I have been in swiss many years, using hanwha cnc lathes, i am pretty happy with the every part and set-up that i made, except one.
I turn a 8 mm bar, 80 mm is part length. Material is 4140. DOC is 2.75 to 0.75 mm..
The problem is i get different lengths from part to part, like +/- 0.04mm.. And I am really stuck with it.
The lathe is ok, i get the same problem while machining this part in other new / old hanwhas, too..
Chucking force is good, barfeeder centerline is good, cutting conditions, oil, tools and tool centerlines is ok.
Running 5k rpms like 0.05-0.08 mm/rev feedrate when turning, and 3k rpms 0.04 mm/rev in cut-off progress.. - I tried different speeds and feeds in cut-off-
I also support the part with a special ejector pin, using spring (soft one) force to push the part out after back turning progress.
It is ok with the machine, when making other parts, harder or softer material i allways get the exact part length in every part.
And cleaning the backside of the part did not solve the problem, i got rid of it.

Am i making a mistake in facing & front radius turn?

O0032
M90032
G0G40T0
M7
M8
M11
G4U0.3
G300X-1.Z82.T0101
G150Z9.5
M10
G4U0.3
G0X20.Z-2.M3S5000
T0
T0202(FACETURN)
S5000M3
G0X8.5Z0.
G99G41G1X-1.F0.07
G1X0.
G2X2.5W1.25R1.25F0.03
G1X8.W4.F0.05
G40G0X20.
T0
....

T0101M3S3000(CUT-OFF)
G50W-9.5
G99G1Z-12.F2.(DEBURR)
G4U0.3
G1Z82.
G0X8.5
M500
M56
M501
G99G1X-1.F0.04

and so on..

Anything wrong with it guys? Any suggestions? Thanks. :S