Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: oakmeadows on January 22, 2011, 11:41:50 AM
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Hello all this is my first post so please go easy on me.I have a small problem regarding my mach 3 setup i have setup my machine in mach 2 to use mm but when i type any g code in
such as
G00 x1.50
my machine moves 1.5 inches and not mm so is there a different gcode for trying to move my machine say 10mm
i know it maybe something stupid im doing wrong but this is why i need advise
i want to cut squares out 100mm by 100mm
any help would be most welcome
thankyou
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Can you attach the xml for the profile you use please. There are a few things that can cause this and the easiest way is if I look at your config. The xml will have the name of the profile you are using and it will be in the main mach3 folder.
Hood
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i would if i knew how to get that file sorry im very new to this but i would like your help
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When you start Mach have a look lower right of the main page and see the profile name. Close Mach and browse to the Mach3 directory (C:\Mach3 is the default) look for a file with the name of the profile and a xml extension, copy it to your desktop and rename to oakmeadows.xml and then use the additional options button on the reply page to browse and attach the file.
Hood
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Hope you can get this one
thanks for your help
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Ok had a look and now need to know what type of motors you have? (steppers or servos)
If steppers what make of drive, if servos what line count is the encoder?
Also any gearing between motor and screw and what pitch is the screw?
You have different steps per unit for all three axis so I am assuming they are all different.
Hood
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im using 3 HT23-400-8 400ozin Stepper Motors from www.probotix.com
and im using the driver that come with it which is 4 x ProboStep VX Uni-Polar Stepper Motor Driver
there is no gearing the ratio is 1 :1
i am also using half steps
x axis moves 15mm per 1x revelution of my screw
y axis moves 5mm pre 1x rev
z axis moves 3mm per rev
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Ok then
Xsteps per unit should be (200 x 2)/15 = 26.6666666666666
Ysteps per unit should be (200 x 2)/5 = 80
Zsteps per unit should be (200 x 2)/3 = 133.33333333333
It would however be better if you could set the drives to microstepping, maybe 8 or 10 as that would give you much smoother motion and better resolution. Not sure if your drives are capable of that.
Hood
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Oh and BTW you will need to increase your Velocity and Acceleration for each axis as well as you have basically had them set in inch units. If it worked well at these settings then multiplying them by 25.4 should be a good starting point.
Hood
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Sorry ive made a mistake
x moves 25mm per 1.69 turns
y moves 25mm per 5.08 turns
z moves 25mm per 8.04 turns
so i worked it out
x axis 200 (steps)x2 (half steps)=400 x 1.69 = 676 steps fer inch
y axis 200 (steps)x2(half steps)=400 x 5.08 = 2032 steps fer inch
i then went into mach3
config
motor turning
and put 676 in the x axis and so on
if i type in g0 x 1.0 the tool moves exactly an inch
so what do i have to do to make it move in mm then
thanks again
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You need to work out the steps per unit, as you are set up in metric a unit is 1mm so you need to find the steps it takes to move 1mm, in other words divide the inch values you have above by 25.4
Hood
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Many thanks for your help i will try that tomorrow and see how i get on.
I can do quarter steps and eighth steps which will be the best do you think
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I would go for 1/8th step, you should get much smoother motion and better resolution. You will however need to alter the steps per unit again if you do that, you would need to divide the inch values you worked out by 25.4 then multiply by 4,or if you already have the steps per mm set just multiply by 4
Hood
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Ive done as you said(apart from the steps ive left them at half steps and ive done a quick test cutting out a 100mm x 100mm piece of aluminum board and its great i havnt allowed for the tool diameter as yet,there maybe a way of doing it in mach3 but not found it yet so i have just added on the diameter of the cutter (when doing the gcode)to get to the size i require but on a whole it seems great.
I do keep getting the mach3 software resetting all the time it might be cutting for 20 secs or a minute but it does reset.I only have a push button reset at the mo i havnt put on my limit switches as yet ,the motors arnt getting hot they are warm but not too warm and if i turn off the drivers and motors it doesnt reset so maybe its a wiring problem but thats for another day
many thanks for your great advise and hope to ask you more questions soon
regard
kevin
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Likely you are picking up noise on the E-Stop input, best to have all signal wiring properly shielded and grounded but as a stop gap you can try increasing the Debounce Interval on the General Config page, try 2000 and go lower if you can.
Hood