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controlling my speeds
« on: October 17, 2011, 12:29:50 PM »
I am having issues figuring out how to control my speeds.  I am using a Syil x5 speedmaster.  I have an A axis running, and it's max speed is 23.5 inches per minute. I don't know what my other servo speeds are, I can only assume they are the same?  My problem is that the x is moving far faster than the A.  I don't mind the speed the A is running at. I'd like to bump it up some, but then the x will move even faster. The problem I have is only when X runs in a straight line. I'm cutting some letters right now, so take the letter M for example. The a will turn to put the bit in position. Then only the x needs move the straight line on each side of the m. It takes off like a rabbit and breaks the bit.  When A and X move together, like the v inside the M, there is no issues, they move nice and easy. I want to bump up my speed, it's taking too long to cut the letters, and the bit is capable of more travel speed, but not the kind of speed it's running in x only mode. If I boost the speed, it boosts both a and x, so that's not good. I want to boost A and slow down x. I am not sure how to do this. I tried going into the motor tuning and dropping the speeds for x, but then i get a pwm error.

Offline Hood

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Re: controlling my speeds
« Reply #1 on: October 17, 2011, 03:37:49 PM »
Your A axis should be set up for steps per degree if its a rotational axis.
Hood
Re: controlling my speeds
« Reply #2 on: October 17, 2011, 06:14:10 PM »
ok, how do I do that?  I did do the set up procedure to auto config the travel of the rotary table...it asked me how far to move it, so I say 20 degrees, then it moved it and asked how far it travelled and it was 15, so then it reset it and I did test again and it was good. Is this the same thing you are talking about?

Offline Hood

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Re: controlling my speeds
« Reply #3 on: October 18, 2011, 06:52:49 AM »
I prefer to calculate rather than have Mach work it out as that way relies on your measuring.
Ok do you have the axis set up as a rotational axis on General Config page?
There is also an option on the settings page I think that allows you to enter the radius of the 4th axis work which you may need t set depending on your code. If the X flies away when it moves on its own then it would seem the feedrates in the code are the problem.
.
Hood
Re: controlling my speeds
« Reply #4 on: October 18, 2011, 10:35:51 AM »
The x does not fly away, it just flies across the piece super fast. It is doing the correct cut path, just at sonic speed, the A is slow. When they work together, there's no problem, it's just when the x moves in a straight line without needing a that the speed jumps way up. The code does set the radius of the piece being cut. Everything is actually cutting perfect, it's just when that x axis has the opportunity to do a cut without combining with a then she speeds way up.  When combined with A it's way slower than i'd like. I need to find the happy medium.

Maybe this will help.  Here is my motor tuning settings

Steps        Velocity            Accel

x 10160     31.158            31.158

Y 10160     100.02           12

z  10160      129.42          50.5

a  400           1000        1000


My software Settings from Visual Mill 6 for cutting 3 letters on a tube, 4 axis pocket

Bit is 0.024

Plunge 25 in/min
Approach 25
Engage 22
cut 17
retract 25
depart 26

Total cut depth is .07
 Finish Rough depth is .056 and finish depth is .014
Rough depth cuts are .0224    <but that's what it's supposed to be.  The machine is cutting right now and each layer is not .0224, it's cutting layers at .0117 for whatever reason I don't know.

Offline Hood

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Re: controlling my speeds
« Reply #5 on: October 18, 2011, 11:38:27 AM »
Your speeds in visual CAM are fast I would say and that is what the X will be running at when it is moving on its own, the reason its slower  when in conjunction with A will likely be because A is a much slower axis  (2.77 rpm approx) so X feedrate will be slowed down accordingly.
Hood
Re: controlling my speeds
« Reply #6 on: October 18, 2011, 12:58:26 PM »
ok..what kind of speeds would you choose?
Re: controlling my speeds
« Reply #7 on: October 18, 2011, 12:59:57 PM »
oh..also, is this the reason that the PWM error kicks on..I am asking the machine to move too fast?

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Re: controlling my speeds
« Reply #8 on: October 18, 2011, 02:07:51 PM »
I dont know what kind of speeds as it would depend on cutter size, amount of flutes, spindle speed capability and material being cut. I dont have a clue about wood so if thats what you are cutting someone else will hopefully answer.

PWM error is likely due to spindle speeds being set too high or the spindle not being set up correctly, afraid again I dont really know as I have only ever used servo spindles with step/dir


Hood
Re: controlling my speeds
« Reply #9 on: October 19, 2011, 10:40:25 AM »
I am cutting plastic rod. I figured out the PWM issue. Right on the very last page, troubleshooting in my mill manual. I needed to change motor control. It was 500 and 15%, I needed to change it to 500 and 0%. Since then, no more PWM error.  Things seem to be working much better now.  I did not change any of my programming speeds. The tiny bit is cutting great at those speeds. I actually think it can handle more, but when I bump my speeds, the rotary table speed does not increase. I think it's just a slow table, does like 1000 degrees per minute..seems to me though that is faster than what it is doing. No doubt i'll get that worked out. Right now I have to figure out what's going on with my software. I'm cutting like a letter A and an M and both letters have a box at each corner. The boxes at the bottom of each letter is cutting out spot on perfect. The boxes at the top of each letter are cutting out perfect except for across the top of each box is not flat it is V shaped. It's strange. I had to do a manual clean up jog across the top of the two letters to clean them up.