Homebrew PCBs

On Tue, 16 Feb 2016 00:02:26 +0000, you wrote:

>Thanks for the advice Harvey...I'll look into the methods
>you suggested.

I have a very quiet vacuum, so it is on all the time with an air scoop
to remove the board swarf.


>
>Yeah, the swarf  from the board is a problem...have a vacuum
>at hand, but some kind of automatic "vac as you go" method
>would be best.

I have a very crude (but quite workable) air scoop made from the
crevice tool of a regular vacuum.  Works surprisingly well.

You can get very very close with a vertical alignment drill press, and
not so close when you have to match the hole at an extreme angle.

Harvey


>
>Charlie
>
>mosaicmerc@... [Homebrew_PCBs]"
>>> I use resharpened carbide in my dremel 395 with 1/8" shanks for PCB 
>>> work. They work fine....I go down to around 0.31 mm. I can go smaller 
>>> but bit breaking happens every 10 holes or so.
>> 
>>>Me too, but I rarely break bits since I switched to a home-brew drill
>>stand that seems to eliminate any "hand wobble" from causing breakage.
>> 
>>>My CNC machine can drill lots of holes with resharpened carbide and a
>>Grizzly pencil-style die grinder.
>> 
>>>Perhaps rigidity in the holding of the dremel is more important than
>>runout? Or at least, *lack* of rigidity is more common as a cause of
>>breakage?
>> 
>>>Posted by: DJ Delorie <dj@...>
>> 
>>I purchased a drill stand from Sears quite a few years ago. It
>>had run-out, but I cured that by tightening/adjusting all the
>>critical screws that caused the run-out. Works just fine since
>>then, and no breakage of carbide drill bits either. I'm using
>>a Dremmel with the collets, mostly the 1/8" size. I gotta say
>>though that the stand sure is CHEAPLY made....lots of plastic
>>parts. Once when using the stand, the sector gear that raises/lowers
>>the drill carriage broke!! (Cheap plastic!!!) I made another gear out
>>of some thick aluminum and it's been good ever since.
>> 
>>My bigest problem is positioning the PC board on the exact
>>center of the pads. My drilling is close but most of the time not
>>dead-on especially if the pad's center holes don't get etched
>>away. I installed a 12v light bulb under the stand and
>>that helps to illuminate the pad locations, but still.....
>
>You're looking at parallax as a problem. You're not looking straight
>down on where the hole should be.
>
>One option would be to put a webcam under the board, illuminate the
>bottom, and drill from there. Your only problem would be the swarf
>from the board.
>
>Mine is upside down, with the camera above and the drill from the
>bottom. It's a bit more complicated mechanically, and involves some
>programming and a stepper motor.
>
>However, a top drill press with a bottom view (and a vacuum sucking
>off the swarf) would be a possible good idea. 
>
>You drill from the side where the pads are. 
>
>A good set of movable crosshairs (if there's any play) and a test hole
>when the drill is changed ought to get you very very close.
>
>Harvey
>
>> 
>>On my drill stand I made a larger platform out of some
>>1/8" smooth hardboard so I could use a homebrew 
>>moveable fence that clamps to the edges of the hardboard. 
>>Using that sure made drilling easy when I needed to neatly drill 
>>holes in a row like for IC's.
>> 
>>Charlie
>
>
>
>
>
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>Posted by: Harvey White <madyn@...> 
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