re:Re: re:Compucut ?

Rab wrote:
<snip>the main commands I use in Roland's version of HPGL are,

>V: Velocity
>F: Feed
>Z: followed by X,Y,Z coordinates

Rab,
NONE of these are HPGL standard codes! The closest is V, which in
hpgl is VS (Velocity Set),followed by a speed parameter in cm/sec.

>so to cut a sphere I'd specify the initial speeds and output many
>lines of Z x,y,z data corresponding to it's shape,<s>

How do you derive the coordinates needed? What program(s) do you use?

<snip>how much variation is there in the G code standard, does every

>company use it's own interpretation ?

A LOT or a little, depends on which flavors we're talking about. You
can usually count on:
G0-fast linear(usually)move
G01-Feedrate Linear move (Fxxxx sets the feedrate)
G02-Clockwise Arc
G03-Counterclockwise Arc
G90-Use absolute coordinates
G91-Use relative(also called incremental) coords
G92-Preload registers (used for shifting the zero point)
M00- unconditional stop

There ARE others which are 'pretty' standard, and you can find
listings in previous posts here. These are the only ones which seem
to be truly universal, IMO. And even here, the G92 and M00 MAY be
implemented in differing ways. Along with the way the center point is
specified for the arcs on G02 and G03.

>There must be convertors between the different formats ?

Not really! This is one of the main problems with G code. However,
most Cad/CAM packages (Vector is one example) allow their output to
be customised for various gcode 'flavors'.

>These following two products seem to put the compcutter in
>perspective price-wise. Servo controlled robotic arm kit including
>servos from £179, http://www.milinst.com/tecpage.htm

This is a radio-control hobby servo operated arm. Usually driven by a
serial link. Not really related to the type of thing we talk about
here although it 'could' be incorporated into a machining system as a
part loader/unloader?? I've seen versions of these sold by some
companies in the educational market. As part of a CIM (Computer
Integrated Manufacturing) setup.

>and a 3-Axis Machine kit including steppers from £189,
>http://www.milinst.com/drilpage.htm ,I don't know how real-world
>usefull they are, but pretty interesting for messing around with at
>the price ?

This machine uses ball bearing drawer guides for linear motion. Some
people on the list have made machines like this and can comment on
their usefulness, or lack thereof... The software and BASIC STAMP
drive scheme may be worthwhile. I'd guess the feeds and power are
very slow/low. Be sure to notice it is a DRILL, NOT a MILL!!!

This machine will be WAY below the rigidity of the compucut, IMO.

Hope this helps.

Ballendo