Re: [Emc-users] Speed issue with EMC
Hi Rob, The computer is plenty fast enough. This is a physics problem, something like possibility #3. If my memory serves correctly, EMC will try to make every little corner to within 0.001mm unless you tell it not to. Try adding this to the top of the program: G64 P0.01 This tells EMC it's allowed to round off the corners a little bit. P is the tolerance value, though it might actually be out of spec by twice the P value, since long stretches of tiny segments get glommed together if they move out of line by less than P. -fenn On Fri, 8 Feb 2008, Rob Jansen wrote: My machine is set to to amax. speed of 4800 mm/min (~ 190 inch/min) and an acceleration of 9600 mm/min. But somehow, during milling I reach only speeds of up to 600 mm/min when doing small steps in the program. The thing is controlled with an older PC I still had standing in a corner - don't know the exact specs but it is a 1.4 GHz AMD / 786 MB SDRAM and a simple VGA card using stepper motor control through the printer port. The G-code is created using DeskProto an contains a lot of small steps like this: F2000.0 G1 Y26. Z-7.6255 F2000.0 G1 Y26. Z-7.5962 F2000.0 G1 Y26.5556 Z-7.5686 F2000.0 G1 Y26.7778 Z-7.5429 I see three possible causes for the low speed reached during milling this (larger steps are going faster): 1. the PC is too slow (there is a fairly high CPU load of about 80% 2. the G-code is not optimal: all the F2000.0 G1 sequences are not needed and just take up valuable time 3. EMC is deaccelerating after each step before proceeding with the next one. Is anyone using DeskProto with these kinds of speeds ? and what kind of PC and/or DeskProto settings are you using ? What is the best thing to try first: create a simple C-program to optimize the G-code or should I just go to the shop for a new PC? Any suggestions on processor type and/or memory, what is the speed difference between Core2 Duo and Quad or the newer AMD cores? I am new to EMC so any help in configuring and building a decent system is appreciated. Regards, Rob - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Speed issue with EMC
With your settings it will take 20 mm to reach max speed. So 20mm to ramp up and 20mm to ramp down. Do a 60mm move and you sould see max speed in Axis. Don't forget that Axis does not update in realtime so it lags a bit behind. If your moves are short you don't have time to reach max speed. If you can increase your acceleration without loosing steps you can improve this. John On 9 Feb 2008 at 18:51, [EMAIL PROTECTED] wrote: My machine is set to to amax. speed of 4800 mm/min (~ 190 inch/min) and an acceleration of 9600 mm/min. But somehow, during milling I reach only speeds of up to 600 mm/min when doing small steps in the program. - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Speed issue with EMC
John, Ben, thanks for the explanations. Meanwhile I fiddled around a bit more with my system and spent quite some time air milling and after playing around with different settings I discovered that , as John suggested, higher accelaration gets faster results. I now got the acceleration up to 500 mm/s and now it only takes half the time to mill one part of the mold. For each little piece of line that DeskProto creates, EMC goes from a full stop via ramp-up to max. speed and a ramp-down to full stop again and since the model is being traced using a 0.2 mm step, it never reaches any speed ... That having said: I just played around with the G64 P... command and now it reaches max. speed during milling. This makes milling in foam 3 times faster and knowing that previous runs took 17 hours to complete that's defenitely worth something :) I used P0.1, close enough since the model will be spray painted with a primer and a high gloss paint afterwards. It will definitely be worthwhile to read up on G-coding, optimizing and setting proper parameter values makes the difference Cheers, Rob - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Speed issue with EMC
My machine is set to to amax. speed of 4800 mm/min (~ 190 inch/min) and an acceleration of 9600 mm/min. But somehow, during milling I reach only speeds of up to 600 mm/min when doing small steps in the program. The thing is controlled with an older PC I still had standing in a corner - don't know the exact specs but it is a 1.4 GHz AMD / 786 MB SDRAM and a simple VGA card using stepper motor control through the printer port. The G-code is created using DeskProto an contains a lot of small steps like this: F2000.0 G1 Y26. Z-7.6255 F2000.0 G1 Y26. Z-7.5962 F2000.0 G1 Y26.5556 Z-7.5686 F2000.0 G1 Y26.7778 Z-7.5429 I see three possible causes for the low speed reached during milling this (larger steps are going faster): 1. the PC is too slow (there is a fairly high CPU load of about 80% 2. the G-code is not optimal: all the F2000.0 G1 sequences are not needed and just take up valuable time 3. EMC is deaccelerating after each step before proceeding with the next one. Is anyone using DeskProto with these kinds of speeds ? and what kind of PC and/or DeskProto settings are you using ? What is the best thing to try first: create a simple C-program to optimize the G-code or should I just go to the shop for a new PC? Any suggestions on processor type and/or memory, what is the speed difference between Core2 Duo and Quad or the newer AMD cores? I am new to EMC so any help in configuring and building a decent system is appreciated. Regards, Rob - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
