Tool Height Setting Probe - Mach3 - solution

[Ger21]

Still not bothered with the homing switch's and I have got the auto tool length setting working just fine without them, I will be putting them on at some time soon though. Set up and tested my soft limits and they should give me enough protection at this stage.

If you don't have Home switches, just Ref the Z at the top of travel. This will allow the macros to keep from crashing the Z axis into the top of travel if you enter some settings that won't work. In order to use the toolchange position, park position, and tool change auto zero, you need a repeatable home position. Switches make everything easier.

Quick question - In the Auto Zero settings, can I set the tool using my height probe on the bed of the machine, put the height of the probe into the plate thickness box (41mm in my case) and then put the distance from the bed to the top of the job (Z0) in the material offset. This is more or less the same method that I have used on larger CNC machines in the past, only difference is the G54 Z offset is not used and the figure in the material offset box is used in its place. The simple auto zero button seems to achieve this but not played enough yet to see if the material offset workaround will work or not.

Theory behind this is quite simple, if i tell the machine how far the top of the work is from the bed by measuring it then the machine only needs to know where the tool is in relation to the bed. For a lot of my jobs I tend to be cutting rough sawn hardwoods which first need facing to give me a flat surface to work on and I usually set my z0 lower than the top surface as it is so uneven. This means setting zero on the top is no good to me.

The short answer is yes. The G54 ofset is still used, bbut the zero position is offset by the Material Offset amount.

I use the material offset so that I don't need to worry about the actual thickness when I program my parts. I just program to cut .75" deep, and it doesn't matter if the part is .78 or .68, it always cuts right to the bottom. I zero to the spoilboard and use a material offset of .75".

Of course, if doing V-Carving you need to zero to the top, but if you're just cutting out parts, the material offset can make things much easier.