operation strategies for complex surface curves

[Anonymous]

I'm in way over my head and am attempting to learn through fusion360 machining some complex AL mold parts where precision is all that matters at this point.  There seems to be a lot of travel in between cutting in most operations I've tried which isn't helping as I don't have the accuracy on my home brew machine required to hold some of the crazy tool paths, especially at speed.  I'm using the generic post for linuxcnc and when I run the gcode it will machine a pocket with straight walls (see pic but not that visible) but the tool path shows an attempt at the airfoil graduation not to mention massive posts.  I'm trying to diagnose where I've created the problems and eventually how to mitigate errors (not sure if any of this is even possible.) 

Please take a look at my first attempts at guessing tool paths/operations and if anyone has suggestions of different approaches I would love to try them.

http://a360.co/28FYMx6

Thanks,

jack

[martha.deans]

Hey Jack,

I took a look at your part and your operations and my first piece of feedback is to likely not use Adaptive Clearing, since the algorithm for that toolpath is great for keeping a constant load on the tool, but was designed with cutting metal on a rigid machine in mind. In your case, using 3D Pocket to clear out the material will keep the tool engaged and work well for cutting wood.

I'm not sure from your choice of toolpath what your end goal is exactly, but I would also generally recommend that the Facing operation goes first, and just faces off all the stock on the top of the part. This will also reduce the amount of travel happening since a Face operation will keep the tool more engaged.

I made another setup with some edits for you to take a look at, let me know if that solves the problems you were experiencing!

http://a360.co/28PUld3

[Anonymous]

Thanks Martha,

I'm still trying to figure out how to take that surface and turn it into a 3D solid mold part in cad but in the meantime sorting out proper machine control and tool paths hence low cost trial runs in mdf.  I have been told by some that the imported bodies are corrupted which explains some issues with picking the surface.  It is hard to know where all my gremlins are introduced but after debugging the linuxcnc side I am getting the post to run better i.e. as simulated and will try your solution.  Facing first is a better strategy but with corian or mdf you need to leave material until after the surface has been polished to keep the required sharp mold edge. 

Fusion 360 tool paths that optimize chip loading and tool life in a production setting on insanely expensive machines are not for me.  As you point out my CNC is the weak link and precision is everything.  I need to minimize unproductive movement that can induce errors and prematurely age a machine that is earning $0/hr.  The adaptive and 'smarter' operations on a 900 mm part meant 40% of a 28 hr job time as "yellow" travel so it is nice to see only blue paths.

jack

[HughesTooling]

It's hard to know what you're trying to make from these surfaces as they're not forming a solid block but one big mistake you're making is you've not select the model\surfaces in either setup. You should always select what you want to machine in the setup or the whole model will be used not just what's visible.

Mark

[Anonymous]

Hello again Mark,

This is all the same project, I have imported files of airfoils from root .dat and create an aluminum wing molds used for fabrication of composite glider wings.

I want to take the surface or bodies in this case and create a negative cavity in the solid mold part, I haven't discovered how to build a solid mold part from these imports yet in fusion (have posted this question several times, not speaking correct CADese I suppose.) You posted solutions to some imported files I'm using for the design, but they're "bad" imports data and design. See a better example file of a wing mold import.

To tune my CNC I'm trying to run gcode to see if the tool cuts the cavity correctly, it hasn't been.  Many builders have used these files to mill surface cavities in stock and don't really design a proper part because they don't have to in rhino cad, as you point out again fusion doesn't work that way, ('hunt and peck' cad/cam/cnc.)

http://a360.co/28V0SAT