M-DRO

[jpigg55]

Just a quick note today.
Finished installing the Z-axis scale with initial test run of full travel. Everything worked great, took a couple pictures of it as well.
The third picture is of the test data sheet that comes in each of the readhead packages, something I forgot to mention earlier. For this particular readhead test datasheet, it lists a Max deviation of 0.002 and a Min deviation of -0.002.
Looking at the rest of the data on the sheet, I take this to mean that the readings coming from the readhead would range anywhere for +0.002 mm higher than the test standard and -0.002 mm less than the standard at various test positions based on the printed and graphed data points.

[woodchucker]

you look like you covered your gitz oil port.

[jpigg55]

you look like you covered your gitz oil port.

Nope, I can still get to it. I've been careful during the install to not cover any or make an access hole to get to it.

[jpigg55]

Almost have the Y-axis scale mounted now. One I thought would be the easiest has turned out to be one of the more difficult. I ended up drilling and tapping a couple ¼-20 holes in the cross-slide for mounting the readhead. Something I hoped I wouldn’t have to do, but ended up to be my best option. I also ended up machining the mounting bracket as I couldn’t make any of the included brackets work.
Now that I have the readhead brackets made up, all that’s left is to align the scale extrusion (hence the magnets in pic #1), drill and tap for the extrusion mounting screws, install and level it, clean the surface and stick on the magnetic tape, install the cover strip and protective cover, and lastly, reinstall, align and space the readhead, and tighten everything down.
Barring some unforeseen interruption, I should finish the install tomorrow.

[jpigg55]

I finished installing all 3 scales, so with the exception of tying up the cords, the install is complete.
For final thoughts, the installation process was a bit more involved than I anticipated, although manageable. For anyone reading this and considering M-DRO scales, ensure you have some material available for making any pieces necessary. Also have drill bits and metric taps for 3 mm & 4 mm bolts and screws. I also recommend using the scale covers since ferrous chips will be attracted to the encoder tape.
For cutting the scales to length, I used my HF metal bandsaw to cut the extrusions and covers, but a hand hacksaw will work fine. For cutting the magnetic encoder strips and stainless cover strips, I recommend either a Dremel (or Dremel like tool) or a sharp pair of sheet metal shears which is what I used, worked great.
Here are a few pictures of the Y-axis final install along with a link to a short video of my completed work.
https://drive.google.com/file/d/17mFHdIlQwyBB1QxiAscbayzcR3Hfmgts/view?usp=sharing

[jpigg55]

More pictures.

[jpigg55]

Next, I’ll be putting together a Touch DRO controller for use with these scales. Partly due to me realizing too late I’d ordered the kit with the lathe display unit and partly due to me liking the Touch DRO App. Along with this, I plan on doing some O-scope runs and getting the CPI count from these scales during the calibration process since I’ll have access to the connections. I plan on posting all this test info in another thread once done. I’ll amend this post with the link to that thread once it’s uploaded.
 Since the M-DRO display I have is for a lathe, I’m going to try using it with the set of quadrature scales I got from “The Little Machine Shop” on my lathe. Maybe I’ll do another thread on that as well if it works.

[jpigg55]

Sorry about the late update. I got everything connected and running, very happy with the new scales.
Initial testing didn't show anything unexpected or out of the ordinary so I probably won't bother posting a thread on it.
Scale CPI was right in the neighborhood of 5080 with them being 5 micron rated scales.

One last thought I figured I'd mention. In the future, I'm considering adding a scale to my spindle for summing with my Z-axis.
Nothing earth shattering there, but since I decided to use Touch DRO for my interface instead of the OEM display, using these scales gives me an added option.
M-DRO offers a scale summing interface for this purpose. https://www.sra-measurement.com/m-dro-linear-encoder-summing-interface
I'm uncertain if other manufacturers offer this option or not.
This can be done without the interface by Touch DRO and other displays by using the 4th axis connection and programming the display to sum the values.
By using the M-DRO unit, I will be able to sum both scales and still have the 4th axis connection available for other uses.