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Fusion 360 CAM Acting Strange

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TomS

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#1
After modeling an aluminum part using Fusion 360 I set up the machining operations using the built in CAM package. It all looked good running in simulation but the final outcome was not right. The machining origin is the top/left corner. As I went through each operation I checked for size and hole placement. Everything was good until the last two operations. You will notice the difference in wall thickness on the pocket outer edges and the counterbores are not lined up with the holes. I double checked my model and it does not reflect these offsets. Checked my machining origin and it was at 0,0. Anyone else have issues with Fusion 360 CAM not generating an accurate tool path?

IMG_0417.JPG
 

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DAT510

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#2
Vs Fusion CAM, could you be loosing Steps in your CNC?
 

JimDawson

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#3
Are you sure your machine zero is not drifting? Maybe a tool offset incorrect? I have seen Fusion do some strange stuff, but have not seen it offset a tool path.
 

TomS

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#4
I checked machine zero and work zero and they were the same as when I started. As Jim noted Fusion has done some strange stuff and I've experienced some of this in the past. It could be me causing these weird moves, but I haven't yet found the cause. Scrapping $50 of material is not fun.

I use CamBam as my default CAM program but wanted to get more familiar with Fusion because of it's CAD capabilities and 3D CAM features. I've modeled the part in CamBam and waiting on material to arrive next week. I have full confidence with CamBam toolpaths, not so much with Fusion.
 

Boswell

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#5
If you have not done so already, I recommend that you analyse the G-Code to see what what exactly is happening. It might be a problem with the Post Processor that you are using or some unexpected result of a CAM setup you used. It should be much easier to troubleshoot if you know exactly what G-Code command was wrong or missing.
 

jbolt

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#6
Is it the same tool for those operations? For an XY positioning error the only thing I can think of is having more than one work offset in the g-code. F360 CAM is essentially HSMWorks which they bought out several years ago. I use it in Solidworks with no issues like that. Most things get caught in simulation if the tool setup matches the tool used but these are usually Z height errors. The only other thing that comes to mind is having the correct post processor for Mach3.
 

TomS

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#7
Is it the same tool for those operations? For an XY positioning error the only thing I can think of is having more than one work offset in the g-code. F360 CAM is essentially HSMWorks which they bought out several years ago. I use it in Solidworks with no issues like that. Most things get caught in simulation if the tool setup matches the tool used but these are usually Z height errors. The only other thing that comes to mind is having the correct post processor for Mach3.
I was running a single part and zeroing each tool as I used them. My gcode files were generated as stand-alone machining operation files and I used the only Mach3 post processor shown in the Fusion drop down window.

The drilled holes are in the proper location. The counterbores and pockets use the same tool but are offset in opposite directions, or thereabouts. I need to check my gcode files as Boswell suggested which I will do tonight. I just got back from checking on our kids in Redding, CA after the Carr Fire blasted through town.
 

TomS

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#8
I've attached my hole drilling and counterbore gcode files. The hole drilling file shows the correct X and Y coordinates. Looking through the counterbore gcode it is evident the X and Y coordinates are different. Why? I have no clue. I understand the I and J moves but I don't understand these types of moves.

X3.749 Y-1.8727
X3.7482 Y-1.8732
X3.7477 Y-1.874
X3.7475 Y-1.875
X3.7477 Y-1.8759
X3.7482 Y-1.8768
X3.7491 Y-1.8773
X3.75 Y-1.8775
X3.751 Y-1.8773
X3.7518 Y-1.8767
X3.7523 Y-1.8759
X3.7525 Y-1.875
X3.7523 Y-1.874
X3.7518 Y-1.8732
X3.751 Y-1.8727
X3.75 Y-1.8725
 

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jbolt

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#9
Wow that is really odd. Send me your part file and I can see what it does on my system in F360 & Solidworks.

I combined the two files and ran it through gwizard editor and that looks worse which is even more confusing.

Hole and Counterbore.png
 

TomS

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#10
Wow that is really odd. Send me your part file and I can see what it does on my system in F360 & Solidworks.

I combined the two files and ran it through gwizard editor and that looks worse which is even more confusing.

View attachment 273238
Thanks for taking a look. I had to change the file suffix to .txt so I could attach it. Change it to .f3d and it should open.

I gave up on Fusion and modeled the parts in CamBam and generated the code. Parts came out perfect! Another post for another day.
 

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rowbare

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#11
Did you do any contouring on the block? If one of your operations uses stock zero and the other uses part zero then you will have that kind of error.

bob
 

TomS

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#12
Did you do any contouring on the block? If one of your operations uses stock zero and the other uses part zero then you will have that kind of error.

bob
You got me thinking. I checked each of my machining operations and they all use stock 0,0,0 as the origin.
 

ChrisAttebery

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#13
Did you post this on the Fusion 360 help forums? They were really helpful in the past when I needed it.
 

rowbare

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#14
You mention in post #7 that you are zeroing after a tool change. If you re-zero on x and y before the counter bore then that is likely your problem since stock(0,0,0) is now gone. If you are zeroing x and y, your reference should be part (0,0,0) for that operation.

bob
 
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TomS

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#15
You mention in post #7 that you are zeroing after a tool change. If you re-zero on x and y before the counter bore then that is likely your problem since stock(0,0,0) is now gone. If you are zeroing x and y, your reference should be part (0,0,0) for that operation.

bob
I should have been more clear in my explanation. I was zeroing the Z axis (tool to the top of the part). My X and Y zero was the upper left corner of the stock and was not changed throughout the machining operations. If you look at images 414 and 415 in my original post you will see that the perimeter profile operation was not concentric with the stock although it is centered in X and Y in my CAM setup. That was a tell tale sign that something wasn't quite right with my CAM setup and I overlooked it.
 

TomS

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#16
Did you post this on the Fusion 360 help forums? They were really helpful in the past when I needed it.
No I did not. I like the environment on this forum.
 

Groundhog

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#17
Yeah, the environment here is nice. But the knowledge base at http://help.autodesk.com/view/fusion360/ENU/?page=support is pretty deep. I can usually find answers to my questions just by searching but the occasional posted question usually gets answers in a matter of hours if not minutes. If you are using Fusion 360 do yourself a favor and find your way around the help and users forums at Autodesk.
 

spumco

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#18
The only issues I've had with Fusion tool paths have been lead-out/in on adaptives that try to run in to fixtures or snipe other surfaces. There is simply no way to adjust the stupid swoopy moves at the edges or corners of parts without over-constraining and leaving more stock than desired.

All other problems - and they are legion - have eventually been traced back to me.

Did the machine make a funny (bad) noise when it machined the feature improperly?

If not, then the geometry was intentional - i.e. Fusion thinks that what you want regardless of what you actually want. If so, then that's lost steps or mechanical issues or stock not matching the CAM stock dimensions.

If you'd like to send me an in vite to your Fusion project I'd be happy to take a look. Shoot me a PM if you want.
 

spumco

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#19
Took another look at the photos, and... shot in the dark... but that offset looks like when I forgot to subtract half the wiggler diameter when touching off an edge. Unless you touched off on the left side of the part - then it doesn't make sense.

Or the actual stock wasn't as wide in X as you set in CAM.
 

TomS

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#20
Took another look at the photos, and... shot in the dark... but that offset looks like when I forgot to subtract half the wiggler diameter when touching off an edge. Unless you touched off on the left side of the part - then it doesn't make sense.

Or the actual stock wasn't as wide in X as you set in CAM.
I use a X,Y,Z electronic edge finder to locate the machining origin. The imbedded script sets the part to 0,0,0. And I did touch off on the left side of the part. I double checked the stock dimensions and made sure they were the same in my CAM. Not saying it couldn't be me. I'm just curious why Fusion did what it did so I don't make the same mistake again.
 

spumco

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#21
Figured, but thought I'd throw it out there.
 
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