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« on: January 22, 2009, 04:12:24 AM »
I can understand your enthusiasm to get going, but unless you spend a little time understanding the basics, you will just cause yourself a lot of heartache.
The prolem is all covered in the video tutorials, if you spend a evening watching those - HOWEVER -
I will try and get you started on the basics.
Your problem is that your machine is not in sync with your program.
I don't know what program you are trying to do, but it will have a 0.0.0 position. You must put the machine is the correct position.
The machine has two sets of DRO's (Digital Read Outs) to tell you the position of the axis. These are both of the same display.
If you press Machine Co-ordinates button, the led surround will light, and the display will show the machine co-ordinates of the machine - sounds odd - but these are the co-ordinates by which Mach3 keeps track of exactly where the machine is at any time. These are normally linked to Home Switches, which you say you do not have, but - no matter - if you press "Ref All Home" you will see the display go to 0.0.0. As far as the machine knows - it is home. The zeroing of these DRO's (in fact the only way to zero these DRO's when you have home switches fitted,) is to hit the home switches. The exact position of these switches is not important. It is just a place to which the machine will return, reliably, time after time.
The display you use when running programs is the Program Co-ordinates display. This is tied to your program, and the machine must be told where the 0.0.0 position for the program is. As someone said, this is normally, but not always, at the bottom left hand corner of your table (or work piece). If you press the Machine Co-ordinates button, the led will go out and the display will now show Program Co-ordinates.
The displays might be the same, but probably not.
Jogg your table to the 0.0.0 position of your program. How accurately you do this depends on what you are doing. If it is a one off test piece, then it is not too important. If you are going to run 5000 pieces off, then you need to start spot on, and be able to place each work piece exactly in the same place. For now, put a small drill or something in the chuck, and the move the table so the drill is above the bottom left hand corner of the table. We will call that 0.0 for X and Y - Z will come in a minute.
Zero the X and Y DRO's by pressing the zero x and zero y buttons.
Your program co-ordinates are now set, and 0.0 is the position at the bottom left hand corner of the table.
From here you can run all sorts of tests. Try jogging each axis + or - and see if they are travelling in the right direction. Try entering on the MDI line a few simple commnds like G0 x2 and see if X travels the right way, G0 X0 should take it back to where it came from. Similarly with Y. You must get each axis travelling in the right direction and the jogging buttons set up to match before you start.
Remember in milling the X and Y movement are in relation to the movement of the cutter NOT the table.
From here the world is your oyster.
We will ignore the niceties, such as backlash etc. and run in your program. The toolpath should now show the program on the table (if it is big enough) with the 0.0 position at the bottom left. To set the Z height - this depends on where the Z height is in your program. Normally this is touching the top of the workpiece, so jogg your Z axis down to the top of the work - and then 0 the Z axis.
Your machine is now ready to start.
Once you have set the 0.0.0 position of each axis (and not necessarily all at once) then anywhere you move will be remembered by the machine and a G0 X0 Y0 Z0 will bring the cutter back to the bottom left hand corner, resting on the workpiece.
If you press the Machine Co-ordinates button, then you will see that the display changes from your 0.0.0 to whatever. This is the offset your program has from the machines 0.0.0 position and if you look on the offset table you will see G54 reflects those offsets.This is not important until you fit home switches, and it is intended for those places doing runs of different programs, where the machine can be homed to a known position. The offset G54 (or one of the other 250 odd offsets available) are included at the beginning of the program, and the machine then automatically goes to the correct position for that program. We are not there yet.
If you are at 0.0.0 and the workpiece is in press the cycle start and see what happens. Kepp you fingers out of the way - or better still, take the cutter out of the holder, and replace it with a bit of flexible tube, when you run first time, until you are sure you have it set up right.
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