we are absolute beginners and we have just finished building our custom dust shoe and after a few attempts we are getting close to a good result. What we have just realized is that with a dust shoe that is attached to the z carriage and therefore is moving up and down with the endmill, we sometimes will need to avoid fixtures and obstacles, even if it turned out quite soon that it’s far easier when possibile to use flat clamps or cam clamps to avoid going through the modelling of the entire setup.
However, we are using Fusion 360 and are trying to use a 3d contour toolpath. We modelled a clamp and referenced it in the fixture tab, both in the setup tab and the 3d contour avoid/touch surface tab. We the default clearance it’s all good and as expected, however increasing the clearance to some 50mm which is half the width of our dust shoe, the toolpatch cannot be generated and we are wondering why. We tried using a simpler model of the clamp, picking single surfaces rather than the whole clamp body or keeping a greater distance from stock edges but nothing really seemed to work.
I copy here the link to my file, if anyone has got time to take a look into it, it will be greatly appreaciated.
Can you use a 2D contour there?
You could create a sketch with an open contour that avoids the clamp area.
Or, less elegantly, you could make one giant tab.
Thanks for your reply. Yes, I could use a 2d contour, that is what it used to be in the beginning, but then I realised that 2d contours do not support fixture avoiding so I switched to 3d because I thought that this was exactly what I needed. Also the clearance parameter would be very useful in certain cases.
So an open contour sketch, is that what you used to get your snapshot?
Also a giant tab, yes I am sure they would both work fine but I’d be also very keen to understand why the avoid fixture method doesn’t appear to work here, is it a bug or am I doing something wrong?
Hi @quicky06 yes it is frustrating, however it looks like a numeric issue, 0.01 to 1mm clearance is accepted, more than 2 leads to toolpath generation crash. I also tried to keep the clearance at 1mm and oversize the model of my clamps by the amount I need to stay clear from, which is just another workaround, but looks more consistent with the process and more acceptable to me.
I also tried using fixtures early on but became frustrated with toolpaths avoiding the fixtures when cutting but sending rapids straight through them, forcing me to set the retract heights much higher than otherwise necessary.
If you do get it to avoid when cutting, watch out for the rapids, simulate with ‘stop on collision’ is not really optional when you have fixtures to avoid.
why do you think this is a unusual use case?
Also, I’m with you with the simplicity of the giant tab, however what is the height the tool moves to when moving above the tab to avoid cutting the material? is it retract height? But this is not what my toolpaths usually do when creating small tabs. In the normal case of small tabs of a few mm in a stock of say 15mm it’s hard to say at what height the tool retracts to to avoid cutting the material and creating the tab, but surely it’s not higher that stock top…don’t know if I made myself clear but a tab can be at max the height of the stock, what I have here is the clamp 15mm above the stock. So if I put in the giant tab this won’t guarantee that the tool does not cut through my clamp, 'cause he is thinking he’s creating a tab that is as high as the stock top whereas my clamp is above…
Sorry for the confused words, let’s see if you get what I mean…
I meant that only as in terms of Fusion machining. It only looks at the cutter. Maybe the thought is that there isn’t a reason to miss something by more than 3mm. There’s no way to model your dust shoe and have Fusion plan motion around that…yet?
Neil, what happens if you model the collet / spindle in Fusion as well? I have the ER20 collet modelled in Fusion and I apply that as the ‘holder’ for the tools so it turns up in all the simulations and I can see if I’m going to start a fire with the collet.
Maybe a really oversized tool holder is a way to express the dust shoe?
Maybe. If the dust shoe moved with the Z (like @Marco_XXL’s must) , I think that would work. My vote would still be the giant tab. Or, CA glue and tape.
@neilferreri now we are talking…thank you so much! Sorry I was being too biased to try and type 100mm in the tab height…i’m not quite sure to understand the opportunity Fusion gives to model a tab that is higher than the stock but anyway, this will serve me perfectly.
@LiamN yes, ideally I would like to model the whole dust shoe and apply it as an accessory that always show up in the simulations…
I never had much luck getting Fusion to avoid things with fixtures, it seemed that the toolpaths would avoid the fixtures whilst cutting and then send rapids straight through them…
This is worth watching if you haven’t already;
Here’s how the holder is configured on my tools in Fusion, you create a holder and then select that holder on each tool you want to use it on;
