Calculation of ramp angle

[mrk]

Guys,

I am working on a utility for 3 axis milling. The idea is that the util will analyze a .NC file to compute statistics. My goal is to scan the file then list sfm (surface feet per minute), fpt (feed per tooth), and ramp angles for each tool. This information is useful for proper management of feed/speed on the mill. When the tool is ready I will make it open source. The idea is that this tool can be run on an NC file to quickly check the cutting parameters so you can determine if the tool usage is optimal.

Sfm and fpt are easy to calculate once I know the tool size and number of flutes. This info is not in the NC file but I can embed it in comments.

I can detect plunge moves and list them separately (so the fpt range does not report really slow stuff). Plunge moves are easy to detect since x and y don't move.

Ramp moves can be detected when the program sees change in x,y, and z.

Calculation of ramp angle for the tool moves is a bit tricky and I suck at trig. Basically I am looking for some help with the math to determine the angle of line for any ramp move that I detect.


double computeRampAngle(double x, double y, double z) {

double xyDistance = Math.sqrt((x * x) + (y * y));
double slope = xyDistance / z;
double rampAngle = /* SOME MATH HERE */;
return rampAngle;

}


If anyone is good at math and willing to help it would be very much apreciated.

The project code is in java. I will post it on my website this weekend so if anyone does java coding they are welcome to take a look. Right now sfm and fpt calculations work for xy and plunge moves. When the ramping stuff works I think it will be ready for a 1.0 release and hopefully someone will find the idea useful.

-Mark

[mrainey]

I think it's just:
angle = ATan(z/x)

I don't know Java - be sure that you're using a trig function that works with degrees and not radians

[Kiwi]

I don't know Java either, but my guess is something like this:

double xyDistance = Math.sqrt((x * x) + (y * y));
double rampAngle = ATan(Z/xyDistance);

[mrk]

Thanks!

it works great.

double d = Math.abs(Math.sqrt((x * x) + (y * y)));
if (d == 0 || z >= 0) return 0;
double r = Math.atan(z / d) * 180 / Math.PI;

[Kiwi]

Happy to help.
Sounds a bit like the type of project I take on, but I use Visual Basic 6.
Cheers.

[brahma.desai]

i have one more question that, for example to some cutter ramping angle is 5º at this stage how we have to calculate depth of cut

[Kiwi]

Originally Posted by brahma.desai i have one more question that, for example to some cutter ramping angle is 5º at this stage how we have to calculate depth of cut

I don't know Java either, but my guess is something like this:

double xyDistance = Math.abs(Math.sqrt((x * x) + (y * y)))
double zDepth = Math.tan(5/180*Math.Pi) * xyDistance