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Trajectory Milling

Participant

Trajectory Milling

Had some free time to work on this today.  Source link

I created a curve by equation and used that to drive a trajectory milling sequence for some long slots I needed to mill.

Capture.JPG

here is the equation I used to create this curve.

/* ENTER TOOL STEP OVER

SO = 0.05

/* EMPIRICAL VALUE TO CORRECT SHAPE ERROR

SF = 0.0175

/* ENTER PROFILE ALLOWANCE (STOCK)

PA = 0.005

/* ENTER TOOL CUTTER DIAMETER

CD = .3937

/* ENTER SLOT WIDTH

SW = 0.811977

/* ENTER NUMBER OF REVOLUTIONS

N = 100

A = ( ( SO * SF ) / 3.141592654 ) / 2

B = ( ( SW - ( 2 * PA ) ) - CD ) / 2

x = ( A * ( t * N * 360 )) - ( B * sin ( t * N * 360 ) )

y = ( B * cos ( t * N * 360 ))

z = 0

I don't understand what the shape error value is about but it seems to work for this application.  Just thought i should share this with everyone in case they wanted to use it or improve it

15 REPLIES 15

Re: Trajectory Milling

Nick,

Nice looking tool path !

Re: Trajectory Milling

Thank you

I'm finding that the cl data and g-code is all points so now am looking into arc fitting but not sure if this is a wise move.

Re: Trajectory Milling

Interesting application.

If you are using creo3you can do something similar using volume-mill and the cl data isn't all pts. This would allow you to control tool selection and parameter adjustment normally. You can also do slots that aren't straight.

Josh

Re: Trajectory Milling

oooh i like the look of that cl data but volumill is extra $ correct?

Re: Trajectory Milling

Don't know, sorry.

Josh

Re: Trajectory Milling

I haven't been doing any programming for a couple years now, but was reading through the forum to see what's new.  I used a similar technique as Nick and also didn't have an accurate solution to the step-over value - I just tweaked the STEP value to get what I needed.  I didn't use it frequently enough to invest time resolving the step over issue.

Throchoidal milling curve:  I used a CSYS to anchor the start of the curve orientation of the path - the default vector for the path is Y+.   I could also juggle the X/Y calculations to control the vector and climb/conventional cutting condition as shown in the example.

/*-------------------------------------------------------------------
/*
/* RAD  = radius of path (slot_radius - cutter_radius)
/* STEP = determines "step-over", **STILL GUESSING ON VALUE**
/* DIST = total travel distance
/* DEGS = CALCULATED, DEGREES: distance_required/step*2*360
/*   -------  FORMAT -------
/* x = (STEP-RAD*cos(t*DEGS))-STEP
/* y = STEP*((t*DEGS*STEP*3.14159)/360) - RAD*sin(t*DEGS)
/* z = 0.
/*
/* -- OPTIONAL -- ADD THE FOLLOWING PARAMETERS TO THE ASSEMBLY --
/* NR: RAD  (REAL NUMBER, 0.0)
/* NR: STEP (REAL NUMBER, 0.0)
/* NR: DIST (REAL NUMBER, 0.0)
/* NR: DEGS (REAL NUMBER, 0.0)
/*
/*
/*------------------------------------------------------------------
/* -- IN SAMPLE BELOW X/Y REVERSED FOR X+ ADVANCING CUTS
/* -- IN SAMPLE BELOW Y IS REVERSED FOR CLIMB:  "-(STEP" & "+STEP"

RAD=.03
STEP=.095
DIST=2.
DEGS=(DIST/STEP)*720

Y = -(STEP-RAD*COS(t*DEGS))+STEP
X = STEP*((t*DEGS*STEP*3.14159)/360) - RAD*sin(t*DEGS)
z = 0.


Re: Trajectory Milling

Joshua - was that curve created using a "Volume Milling" sequence in Creo (constant load?), or using the third-party "VoluMill" addon from Celerative?

Re: Trajectory Milling

Creo "Volume Milling" with constant load, need creo3 and there are required parameter settings to keep the tool down.

Josh

Highlighted

Re: Trajectory Milling

Joshua - Thanks for the response.  The toolpath looks promising.  I believe I read an earlier thread that detailed the parameters required.

We're still Creo2, but moving up to the next release of Windchill this weekend, so we're getting closer to new releases of Creo.