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Flaws of 2d highspeed algorithm

Teh Bear without Brains kinda idiot
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Teh Bear without Brains kinda idiot Newbie

Teh Bear without Brains kinda idiot

Posted
Posted

Hi ,folx

 

What I mean is this algorithm does not takes in mind real material properties

Suppose I mill 316l stainless with 16 varimill and take cuts of 35 mm depth

In area milling you can easily get the situation were you start to mill the rest of material that is high long and

thin walls looking like fins

If you use climb milling you gonna break your mill when this stuff will get under the mill tooth rolling over the sharp end .

So you can use only conventional that pushes it out of the mill but still you can breake it

when you move your mill with fast feed from the other side of the fin

Still this is a problem

I use high speed on everyday basis and this is huge problem for me

 

Do you see what I mean?

 

BR

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peon Newbie

peon

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Posted

Yes BR. That is a huge issue with me with the dynamic toolpaths. A few versions ago I sent a couple files to CNC describing the situation with some screenshots from verify showing that ridiculously thin fin causing the cutters to break. Right now I may add some geometry to help avoid the situation. It would be nice if we had another parameter to dictate that so called fin size. Eg: "Min fin size = 10mm" That setting would NOT allow any radial stock to get thinner than 10mm. Of course following that dynamic path using that setting, you would follow up with another toolpath to remove that left over stock. OR maybe also within the dynamic toolpath, the leftover stock would be approached with a peel mill style movement which would prevent the tool from wrapping around that fin. Hope this makes sense. Of course I didn't get a reply with that enhancement request from CNC at the time.

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crazy^millman Veteran

crazy^millman

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Yes it makes perfect sense unless I am really crazy. You want the algorithm to respect mass of material near the areas it is cutting. To exert the same amount of cutting force proportional to the mass that is supporting the area it is cutting. Problem is all masses and harmonics for materials are different. What I would suggest is figuring out the sweet spot of thickness and then making a offset surfaces of the fins. Now leave them for the dynamic rest milling operation where you can have better control over the speeds and feeds. You are getting into finite analysis of the model for machining not just strategies for cutting the material. This type of a calculations is high level and requires a constant recalculation of the cutting conditions realitve to the mass and the area of the cut. Now clamping pressure, coolant pressure, helix angles, sharpness of tool along with plasticity of the metal has to be taken into account. How fast does the edge wear what is the grain structure you are cutting and how is the cut being programmed? It it with the grain against the grain? When I did wood work you have certain material you had ot pay attention to grain direction and metal is no different. Has the engineer thought about that in his design and went with a forging for the part maintaining grain direction to maximize strength in those area where the parts get thin? Now is the part being support with a vacuum chuck, risers, bolts through the part or a host of other parameters would then have to be added to the algorithm.

 

Maybe I am off track here, but I have known you for a long time and you may come across to everyone else not smarted than the average bear, but I know different. :thumbup: Is this what you are asking?

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Rstewart Apprentice

Rstewart

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I know exactly what you mean! Currently I'm machining some parts (luckily Alum) that just shreds of a Chunk of material!! It's really like POW! two times over the 4 min cycle time. couple dozen parts with the same endmill so.....

 

Some sort of control over this would be a huge step forward in the Dynamic paths.

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K2csq7 Newbie

K2csq7

Posted
Posted

Yes it makes perfect sense unless I am really crazy. You want the algorithm to respect mass of material near the areas it is cutting. To exert the same amount of cutting force proportional to the mass that is supporting the area it is cutting. Problem is all masses and harmonics for materials are different. What I would suggest is figuring out the sweet spot of thickness and then making a offset surfaces of the fins. Now leave them for the dynamic rest milling operation where you can have better control over the speeds and feeds. You are getting into finite analysis of the model for machining not just strategies for cutting the material. This type of a calculations is high level and requires a constant recalculation of the cutting conditions realitve to the mass and the area of the cut. Now clamping pressure, coolant pressure, helix angles, sharpness of tool along with plasticity of the metal has to be taken into account. How fast does the edge wear what is the grain structure you are cutting and how is the cut being programmed? It it with the grain against the grain? When I did wood work you have certain material you had ot pay attention to grain direction and metal is no different. Has the engineer thought about that in his design and went with a forging for the part maintaining grain direction to maximize strength in those area where the parts get thin? Now is the part being support with a vacuum chuck, risers, bolts through the part or a host of other parameters would then have to be added to the algorithm.

 

Maybe I am off track here, but I have known you for a long time and you may come across to everyone else not smarted than the average bear, but I know different. :thumbup: Is this what you are asking?

 

I think it would be best for the programmer (and easiest for the developer) to just add a place to enter a "Minimum thin wall" amount as Peon suggested. You have been hanging around with to many 6 year olds Ron!

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YoDoug® Newbie

YoDoug®

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Curious if any of the other cam packages have figured this out in their dynamic modules.

 

Anything Catia boy? :D

 

I've been using HSMworks a lot lately and their dynamic paths act similar to Mcam as described above but they don't have as much control over options like ramp speed/feeds.

 

Their flow line, scallop and especially pencil tool paths are friendlier though.

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