Stephen Hawes’ open source Index PnP machine is a work in progress, but it’s no less impressive in its current form. According to Hawes, the Index is designed to aid in mid-scale, or level 2 manufacturing, where users outsource a portion of the work and perform some in-house fabrication techniques to make things at a much larger scale.
“The Index is designed to be low-cost enough that someone could buy or build one to support making production runs at home or as a small business. It runs using OpenPnP. The Index will eventually be able to do every component of PCBA manufacturing. It is currently capable of picking parts and placing them, but eventually, the Index will support solder paste dispensing, automatic reflow, and even AOI,” Hawes writes.
As mentioned earlier, the Index PnP machine is controlled using OpenPnP, which sends G-code (based on PCB design files) over to an Arduino Mega and RAMPS shield that uses a modified version of the Marlin firmware. The setup drives the Nema 17 stepper motors, vacuum pump, limit switches, and downward-facing camera. Additionally, OpenPnP controls a custom “Piggyback” board that he designed to handle up to 30 feeders, which uses a tiny communication protocol he created called “Ring” to send instructions from the board to the feeders and back again.
Hawes states the Index mechanical design is based on OpenBuilds’ ACRO 55 and employs a V-Slot/roller motion control system with a pair of motors controlling the Y gantry, along with one for the X and another for the Z. It’s also fully optimized to handle FDM 3D-printed parts, and according to the BOM, costs just $450 to build (in its current form).