New to Fusion, what's "rapid collision with stock" error and how to fix?

[winterminute]

I'm a brand new Fusion 360 user.  I've generated the model and am at the point of generating the toolpaths for otherMill.  However, I'm getting quite a few "rapid collision with stock".  This sounds like maybe it's a too-much-speed problem, but I found one post that talked about increaseing the Top Height (Stock with .025 offset) which seems to indicate a different root cause.  Either way, increasing the Top Height didn't make a difference.  Looking at the simulation where the first error occurs (see first screenshot) doesn't show me any obvious problems.  I found a second occurence of this error (screenshot #2) and that also doesn't show me anything obvious.  I'm sure that's because I'm new 🙂  I'm not sure the best way to share info about my project, but below are a couple of screenshots.  

Project Info (if it helps): A pinewood derby car that has been scaled down to prototype on a small otherMill.  Using 1/8" Flat with a facing pass to drop the original height of the 2" block and then an adaptive clearing pass to shape the car.  The simulation was run from the top so it does includes the facing pass.

Here's the defaults that get loaded from otherMill's tool library.

[ProteumMachining]

2 possible causes. Are you simulating one tool at a time? It will think the top stock from the Face operation is still there unless you Control+click on both and run them both. Also do you have stock contour turned on in 2D adaptive. Either way if you can post your .f3d file it'll be heaps easier to help you

Dylan
Proteum Machining

[winterminute]

Thanks for the reply and thanks for your help!

I did multi-select both tool/paths when I ran the simulation so that shouldn't be it.  I'm using a 2D face operation (not adaptive, should I switch) and I don't have anything selected under Stock Contours.  I wonder if this has to do with the amount remaining material.  I've removed the top layer (using the facing option) but there's still a fair bit of material remaining on the side of the car.  Maybe there's a better order of operations for dealing with that material.  Attached it the f3d file.

[HughesTooling · Accepted solution]

Part of the problem is you have not enabled rest machining so the adaptive clearing doesn't know you've machined the stock down to the top of the model. Also the stock is a lot wider than the part and you've not enabled stock contours so it plunging into the stock, see the left side of this image,

I,ve modified your addaptive setup in a few ways. I set the heights to take into accout the facing op, then enabled rest machining and set source to from previous op. 

I also changed the stepdown and the toolpath looks like this, notice the toolpath now machines to the edge of the stock.

File attached.

[HughesTooling]

One thing I don't like about the toolpath, looking at this image below on the left side it lifts rather than going around the edge like it does on the right side. At certain stepdowns it leaves a feather edge that causes a collision and I can't get the toolpath the same on both sides.

Mark

[winterminute]

Thanks Mark for helping out. Using the version you upload, I don't get an errors so I'm going to prototype this on some foam and see how it does.  If it's relatively close, my son (it's his design/car after all) can sand out the imperfections.  I think I see what you're saying about lifting vs going around.  I thought maybe the location of the model within the stock was creating problems so I centered the model and then I see a collision at the point you highlight.  So I think I'll just go with the file you uploaded.

Dumb question: Is rapid collision with stock a bad thing?  If the material or project is forgiving can you deal with it?  For example, foam or soft woods that can be filed or sanded afterwards.  Or is it pretty disasterous and will damage the bit/mill and should be avoided at all costs?

One other thing ... for whatever reason I had no trouble getting started with the MODEL side of Fusion, but the CAM module is a lot more difficult.  Most of the tutorials (e.g. from Autodesk) don't really going into the hows/whys.  They just say do this and do that.  For example, I picked adaptive clearing because that's what the otherMill Fusion tutorial said (which by the way, also said don't enable Rest Machining) but I have no idea if that was the right approach given there are quite a few menu options.  Anything tutorials you recommend for the CAM side?

Thanks again!

[HughesTooling]

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@robintV7UB9 wrote:

Dumb question: Is rapid collision with stock a bad thing?  If the material or project is forgiving can you deal with it?  For example, foam or soft woods that can be filed or sanded afterwards.  Or is it pretty disasterous and will damage the bit/mill and should be avoided at all costs?

You probably want to avoid rapid collisions even with a soft material you might take a chip out of the material and spoil the finished job. That said you can use your own judgment, in this example from your file the thin sliver of material will probably break off before the plunge, even if it's still there it'll break away but it might spoil the corner.

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@robintV7UB9 wrote:

One other thing ... for whatever reason I had no trouble getting started with the MODEL side of Fusion, but the CAM module is a lot more difficult.  Most of the tutorials (e.g. from Autodesk) don't really going into the hows/whys.  They just say do this and do that.  For example, I picked adaptive clearing because that's what the otherMill Fusion tutorial said (which by the way, also said don't enable Rest Machining) but I have no idea if that was the right approach given there are quite a few menu options.  Anything tutorials you recommend for the CAM side?

Thanks again!

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Sorry can't help with the tutorials but a lot will come down to experience, hard to teach that. 

Mark

[winterminute]

Thanks for your Mark help, the small scale prototype turned out great.  I had balsa and foam on hand so ran them both through.  Now time to super size it on a Roland.