceed
my requirements (which are actually pretty tight if you don't want to
be frustrated with your QFP variants not lining up quite right), but
trying to get something for home use?

My big concern with a used training Sherline (which might or might not
have originally had the specs you need) is worn lead screws and/or
ways.  The lead screws at least can be easily replaced.  The ways, not
so much.

Given the race to the bottom on both pricing and time multi-layer
circuit board turn-around from China, I don't see a compelling case
for the milling machine.  Likewise, I've given up on the ferric
chloride and am never looking back - that stuff was yucky.

-r

Martin <dcmk1mr2 at gmail.com> writes:

> I had access to a Taig mini mill fully tricked out with nice steppers,
> electronics, software, etc.  I forget which software had it but some include
> the notion of registration holes that get milled first and are used to
> accurately align the PCB so that both sides match up.  I did get usable SMD
> and through hole PCBs.  I tried a lot of engraving mills and end mills but
> eventually gave up.  There was a lot if set up time and poor yields.  Maybe
> If I did more it would have gotten faster and more reliable.
>
>
>
> If I had the dollars to burn I'd look into one of
> these:Â [[https://othermachine.co/othermill/tech-specs/]] Â I believe there
> some write up about their design and how they hold their accuracy.
>
>
>
> Until then OSH Park [[https://oshpark.com/]] has 12 day turnaround, $15/square
> inch for 3 each two layer boards.
>
>
>
> 73 Martin W6MRR
>
>
>
> On Wed, Dec 30, 2015 at 10:23 PM, Terry Fox <[[tfox at knology.net]]> wrote:
>
>           Thanks sandy and Alex.  I think technology has moved forward
>      since then.  I heard the same comments about 3D printers, but my
>      experience is that the comments that I heard here about them were
>      based on older units.  I like my 3D printer, except that the vendor
>      is constantly moving forward with newer designs.  However, I can
>      get most parts from Amazon or eBay, so no worries.
>      
>      There are a lot of cnc mill designs out there, but many don't have
>      the accuracy for pc milling.  I'm pretty comfortable with steppers
>      and electronics for them now.  I'm not as comfortable with "MDF"
>      wood for some of the frames.
>      
>      Alex, is there a place of look on the Internet for used machines? 
>      A proper mechanical cnc that I could upgrade would save time.  I
>      already have a few nema23 steppers, controllers, and 24V supply from
>      other projects around here - mostly a magnetic loop antenna
>      controller project.  I'm not in any rush, as my interest is moving
>      faster than my budget allows!!
>      
>      But, the primary usage will be pc board work, so I need pretty tight
>      tolerances.  I'm familiar with rods and linear bearings, and acme
>      rods to some degree now!
>      Thanks & 73, Terry, N4TLF
>      
>      
>      Sent from tfox iPad
>      
>      
>      
>      Sent from tfox iPad
>      
>
>                > On Dec 31, 2015, at 12:43 AM, Nan and Sandy Sanders
>      <[[radiodog77 at pobox.com]]> wrote:
>      >
>      > Terry, I think we had an AMRAD meeting with a talk on PCB milling
>      with the conclusion being it works but not well. When we looked at
>      getting one for work it seemed like the biggest use was for RF
>      prototyping.
>      >Â  Â Sandy
>      >Â  WB5MMB
>      >
>      >
>      > At 10:53 PM 12/30/2015, Terry Fox wrote:
>      >> Hey guys, I am considering building or maybe buying an
>      inexpensive CNC milling machine that can make circuit boards, as a
>      2016 project.  I often design stuff, and then hand build a
>      prototype using point-to-point soldering.  It's getting old, and
>      doing grounds is not simple - even though I have a few techniques
>      for that. I've seen the prices of PC milling machines coming down,
>      but I thought that I would try my hand at building one instead. 
>      With my exposure to 3D printers, and reading up on a few homebrew
>      CNC machines and plans, I believe that I can build one that can do
>      through-hole and simple SMT devices, down to about 10 mil or so
>      traces/isolation runs.  For smaller parts, I would put the parts on
>      small commercial chip carriers, and add those to the layout.  I
>      don't need a huge 4x8ft mill, a smaller desktop unit would be
>      fine. Has anyone built a CNC milling machine that can SUCCESSFULLY
>      do PC boards? If so, what and how much?  Can it do double-sided
>      (lining up both sides)?  I plan to add many through-holes for vias
>      between layers. 73, & Happy New Year!! Terry, N4TLF
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