Homing switches & 'methods of working' (Mach3)

[C_Bubba]

Even i am doing the exct same thing, with the 2 limit switches on the min and the max end of the axis, and the home somewhere in the middle. Even i am using the Work offset option.

The only problem i am having is that when i click the "Ref all home" button, sometimes the tool is at the negative side of the home switch and it keeps going negative until it hits the limit switch and the machine shuts down. Now i have no way of telling the machine which side of the home switch the tool is.

so any views?

This is why you put the machine coordinate at one of the limits of the axis. That way the Machine will always home in the proper direction. From there, you set your offsets for the various fixtures as previously noted. Fixture offsets are your friend! When you make a setup, you have the option to "save" the offsets. Now if you have a crash, power failure etc. You can simply restart the machine, home it and load the offsets and your back in business with no additional setup time. Sure, it may take a few seconds longer to make the setup, but it only takes one time to see how useful this can be. (Don't ask how I know:})

[Jonathan]

2 years 8 months lather and the thread is resumed, that might be a record!

[Robin Hewitt]

so you could set up a fixture in the center of the table then using the offset go to the exact same start position every time.

Andy hit the nail on the head. Homing switches are useful if you are working with a fancy metal clamping jig bolted down at a known location on the machine bed.

I don't use MACH because as soon as you start working from G code you lose touch with the original drawing and cannot refer back to it when you want to align tool to metal.

I locate by circles on the drawing, circles with a zero thickness do not cut but I can still see them.

I pop the drawing on the screen and every circle has a little pick box dead centre. Left mouse button on a pick box moves the tool to the circle centre, right button sets the mill XY co-ordinates to the circle centre.

Drilling holes becomes a doddle on my mill/drill, alignment is all sorted at the drawing stage.

[audioandy]

Even i am doing the exct same thing, with the 2 limit switches on the min and the max end of the axis, and the home somewhere in the middle. Even i am using the Work offset option.

The only problem i am having is that when i click the "Ref all home" button, sometimes the tool is at the negative side of the home switch and it keeps going negative until it hits the limit switch and the machine shuts down. Now i have no way of telling the machine which side of the home switch the tool is.

so any views?

The only thing I can think of for a work around on this is at the end of your G code when your tool maybe goes to X0 Y0 Z30 (example only) you can change the code so your axis finish on the positive side of your home switch so X50 Y50 Z30 (example only) then when you reference you should be ok.
Other than that move your home switch to the Neg side of movement on your X and Y axis.

hope this helps

Andy

[motoxy]

I don't use MACH because as soon as you start working from G code you lose touch with the original drawing and cannot refer back to it when you want to align tool to metal.

I locate by circles on the drawing, circles with a zero thickness do not cut but I can still see them.

I pop the drawing on the screen and every circle has a little pick box dead centre. Left mouse button on a pick box moves the tool to the circle centre, right button sets the mill XY co-ordinates to the circle centre.

Drilling holes becomes a doddle on my mill/drill, alignment is all sorted at the drawing stage.

May I ask what you use if you do not use g code?

bruce

[Robin Hewitt]

May I ask what you use if you do not use g code?

You only need G code to transfer the cut from the program that produced it to the program that does the cutting.

My software creates the cut then pumps it directly to the mill so I miss the file copying stage, no need for G code.

Having the original drawing as well as the cut available makes setting the mill a doddle, but I can't say I'd recommend it