Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Personally i think a direct drive brushless motor is the way to go for
these speeds.

Also i think you need to pre-load the bearings to reduce runout. And i
would select oil lubricated bearings over grease lubricated ones.

I may be wrong i am not a mechanical engineer.

ST


On Mon, Jan 19, 2009 at 9:32 PM, Simão Pedro Cardoso
<simaocardoso@...> wrote:

> Hi,
>
> Is very difficult to find a pcb spindle. Drilling a pcb hole of 0.5mm in
> a FR4 laminate needs carbide tools and 50.000rpm spindle. This things
> cost more than all other things to make a good CNC router.
> I have found a away, but still didn't make/test the thing. From this
> great sites (and thanks to them)
> http://www.cnconabudget.com/dan_d.JPG
> http://www.buildyouridea.com/cnc/spindle_05/spindle_05.html
> http://www.cncathome.com/spindles.html
> http://www.students.tut.fi/~kontkant/jv2.php.html
> http://members.home.nl/zoltar/CNC/classicsystem/10%20euro%20frase.pdf
>
> I think to have found a way to do my 50.000rpm or more (i think i can
> get 80.000rpm) pcb spindle.
> Using this tool from ebay seller (he made the tool from my request!!)
> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=110329201156
>
> And high speed skate bearing or better like this
> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=400000902567
>
> And a AC brushed (universal) motor from a electric wood plane. It has a
> 30.000rpm motor and a 2:1 or similar reduction that can be inverted to
> give 60.000rpm, using the same timing belt and pulleys.
>
> Do you think it will work nice? I have made a circuit to pwm control the
> motor speed. And i think if i give DC to the motor it will run in lot
> more than 30.000rpm.
>
> I want to post the circuit online, but which cnzone forum pcb spindles
> should go?
>
> Simao
>