Need guidance on manual tool changing best practice (and other things)

[Neale]

Lots of questions, but just thinking about the tool-table thing - one reason is that you can generate gcode with a toolpath where the the CAM software knows tool diameter and offsets the toolpath by tool radius, or the toolpath follows the centre-line of the cut and the motion control software uses local tool data to generate the offset on the fly, so to speak. One advantage of the second approach is that you can change tool size without needing to regenerate the gcode, or more likely you can tweak the tool table numbers to allow fine adjustment to cope with tool sharpening or tiny variations in tool size if you change cutters. For home use, I can rebuild the gcode very quickly if I need to make tool size allowance, but commercially where the guy running the machine can't or shouldn't change gcode but still needs to recalibrate for tool changing, the local tool table makes sense.

[komatias]

Tool tables in the CAM software are fine if you use repeatable tooling and have the same numbers programmed into the Mach3 tables. I see much danger if the CAM spits out a H204 (height offset for tool 204) and it crashes through your part, table or worse. So for you keep the tool table in Mach3 clean and make sure there are 0's everywhere. Some CAM programs will put a description comment in the code to tell you what each of the called tools is. This is useful so you know which one to select next. You will need to re-zero the height each time manually.

Toolchanges are called using an M6 code. You will need to tell mach to stop at these in general config. M6 allows you to move the head in all axes so you can touch-off. If you set up a touch off plate you can do this automatically.

I would suggest you look up Ger21's mach3 screen (Mach2010) on here, CNCzone and youtube. It will make life much easier and is worth every penny. Just remember to keep all the tool table values set to 0.

http://www.machsupport.com/forum/ind...c,17004.0.html


For the two sided machining you have the answer already. It is all about making fixtures to ensure you can flip the part over and find x0, y0 again for that face. You can use dowel pins, rails or whatever else. Plenty on Youtube to keep you learning.

Regards

George