Homebrew PCBs

On Sat, 16 Aug 2014 08:51:49 -0400, you wrote:

>Thanks, Harvey, for the detailed description - Very interesting 
>setup. One of these days I'll work on something similar, though I 
>rarely drill a lot of holes. I use almost exclusively smt and usually 
>make single sided pcbs using zero ohm resistors as jumpers.
>

I do double sided boards, with the boards made from two .021 boards
epoxied together (use 1 hour epoxy!).  Alignment is very critical and
the drilling setup (finally!) makes that work a lot better.  Since I'm
doing 64/100/144 pin TQFP chips, I can't live with the luxury of
exclusively resistive jumpers.

Latest project involves a graphics panel driver with an S1D13781
graphics chip (Epson, anyone wanting to use it please talk to me,
there are some non-obvious things you need to do to make it work). an
Xmega, a touch panel controller, -24 volt supply, I2C communications
(dual channel).

Harvey

>Mark
>
>
>At 06:50 PM 8/15/2014, you wrote:
>>On Fri, 15 Aug 2014 12:52:18 -0400, you wrote:
>>
>> >Hello Harvey,
>> >
>> >I'm interested in getting more information on your drilling setup,
>> >mostly the optical stuff - camera, software, monitor. What supplies
>> >the reticule image for the crosshairs?
>>
>>OK, in short.  The optical stuff is a 12 volt/24vac camera with almost
>>any lens that works well.  You want to move it out away from the CCD
>>so that you have the equivalent of a closeup extender.
>>
>>That goes to a standard color monitor.  This is an LCD monitor that I
>>found (runs off 12 volts DC), and has an overlay with a graticule on
>>it.  I've been tempted to make it more complicated by adding a
>>crosshair generator, but that'd be another PC board and some video
>>work.  The graticule is easier.  Just make the pattern on a
>>transparency and put it over the monitor itself.  Almost any old TV
>>would work.
>>
>>The software is custom, and is a simple Z axis setup.  There are two
>>pushbuttons (green/red) and a rotary encoder with a push switch
>>(Electronics goldmine sold them).  There's an end travel (and top
>>travel) led sensor.
>>
>>Boot up, the display says to push green to home.  That homes the drill
>>and runs it up to the rest position.  pushing the footswitch (or the
>>green pushbutton) starts a drill cycle, three speeds possible, up to
>>the drill top position.  At that point the drill retreats back to the
>>rest position and turns off the Proxxon tool (solid state relay, works
>>better with the 12 volt model and transformer).
>>
>>Pushing the red button puts the drill at the top position, which is
>>where I can change the bit from the top.
>>
>>Pushing in the rotary switch/encoder put it into an adjust mode, where
>>I can set the rest and top positions (stored in the processor's
>>eprom).
>>
>>Basically, the software is not all that complicated, but does rely on
>>an infrastructure of display drivers (it's a smart display that I
>>built), a modified keyboard driver package, and a few other bits and
>>pieces.
>>
>>Physically, the camera is mounted on a PACE hot air station stand (I
>>managed to find two for not so much money), which gives me an
>>overarching arm for the camera.  I can move it up and down to focus
>>the camera and move it out of the way for drill change.  I suppose
>>another enhancement would be to put a stepper drive on that.
>>
>>You will have to align the camera center point to the tip of the
>>drill.  In my case, the adjustment is entirely mechanical, with the
>>camera swinging left/right on the mounting screw, but tilted (spring
>>used on screw) forwards/backwards as needed.  That's a trifle awkward,
>>and the electronic crosshair generator would be better.  That would
>>require a small CPLD, a sync separator, a synchronized pixel clock,
>>and some counters.  Ideally, the graticule has ticks on both axis
>>lines, since that helps align the center of large holes.
>>
>>The smallest hole I drill is 0.021 for a via, and I estimate that I
>>can repeat that hole to within 0.002 inches roughly.  The size of that
>>hole on the monitor is the critical part.
>>
>>You'll want to backlight the board.  Red light may be most useful, but
>>I haven't experimented with that yet.
>>
>>Hope that this helps.
>>
>>Harvey
>>
>>
>> >
>> >Thanks.
>> >
>> >Mark
>>
>>
>>
>>------------------------------------
>>Posted by: Harvey White <madyn@...>
>>------------------------------------
>>
>>Be sure to visit the group home and check for new Links, Files, and Photos:
>>http://groups.yahoo.com/group/Homebrew_PCBs
>>------------------------------------
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