I am running a cut that is going to surface a piece two 10th of an inch and then do some v carving. If I run my XYZ probe with my quarter inch end mill it will set the zero at the lower left corner of the work piece. But then when I switch to my v-carve bit. I will have to use the probe again to measure the new tool length and I suppose I do this by only probing the z height with the probe upside down on the workpiece. My question is, since I've removed 2/10 of stock from the workpiece, will the machine compensate for this or will it mistakenly view the tool as 2/10 too long?
It will not compensate - the probe routine has no way of "knowing" what you have done. Is the surfacing operation a completely separate job (don't see why it shouldn't be) if so, and your V-carving is also a separate job you just need to re-probe Z on the new surface. You are correct about only re-probing Z. The probe sets the X, Y position where the centre of the bit will be (your cam software allows for the diameter of the bit when calculating the toolpath), so that doesn't change when you change bits. Alex.
Thanks, I am now realizing how spoiled I have been only working on a machine that has a tool length measure.
In cases like this, I do one of two things 1 - If I have a scrap piece (or cutoff) from the original piece of stock, I'll use that to set my Z0 during tool changes. 2 - Most times though, I set Z0 to my spoilboard and tell my CAM software the thickness of my material. It will make all the adjustments for you.
There's a macro that I wrote for Control which allows you to reference one tool from another. This will work with the 'upside down' probe plate in lieu of a tool length probe. Getting started with Javascript Macros in CONTROL / Library of Macros created by the community You would probe with the first tool to set a reference - either before or after setting Z zero for your first toolpath. After changing tools, probe with the new tool and the work offsets are adjusted to maintain the same tip height. Repeat as required for each tool change. Not as good as a tool library with a length offset table, but usable (for me).
Yeah this is why I was interested in the first place. If it would actually account for the change of depth. I figured it could see the first step of cut and maybe account for it. Your reference to a tool library with length offset. Would that mean that you essentially have depth collars on each of your cutters? Also I am running my first cut and I was using carbide create to make the g code. I selected GRBL as the post processor. But there are some strange things happening. When I click run the job it immediately pauses and there doesn't seem to be any menu or window that comes up. When I unpause it continues to go through the job accurately. I went ahead and hit the stop button as it ended with the first tool because I was just unsure of what would happen. I don't seem to be getting prompted for a tool change or have that nice little drop down menu on the run job button that lets me select the different cuts within the file.
No, that was just a nod to full blown CNC with tool changers, sorry - I don't have any such thing I run each tool as a separate job (I use F360 to generate the GCode). I don't think OB Control is set up to deal with multiple tools within one file at the moment (but I think there has been some beta testing). All that the macro does is to measure the tool offset of the working tool, and then adjust the WCS offset of the new tool to match it - In the case you describe, with the Z zero set to the top of the stock, you could face 2mm off the top of the stock, use the macro to adjust the offset of the new tool, then continue with your program - the Z zero on the new tool would still be at the top of the original stock (so new surface would be at Z -2 ). Difficult to explain well (perhaps I should make a video?) and it's only one option that would get you what you want - Setting Z zero from the bed would probably be easier if your work allows.
Ah - yea wouldn't that be nice to have. Your explanation is clear. I will definitely be checking out the macro - but I think I should get my dust collection under control first. I have a carbide 3D machine at my work so I have started to use carbide create. That is what I use for g code. So far it seems to be working fine but only the pro version will let you export g code and I'm already on my second email address trial ... I am hoping that on shape will come through with their cam add in soon, but I have a feeling that I will have to bite the bullet on carbide create pro or vcarve pro and I'm also considering mesh cam.
