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Having trouble using and understanding Mach3
« on: June 09, 2008, 11:04:56 PM »
As you can tell i am a first time user of this software.I am stuck at the basics still...Setting up homing limits,calibration,motor tuning.I have tried multiple things that i have read on this site and also other sites.Help?Does anybody know of anybody in the NewHampshire area that could do some one on one training???

Offline jimpinder

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Re: Having trouble using and understanding Mach3
« Reply #1 on: June 10, 2008, 02:04:33 AM »
Unfortunately America is BIG. - and I am stuck on the other side of the pond.

Stick at it - if you read some of the posts there are those much worse than you. How far have you got and what is your problem.

You can get Mach 3 running, with very little effort or expenditure, and produce some worthwhile stuff, without all the bells and whistles, limits and homing of a commercial set up.

I think most people try to get it all up and running at once, which is a mistake (because there is a lot more to go wrong). I am also in a theatre organ forum - again based on a PC and on that if you get one note to sound you have mastered the basics - only several thousand to go before you get the full organ.

From your other posts, it seems that you are a fair way into it, I know I have just answered a post about acceleration from you. If it is the principles you are not sure about, that I can answer on the forum (and benefit other people).

If you have your three axis working (dont worry if it is at optimum speed yet) then you are ready to try cutting one or two things on your machine. If you are already confident with machines manually, then converting to a CNC is no problem.


Not me driving the engine - I'm better looking.
Re: Having trouble using and understanding Mach3
« Reply #2 on: June 10, 2008, 06:49:02 AM »
Thanks jimpinder for your great advise i will try it today

Offline jimpinder

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Re: Having trouble using and understanding Mach3
« Reply #3 on: June 10, 2008, 09:34:13 AM »
I must admit, I didn't expect such a simple answer.  If you are "up and running" try writing some GCode to make a program.

Again forget all the bells and whistles. There are two commands (4 to be really truthful, but start with two)

G0 is the command to move from where you are to another specified point. The axis are split into inches. We will assume you are starting in the bottom left hand corner of your table. There are two co-ordinate systems running simultaneously on your machine. One is machine co-ordinates and the other is program co-ordinates (or work co-ordinates). These are displayed on the same DRO's. If the Machine Co-ordinates button is lit, the machine is displaying machine co-ordinates, if the button is not lit you can see the program co-ordinates. (Click the button to toggle between the two).

We will use program co-ordinates - becasue this is how you write your programs.  Change the display to program co-ordinates, and then zero the axis DRO's. This now says the place where my cutter is in 0.0.0. Normally when milling, this is the bottom left hand corner of the work, with the cutter just resting on the top of the work.

If you now type in directly on the MDI page ( page 2) G0X1 (return) the machine will move the cutter to position X1 Y0. You could have repeated the Y position in the instruction it would have made no difference. Iy you type G0X0 the cutter will return to 0.0.0

If you type in two co-ordinates e.g. G0X3Y5 then the cutter will move positioin to X3Y5 simultaneously moving each axis i.e. a diagonal move (not strictly diagonal but) Note the y axis will move more slowly than the x axis so as to reach it's position at the same time. If you also typed in in a z co-ordinate then the z axis would move simultaneously as well.

The axis with the longest movement moves at the speed set in motor tuning, the other axis move accordingly.

G1 is the same command, but this is the cutting move and you can add a further parameter F which is the feed rate. i.e. it does not move at G0 (warp speed) F is in inches per minute.

You can now cut some thing - start the spindle, drop the z axis to cutting height, and move from here to there
three commands  - M3     G0 Z-1  G1F2X6
We will cover M3, M4 and M5 later, which start and stop the spindle.

G2 and G3 are cutting moves (F parameter if required) but these deal in arcs of a circle - G2 is clockwise, G3 is counter clockwise.
There are other parameters to add in, and I tend to use the R parameter which is the radius of the circle (or arc) (You can use I,J or K which are offsets for the centre of the arc, but R is a lot easier). R can be plus or minus - and if you use the wrong one you will get rabbits ears - try it and see.

The beauty about Mach 3 is that you can make up GCode programs and when you enter them , your movement will be shown in the toolpath window, wich gives you an idea if you have done it right or not. You can also run it on Mach 3, without your machine being connected. I have Mach3 on this computer which is in my office/study/front room and I write most of my programs here and then transfer them to the workshop on the wireless connection to run them in the workshop - but most of the testing is done here in comfort.

Have a crack at it, and you will find that it is great fun, and you can soon get quite proficient at it.

I forgot to say that that is all there is to GCode. Those four commands cover all the moves. All the other commands are to do with positioning,  and incidentals - yes there are a lot of them, but you don't need them.
« Last Edit: June 10, 2008, 09:38:46 AM by jimpinder »
Not me driving the engine - I'm better looking.

Offline Kristin D

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Re: Having trouble using and understanding Mach3
« Reply #4 on: June 10, 2008, 12:27:15 PM »
Jim,

That reply should be a sticky at the top of the page! I wish someone had made it that clear when I was begining to figure out the G-code a month or two ago.

Kristin

Offline Chaoticone

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Re: Having trouble using and understanding Mach3
« Reply #5 on: June 10, 2008, 12:50:30 PM »
Great post Jim.

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

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Re: Having trouble using and understanding Mach3
« Reply #6 on: June 10, 2008, 01:07:32 PM »
Great post Jim.

Brett

One of many, how the hell has has any time for machining i do not know  ;D ;D ;D

Phil_H
The Good Thing About Mach3, Is It's very Configurable

The Bad Thing About Mach3, Is It's Too Configurable

Offline budman68

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Re: Having trouble using and understanding Mach3
« Reply #7 on: June 10, 2008, 02:31:58 PM »
Jim,

That reply should be a sticky at the top of the page! I wish someone had made it that clear when I was begining to figure out the G-code a month or two ago.

Kristin

Couldn't agree more, my friend.

Jim, for us newbs, i want to thank you for providing such an amazing amount of help and information on this forum. Not only that but the detail that you're able to make things seem so "clear" is truly appreciated.

Thank you-
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