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Author Topic: 4th axis runs too slow !!!!  (Read 10388 times)

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4th axis runs too slow !!!!
« on: August 03, 2006, 07:58:00 PM »
I have a Taig and am using Mach3 1.9.  When I run rotary axis movement it takes a long time to get to the proper position, because the G-code is in inches and Mach3 and Taig move in degrees/min. Example. 2 inches per minute gets there fast but 2 degrees/min goes by tick ------ tick ----- tick, etc. and there is 80 ticks per degree. This adds a lot of time to the cutting process.

Does someone know a way around this problem. The code is too big to edit all the A moves with a higher F value. My code is generated by Visual Mill.

Larry

Offline Graham Waterworth

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Re: 4th axis runs too slow !!!!
« Reply #1 on: August 04, 2006, 02:36:59 AM »
Sound as if you have 1 of 2 options

let visual mill re-post the code with new feeds or drop the code into notepad and do a search and replace of the a feeds.

Graham.
Without engineers the world stops
Re: 4th axis runs too slow !!!!
« Reply #2 on: August 04, 2006, 11:12:00 AM »
There are thousands of lines of code to change which would take hours and it seems that there should be a way to automate the solution to this problem. I asked this same question about 2 years ago, also with no answear at that time. It seems that by now someone would have a solution.

I can't find anywhere in Visual Mill to introduce a 4th axis movement speed. Best I can tell is that it assumes the same speed and feed of the x axis which is in inches/per minute. At 2.7 degrees/min it will take 130 minutes to travel 360 degrees just for 1 pass. The G-code will make 6 passes of the a-axis, wihch will take 13 hours. And then 2 more finishing passes.

If someone knows a way to change that in Visual Mill I would be thrilled to hear it. What about Mach-3, is there no way to change it there. What about some VB script to adjust the feed for a-axis?

Now, I can spend a few hours manually changing the G-code. But what about next time I generate code. It seems like we should be able to have this done automatically.

I cant believe that I am the only one having this problem. If I am, I sure would like to hear how the rest of you guys are doing it that is different from me.

I am extremely frustrated and need help BADLY.

Offline ART

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Re: 4th axis runs too slow !!!!
« Reply #3 on: August 04, 2006, 12:31:57 PM »
Hi Larry:

  On the settings page, there is a DRO labeled A-Axis rotational diameter.
Set it to the diamter of th eobject, or to .0001 , if .0001 is entered, then Mach will use the Z position as the diameter calculation,
it will then correct the feedrate..

Art
Re: 4th axis runs too slow !!!!
« Reply #4 on: August 04, 2006, 02:28:42 PM »
Thank you for the response, Art.

I briefly tried it on my desktop, with no machine attached, and it looks like my problem is solved. Next I'll try it in my workshop, although I'm sure it will work.

Does this keep the 360 degrees intact so that the rotary table will go from 0 to 360 then back to 0 again? I'm not sure that I asked the question correctly.

Larry

Offline ART

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Re: 4th axis runs too slow !!!!
« Reply #5 on: August 04, 2006, 03:05:05 PM »
Hi LArry:

 Yes, all else remains the same, it just fixes the feedrate to units/minute around the ouside circumferance on an object..

Regards,
Art
Re: 4th axis runs too slow !!!!
« Reply #6 on: August 04, 2006, 10:51:38 PM »
Everything worked perfectly, thank you for the help.

Larry

Offline John S

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Re: 4th axis runs too slow !!!!
« Reply #7 on: August 05, 2006, 03:07:36 AM »
Larry.
This DRO labeled A-Axis rotational diameter has to be altered for each job where the diameter is different.
A large diameter has to move slower than a small one.

I have put that A Axis DRO on the first page as a reminder.

have a look at the latest version, 071 as it has a brilliant toolpath display for 4th axis, watch this video first for the settings.

http://www.machsupport.com/toolpath.wmv

John S.
 
 


John S