Tool offsets on mill DRO w/o library - Haimer 3D probe - Shars tool setter

durableoreo

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
May 3, 2020
Messages
365
I am desperately short on time and I have heard that quick tool changes and a tool library really speed things up in the shop. So this post is my beginner questions about setting tools and using a DRO to keep track of cutters length on a mill.

I purchased a 5-axis import DRO labeled ToAuto. It came with 4 glass scales cut for the table, column, and quill of a G0755. The tool-library buttons are not on this model, which is a surprise. I assumed models with additional features had all of the features of models with 2 or 3 axes. So I'm trying to work around this mistake. I may be forced to buy a different readout but maybe it's not necessary.

Several people on the youtubes have shown how to use SDM settings to approximate the tool library. I gather SDM points are work offsets and the Z length is simulated by moving the work closer or farther from the spindle. For example, you set up a 1/2" endmill as Tool 1. You zero the ABS coordinate system on the corner of the work (x, and y) and use paper to find the top of the parallels. Now, with the Master Datum, established, other tools can be set up relative to this position, right? So change to 2nd tool and find the top of the parallel with paper and save the result for Tool 2, setting the z-value in SDM 2. Is that all that's required?

Should I also set X and Y for the tools saved in the SDM quasi library? It would take a little longer to drive the mill around to x=0, y=0 but maybe it would be worth the effort. That way, no matter what SDM you're using, the x-y position would be clear. To use sub-datums in the normal way, can you temporarily set x and y for that tool? After the operation you can return them to the origin.

Can I speed things up with a Haimer 3D probe? What if I use the Haimer 3D to set (0,0,0) in the ABS coordinate system? I suppose that would work but all the tool lengths would be relative to the length of the Haimer...

I'd like to avoid using paper to find the top of the parallel. It takes me a while to drive the table around and get everything set up. Also, I'm not convinced that it's very repeatable---depends on feel that I haven't developed yet. One possible solution is the Shars 2" tool setter. Obviously there's no point in probing the top of the tool setter with the Haimer because they're both moving parts. But the setter plunger can be compressed to be flush with the top. It reads reads -0.0554 when flush. What if I probe the top ring of the setter to establish z=0 in the ABS coordinate system. Then I can use the setter to establish z offsets of each tool but driving them down until the setter reads -0.0554 and teaching the z height for each tool. Then, after tools are entered, use the Haimer to probe the corner of the work (to establish x and y) and find the top of the parallel (z=0) in ABS mode. Once those new values are set, SDM positions will automatically shift, right?

Obviously I'm struggling with the basics here. Is it a good idea to deal with tools thisway? What's your routine? Is this even a good way to save time?
 
I am also using the Chinese-made ToAuto DRO. The price is half of those of more established Chinese brands such as Sino. Happy with it so far although I need to take apart the scale to clean the dust inside before installing. I have got their latest touch-screen display but there is nothing close to the mentioned tool library function in the software.

To avoid doing math, I always make a drawing of the parts I want to make in nanoCAD which is essentially an old and free version of AutoCAD made by Russians. All the commands are exactly the same. My routine is to locate a chosen reference corner of the vice with edge finder and set ABS X and Y to zero in the DRO there. Then I draw a circle of the same diameter as the tip of the edge finder at the same location in nanoCAD and move the center of the circle to (0,0) together with everything else in the drawing.

The vise has got a side plate which allows the workpiece to be clamped at known XY distances from the reference corner. For small parts guage blocks are used to allow the workpiece to be positioned around the center of the vise to avoid asymmetric clamping load which is bad for the vice.

From this point onward, I can get from nanoCAD the required XY locations of the tool in all subsequent cutting operations no matter how many times the tool is changed or the workpiece is re-positioned. There is no need for any re-zeroing, touching off the workpiece with edge finder, paper, tapes or whatever until the DRO display is powered off. For me that's a lot of time saving.

For the Z axis, I use Z-axis tool setter. Setting need be done again after changing the tool but doing so is not needed after re-clamping the workpiece. This device is good value for the money. Mine is made in Taiwan and just costs 50 bucks. With care, the error in the resulting dimension of the workpiece along the Z axis is well within a thou.
 
Last edited:
Back
Top