Strange selection in CAM - Bug?
Selecting the end profiles always works as long as the profiles are on the same plane. At last, that is how it always seemed to work before...
When this first happened in this file, I thought for some reason that the profiles were on different planes - but they aren't. It is just 3 of the same linked component. I guess that's what really gets me - it is 3 of the exact same thing - but I get different behavior selecting each one. That seems more like a bug to me.
I've never managed to get sketches to work well for me in CAM...Is there a training page to show how that would work? What I'm doing now is making a solid block with the hand cavity carved out and using that as a guide which is working okay.
Whenever possible, I like to use the actual model to do my cutting, instead of making guide blocks or sketches just for CAM.
Thanks!
@Anonymous wrote:Selecting the end profiles always works as long as the profiles are on the same plane. At last, that is how it always seemed to work before...
When this first happened in this file, I thought for some reason that the profiles were on different planes - but they aren't. It is just 3 of the same linked component. I guess that's what really gets me - it is 3 of the exact same thing - but I get different behavior selecting each one. That seems more like a bug to me.
I've never managed to get sketches to work well for me in CAM...Is there a training page to show how that would work? What I'm doing now is making a solid block with the hand cavity carved out and using that as a guide which is working okay.
It's worked up until now because you got lucky. When you use open profiles it's generally a good idea to also use stock contours to define what areas you specifically want to cut. Without defined stock contours you're basically at the mercy of whatever the system wants to do. It may do what you want, but I find that usually it doesn't. And when you have interrupted pockets like you have, it's even harder for the system to figure out what to do.
Therefore, in situations like this it's many times better to define a closed area to cut with a sketch. As an example, the included file has a sketch driving the area to cut in the second pocket operation. General sketching in Fusion is covered in the tutorials under "Learn Fusion 360" in the Fusion help menu.
Autumn.S wrote:Whenever possible, I like to use the actual model to do my cutting, instead of making guide blocks or sketches just for CAM.
Thanks!
I do too really. Thing is the 2D operations are essentially dumb, in that they have no concept of the 3D model geometry. All they know about is the 2D profiles that have been selected, and they will happily cut right though the model if there is no selected geometry there. So many times they require extra help in the form of sketches.
Have you tried using 3D pocketing? The 3D ops are model aware and usually don't need helper sketches. They work really well for prismatic parts too, not just part with complex contouring.
C|
Hi @kb9ydn
I know how to make/use sketches (I am both CAD and CAM here in my shop) but I just can't get them to work in CAM for some reason - either it cuts too deep, it cuts using the sketch line as the centerpoint of the bit, etc. Eventually I just gave up and starting making dumb blocks of what I needed when it doesn't read the model right. What I really need is an intro to how to use sketches in CAM workspace - how to know how to set the bit so it travels within a sketch, for example, and how to know how deep it will cut, etc.
Your file helped a lot here - I can see how you managed this cut, so I will definitely be able to get this file running, and use this information to fix future cut files.
Hmm, I've worked with the 3D ops a lot, but I can't seem to get the same results with any type of 3D op as I got with the 2D. I'm not usually the lucky type, haha! 
Do you have any direction you can give me as to what type of 3D op/selection can accomplish the same as in my screencast above (cutting across in one motion)? For me, it either tries to cut each individually (so I end up with rounded edges where they shouldn't be, as well as a lot of lifts/plunges) or it tries to cut out the vertical through slots (our knife takes care of those, much faster).
I really don't need it to clear out the "through" vertical sections with the routing bit - we have an occilating blade that cuts it out, then the shop guys just toss that inner part away (there's no depth, the inside part is basically garbage). The occilating blade's much faster than wallowing it out with a router bit and ends up with a smoother cut in our foam. But anytime I use a 3D op it tries to clear everything, I can't seem to find how to contain it just to the parts I need routed like I would with the contours in the 2D op.
You also say "they will happily cut right though the model if there is no selected geometry there"...I have used 2D contours in this manner for this exact reason. Usually it just cuts between selected contours on the same plane, ignoring everything in between, and I love that about it! I guess I'm weird. 
But I still have to ask - and I know you may not know the answer - why does it work on one but not the others, when they are the same part? If it all worked the same, that would make infinitely more sense to me. If it worked correctly, or incorrectly, it doesn't matter - it's the inconsistancy that's really got me spinning in circles.
I'm just confused and lost I guess! 
Thanks for the file, the explination, and the help!