Hey Guys I decided to build an Auto Tool Changer for my RF45 converted machine. When I built the tool changer I wanted it to be adjustable so that I could use it on more than one style machine. I have aspirations of upgrading to PM940 and doing a linear rail + servo conversion. I have been thinking about this tool changer for at least a year, but struggled to find time until the last few months. Over all I am very happy with how this has turned out. The ATC is very reliable due to the sensors that I built into the design. So far I have installed the ATC on my RF45 and a G0704. My personal tool changer has completed over 6,000 tool changes without issue. It takes about 11-16 seconds per tool change depending on your settings.

I used proximity switches to signal the ATC extend/retract and the carousel home position. I am using the Mach 3 ATC screen set made by CNC4XR7 to control the ATC. That screen set makes it really easy to set up and control the ATC. With the screen set it feels a lot like a true commercially available ATC, not DIY project. I would highly recommend that screen set.

The installation/set up of the tool changer was actually really easy. To install the tool changer, I only had to drill and tap four ¼-20 holes in the side of my column so the mounting plate could attach to the column. Other than that, no other manipulation was required to the Mill or the ATC parts. Installation and set up only took about 2.5 hours once all my parts were completed. I will make a Youtube video of me assembling and setting up the machine in the near future. Overall, The install was much easier than the original CNC conversion as all the parts were designed to work together. Instead of trying to retrofit parts existing parts.

If you want to add a tool changer to your machine you will need to have a Z axis homing switch, power draw bar, and computer control (start/stop at) control spindle.

I use a belt drive to control my Carousel. There are other folks that like using a geneva mechanism. But I didn't like that approach. With a Geneva mechanism the tool changes are much slower, since you need to index through each position. Additionally the geneva mech, just felt clunky. And you are locked into a specific number of tools. With the belt drive, you have a lot more flexibility. With the right belt selection and proper tension, there is zero backlash in the system.

What makes my design unique is the sensor integration. Without the sensors I do not think I would trust the tool changer to operate unattended. The sensors have saved me a lot of potential headaches, and prevented lots of potential painful mistakes. I would not run a tool changer without error checking sensors installed.

Whenever, I start the machine I do the following 3 steps prior to prior to a tool change:
1. Home the Z axis, as mach 3 needs to know where the Z hight is for tool changes.
2. Home the C axis, as mach 3 needs to know where here the ATC carousel is.
3. Check the Power Draw Bar is functional, using the foot pedal.

When I built the kit, I ran extra parts so I would have spares for my own tool changer and one additional ATC if someone was interested.