RapidChange Automatic Tool Changer on the Duet

meeloo

Hello,

I have installed and configured a new kind of automatic tool change from RapidChangeATC.com . It's a very smart and very simple/cheap system and enables hobbyists to have an ATC for a fraction of the price.

Adapting it to the Duet implied to create a number of macros and configurations as we need to be able to control the speed of the spindle, as well as the direction (forward and reverse). I used the regular method of hooking up a PWM to Voltage converter in between the duet and the VFD. To control the FWD/REV direction I used an I/O port to switch a relay that is then plugged in the VFD's digital control pins. I also have configured an XYZ probe to be able to easily setup the work offset, as well as a static Z Probe to update the tool length after each tool change.
I had to adapt an existing fusion 360 post processor to have everything work perfectly and it's now great. I have done a couple of jobs with it and it performed fine!

I put my full config (based on a work bee, adapted to my UltimateBee, spindle and VFD) + post processor and some 3D models on a GitHub repository https://github.com/meeloo/Duet3Config .

I'll try to post some more videos showing the machine doing some tool changes on YouTube, here is one showing a couple of tool changes during development https://youtube.com/shorts/bFGX5Maj3ng?feature=share

tierod

@meeloo
that’s great meeloo, i for one appreciate very much your willingness to share, especially the post processor. looks like you have it dialed in.
i have atc on the wishlist but would like to build it myself. so much to do, so little time

SDJ

Oooh this looks great. I would like to try this out on my next machine. Thanks for sharing.

What are you using reverse for? I don't really see why you would require this for tool changes.

meeloo

@SDJ The way RATC works is it's using the torque from the spindle to screw and unscrew the ER collet nut onto the spindle shaft. If you can't reverse then you can't unscrew the nut. Check out the videos on rapidchangeatc.com, typically the case of a pic is worth more than a thousand words

SDJ

Oh I get it. This is screwing and unscrewing the collet nut. Crazy. I noticed you are using an air cooled spindle. I'm not sure I can run my spindle that slow without pissing off the VFD. It's a very short span of time I guess? I would have to lower my programmed limits to try this.

"Tu fait quoi papa"

"Un truc"

Lol. Genial.

meeloo

@SDJ Yes, it has to run in between 1400 and 2000 RPM which is very slow but for a super short duration (a couple of seconds really) which is not doing much to the spindle, it only has the time to get up to speed.

I currently have a 1.5kW air cooled spindle but I'm in the process of moving to a 2.2kW water cooled one. As I'm going from ER11 to ER20 my current ATC will be for sale as soon as the nice guys at RapidChangeATC send me the ER20 version I just ordered...

(Hehe, yes I have a very inquisitive kid that also doesn't like to follow instructions, he lightly cut the tip of a finger on a sharp router bit right after I told him explicitly, multiple times, not to touch it ;-). Also, he has 3 brothers )