Re: Programing a DRO

I have not yet made the move to real CNC but I do use my DRO for
repetitive parts on the Bridgeport. in some thing I call MNC for
Manual Numerical control(G). By following the Cursor in the display
of the DRO I turn the cranks instead of having servos... this works
well for me for now fro short runs of parts... but I have some
problems with the programing of it... I Use 2 different methods

#1. is the teach in mode where I make the first part by hand and the
DRO remembers my moves and creates the program (unless I am very
smooth this makes a messy program that needs quite a bit of editing
and for that I normally send it over to the Mac where I can use a
text editor with cut and paste and drag and drop... and then annotate
it with comments then send it back to the DRO for use)

#2. is the do it by hand mode... Type up the program on my mac and
transfer it to the DRO Via the RS 232 connection... to do this I have
VS99 dimension the part with absolute dimensions to a single datum
point. that speeds creating the program up a bit but I would love an
automated process. and of course the only way to check the work is to
run it and cut one...


I do my cad work in Ashlar's Velum Solids 99
http://WWW.ashlar.com/Products/Solids/solids.html
And I can output files in almost any format from .sat to .stl to .dwg
to .igs etc etc...
and while the web seems to have lots of converters from say .dwg or
.dxf to things like g code (though in Wintel formats which means I
have to run under SoftPC on the Mac to use them (BTW Any other Mac
users on the list attempting to do CNC with a Mac?{short of shelling
out the big bucks for Gibbs Cam software}) I have not found anything
for converting a CAD file into the Programing language the Heidenhain
used in it's DRO... Since this seems to be the same language used in
their TNC series of CNC controls I was wondering if the experts here
had any tips for me...

My DRO Is a Heidenhain Positip 855 see the link for details
http://www.heidenhain.com/Products/DigitalReadout/positip.htm
And I have scales on X and Y and the Z knee and Z quill so I can set
a floating datum point...

At the end of this msg I append a few short Positip 855 programs as
examples of the language used.

Thanks for any pointers the list may have... I know that the List is
90% CAM/CNC but the title does Have CAD and DRO in it So I hope I am
not to far off topic.

BTW the article below may be if interest to list users it has some
nice explanations that helped me understand some of what was being
chatted about here...
Position Measurement on Machine Tools:
by Linear Encoder or Ballscrew and Rotary Encoder?
http://www.heidenhain.com/posmeas.html

Here is a Sample of a simple program to mill 3 slots for My
Heidenhain Positip 855.

0 BEGIN PGM 30 MM |Start of pgm,pgm #, unit of measurement

1 Z+20.000 |Clearance height

2 X+20.000 R0 |X cord of Recess point slot#1(radius comp off)
3 Y+10.000 R0 |Y cord of Recess point slot#1

4 CALL LBL 1 |call subpgm #1, (execute blocks 12 to 16)

5 X+40.000 R0 |X cord of Recess point slot#2(radius comp off)
6 Y+50.000 R0 |Y cord of Recess point slot#2

7 CALL LBL 1 |call subpgm #1, (execute blocks 12 to 16)

8 X+60.000 R0 |X cord of Recess point slot#3(radius comp off)
9 Y+40.000 R0 |Y cord of Recess point slot#3

10 CALL LBL 1 |call subpgm #1, (execute blocks 12 to 16)

11 Z+20.000 |Clearance height

12 LBL 1 |Start of subprogram 1
13 Z-10.000 | Recesss to slot depth
14 IY+20.000 R0 | Mill Slot
15 Z+2.000 | Retract
16 LBL 0 | End SubProgram 1

17 END PGM 30 MM |End of pgm,pgm #, unit of measurement

and here is a variation on it for 5 slots in a line at X=+30 with a
15mm Y spacing

0 BEGIN PGM 70 MM |Start of pgm,pgm #, unit of measurement

1 Z+20.000 |Clearance height

2 X+30.000 R0 |X cord of Recess point slot#1(radius comp off)
3 Y+10.000 R0 |Y cord of Recess point slot#1


4 LBL 1 |Start of subprogram 1
5 Z-12.000 | Recesss to slot depth
6 IX+16.000 R0 | Mill Slot
7 Z+2.000 | Retract
8 IX-16.000 R0 | Position in X
9 IY+15.000 R0 | Position in Y
10 CALL LBL 1 REP 4/4 | Repeat program section 1, 4 times

11 Z+20.000 |Clearance height
12 END PGM 70 MM |End of pgm,pgm #, unit of measurement

the Linear hole paterns and pocket milling an circle hole paterns
that are pre canned can also be called as subprograms for example

0 BEGIN PGM 20 MM |Start of pgm,pgm #, unit of measurement

1 Z+20.000 |Clearance height

2 CYCL 1.0 FULL CIRCLE |Circle data for a a full circle to follow
3 CYCL 1.1 NO. 8~ |Number of holes
4 CYCL 1.2 CCX +50.000 |X cord of the center of the circle
5 CYCL 1.3 CCY +50.000 |Y cord of the center of the circle
6 CYCL 1.4 RAD 20.000 |Radius
7 CYCL 1.5 START +30.000 |Starting angle of the first hole
8 CYCL 1.6 DEPTH -5.000 |Hole depth

19 Z+20.000 |Clearance height
12 END PGM 20 MM |End of pgm,pgm #, unit of measurement

Randolph Lee boss@...
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Windshadow Engineering Nantucket Island, MA USA
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