Need Help!- g41 g42 problems

[nc novice]

hi everyone, as an example I'm trying to face and turn od on a part, but my start point is wrong eg. z0.0 x108.0 but the position on x is 104.0 and sometimes the z value while machining is shorter eg. z-40.0 the cut stops at z-29.0
i did not have this problem when i first started to program, one day i came in and the problem just started. the controller is fanuc series oi-tc and is always in absolute mode. i reset all tools with touch probe but still problem persists. g41 g42 is always in g00 line. now with every new job i have to make changes to the tool wear in x and z, and im only cutting plastic so no load what so ever. did i touch or change a setting by mistake or is it a controller issue? help would be greatly appreciated, thanks in advance

[dcoupar]

If you're just turning and facing, you don't need G41 or G42. They can be more trouble than they're worth. Why not post your program here so we can see what the problem is?

[nc novice]

thanks for replying, here is the program.the part was already machined to 100 dia on reverse side, this side i'm machining has stock of 104 - 106 dia.
I'm just trying to rough a taper then do 1mm chamfer and finish taper.

O0006;
g28 u0 g28 w0;
t0000;
t0202; roughing tool (t is set as no. 3)
g00 g41 z0.0 x110.0; here is where x is 106.2
s700 m04;
g01 x40.754 f1.0;
g01 z2.0 x34.354;
g00 z5.0;
g00 x110.0 again all x values are 106.2
g00 z-3.0;
g01 x50.354 f1.0; start to rough a taper
g01 z2.0 x34.354;
g00 z5.0;
g00 x110.0;
g00 z-6.0;
g01 x59.954 f1.0;
g01 z2.0 x34.354;
g00 z5.0;
g00 x110.0;
g00 z-9.8;
g01 x72.114 f1.0;
g01 z2.0 x34.354;
g00 g40 z15.0;
s0 m05;
g28 u0 g28 w0;
t0000;
t0101; finishing tool (T is set as no. 3)
g00 g41 z-12.0 x102.0; starting 1mm away from job
s1400 m04;
g01 z-10.0 x98.0 f0.2; 1 x 45 deg(looks more like 30 deg)
g01 x72.0; x measures 71.5
g01 z0.0 x40.0; x measures 39.0
g01 x15.0;
g00 g40 z15.0;
s0 m05;
g28 u0 g28 w0;
m30;
%

the program is prob a bit long for what I'm machining, but you you gotta start somewhere, any suggestions on better programming technique will be appreciated, thanks again.

[Torsten]

Originally Posted by nc novice thanks for replying, here is the program.the part was already machined to 100 dia on reverse side, this side i'm machining has stock of 104 - 106 dia. I'm just trying to rough a taper then do 1mm chamfer and finish taper. O0006; g28 u0 g28 w0; t0000; t0202; roughing tool (t is set as no. 3) g00 g41 z0.0 x110.0; here is where x is 106.2 s700 m04; g01 x40.754 f1.0; g01 z2.0 x34.354; g00 z5.0; g00 x110.0 again all x values are 106.2 g00 z-3.0; g01 x50.354 f1.0; start to rough a taper g01 z2.0 x34.354; g00 z5.0; g00 x110.0; g00 z-6.0; g01 x59.954 f1.0; g01 z2.0 x34.354; g00 z5.0; g00 x110.0; g00 z-9.8; g01 x72.114 f1.0; g01 z2.0 x34.354; g00 g40 z15.0; s0 m05; g28 u0 g28 w0; t0000; t0101; finishing tool (T is set as no. 3) g00 g41 z-12.0 x102.0; starting 1mm away from job s1400 m04; g01 z-10.0 x98.0 f0.2; 1 x 45 deg(looks more like 30 deg) g01 x72.0; x measures 71.5 g01 z0.0 x40.0; x measures 39.0 g01 x15.0; g00 g40 z15.0; s0 m05; g28 u0 g28 w0; m30; % the program is prob a bit long for what I'm machining, but you you gotta start somewhere, any suggestions on better programming technique will be appreciated, thanks again.

Is your 02 toolradius 3.8 ?
If it is then the 106.2 x-coordinate is what I would expect.
On the 45 degree, is your machine set for Radius or Diameter?
Seams Toolpath is programed for Diameter mode.

[nc novice]

t02 tip rad is 0.5
machine in absolute mode
diameter machining

[nc novice]

sorry but this is off topic from my Question regarding g41-42. but can someone post a very simple program on how to use a bar puller. last week i machined 7 jobs, each with 50 parts, i had to open chuck and set length then cycle start again. our machine shop is small so no bar feeder is possible.
lets say if i was machining a tube (drill, od then parting) what happens after i part off, and what is the code to cycle through the program again. sorry all for being a pain on such a simple thing. thanks again in advance.

[Geof]

The code for bar pulling will depend on your machine. The shortest way to program it that I know is to use sub programs with nested calls. On some machines, Haas is one, you can have all the subs in one long program but on other machines they have to be completely separate programs such as in this description.

First program starts machine with the bar ready for first piece, and uses M98 with an L count to call second program.

Second program does first piece and parts it off then calls third program using M98 but no count.

Third program pulls the bar and the machine returns to the second program with M99. The second program also has M99 immediately after the call for the bar pull program so it returns to the first program and the sequence repeats until the L counts down to zero, then the first program stops the machine.

[nc novice]

thanks Geof, will give this procedure a go and try to build on from this.
As far as g41-42 goes, i swapped tool 1 and 2 around reset the geom with probe and i got my 45 deg chamfer on the finishing tool (now tool 1)but i did have to adjust the wear on x an extra 1.5mm. rapid position on the roughing tool still the same, but profile of the cut is good. i think it could be a touch probe issue. we got a tech coming out in the next couple days will ask to check it out. thanks again guys

[sinha_nsit]

If there is some error in offset setting, one way is to measure the error, and edit the geometry offset appropriately. Wear offset should be manipulated only if the error is due to tool wear. This is because when you replace the insert with a new one, the offset procedure would not need to be repeated; just make wear values zero.

[rr1021ab]

You need to rapid to .100 off the part . if you are faceing the part and the part is 1.00 in diam. and z zero is at the face of the part.You should do this before you turn your taper.
G54T0101(FINISH FACE)
G30U0
G30W0
G97S2500M3
G0X1.1Z.1M8
G1G41X1.00Z0F.002
X0.00
Z.2F.025
G40
G0X0Z.10(TURN PROFILE)
G1G42Z0.00F.002
X.980
X1.00Z-.01(.01 45 DEG. CHM
G1Z-1.00
X1.0
G40
G30U0
G30W0
M9
M30