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Welcome to the Index wiki!
The Index Pick and Place is an open source pick and place machine.
This project is under development. It is not currently in a stable state. Development is active and ongoing, but this is not yet a finished design. If you'd like to build one to help find bugs and design issues, please do!
The Index runs using OpenPnP. The Index will eventually be able to do multiple parts of the PCBA manufacturing process. It is currently capable of picking parts and placing them, but eventually the Index will support solder paste dispensing and interfacing with other machines, such as a PCB panel hopper and reflow oven.
Along with the Index machine itself, the project also includes feeders designed to work with the Index. Although they were designed with the Index in mind, they can work with any OpenPnP pick and place with a 20mm x 20mm rail for mounting.
The goal of this project is to create a machine that allows people to create products at a larger scale than they could have otherwise. This blog post explains the ethos of the project, but in summary: Consider breaking the scales of producing a product into three broad categories. The smallest scale is prototyping, where you make 1-100 a year, using all hand tools, and very manual fabrication processes. The largest scale is mass production, where you hire a contract manufacturer to manage production of your product, use machines that cost upwards of a few million dollars, and requires a tremendous capital investment. There currently isn't much to help facilitate the third category, mid-scale production. This is where you have a significant number of units to produce (100-5000 a year), but not enough to justify hiring a contract manufacturer to make them for you.
The goal of the Index (and other machines in the works) is to help folks bridge the gap between prototyping and mass production. They should help with the production of a product at a moderate scale, with a cost that is reasonable for a business that does not have the resources to invest in expensive contracts or machines.
The following are milestones for the project. These are technical definitions of where things stand with the design and testing of the Index.
Core functionality of all basic PnP actions working as tests, using final architecture, but not necessarily integrated with each other or lifetime tested. This includes:
- X, Y, and Z linear motion, and two auxiliary axis for each nozzle
- Feeder design operational, moving tape and peeling film
- Integrated up and down vision, along with part lighting
- Vacuum system operational and able to pick parts
- Driving the machine using OpenPnP
- Motherboard that supports these functions
Fully working and tested machine with all core functionality. We recommended that folks wait until this milestone is complete before building for practical usage, as opposed to R&D purposes. This milestone includes:
- Index PnP
- XYZ and rotation motion precise enough for 0603 placement
- All printed parts designed for minimal/zero support material
- All machine actuators (motors, pumps, lights, etc) lifetime tested
- Feeder
- Communication protocol implemented and tested
- Lifetime testing of mechanical functions across all four supported tape widths
- OpenPnP
- Tuned and validated machine.xml file
- Custom Index Feeder type merged into mainline OpenPnP
- Docs
- Complete and accurate Bill of Materials, tracked and updated with the repository
- Complete and accurate build guide
- Complete and accurate usage guide
A fully working and tested paste dispensing upgrade for the Index. This includes:
- Software solution for toolpathing and execution of the paste head (reimplementing in OpenPnP or creating separate tool)
- Finalized and lifetime tested mechanical design and settings
- Complete and accurate Bill of Materials, tracked and updated with the repository
- Complete and accurate build guide
- Complete and accurate usage guide
The automation upgrade includes a conveyor belt and PCB panel hopper for automatically loading in panels to be pasted and placed. This includes:
- Finalized and lifetime tested hopper and conveyor design and firmware
- Software support for integrating into the existing machine
- Complete and accurate Bill of Materials, tracked and updated with the repository
- Complete and accurate build guide
- Complete and accurate usage guide
Creating, modifying, or supporting a reflow solution that can be added to the output of the conveyor belt. This could mean recommending an off-the-shelf oven that can be integrated with the Index, modifying an existing open source project to integrate with the Index, or building a reflow oven from scratch.
-last updated 2020-12-28-
Right now, the motherboard design is very nearly finished. Any design changes will likely not be functional changes, but instead board layout and connector changes. The only thing that might functionally change are:
- Adding header for E-Stop
- Switching out the opamp and instrumentation amplifier circuit for an HX711 for the vacuum sensors. This is very low on the list of priorities and might not happen.
The frame is undergoing an overhaul at the moment, which resides in the master branch. These updates:
- Give the camera more space to observe parts on feeders before picking
- Add proper part number versioning to all parts
- Switches all CAD to FreeCAD so PRs can be accepted
- Improved limit switch mounting
- Improved method for tensioning gantries
- Added mounting points to attach the Index to a table
- Improved cable management with dedicated umbilical cable mounts and cable guides
- Dampened mount for the vacuum pump to not interfere with the camera
- Updated BOM including all tubing and pneumatic connectors necessary
The feeder architecture is pretty well defined, but there are still required changes before it can be recommended that they are built. A new revision is currently being worked on, which will include the following:
- Mechanical lock to hold the feeder onto the rail
- Finalized feeder identification method and connection to the feeder floor
- Updated indexing wheel PCB
- Magnetic sensor for detecting film tension
- Improved CAD for more reliable tape movement and less friction
- All CAD in FreeCAD
Currently, stock OpenPnP can be used with the Index, but configuration is a bit tedious and less than ideal for the hardware features available to us. We are currently working on adding our own feeder type into OpenPnP that will support our hardware specifically, and will take advantage of the features we've included.
The firmware running on the motherboard is a build of Marlin. A few changes were necessary to facilitate all of the motherboard's functionality. We are adding in:
- RS-485 support (effectively UART out with a dedicated pin for RTS)
- ADC support (for reading an analog voltage from the vacuum sensors)
- Board Config (having a specific board type for the Index Mobo with all the correct pin mappings)
Feeder firmware is much easier to edit and update because it is not based on an existing open source project. Working firmware has been written for the feeder to receive commands over RS-485 and execute them. We are currently working on rewriting it to support a specific protocol we created for motherboard <-> feeder communication.