Re: Gcode and CNC (Turbo CNC)

Hi Owen,

It would be easier if you posted the first lines of code, but here is
my guess.

You mentioned home. regardless where you position the table, when
you call a home in T-CNC and you have axis set for seeking home, they
will go to the home switch to verify.

It is more difficult but offers easier tool changes if you locate
your X0 Y0 a few inches from the part. This way a G00 X0Y0 call will
send your tool to a clear area.

If I am understanding, you position your table so you are in the
center of a hole to be drilled (milled?) and then zero your X and Y
in the program.

I found that using a M00 as my first line makes it easier to see the
program start, and it eliminates the first line bug.

M00 is user input and you need to hit the spacebar to go to the next
line of code.

Position your zero (set your zero in your program as you indicated by
Z for all axis or 0 on the current one) over your first hole.

M00 ( wait for user input you can drill your first hole here.
G00 X1 Y1 ( go to NEXT hole go to SECOND HOLE
M00 ( wait for user input, allows you to drill your hole.
G00 X0.5 Y2 ( go to next hole
M00 (wait for user input while you drill
G00 X-5 Y0 ( clears part while you add your clamps
M00 ( waits until after you are done clamping
-> your milling cycle starts here.

or...

M00
G83 X0 Y0 Z-1 F10 R0.5 I-0.10 #20

that would be the basis of drilling after you hit the spacebar. if
you zeroed your axis and your readout is all 0.000 for all your axis,
then it would just start the canned drill cycle there.

Change your parameters as needed, those are just an example.

As a note, a dwell (#20) should be no more than enough for the
flutes to finish the cut, NOT sit at the bottom of the hole spinning.
It would be one half revolution for a drill. Longer may work harden
the hole bottom, a shorter retract my damage the drilling edge,
especially carbide.

HTMS and HTH

(hope that makes sense)

Dave



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Owen Lloyd"
<sportbikewest@t...> wrote:

> I was wondering if any one in the group could take the time to

help me

> with a Gcode problem. Please be patient because I'm not really sure

how to

> word my problem in a short direct way.
> So here goes.
> I design a part in my CAM software and post process to Gcode. No

problem

> there. My parts are small. This example is a "V" shaped bracket

with rounded

> bolt holes on each end and the point. 3 holes to drill and a V

pattern to

> cut out after bolting down. It is approx 2 1/2 across the open end

of the V

> and 4.2" down the longest side.
> My first point is laid out at 0,0 and rest of the points move

from there

> [up in Y and along X.] This means that the actual outside of the

rounded

> bolt boss hole is at a negative value [bolt hole boss is .800 in

diameter

> with a drilled hole in the middle]
> That's the lay out.
> Now I fire up the CNC and Turbo CNC. Move my cutter to with in 1"

of the far

> left of my stock [viewed facing the machine] indicate to TCNC that

my X&Y

> are at 0,0 and commence the machining cycle [move to first drilling

point.]

> Here comes the question.
> Though the Gcode says my first drill point is @ X0Y0, the table

begins to

> move for several inches at a 45 degree and stops. As if it was

moving to 0,0

> for me to commence drilling. I thought I'd already indicated to

Turbo CNC

> that I've zeroed the table. Wouldn't my first hole be right there

with no

> movement? How do I control the distance from my home point relative

to my

> first point of machining? Like, if [for example] my first drill

point was at

> X1,Y2. I place the cutter on the left corner of the work piece.

Zero all

> axes in the Tcnc program. Commence machining cycle. Shouldn't the

table move

> only 1 inch along X and 2 up Y?
> I've got a sneaking feeling this has some connection to Absolute

versus

> Incremental machining but can not make the connection.
> I'm sorry this is long and I've probably only confused anyone that

actually

> endured this long rambling.
> Still thanks to all that consider my plight.
> regards
> Owen