Re: cnc lathe programming question


ouremail@xxxxxxxxxxxxxxx wrote:
hiya,

Here is the question and a brief run down.

We do all programming with Mastercam and we also DO NOT use tool raduis
comp
on the machines so all start and end points are with the insert radius
in
mind.

The programmer was gone and i needed a simple program change. I was
trying
to figure the start points and end points for a simple radius into a
champher then linear move to another radius to a straight turn.

So a .01 radius on the begining and end of a .0625 champher.

An engineer once showed me the (magic) number for figuring this but i
have
lost my notes.

I know how to trig the real numbers, this wasnt the problem. If we used
nose
raduis comp it wouldnt be an issue but we dont.

So what i need is the formula that will figure the contact point of the
radius when a tool goes into motion.

To make it a bit more clear here is what i was trying to do.

champher started at Z zero and X of 8.110, radius of .01 to a 45 degree
champher, linear move to the raduis of .01 and ending at X 8.235 and Z-
.0625. With the real numbers programmed i was at about a .032 champher.
So i
need the formula for figuring where the tool actually contacts.



You need know the tool nose radius, are you using .05 (1.2mm) ?

Without TNRC you must add/substract an offset for your radius/chamfers.

Convex radius -> RealRadius = ProgRadius - Rtool
Concave radius -> RealRadius = ProgRadius + Rtool

External chamfers -> RealChamfer = ProgChamfer -
(1+tg(a)-1/cos(a))*Rtool
If a = 45 deg -> RealChamfer = ProgChamfer - .5858*Rtool
(valid for tool setting case Fanuc 2-3 , Fagor 3-5 , Sinumerik 2-3 )


Eduardo.




Now this is bugging the hell out of that i forgot and i want the answer
so i
came here. Sure we can use cad, sure we maybe or maybe not should
program
differnt. I WANT TO DO IT BY HAND.

thanks for the help
DM

.

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