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General Mach Discussion / Z axis craziness at program start
« on: November 08, 2017, 02:02:09 PM »
I'm new to Mach3, and the search engine is failing me - apologies if this has been asked before. (If so, links are appreciated!)
Homebrew CNC with a C10 parallel breakout board, Win7, using fusion 360 for CAD/CAM.
When I load a g-code program, and look at the tool path limits, the upper Z limit seems to be randomly chosen by Mach3. For instance, when cutting a 3D contour from 3/4" stock, Mach3 initially tries to move the Z to +9 inches (this number changes from program to program). Note that my Z has an 8" travel, and a bad limit switch - disconnected at the moment - so I have to stop the program, jog Z, run the program, stop the program, send it back to the correct zero, and continue the program. This is entertaining on some levels, but frustrating.
The piece I'm talking about in this example scenario is less than 3/4" tall (height of the stock). Once I get past the initial step where Mach3 wants to move the carriage off of the top of the rails, it works relatively well.
I don't understand why it's trying to move the carriage all the way up by some weird value before going down again to start the cut.
This occasionally happens with X/Y as well. After cutting the part - in this case, about 12" x 3" - it wants to go to a point 4' away from the origin (which is in the center of the part I'm cutting). My machine isn't that big, so I have to make sure I'm near the stop button when the cut is done. There is no work to do at that location - it just likes to go there. Note that I zero all axes before starting the job, XY in the center of the stock and Z at the top of the stock.
So: WTF?
Homebrew CNC with a C10 parallel breakout board, Win7, using fusion 360 for CAD/CAM.
When I load a g-code program, and look at the tool path limits, the upper Z limit seems to be randomly chosen by Mach3. For instance, when cutting a 3D contour from 3/4" stock, Mach3 initially tries to move the Z to +9 inches (this number changes from program to program). Note that my Z has an 8" travel, and a bad limit switch - disconnected at the moment - so I have to stop the program, jog Z, run the program, stop the program, send it back to the correct zero, and continue the program. This is entertaining on some levels, but frustrating.
The piece I'm talking about in this example scenario is less than 3/4" tall (height of the stock). Once I get past the initial step where Mach3 wants to move the carriage off of the top of the rails, it works relatively well.
I don't understand why it's trying to move the carriage all the way up by some weird value before going down again to start the cut.
This occasionally happens with X/Y as well. After cutting the part - in this case, about 12" x 3" - it wants to go to a point 4' away from the origin (which is in the center of the part I'm cutting). My machine isn't that big, so I have to make sure I'm near the stop button when the cut is done. There is no work to do at that location - it just likes to go there. Note that I zero all axes before starting the job, XY in the center of the stock and Z at the top of the stock.
So: WTF?