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Author Topic: Do i need a bigger pc for mach..  (Read 12967 times)

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vmax549

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Re: Do i need a bigger pc for mach..
« Reply #20 on: September 03, 2009, 10:32:27 AM »
What kernal speed are you running?   How many steps per unit?

(;-) TP

Offline Chris.Botha

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Re: Do i need a bigger pc for mach..
« Reply #21 on: September 03, 2009, 05:54:53 PM »
i was running 60 000 hz and 1548.******************x steps per. Vel = 1200mm/min and Acc = 350

no issues..  (other than the harmonic shudder at 800mm/min) 

i finally backed Mach all the way back to 24 000 hz and vel 780 and Acc 200 and cut this at 400mm/min to finish that job. anything more than 400 and it started skipping like mad..

thats like being in the dark ages....

vmax549

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Re: Do i need a bigger pc for mach..
« Reply #22 on: September 03, 2009, 06:29:48 PM »
I would try it at  45  and see IF it will help out.  I run at 45 and use 40,000 steps per inch at 50 IPM  which is similar to what you run @ 1200mm/M

I use a 2gb board with 2gb mem.

IS the problem JUST with large files?   At what size does MACH start to act up?

Offline Chris.Botha

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Re: Do i need a bigger pc for mach..
« Reply #23 on: September 03, 2009, 11:39:48 PM »
untill now the biggest files I have run have been at about the 12 to 20mb mark. that file was by far the largest.. the 20mb files gave grief if the toolpath display was on even for jsut index stuff, but much smaller files clocking in at only 4 to 7mb will also stall mach if the toolpath display window is on and the toolpath requires a rotation of A.

In answer to the last question, with this toolpath was the first time i got the complete failure where it actually cuts through my models. with other large paths until now its like the machine will stall then start again but in the right postion at least. so i get warning to run  down feedrate by hearing the jerky motion of the mill..

Offline Jeff_Birt

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Re: Do i need a bigger pc for mach..
« Reply #24 on: September 03, 2009, 11:56:09 PM »
Quote
i was running 60 000 hz and 1548.*

Ah! Now we are getting somewhere. Higher kernel speeds use up a lot more processor time, some PCs won't do them even under the best circumstances. It has as much to do with the design of the motherboard as it does with processor speed. Some new uberfast MBs won't won't at all. If you couple that with huge GCode files and a relatively small amount of ram (lots of page file swapping going on, lots of HD access) and the PC can't keep up with the precise timing Mach needs.

If you want to run really fast pulse rates then jump over to my website and grab a SS. It will pulse faster than you will ever need AND take a huge load off the PC making it a lot easier for it to handle the large files. (I'm not just saying this because I sell them. Given what your trying to do I would heartily recommend one though.)
Happy machining , Jeff Birt
 
Re: Do i need a bigger pc for mach..
« Reply #25 on: September 04, 2009, 01:36:05 AM »
Smoothstepper may be what I'm after, I've got a fairly big and quite powerful machine but I could do with faster movement. My stone ages PC will send it round at 1100mm/min tops. I'll investigate.

Offline Chris.Botha

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Re: Do i need a bigger pc for mach..
« Reply #26 on: September 04, 2009, 06:44:42 AM »
i may look at a smoothstepper but Im a little nervous after hearing about kens G00 problems with his smoothstepper and his mill crawling and having to edit those codes out. He is on holiday now but I will hear from him when he gets back whether he got that resolved or not. I think the code itself may be very painfull .. my roland which can maintial 900mm/min on xyz is also crawling with the same code output to rml.. i think the lack of arcs to optimize movement is the issue here...




Offline Jeff_Birt

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Re: Do i need a bigger pc for mach..
« Reply #27 on: September 04, 2009, 08:57:19 AM »
What is strange about the G0 problem is that there are only two reports of it. I've sold 50+ SS and have not had a customer have that problem. I suspect there has to be some obscure Mach variable being set in the profile, perhaps one not even visible to the user, that causes this. A similar now defunct mach Variable is responsible for a Limits responding slow on the SS, Greg found that problem and is taking care of it now.

Lots of teeny-tiny moves will make things creep as the machine is trying to accel/decel on every one of them. You might try turning on CV mode and see if that helps. When you combine a huge file and a high pulse rate you are creating a big strain on the CPU so the precise timing needed by the parallel port driver is not possible.
Happy machining , Jeff Birt
 

vmax549

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Re: Do i need a bigger pc for mach..
« Reply #28 on: September 05, 2009, 05:13:34 PM »
CV  SHOULD be blending those Micro moves into a fluid fast movement (;-) That is how the big boys do it.

(;-) TP
Re: Do i need a bigger pc for mach..
« Reply #29 on: September 05, 2009, 08:05:52 PM »
Good point, is the code setting the machine into exact stop mode? that would cause juddering. Constant velocity mode is a lot smoother.