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Hernault Somua mill with Acorn and DMM servos

Posted: Wed Jul 08, 2020 2:48 pm
by yellow_submarin

My second Acorn project came to life today.

This is an old French mill with a travelling column. I bought it partially converted to CNC with DMM 750W servos and DYN2 drives. I gathered an Intel NUC, an Elo touchscreen and a fresh Acorn.

Right now homing is set with inductive sensors (already had them) and ZRI from the servos. I still need to install a new spindle motor and drive (2.6kw AC servo on the way) and auto lube. A fourth axis and power drawbar will come later.

Re: Hernault Somua mill with Acorn and DMM servos

Posted: Fri Jul 10, 2020 1:25 pm
by cnckeith
Nice! cool machine. thanks for posting, i shared the video on the Acorn Facebook page.

Re: Hernault Somua mill with Acorn and DMM servos

Posted: Sat Jan 09, 2021 12:41 pm
by yellow_submarin
A quick update on this one.

I was having repeatability problems, losing a couple of microns on each back-and-forth move. After trying a couple of things, I concluded this was probably electrical noise causing lost steps between the acorn and the DMM drivers. Lots of AC power in that cabinet.

I changed the wiring to go through CNC4PC rj45 adapters for the Acorn and the DYN2. Not as easy as I thought because the rj45 wires are very stiff. But it did solve my problem !

I finally found a cheap Haimer 3d taster and got some more BT40 tool holders from (highly recommended !). So i'll be in the making of a BT40 power drawbar very soon, and most likely a partial enclosure and air mister. Then the mill will be fully operational.