Re: HP plotter servo

Dave:

I'm going to take a stab at this (no direct knowledge of the CNC end,
but more than a bit on the plotter end):

The typical pen plotter was designed to take HPGL directly through a
serial (and frequently parallel port as well). Its internal
controller did not optimize the code for best path (that was done, if
at all, by the CAD package). They tended to be accurate to
about .001" in the X and Y axis and frequently had some sort of
algorithm for slippage in the Y direction (many didn't bother
figuring that the errors would compensate out). The Z axis was
generally not adjustable (just pen up/down) other than a mechanical
adjustment for pen pressure on paper if anything. Many just depended
on a spring for proper tension. The good news is that most were 8 to
12 pen and had "tool changer" functions built in. The problem is, I
suspect that the landing positions may be pre-defined and impracticle.

The controllers are "trained" to think in 2D, but for things like PCB
layout drilling, might be able to directly take HPGL output without a
CNC or CAM intermediary (eg: AutoCad to manufacture on direct HPGL
output).

Just a thought :-)

Jeff



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
<davemucha@j...> wrote:

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "josef wagner" <josef-
> wagner@c...> wrote:
> > good morning dave
> > i am afraid these motors are in the power range of 10 to 15 Watt
> only.
> > and for the three axis control you need at least 80 to 100 watt

if

> you are
> > going to use a mill tool of say 5 mm diameter.
> > some years ago i have got two of such HP motors from a plotter
> > and used them in gauge I railway models for single axle drive -

was

> > jsut sufficient, the motor size was 42 mm diamter and 75 mm

length

> without
> > decoder
> > best regards from vienna
> > josef wagner
> > +++
> >
>
> My current project is a small PCB drilling machine. I am not

looking

> for real power and these would seem to be around teh power of a
> NEMA23 triple stack or NMEA34 single stack stepper ? I'm assuimg

10-

> 15 watts would compare.
>
> But, the big question is how to drive them cheaply !
>
> Has anybody hacked the driver board and controlled it directly ?
>
> I never thought about the output of a CAD program like HPGL as a
> driver software.
>
> Also, since it has a pen up/down signal it may be possible to

convert

> that to a self contained peck driller driver.
>
> I could not find any manufactures markings so am not sure if they

are

> Hathaway.
>
>
>
> Dave