Just wanted to share a little about my custom Avid build.
My day job is as a Controls Engineer programming and commissioning industrial automation equipment. I wanted a CNC for a side business and Avid fit the bill. I wanted to use my own custom controls platform because it was a fun project, it helped advance my controls skillsets, and allowed me to really customize the machine to fit my needs.
I bought the PRO 4896 set from Avid, then procured all the electrical components, wired them up, and programmed everything. Took me the better portion of 2 years (working on weekends and moved houses 3 times) but the end result was definitely worth it for me.
Mechanical Hardware :
Avid Pro 4896
Home built wooden base structure
Controls Hardware :
Dell optiplex 7020 ($150 used on eBay, quad core, SSD, etc)
Beckhoff EK1100 Bus coupler (connects hardware IO to the control PC)
Beckhoff EL7040 stepper motor control cards
Beckhoff EL6020 serial communication card (for controlling the VFD drive)
Beckhoff Nema 34 stepper motors
Beckhoff EP (for proximity sensors)
Invertek optidrive E3 3 HP VFD
Avid GMT 3HP spindle
Software :
TwinCAT 3 (for the real time motion controls platform)
TwinCAT HMI (For the user interface to control the machine)
Vcarve Pro
TwinCAT is a real time controls platform that includes functions for motion control, safety, standard control logic and IO, and an HMI all in one. It runs alongside windows, and uses EtherCAT (ethernet based) as its communication protocol. It is a very high performance controls platform and is used professionally in the industrial automation industry because of its reliability, adaptability, and high speed performance.
It runs alongside windows in kernel space, which essentially means its operation is unaffected by general windows issues (slowdowns, crashes, network utilization, etc…). For this, it makes an excellent motion control platform that is extremely reliable.
Here are some pics :
I mounted the main power control cabinet underneath the front here, keeps it out of the way and pretty easily accessible
Inside the main power cabinet, houses the 48V supplies for the steppers, 24V supply for all the logic and IO power, and the large yellow relay is a Pilz safety relay. It has normally closed contacts that are redundant, so that when I e-stop the machine it removes power from all the steppers, and won’t allow the motors to be powered until I release the e-stop, and push the white control power button (on the top of the cabinet), which effectively resets the safety circuit. Wiring is a little messy but I’ll clean it up later
Side view, dust collector motor is mounted underneath the table and the ducting runs along the wall at 45 degree angles to maximize airflow
My IO control cabinet, each of those cards is a stepper motor driver, I also have an 8 channel output module in there , the black box to the left is an IP rated input module, and has up to 16 inputs available. I use that to run all my prox sensors/limit switches.
My VFD control cabinet, Modbus communication to start/stop/set spindle speed
My dust collector is setup as an output from TwinCAT on a relay, so during program execution it kicks on and off automatically. I can also toggle it from the user interface
My HMI, obviously I took some inspiration from the Mach4 layout
This is the TwinCAT Development Environment. It is based on Microsoft Visual Studio with Beckhoffs tweaks to make it their own. The programming/code running here is run in real-time, and I can login to see the code executing live and debug if necessary. I have a github repo for everything if anyone is interested.