Jul 21, 2023

Brian Brocken Upcycles a Broken 1990s Two

Maker Brian Brocken has carried out an impressive feat of upcycling, turning a broken welding robot weighing over two tons into a functional if not a little terrifying Computer Numeric Control (CNC) milling machine.

"[I've been] resurrecting this two ton cast iron beast from the dead and turning it into a CNC milling machine, mainly for foam," Brocken explains. "The robot came with a defective controller, empty backup batteries, and floppy drives. Once I got some movement out of it I realised the project had only just started. It would take a lot of time and effort to transform this tech from 1999 into a usable CNC milling machine."

Released, as Brocken says, just before the turn of the century, the ABB Robotics IRB 6400 S4C was, prior to its retirement, a popular choice of robot arm for a range of use-cases — thanks in no small part to an impressive 400lb payload capacity and a ±0.1mm repeatability across its six axes. Brocken's particular example came with documentation putting the robot's provenance with the Eurostar train factory in Austria, where it had been equipped with a welding head for carriage assembly.

It did not, however, work. First, Brocken had to replace the internal computer, then the S4C controller's backup batteries. Even then, while the giant arm showed signs of life it couldn't be directly programmed thanks to a broken floppy disk drive — replaced with a modern emulator, allowing the use of USB storage devices with floppy disk images.

"Even with the floppy drive swapped for a USB one, the internal memory size was still about the size of a floppy disk (1.4MB)," Brocken notes. "Which means I was still only able to execute programs of max 1.4MB, or around 15,000 lines of code. Anyone who ever worked with CNC machines know that even the simplest programs exceed 15,000 lines. So that's why I made the Rapid2Serial application. I'm now able to execute any file size that I need."

Developed using an Arduino Mega 2560 as a simulated S4C controller, so the real arm wouldn't go crazy during testing, Rapid2Serial provides direct serial-port control of the machine for unlimited program length. A 3D-printed motor mount completes the build — "I'm only going to use it to mill foam," Brocken explains, "and also because I don't know how to make shiny aluminum piece" — and provides a free-standing CNC mill big enough to turn a block of foam into a full-scale car wheel replica.

More information on the project is available on Brocken's page. along with the source code for the S4C emulator.