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Author Topic: continuous motion and tangential cutting problem  (Read 6708 times)

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Offline Hood

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Re: continuous motion and tangential cutting problem
« Reply #10 on: November 23, 2010, 08:19:40 AM »
Ok try setting lookahead to maybe 2000 and see what it does.
The rotation is because of the arcs so you will have to eliminate them in the code if they are not needed or make them lots of short line segments if they are.
Hood
Re: continuous motion and tangential cutting problem
« Reply #11 on: November 23, 2010, 08:48:01 AM »
2000 causes errors - only part of the file was cut and there were some strange movements added!  tried 200 but this didnt help.

i went down the route of trying to use arcs to solve the problem and get faster smoother motion, but as we know got another problem with the A axis spinning in the material.  i am amazed that tangential cutting is not designed to work with arcs since knife cutting needs to be high speed, and the only way to get high speed is with arcs unless you are only cutting straight lines.  do you think it is worth me experiomenting or are you certina thta arcs and tangential mode do not work?  i can cut without the problem of the knife spinnign on axis for most of the job but it seems to occur at least once apparently at random.

Offline Hood

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Re: continuous motion and tangential cutting problem
« Reply #12 on: November 23, 2010, 09:20:48 AM »
I have never used tangential so I can only go by what the manual says and according to the manual Tangential does not work with arcs.

Might be worth messing with the CV settings in General Config page for your other problem but it may just be that your machine is not rigid enough for the speed and accel you are trying to move at.
Hood

Offline ger21

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Re: continuous motion and tangential cutting problem
« Reply #13 on: November 23, 2010, 11:59:45 AM »
Do you have CV distance or angle set?
Gerry

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Re: continuous motion and tangential cutting problem
« Reply #14 on: November 23, 2010, 01:47:49 PM »
CV Dist Tolerance is set at 180

Stop CV on angles > is on zero, and not ticked.

i have ticked this now and set to 90 but no improvement. i also tried bigger values for CV Dist Tolerance but again no change, machine still goes very slowly on a curve as it goes through the many small points and shakes violently.
Re: continuous motion and tangential cutting problem
« Reply #15 on: November 24, 2010, 08:15:50 AM »
hi again

i thought i would try a simple test to see if i really am in constant velocity mode by running this g code:

g0x0y0
g0x100
g0x200
g0x300
g0x400
g0x500
g0x0y0

simply moving in a straight line but in stages. when i ran the code the machine stopped for each point or line of code and did not run at constantly velocity.

i added g64 at the beginning but that didn't change anything.  so am i not in constant velocity mode? I don't understand!!

Offline Hood

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Re: continuous motion and tangential cutting problem
« Reply #16 on: November 24, 2010, 08:19:56 AM »
Can you attach your xml please.
Hood
Re: continuous motion and tangential cutting problem
« Reply #17 on: November 24, 2010, 08:53:55 AM »
here it is

Offline Hood

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Re: continuous motion and tangential cutting problem
« Reply #18 on: November 24, 2010, 09:22:09 AM »
First look it seems fine, however you do have a fast Velocity and fairly fast accelerations set especially for X (23502mm/min to zero in 0.75 secs if my calcs are right). This may be needed due to the type of machine but if the machine is not extremely rigid you will get shaking. You could try dropping the X Rapid and the x and y accel down a bit to see if it helps.
Another thing that may help is to try the tempest planner, not sure if it will work for tangential control but have a read through that part of the forum and see if you think it would help.

Hood
Re: continuous motion and tangential cutting problem
« Reply #19 on: November 24, 2010, 04:48:18 PM »
On the settings page, what have you set the CV feedrate and CV distance to? And are they both active, that is green light?