Thanks Tom , that makes it more clear. If its not too much
effort, I would like to see a few basic pics of the machine you
own. With Nawide machine having belt drive, what RPM did this run
at ? I'm curious, what do you think is a "good" RPM for manual
drilling around the 0.6mm - 1.5mm diameter range ?
I know your talking 100k RPM and above for the very large and
expensive Excellon CNC production drill machines.
Was it quick to change drill bits on these machines ? My guessing
is the spindle would feed far upwards so the collet pops up
through the flat panel giving you access to it.
Adam
twb8899 wrote:
> Adam,
>
> The Excellon Uni-Drill uses a dc motor and lead screw to move the
> spindle up and down. There is a series of adjustable limit switches
> to set the travel distance. The air operated clamping "foot" is
> between the optical scope and table surface and clamps the board
> before drilling to prevent movement that would break drill bits.
>
> When the foot switch is depressed the pressure foot clamps the board,
> spindle travels upward, drills through the panel, drill retracts and
> the clamp releases. You can watch the drill bit come through the
> board in the screen.
>
> The Nawide and Aetna machines use an air/hydraulic spindle feed with
> the feed rate controlled by a needle valve. The Nawide machine is
> very quiet because it has a dc motor and belt driven spindle. Any of
> these machines can also be operated with a stylus and drill template.
> The optical scope is used to make a master template and then the
> stylus is used to "trace" the template pattern and drill the board.
> An experienced operator can drill 80 holes per minute in a stack of
> three boards in the stylus mode. If I'm drilling a single lot
> prototype I just use the scope at about 20 holes per minute.
>
> If there is any interest I will post some photographs of these
> machines which would answer most of your questions. You would be
> impressed with the accuracy of these machines not to mention the ease
> of use and reduction of operator fatigue.
>
> Tom
>
>
> --- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
> <adam_seychell@y...> wrote:
>
>>
>>twb8899 wrote:
>>
>>>Adam,
>>>
>>>I like your drilling machine. If you flipped it over and put an
>>>optical scope and air clamping foot on it you would have almost
>>
> the
>
>>>same machine John is referring to. There were several
>>
> manufacturers
>
>>>of these machines with the most popular one made by Excellon. It
>>
> was
>
>>>a Uni-Drill model 1230. The actually came with a stylus assembly
>>
> for
>
>>>template drilling and the optical scope was optional but almost
>>>everyone bought the scope.
>>>
>>>They use a Precise #65 spindle with a variac speed control. You
>>
> can
>
>>>still find these machines if you look hard enough but many of
>>
> them
>
>>>went to the dump which is a shame.
>>
>>That would be a sore sight. Although I can understand many
>>professionals simply have no use for a manual drill machine. I've
>>heard the stories about the PCB business going through a rapid
>>change in 1980's, even here in Australia. One business man told
>>me the only places who survived were the ones who could get the
>>new and automated processes working the quickest. This guy's
>>business specializes in low volume, DS PTH, aimed at a lower cost
>>solution for prototyping. He knew of PCB fabricator that went
>>under, simply because they had reliability problems in the new
>>plated through hole line.
>>
>>Unfortunately I haven't seen any of the drill machines here in
>>Australia. I'd be very interested just looking how they are
>>built. How was drill feed operated ? Was this foot pedal control
>>or more elegant motor drive feed or hydraulics ? For quick
>>experiment I attached a bike brake cable to the arm on my
>>machine, hoping to operated the down feed by pulling the cable.
>>It turns out there is far too much friction in the cable and you
>>loose the "feel" and fine control of the drilling.
>>
>>What is an "air clamping foot" ?
>>
>>I'm imagining foot control would make drilling a lot easier
>>because it gives you two hands to position the PCB for drilling.
>>
>>Adam
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>