Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Satbeam on August 28, 2008, 10:29:42 PM
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When I load mach 3 and try 2 cut a part the table only moves about .0125 in a ismall circle . All settings are on " , so why is this happing ?
I need Help
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Satbeam,
Can you provide some additional information on what your trying to do?
RICH
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Maybe this is crazy but already happened to me. My post processor changed my units to metric instead on inches.
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I take it you are running some program generated by a CAD/CAM program.
Try typing into your machine on the MDI line - assuming your are at x0y0 -
G20
G2 x2y0r1
The machine should then describe a half circle of radius 1 inch
Your machine is set in inches.
Have a look at the GCode you are trying to run and seee if, near the beginning on the code the code G21 is included.
This changes to machine to run in millimeters and the whole thing is then 25 times smaller.
To put it right either delete the G21 or change it to G20
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I have used BMP2XYZ and Mach1Filter to make my G codes . I think I need to learn to set my table size and how to change my units to inches , that might help me get started . The problem is the movement is very poor , just the way it set up now . Maby some of my settings are wrong .
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What PC/OS are you running? Did you build this yourself?
Dave
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I have a Gateway with XP , and yes I built myself .
What PC/OS are you running? Did you build this yourself?
Dave
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Have you optimized XP to try and get Mach 3 to run smoother?
Dave
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No , I do not know how to do that .
Have you optimized XP to try and get Mach 3 to run smoother?
Dave
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What exactly is wrong with your machine, if you can try and explain then we will get you sorted quicker.
The optimisation steps are on the Mach Download page, you will find it from the downloads tab at the top of the forum. Before you do that run the DriverTest and see what the graph looks like, if it has lots of large spikes then optimisation will help, if its smooth then you shouldnt need to do the optimisation.
Hood
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I did the optimistion and there was spicks everywhere . Now to the problem = my softwear will only let the machine move about 1/2 eather direction . But , I can move the table anywhere I won't = manuily . Can't make a part like that . It's all in the movement .
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What happens when the movement stops? Do the motors whine?
Hood
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No it just stops .
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Please attach your xml and I will have a look.
Hood
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Here ya go =
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OK first thing I notice is you are set in imperial units but only have 200 steps per unit, I dont think that is correct. Can you give some info on the drives and motors you have and how they connect to your machine and what pitch ballscrews you have.
Hood
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Here is something from another post of mine = The motors are 3 (MT23-60-5 Uni-Polar Stepper Motor) .
Here is a little more about them -
60 Oz In. Hybrid
1.8° /200 Steps Per Rev.
24 Volts*
0.18 Amps Current Draw Per Phase
5-wire Uni-polar
NEMA 23 Frame
This is where I baught all = http://www.probotix.com/ My rods are 1/4 20 rod .
How can I change imperial units to Inches ?
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OK need to know whether you have any gearing between the motors and the screws and if so what is the gearing. Also need to know what you have the drives set to, they can be set 1/4, 1/2, 1/8 or 1/16 microsteps.
You are using Inch, Inch = Imperial.
Hood
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NO , I use lovejoys on all . How do I change to inches , where con I find it in the program ?
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You are in Inches, you do not need to change. Your steps per unit are set wrong but until you tell me whether your drives are set to 1/2, 1/4, 1/8, or 1/16 I cant tell you what they should be.
Hood
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I do not realy know what that is or where I find them . Or is it the diamitor of the shaft = 1/4 shaft , motor settings 200 = 720 = 287.5 Step pulse 0 and Dir Pulse 0 .
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You say you have the stepper drives from Probotix so looking at the manual there on page 1 is a diagram showing the dip switches, see what they are set to and read from the table. 1/8 step will probably be the best for you but whether they are at that I dont know.
Hood
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Send me the page , I can't find it .
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Heres the manual for one of their drives http://www.probotix.com/manuals/ProboStepVX.pdf Is that the one you have?
Hood
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Unfourtionitley that is not it . The board I have they do not make or sell anymore . Mine has lights yellow -red & green with no dip switches . This is the highest volts or amps . The only think is to write Probotix , I will do that if you its need . Or is their another avanue we can go ?
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OK you can do it by trial and error, enter 4000 in steps per unit for the X axis and save, then go to the MDI page and type G0X1 and see if the axis moves 1 inch, if not roughly measure how far it moves and we can go from there.
Hood
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Sorry I do not know where to tip on the MDI page .
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Click on the window as shown in the screenshot, type in G0X1 like in the screenshot and then press your keyboards Enter key
Hood
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It went almost 1/4 " and very slow .
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OK so try 16,000 now for x axis steps per unit then repeat the MDI but remember to zero the X axis first.
Hood
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That time it went 3/4 " . Does any of the other settings in their need to be changed .
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Not at the moment, you want to get your steps per unit done first then you can start tuning the motors to get the best performance without losing steps.
That is strange that it only moved 3 times when the steps per unit were increased by 4 times., maybe the motors lost steps. What to do is keep it at 16,000 but instead of a G0 do a G1X1F20 and see how far it moves this time.
Hood
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Sorry I had alreaty changed it to 18000 and it went 1" . Now , this went 1" as slow as it could go .
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Well if 18,000 works then there is something wrong in the figures you supplied, motor 200 steps per turn x 20 turns of screw to move 1 inch = 4,000, now figure in the microstepping and for 18,000 that would be 1/4.5 microstepping, you don't get that ;)
Anyway if 18,000 is working then stick with it for now, next thing to do is go back to the motor tuning and start messing with the Velocity and acceleration settings, best to lower the accel near the start and increase your velocity a step at a time then use your keyboards up/down arrow keys to jog back and forth. When your motors start squealing (missing steps) turn the velocity down a bit until they are again OK. Next start increasing the Accel and repeat. Find the sweet spot for your setup for Vel and Accel and yu are done, save and move to the next axis.
Hood
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Thanks Hood - if we ever hookup in the futer , its Red Lobster - all you can eat .
I do aperasate all you have done and all the time you spent helping my and everyone that will read this .
"Thank You Very Much"
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No problem, but think I will give the lobsters a miss, spent too many years catching them LOL
Hood
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This is why we call him "St. Hood" around here..........ok, we really don't but we're thinkgin it, for sure! ;) :D
Dave
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Think you missed out the "hi" between the first bit ;)
Hood
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Hood = So I turend back to 16,000 . Where would be a good place to start with the other 2 settings ? Do you have an idea where to start setting the Velocity and acceleration ?
Well if 18,000 works then there is something wrong in the figures you supplied, motor 200 steps per turn x 20 turns of screw to move 1 inch = 4,000, now figure in the microstepping and for 18,000 that would be 1/4.5 microstepping, you don't get that ;)
Anyway if 18,000 is working then stick with it for now, next thing to do is go back to the motor tuning and start messing with the Velocity and acceleration settings, best to lower the accel near the start and increase your velocity a step at a time then use your keyboards up/down arrow keys to jog back and forth. When your motors start squealing (missing steps) turn the velocity down a bit until they are again OK. Next start increasing the Accel and repeat. Find the sweet spot for your setup for Vel and Accel and yu are done, save and move to the next axis.
Hood
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Each system is different, it all depends on motors, drives, weight of axis, pitch of ballscrew, geariing etc and unless someone has an identical machine in every way they cant tell you. Best thing I have found to do is set the acell low and start increasing the Vel testing all the time by using the Up/Down arrow keys. When it starts to miss steps (motor squealing) back off a bit. Then start increasing the Acell until the same happens and back off. You may find it is better for you to have a lower Velocity and have the Acell increased, all depends on your individual machine so its trial and error I am afraid.
Hood