Centroid Community CNC Support Forum

DMM AC servos arrived today. I did a lot of measuring prior to ordering. I knew they were close. They are! The original servos had 3/8” shafts. I found a 1/4 coupler of the same style. Worked great with the DMM’s 1/4” shaft. I had to turn down the heads of the socket head cap screws so they would go in to the bracket straight.

The X axis bracket is going to have to have about 0.4” milled off so the coupler will engage. I’m thinking I can modify the existing part. Not sure about extending the existing threaded mounting holes further in.. I may have to make a new bracket.



Line scratched showing where motor would mount up:




The Z axis coupler has a much smaller gap. I think it will need to be closed up, too.

NEMA 23 or 34? 400W?

DMM NEMA 23. The little guy. Yes, 400W.

slodat wrote: ↑Sat Aug 01, 2020 10:57 am DMM NEMA 23. The little guy. Yes, 400W.

Should do quite well. What power supply are you using? I used a 57VDC from Antekinc.com
Encoder on the spindle already?

It has a spindle encoder. I’m using DYN4 with 120vac supply.

Got the X axis motor mount modeled.



All I have on hand is some 3.5” round stock. This is definitely the most complicated (feature rich?) part I’ve made. I’m sure the first will be a test part.


I ordered a 3 x 3.5” x 12” bar from Xometry. Hopefully I’ll only use a 3” chunk of it for the final part and have plenty left for the Z motor mount.

Slodat,
I don't know which software you are using (maybe Fusion 360), but I am in the process of using Fusion 360 to draw some parts for a steam engine. I have done the frame and crosshead brace so far, in any case a few things that I have learned so far.
1. Pick tools that are big enough to take some abuse without breaking (1/4" is a good start)
2. Layout the part to make machining the easiest, how are you going to hold it? Bore through it, tap the holes etc.
3. Filet the corners, in you part the inside has sharp corners, end mills are round, a radius slightly bigger than the end mill 0.30" for 1/4" end mill makes clean corners.
4. Through hole are easier to tap, but penetrating into an edge can break the drill bit.
5. If thread milling the holes and you break the cutter you can sometimes get the broken end to fall out.
6. Make sure mill is calibrated for turns per inch if dimension is critical, it is easier than having to rebore to correct size, in Fusion 360 for stock to leave you can set it for a negative number. For example I had a hole that was 0.875" in diameter, but the bearing was 0.875" (tight press fit), I set the stock to leave to 0.0015" for a push fit.

Hope this helps some, if not maybe it will help someone else,
Chuck

Thanks Chuck! Learned a couple things. I appreciate it! I don’t fuss with drawing edge chamfers in the model, just grab the geometry and use a chamfer tool path. Seems easier to me.

I believe this ends up being a four sided part.. That’s how I’m seeing it thus far. Previous post didn’t show these two counterbored holes.

Starting to get the components laid out. I’d like to get everything in the existing two enclosures.

Spindle drive and AC components:



Control and servo drives in the control panel enclosure:

Hmm, looks like an accessibility problem?