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Author Topic: 4th axis setup  (Read 27111 times)

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Offline Hood

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Re: 4th axis setup
« Reply #10 on: March 30, 2011, 05:26:02 PM »
Try removing the Rotational Rollover from General Config and see if that helps.
Hood

Offline lgr

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Re: 4th axis setup
« Reply #11 on: March 30, 2011, 06:24:36 PM »
I removed the "rot 360 rollover" and that seemed to fix the ratio, but now it's back to being stone slow. I removed the "Ang short rot onG0" as well and didn't notice any difference. I've tried the rotation radius at both 6.25, and .001 no change. Any axis that runs with the 4th axis slows right down to a crawl even though "units a minute" reads around 330, is that degrees a minute? I have the machine set to inches. This is the case when going to "zero" as well. The A axis motor speed is set to around 2000 the sllider will let me go to about 7000. Thanks

Offline lgr

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Re: 4th axis setup
« Reply #12 on: March 30, 2011, 06:37:34 PM »
Just to add some ifno to the above, with the feed set at 300 it took 4 minutes to run through 200 lines of code and that's just a test cylinder no detail on the object what so ever.

Offline Hood

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Re: 4th axis setup
« Reply #13 on: March 30, 2011, 06:39:06 PM »
Yes units on a rotational axis are degrees so 330 degrees per min.
There are settings for radius on I think settings page, try entering 0.0001 for the A and see if that helps, Ger is the guy for rotational axis so maybe he will pop in and advise.
Hood

Offline lgr

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Re: 4th axis setup
« Reply #14 on: March 30, 2011, 09:08:23 PM »
I've played with the radius a couple of times both .0001 and the 6.25 which is the rad for the part in the test file, without any change. Any suggestions for soft limits/  I set them at +999999. and -999999. not sure if thats right it doesn't mention 4th axis in that section of the manual.
Thanks for all of the suggestions. I'm going to give up for now and index it with the the jog buttons every 20 degrees or so and run it in 3d. I have to get some parts out for Monday and I've got 3 full days into computer wrestling with only a small amount of progress. If you think of anything let me know

Offline lgr

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Re: 4th axis setup
« Reply #15 on: April 14, 2011, 06:42:40 PM »
I'm back! Finally got the project made and shipped by indexing the 4th axis with the jog buttons and running a normal 3d file. Now I want to trouble shoot it again without the deadline pressure. I did some more reading on the forum and i wondered if someone can comment on these ideas. I was trying to run the file of off a USB thunb drive which I now understand is a no no and I'm running off of a motherboard mounted parrallel port and no stand alone graphics card. Would you suggest adding a high quality parrallel port card and a stand alone graphics card or a smooth stepper card or some combination of both? Thanks for your help.

Offline lgr

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Re: 4th axis setup
« Reply #16 on: June 14, 2011, 08:41:10 PM »
It's June already and I still haven't got this 4 axis working properly. Just a quick update I added a stand alone graphics card and increased memory to 2 gb and stopped running programs off of a USB thumb drive. i also bought a smooth steeper card but I haven't got that installed yet. The combined motion seems a lot smoother now. The problem is every time I try to run a 4th axis program and the G code calls for movement even if it's only 1 degree the 4th does a complete revolution
before any of the other linear axis move. For instance if you look at the code below, the "A" or 4th axis rotates a full revolution until it hits the A -1.818 location then the Z moves from  Z5.4337 to Z5.4337 the 4th axis does another full revolution until it reaches A -2.727 and so on. Why would it not just move from A-1.818 to A-2.727 with out  doing a complete revolution? Any suggestions would be appreciated.
G00 G49 G40.1 G17 G80 G50 G90
G20
(4th Axis Roughing)
M6 T1
M03 S4583
M8
G01 X0.0000  Z6.7306 A0.000 F200.
X0.0000  Z5.4091 A0.000
X0.0000  Z5.4337 A-1.818
X0.0000  Z5.4452 A-2.727
X0.0000  Z5.4455 A-3.182
X0.0000  Z5.4410 A-3.636
X0.0000  Z5.4318 A-4.090
X0.0000  Z5.4174 A-4.545
X0.0000  Z5

Offline Tweakie.CNC

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Re: 4th axis setup
« Reply #17 on: June 15, 2011, 03:18:49 AM »
I think you may need to change to Incremental mode to achieve that. Change the G90 to G91 on the first line.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline RICH

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Re: 4th axis setup
« Reply #18 on: June 15, 2011, 06:21:27 AM »
G91
G0 A-1.818......... rapid / rotates to that angle  at max velocity
G01 F200 Z5.4452 ......Z move at the commanded feedrate
G0 A-2.727  ......... rapid / rotates to that angle  at max velocity

You can play with the above trying different checked Rotation in Config but should just index.

RICH




Offline BR549

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Re: 4th axis setup
« Reply #19 on: June 15, 2011, 10:35:07 AM »
The 4th axis should not be a problem BUT it requires a FAST A axis to do basic 3d work. The combined moves can ONLY move as fast as the slowest component (A axis) . Using Radius COMP is required for MACH to be able to correctly comp the feedrates. Even then the calculation is BASE on how fast the A can move.

IF you need XAZ to go FASTER make the A go faster. The rest of the axis's will follow (;-)

Just a thought (;-) TP