Numerical simulation of surface roughness in NX
Numerical simulation of surface roughness in NX
(OP)
Greeting everyone!
I would like to simulate the surface roughness of peripheral milling in NX.
This means I have to deal with cycloids in order to get the accurate roughness values, because the cutting edges of the tool are moving on a cycloid path.
I created a few of them using the law curve command, and then created a point at one of the intersections (see on fig. 1).

My goal is that, by changing the parameters of the law curves, get the actual roughness values by reading the y coordinates of my created point. I would like to repeat this in an automated way, to get the a roughness funcion.
My first thought was to use GRIP or NX Journal, because a saw a few solved examples on the forum:
#for k 1 to 1000 do
#[law curve parameter] := 0.1*k
#read point(x,y)
#write xls [k,law curve parameter,y coordinate]
#end
I scanned through the documentation of GRIP and NX Journal, and found myself a little bit lost in those languages. Could you give me a little help, how should I create a program like this?
Thanks in advance!
I would like to simulate the surface roughness of peripheral milling in NX.
This means I have to deal with cycloids in order to get the accurate roughness values, because the cutting edges of the tool are moving on a cycloid path.
I created a few of them using the law curve command, and then created a point at one of the intersections (see on fig. 1).

My goal is that, by changing the parameters of the law curves, get the actual roughness values by reading the y coordinates of my created point. I would like to repeat this in an automated way, to get the a roughness funcion.
My first thought was to use GRIP or NX Journal, because a saw a few solved examples on the forum:
#for k 1 to 1000 do
#[law curve parameter] := 0.1*k
#read point(x,y)
#write xls [k,law curve parameter,y coordinate]
#end
I scanned through the documentation of GRIP and NX Journal, and found myself a little bit lost in those languages. Could you give me a little help, how should I create a program like this?
Thanks in advance!





RE: Numerical simulation of surface roughness in NX
www.nxjournaling.com
RE: Numerical simulation of surface roughness in NX
Mark Rief
NX CAM Customer Success
Siemens PLM Software
RE: Numerical simulation of surface roughness in NX
(Sorry for my late answer, for some reason, I wasn't able to access this site, meanwhile other pages were still available for me.)
My goal is to compare the theoretical surface roughness of endmilling (http://www.custompartnet.com/image/machining/end-m...) and peripheral milling (http://www.nzdl.org/gsdl/collect/cdl/archives/HASH...).
The blue curves represent the path of the teeth of the peripheral milling tool. It is a cycloid, because it moves forward and rotates. There are forumalas to do this, but I would like to make a more accurate simulation. (You can't calculate the intersection of the cycloids, because it leads to a transcendent equation, which can't be solved with algebra. So there are only approximating formulas.)
So I would like to generate cycloid curves, which I already did. I placed a point at one of the intersections. The y coordinate of the point would give me the maximum of the surface roughness. It would be good, if I was able to repeat this some automated way, so I don't have to set manually different parameters to the curves again and again - to get a proper roughness(feed) function.
And yes, maybe NX is not the best tool for this, but it would be so elegant (and also a great skill), if I was able to do it with NX. :)
RE: Numerical simulation of surface roughness in NX
Mark Rief
NX CAM Customer Success
Siemens PLM Software
RE: Numerical simulation of surface roughness in NX
much like Radial Chip Thinning Factor formula to help CNC machinists determine proper feed rates when not milling along centerline.
i would think this RCTF formula is derived from the graphic he just posted. (cool graphic btw)
nice chart
RCTF= sq RT of 1-(1-(2 x woc/ tool dia)^2)
RE: Numerical simulation of surface roughness in NX
LOL
trying to simulate this function seem like i could turn quite complex, especially with the need to factor tool nose radii and interpolating outside and inside arcs/ curves / splines where the feed rate at centerline does not match feed at cutter OD. which prolly explains why no CAM company has bothered to simulate it when a machinist can just cut the feed in half for the finish pass if at first the surface finish is not acceptable.