topic Re: Bad surface finish with parallel milling in Machining Discussions Forum

Bad surface finish with parallel milling

Anonymous — Sat, 31 Mar 2018 14:15:49 GMT

Hi, I am having a problem with HSM. I have been using Edgecam for the last 20 years and last year we switch over to inventor HSM. Now I have run into an obstacle with parallel milling.

I have a part from a customer who uses solid works. X_T file. We import the SW model into HSM and we use parallel to machine the part. The tolerance is set to 0,002 mm and the tool is a 12.mm ball nose, stepover is 0,2 mm. On the part there is surface with a R450.mm (see photo).

The finish product is not smooth, it has a stepped finish. (see photo). To me this looks like a tolerance problem in the model it self from my customer. I talked to them about this and there answer was that there are no changes in the way they draw and save the model. The model is a X_T file version 25

I machined the same model in Edgecam with the same parameter as in HSM and the finish product is perfect.

Can anybody help me out with this.

Re: Bad surface finish with parallel milling

Marco.Takx — Sat, 31 Mar 2018 17:11:55 GMT

Hi @Anonymous,

I haven’t seen the part itself but as you descriped I think you have to play with the Smoothing setting.

If you can share your part we can take a look at it if you keep having problems.

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Re: Bad surface finish with parallel milling

Anonymous — Sat, 31 Mar 2018 20:23:55 GMT

Hi Marco

Thanks for the quick response.

Here is the model and pic of the finished work piece.

This is what PP looks like

Best regards

Rúnar Gregory Muccio

Baader Iceland

Re: Bad surface finish with parallel milling

Marco.Takx — Sat, 31 Mar 2018 22:23:39 GMT

Hi @Anonymous,

I think you forgot to attach the files

Happy Easter.

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Re: Bad surface finish with parallel milling

Anonymous — Sat, 31 Mar 2018 23:32:55 GMT

Take two.

Re: Bad surface finish with parallel milling

Marco.Takx — Sun, 01 Apr 2018 11:48:09 GMT

@Anonymous,

Take 3 ?

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Re: Bad surface finish with parallel milling

Anonymous — Sun, 01 Apr 2018 14:26:17 GMT

Hi Marco

I've been answering you by email through outlook and not on the discussion broad. Sorry about that. Stupid me.

I can´t share the model on the discussion broad, but I can send it to your private email. Company policy.

Re: Bad surface finish with parallel milling

Laurens-3DTechDraw — Sun, 01 Apr 2018 14:37:28 GMT

That is weird.

Really curious to see what is going on.

Haven't seen that happen.

What kind of machine, control and post processor are we talking about?

Maybe the post screwed it up?

Did you set the general tolerance to 0.002 or the smoothing tolerance?

Re: Bad surface finish with parallel milling

Anonymous — Sun, 01 Apr 2018 14:45:53 GMT

The machine is a new Emco MMV 2000 with Heidenhain iTNC530 control.

and this is the part we made in December.

Re: Bad surface finish with parallel milling

Marco.Takx — Sun, 01 Apr 2018 20:26:21 GMT

Hi @Anonymous,

I haven’t recieved a email?

in the picture I see a Smootingtolerance from the post setttings, but did you also play with the smooting settings within the operation?

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Re: Bad surface finish with parallel milling

Anonymous — Sun, 01 Apr 2018 22:53:21 GMT

Ciao

No i didn´t touch Smoothing tolerance in the machine. I didn´t think that would help. 0,002 mm is as good as it gets.

We there pressed for time so we finished the job in Edge cam. This same problem came up with Edge cam back in 2004

when we stop using Alpha cam and switched over to Edge cam. We put the tolerance down to 0,002 mm and we where good to go.

I have made 100´s of these parts over the years. Then about 12 years ago this same problem started again. We talked to your costumer

and they said they would look in to it and they did and fixed the problem. I don´t know what they did but it work.

Re: Bad surface finish with parallel milling

Laurens-3DTechDraw — Mon, 02 Apr 2018 08:37:07 GMT

I think I know what is going on.

You are setting the tolerance of the post processing. (You shouldn't need to mess with those normally.)

But the toolpath is calculated to the tolerance set in the operation. That by default is 0.01mm for finishing operations and 0.1 for roughing operations.

If you set that at 0.002 you should get similar results to Edgecam in surface quality.

Re: Bad surface finish with parallel milling

Anonymous — Mon, 02 Apr 2018 10:08:16 GMT

The tolerance is set to 0,002 mm

Re: Bad surface finish with parallel milling

Laurens-3DTechDraw — Mon, 02 Apr 2018 11:56:47 GMT

In that case we would need a lot more info to dig into it.

So maybe we should get some of the Autodesk Crew to assist and get to the bottom of this with you.

Re: Bad surface finish with parallel milling

lenny_1962 — Tue, 03 Apr 2018 13:41:56 GMT

is this inventor hsm or sw\hsmworks?

Re: Bad surface finish with parallel milling

Anonymous — Tue, 03 Apr 2018 13:51:52 GMT

Inventor hsm ultimate

Re: Bad surface finish with parallel milling

lenny_1962 — Tue, 03 Apr 2018 15:23:11 GMT

seems to be fine in the latest development release of HSMWorks, drew up the 450mm radius and ran a parallel cut over it with a .002mm smoothing.

so it could be the release of inventor hsm you are using

Re: Bad surface finish with parallel milling

Anonymous — Mon, 09 Apr 2018 22:19:26 GMT

I´m back with some info.

I´ve been playing with the tolerance and smooth tolerance

And no change in the surface finish.

This morning I made a test piece 300.mm x 100.mm with a R450.mm top.

I put in 3 Boundaries and 3 separate parallel operations

The right-side boundary I machined with the tolerance and smooth tolerance of 0,1 mm

The middle boundary I machined with the tolerance and smooth tolerance of 0,01 mm

The left side boundary I machined with the tolerance and smooth tolerance of 0,001 mm

The right surface with the 0,1 tolerance was as expected it has a stepped surface 10.mm between steps

The middle surface with the 0,01 tolerance was better 5.mm between steps

The right surface with the 0,001 tolerance was the same as the surface with 0,01 mm Tol.

It makes no difference if the tolerance is set to 0,01 or 0,001

Is there something blocking the post processor form out putting a nc code with a 0,001 tolerance ?

0,1mm0,01 mm0,001 mm

Re: Bad surface finish with parallel milling

Laurens-3DTechDraw — Tue, 10 Apr 2018 04:13:19 GMT

Could you attach the file you used for that test here.

I'd be trying to find some time to cut the same thing and see what happens and try to find out what is going on.

Re: Bad surface finish with parallel milling

Anonymous — Tue, 10 Apr 2018 08:06:46 GMT

Have fun