Deph and multiple passes

[cmurphy@nsn.k12.nv.us]

When you start a sb session you can tell it the number of passes and the deph for each pass. this is fine for the outside of parts, but what can you do if you want parts cut out from the middle where to need to jz and then go back down? Once you put in a z it messes the deph up.

[tlempicke]

Actually you can spoof the Z axis pretty easily. Say for instance that I have cut a piece and it still has about .020 of material left that I would like to cut. After the machine is finished just give it the command "Move Z" to .020 LESS than what it is at. For instance if the z axis shows to be .250 on the screen issue the command "MZ .230". After you have done this give it the command to zero the Z axis. (ZZ) then simply cut the file all over again and it will do the whole thing over, only .020 deeper.

I know that this is a time wasting way to do it but in a lot of cases it is the quickest easiest way to get what you want.

Using this system I was able to engrave an image .010 deep in an aluminum plate. I made three cuts - one .010 above the surface to make sure I wouldn't mess up the bit, one AT the surface to make sure I had the plate true to the table, and one .010 deep that turned out just perfect.

[jkforney]

Tom
The VA command is a different solution. The va command tells shopbot it is now at a new location and won't require a zz command.

If you are at .25 you only need va,,.23 and Shopbot now set the z height to .23. The first two commas are the x and y location. You can use the system variables in the same manner to pick up a location and subtract (va,,(%3)-.02) would take .02 off the current location of the z axis.

The nice thing about the va command is that you don't have to physically move the axis to change it.


John Forney