Re: G81

I'll mix my comments in with your questions.
I will keep the terms simple.

--- In CAD_CAM_EDM_DRO@y..., edwardhall@s... wrote:
> Hi,
>
> Tried the drill tutorial in Deskam and wondering if others on the
> list are familiar with the drill tutorial?
>
> What is G81?

g81 is what is known as a canned drill cycle. It drills the hole in a
single stroke.

g83, on the other hand, will drill a hole in a series of pecks. The
peck depth is usually commanded by a Q(value) on most systems.

> If one is using a 5/16" drillbit, what does a command like the one
> below does?
>
> N100 G81 x0.4 Y0.2 Z-0.3 R0.1 F10

G81 - drill the hole in a single stroke

X0.4 Y0.2 is the x,y coordinate (location) of the hole to be drilled

Z-0.3 is how deep the hole is to be drilled

R0.1 is the specified rapid point (or height) for the z axis.
in essence, in this situation the z axis moves down to this distance
above the part before it executes the move to drill the hole to depth.
It then then returns to this point above the part after the hole is
drilled. Any moves to the next hole to be drilled will be made at
this height also if multible holes are being drilled in the same
cycle unless there is an additional command in the same block that
specifies otherwise.

F10. is the feedrate in inches per minute that the drill is fed into
the part.

This g81 block (line)of instructions is usually followed by a line
that contains the command g80 which cancels out the g81 or g83
commands.


> The parameters given were
>
> Tool : 5/16" drill bit
> drill depth: 0.373
> rapid ht. : 0.1
> Tool dia. :
>
> The input for the tool diameter appear to be irrelevant as
> irrespective of whatever one input for the tool diameter, the above
> remains ....R0.1
>
> What is the significance of R0.1?

explained above


> Or other examples (not from Deskam) like
>
> N200 G81 R.50 Z-5

rapid point is 1/2 in. above the part
the drilled hole is 5" deep


> N300 G81 V1=5 V2=-7

haven't seen it quite like this before.
these are variables, used in a way unique to a particular system.
usually encounterd in parametric or macro programming


> What does these figures mean
>
> Thanks
>
> Ed

Don