Internal Profile simulation does not match GCODE

[hatch789]

Hi Guys,

OK I have to be doing something wrong. I'm trying to figure out why the simulation looks perfect but my GCODE does not come out the same. I have tried multiple POST Processors thinking this was a bug but in each case it does the same thing. 

Here's the file:

https://a360.co/3KjCxXa

If you run a simulate and look carefully at the internal profile operation it starts cutting with X at 0.4286. -Everything looks great here. But now look at the attached gcode file. It's up in crash land with X at 0.8573 in line 76 of the file. I assume I'm doing something wrong here. Again I have tried multiple POSTS and it does the same thing in each.

[a.laasW8M6T]

Hi

It seems the Values in Simulation are showing Radius, not Diameter which is why your seeing a discrepancy.

Also the inserts are defined incorrectly for your tools, You have them as CPMT215, but they should be CPMT212, OR CPMT060208(metric designation), It seems the Kennametal website is showing incorrect info for the Inches translation(CPMT2152, rather than CPMT212)

[hatch789]

Yes I realized that the simulation was showing radius values but that seemed correct since diameter values would crash into stock. What I'm asking is how to fix this since I'm stuck. Is this a Fusion bug or something I'm doing incorrectly?

The inserts are something I can look at more closely but I don't think that alone won't fix my issue.

[CRANDALLPRECISION]

With the Okuma turn post code looks right to me. Files attached.

[hatch789]

Crandall how do you figure? In your 1001.min.nc file you show the same error that I do. Look in your generated file line N55 and N57 N60 ...etc. All of those X values are DOUBLE what they should be just like the original problem I reported above. It's like fusion is sending Diameters to our POSTS instead of Radius values which is going to cause a very bad crash into stock.

[seth.madore]

Most modern lathe controllers are built to be used with Diameter values, not radius. Quick skim thru the thread, but I don't see where you stated what machine/control you are using?

[hatch789]

It shouldn't matter what machine we're using if the SIMULATION is trying to move up to an X value and you see that value in simulation. Then the posted code should be the same value. I have never (not ever) been in a situation where the simulated value was different from what the .NC file was doing. Here we're vastly different. The values in the NC file are double what they should be and single stepping through the process I stopped it because I could see the crash was going to happen if I let it go just 1 line more.

For the record I'm running an Okuma and this issue is present in several posts that I've tried including Haas posts.

The only thing I can think is that I must be doing something wrong in setting up this operation ...how can I be the only one seeing this issue?

[CRANDALLPRECISION]

x is diameter on our Haas, Mazak and Doosan controls we use. Is your lathe different?

[hatch789]

X is diameter also on our Okuma Multus B300-W. I have X and Y control so that's why I was asking if perhaps I'm doing something incorrectly in my fusion operation. I would not think that I'd see this discrepancy if I'm doing things properly. My simulation should match my posted gcode. -Right guys?

[CRANDALLPRECISION · Accepted solution]

No the simulation is just giving you the x dimension from centerline of the part or your x zero in the setup. That is why it is exactly half the posted value. If I don't setup my mastercam plane as diameter it does the same but the posted code is correct.

[seth.madore · Accepted solution]

As @CRANDALLPRECISION points out; what is shown in Simulation is a radial value, we've not yet improved the display to show diameter. What is posted out IS diameter, which is what your machine is looking for.

Does the diameter values of the posted code align with the actual dimensions of the part you are trying to machine?

[hatch789]

OK Thank you Seth. I also knew from my original post that it was showing radius in simulation and diameter was being spit out in the gcode. But that's why I was so scared about causing an issue. Thank you for the clarification. Like I said I figured I was doing something wrong or in this case didn't have all of the necessary information. I'm new to lathe stuff and this is very helpful to know going forward. I just didn't want to cause a catastrophe in my machine.

I thought that simulation values were always going to agree with the GCODE that came out of the post.

[seth.madore]

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@hatch789 wrote:

I thought that simulation values were always going to agree with the GCODE that came out of the post.

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No, this is only true in the case of 3 axis work. Once you move into lathes or multi-axis milling (even 3+1), all bets are off in regards to parity between Sim values and posted code (with some exceptions)