Poor surface finish with 3D contour

[michelena_pau]

Good morning, 

I am having problems with the finishing quality of a mold whose walls have an inclination of 1 degree.
As you can see in the pictures, there is a pattern of marks that I can't get out.
I imagine that it is a problem of tolerances...but I don't know.
Any help would be welcome.
Thank you very much.

[seth.madore]

What is the material and what is your machine?

[michelena_pau]

Material is Toolox 44.

Machine: Mazak VCN530C with Smooth G control.

Thank you in advance.

[seth.madore]

Hmm. It's not in the toolpath that I can see. If we toggle the display of points (and turn off lead and link display), we can observe that the toolpath is rather "clean", lacking numerous points, so it should be smooth:

 

I can't say I have any experience with that material, I'll have to do some reading and see what the machinability comparison is with other materials I may be familiar with..

[david.lundbergC7AM5]

You can actually see that something strange is going on, this also shows in the stock after roughing.

@seth.madore Toolox 44 is a pre- hardened tooling steel, 45 HRC

/ David

[seth.madore]

@david.lundbergC7AM5 I'm not entirely sure what it is you're showing in your photo. Could you provide more context?

[david.lundbergC7AM5]

That is the simulation of the roughing operation, with viewcube set at 45°, the layers of stepdowns don't seem to be consistant in X & Y. Or is my screen (or old eyes😊) fooling me?

/David

[weber_dominic]

Not sure either if the Stock is just inaccurate on my computer. It looks like to me that the roughing toolpath is not clean enough and it translates the vibrations into the smoothing operation.

[david.lundbergC7AM5]

Exactly what I'm seeing in the simulation.

I seem to recall a problem I had years ago, That time the issue was that I used R for arcs instead of IJK.

A similar toolpath, and a similar electronics, that was a Mitsubishi control, and I think Mazak use Mitsubishi components.

EDIT: on the other hand, that time it was the posted program that came out wrong, in this case it's already strange.

/ David

[michelena_pau]

Thank you very much for your answers.

So, do you think it is due to roughing?
I am going to try machining another part with a softer roughing.

When I have it, I will share with you the result.
Thank you all very much for your quick response.

[david.lundbergC7AM5 · Accepted solution]

@michelena_pau are you sure that there's any stock left for the finishing operation?🤔

I'd suggest you try a little more radial stock to leave in the roughing op. Like 0.25?

I walked through a part of the code i posted, and noted that the stepover per stepdown of 0,077 is less than 0,001...

... so that shouldn't be a problem with an 8 mm endmill.🙂

/David

[psx2]

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I'd suggest you try a little more radial stock to leave in the roughing op

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yes,

more radial thickness and the problem disappear

[michelena_pau]

I agree. I will give it a try.
I'll try it at work tomorrow morning and let you know.
Thank you all very much for the help.

[michelena_pau]

Sorry for replying so late, but I have not been able to test the part until now.
You were right, now it has gone perfectly.

I have left 0.25 mms stock to leave and solved.

Thank you very much for your help !!!