Turned sphere is faceted

[Anonymous]

I am turning a small probe tip with a .100" diameter ball at the tip. Simulation shows severe faceting - the arc is made up of a string of straight line chord segments:

Close up with toolpath:

closeup showing smooth arc on toolpath.

When I machine the part, it looks like the simulation, with the facets.

tolerance is set to .0004"

How can I make the part look round?

[akash.kamoolkar]

@Anonymous Does your NC code contain arcs or lines? Can you attach your file here?

Regards,

Akash Kamoolkar

[Anonymous]

Here is the posted output.

%
(PROBETEST)
(T4 NR=0.0079 - ZMIN=-0.9354 - GROOVE TURNING)
N10 G7
N11 G18
N12 G90
N13 G20

(PROFILE FINISHING1)
N14 M0 (CHANGE TO T4 ON REAR TOOL POST)
N15 T4 M6 G43
N16 G54
N17 M8
N18 G97 S1500 M3
N19 G95
N20 G90 G0 X1.3 Z0.1969
N21 G0 Z0.09
N22 X-0.0757
N23 G1 Z0.01 F0.001
N24 G2 X-0.0157 Z-0.02 I0.03
N25 G3 X0.0984 Z-0.0771 K-0.0571
N26 G1 Z-0.1401
N27 G3 X0.0787 Z-0.1721 I-0.0571
N28 G1 Z-0.2721
N29 X0.1969 Z-0.3902
N30 Z-0.5889
N31 G2 X0.2598 Z-0.6204 I0.0315
N32 G1 X0.4475
N33 X0.4724 Z-0.6329
N34 Z-0.9354
N35 X0.5
N36 G2 X0.53 Z-0.9313 K0.03
N37 G1 X0.6166 Z-0.9063
N38 X0.6324
N39 G0 Z0.09
N40 X-0.0757
N41 G1 Z0.01 F0.001
N42 G2 X-0.0157 Z-0.02 I0.03
N43 G3 X0.0984 Z-0.0771 K-0.0571
N44 G1 Z-0.1401
N45 G3 X0.0787 Z-0.1721 I-0.0571
N46 G1 Z-0.2721
N47 X0.1969 Z-0.3902
N48 Z-0.5889
N49 G2 X0.2598 Z-0.6204 I0.0315
N50 G1 X0.4475
N51 X0.4724 Z-0.6329
N52 Z-0.9354
N53 X0.5
N54 G2 X0.53 Z-0.9313 K0.03
N55 G1 X0.6166 Z-0.9063
N56 X0.6324
N57 G0 X1.3
N58 Z0.1969

N59 M9
N60 M5
N61 G53 X6. Z5.
N62 M30
%

[akash.kamoolkar]

@Anonymous Could you also attach your F3d file?

Regards,

Akash Kamoolkar

[HughesTooling]

This is what I see in a back plotter, pink curves are arcs. So looks like the code is OK,

Is it a small part and have you tried adjusting the accuracy on the simulation dialogs

Mark

[HughesTooling]

---

@Anonymous wrote:

When I machine the part, it looks like the simulation, with the facets.

tolerance is set to .0004"

How can I make the part look round?

---

Odd that the actual part is faceted. You can see in the code it is definitely creating arcs in the G code.

[Anonymous · Accepted solution]

maybe it is just my poor eyesight on the actual part (which is quite small)  or a coincidence that the part looks faceted for a different reason, like backlash.

So I'll take a look at the actual machine performance next, but can you tell me if the simulation display can be improved to show the arcs? it seems like it should show curvature on the spherical part.

[Anonymous]

probe.f3d is attached.

[Anonymous]

I had not noticed the accuracy slider before on the sim dialog. that did make a difference on the curvature display.

thanks, I'll just look at my machine performance now. I think that I was seeing the faceting in the simulation and thinking that was explaining the imperfect machining. but now I see it has to be in my machine.