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Author Topic: Hesitation at intersections  (Read 3339 times)

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Hesitation at intersections
« on: October 31, 2010, 12:07:47 PM »
I wasn't quite sure how to describe this.  I'm getting a hesitation similar to what you would see in exact stop mode at the transition between lines and arcs.  Seems to be just were the trailing end of a line segment meets the leading end of an arc.  On intricate cuts where there are lots of line and arc segments back to back, it acts almost as if it's in exact stop mode.  Seems to be just on line/arc transitions.  Arcs are smooth and a chain of line segments are smooth.  See the image.  red arrows indicate where there is hesitation.  CV is on and none of the CV Mode boxes are checked.  Velocity is set at 500IPM and acceleration is fairly low at 25.  This seems to get worse at higher speeds, but we're typically cutting at anywhere between 80 and 200IPM and we see this a lot at those speeds.

Here is the code.

N0060 M03
N0070 G04 P.5
N0080 G01 Z0.1250 F30
N0090 G02 X-0.03Y0.25I0.0000 J0.25 F90
N0100 G01 X-0.03 Y1.75 F90
N0110 G02 X0.25 Y2.03 I0.28J0.0000 F90  (Hesitation Here)
N0120 G01 X1.75 F90
N0130 G02 X2.03 Y1.75 I0.0000 J-0.28 F90 (Hesitation Here)
N0140 G01 X2.03 Y0.25 F90
N0150 G02 X1.75 Y-0.03 I-0.28 J0.0000 F90 (Hesitation Here)
N0160 G01 X0.25 F90
N0170 M05

Thanks in advance...
« Last Edit: October 31, 2010, 12:09:47 PM by rrc1962 »

Offline Hood

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Re: Hesitation at intersections
« Reply #1 on: October 31, 2010, 02:12:49 PM »
What value do you have in General Config for the CV settings?
Hood
Re: Hesitation at intersections
« Reply #2 on: October 31, 2010, 05:20:49 PM »
Under "CV Control", "CV Dist Tolerance" is set to .05 and "Stop CV on Angle >" is set to 85.  I didn't think I had anything checked there, but I did have "Stop CV on Angle" checked.  If I un-check that, everything works great.  Why would a setting of 85 stop CV on these transitions when the angle is clearly less than that?  Does Mach figure the angle of an arc to be the difference between the start and end?  For instance, would the arcs in the photo be considered 90 degrees?

Thanks

Offline Hood

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Re: Hesitation at intersections
« Reply #3 on: October 31, 2010, 05:44:20 PM »
Figured that would likely be the issue but afraid I dont know enough about it as I have never used it.
Hood
Re: Hesitation at intersections
« Reply #4 on: October 31, 2010, 06:09:30 PM »
Thanks Hood.  I must have set angular check for a part that needed sharp corners and forgot to set it back.  I'm generally OK with the slight rounding of corners.  Considering the speeds I run, the small amount of rounding I get is acceptable.  Might try playing around with CV distance.

Offline Hood

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Re: Hesitation at intersections
« Reply #5 on: October 31, 2010, 06:17:46 PM »
I never use it as I never have issues with rounding due to high accelerations, but have it in the back of my mind that it is the opposite way to what you think with the angle you set. Could well be wrong though so if you do mess around with it let us know your findings please.
Hood

Edit, then again  maybe not, the more I think about it the more I am confusing myself so I think I will stop thinking  ;D
« Last Edit: October 31, 2010, 06:28:12 PM by Hood »

Offline Hood

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Re: Hesitation at intersections
« Reply #6 on: October 31, 2010, 06:25:26 PM »
Just looked and I know what the thing was that was in the back of my mind, it has >(greater than  symbol) there when it should to my mind actually be < (less than symbol).

Still interested in what you find out.

Hood

Offline ger21

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Re: Hesitation at intersections
« Reply #7 on: October 31, 2010, 07:07:48 PM »
I've seen it stop on some tangent arcs and not stop on others.
Gerry

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Offline Hood

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Re: Hesitation at intersections
« Reply #8 on: November 01, 2010, 03:13:51 AM »
Just looked and I know what the thing was that was in the back of my mind, it has >(greater than  symbol) there when it should to my mind actually be < (less than symbol).

Still interested in what you find out.

Hood

Forget what I said, I am awake now ;D

Hood