Unchecking Lead In / Lead Out when creating a 2d face to surface a cnc wasteboard doesn't work.

[mrkevans]

I just got a CNC and want to Surface it. 

The spoilboard I want to surface is the size of the max cut dimensions.

So I drew a rectangle, made in 3/4" and then used the 2d face tool in hopes i could create a surfacing pattern. 

It works, except unchecking lead-in under links doesn't work.  So the tool path that gets created is outside the limits of the machine. 

I'm on the latest osx using Fusion 360 for mac. Any 

[jhackney1972]

Please attach your model.  It may sound silly but there are is some settings that need to be tested with it.  If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it.

[seth.madore]

To use the Face toolpath, you might be able to get it to work by applying a negative Stock Offset (Passes tab). However, For cases such as this, Parallel does an easier job:

 

[mrkevans]

Doh! I should have done that to start with. See attached file. 

-Thank you!

[mrkevans]

I tried your suggestion using the  parallel tool, and it almost works. But it still leaves the tinniest lead in. 

 

I get this error from my cnc when loading in the GCODE.

Warning: The current tool path dimensions (1,221.758 mm) exceed axis dimensions (1,220 mm) by 1.758 mm.

So close!

[seth.madore]

Than use a boundary sketch to constrain it closer, seems the simplest way to do it

[mrkevans]

Ok. So I did a google and read about machine boundry. Below is a video of me using the parallel  option, and playing around with the boundry selection / bounding box options. Unfortuneatly Fusion 360 seems to disregard the 0mm lead in setting.  However, at the end of the video I was able to use parallel, with a machine boundry of bounding box and tool inside, and then i just set a -10mm offset.  I just loaded that into my machine and at least it didn't give me any errors.

* My assumption about lead in / out would have be that the machine should default to start right above the entry point, and then I should be able to control lead in. (and perhaps it's fine that it assume lead in, and I should turn it off) but I don't understand why when i uncheck it, or set it to 0, that Fusion 360 doesn't listen. 

[engineguy]

@mrkevans 

OK, this may be an irrelevant question but what control is on the CNC and does it use physical switches for Homing and Limits ??

If it is only using "Soft Limits" then as your uncut area is only 1.758mm you could easily change the setting at the CNC.

Depending on the control used it may even be possible if switches are used to disable one of the limit switches and use a "Soft Limit" for that one so allowing a couple of mm more travel in one specific direction.

I have done this many times over the years to get to normally unreachable places, you do need to know what you are doing at the CNC but once understood it is a very easy "fix", easy to do and easy to re-set.

Or, if you want a "workaround" in Fusion that may do the job for you try the "Horizontal" toolpath, that you can set with the tool center boundary on the edge of the board so you should not get any over li its errors and fully machine the desired area, playing with the "Lead-in" settings should get you there, see image below and attached file for a very simplified example, may be of some help for different ideas  🙂 🙂 🙂

[programming2C78B]

IF facing a spoiler the size of your machine travel, model it is a shallow inset pocket with a 2d contour on centerline of your max axis limits. 

[mrkevans]

I have a OneFinityCNC so i think it's soft limits.

Fortuneatly the last thing I tried above this post got me there, use parallel and negative offset. But I still don't understand why Fusion360 distregards the no lead in setting...

[Xilef1]

I have the same problem as described in the very first post of this thread. I want to face my spoil board, but because Fusion forces this lead in at the beginning, I cannot run the code on my machine, because I would have to start outside of my soft limits. I do not want to use another operation like parallel, because my spoil board has other features (e.g. a pocket for a magnet to hold my tool setter). If I’d use parallel, the tool would also go into this pocket which is not what I want. I just want to face my spoilboard and the facing operation would be perfect to do it. But it is missing a checkbox to allow for a vertical plunge instead of a horizontal lead in from outside of my working area. Maybe this could be implemented in a future version of Fusion?