As you have probably read in our AXIOM Beta Manufacturing Report, we are still building all the early adopter AXIOM Beta developer kits completely manually. Obviously we need to increase our production speed to grow the project and to be able to deliver a reasonable amount of cameras any time soon. So in the last four months, we have put a considerable amount of time and resources into automating our production processes. The most time consuming aspect is picking and placing components onto the PCBs, so following our project philosophy, doing this the open source way is the number one priority. In this article we want to report about the automated pick and place options, our experiences and also the ups and downs along the journey.
We consider being able to build and enhance affordable yet powerful electronic production machines a huge thing for hardware startups as well as open source projects. This technology in our opionion is an extremely enabling asset, so we see it as our duty to give back to these communities and push this technology forward ourself - not just for us, but for anyone else following with their own projects. Some people might see this holistic approach as a diversion from our core goals of developing and building a camera, but we think that only by being in total control of all aspects of camera production, can we stay truly independent as a community in stormy seas while reducing our dependencies on others.
The Liteplacer is delivered as a self-assembly kit. It consists of so called 'Makerslides' and laser cut steel plates, electronics and a lot of screws and small parts. It's made and sold by Juha Kuusama from Finland. The mechanical assembly guide is excellent and depicts every step visually. Although the Liteplacer is not technically open hardware, it's very close as it's released under the creative commons non-commercial license - http://www.liteplacer.com/downloads/ states: "The licenses restrict commercial use. By “commercial use”, I only mean selling pick and place machines or software as a business. Selling boards made by the LitePlacer is perfectly ok".
Once the mechanical machine frame has been assembled, you are a bit on your own when it comes to sourcing the remaining electronic, cables and connectors and putting everything together. The Liteplacer comes with its own .Net application which is released as Windows binary only (Source Code). It is great to get the motors and sensors up and running and test all aspects of operation but for production we selected OpenPnp - more about that below. We have been upgrading and improving upon the basic machine by created a custom plate holding the TinyG motorcontroller and also ordered better top and bottom vision cameras and LED rings - the default Liteplacer cameras are 640 x 480 px and we need higher resolution for small parts. E.g. the 0201 (0.6 mm × 0.3 mm) components in the placement tests are sometimes incorrectly rotated 90 degrees because the component was just a few pixels in size and the camera couldn’t reliably see the orientation. The Liteplacer doesn't have the placing speed or accuracy of an industrial machine - but at a price tag roughly 97% cheaper, the bang for the buck is quite unbeatable. We are currently trying to find out why we have a changing camera/nozzle offset of up to 0.5mm and why it depends on where the head moves - we suspect a slight unevenness in the makerslides or V-wheels but it's proving hard to confirm - if you want to help out here please get in touch with us.
When it comes to placing components, OpenPnP (open source software under GPL V3) offers some very valuable additional features when compared to the Liteplacer software - for example it runs on Linux and also offers bottom vision, part offset and orientation recognition. OpenPnP is under very active community development and we've already done our part by pushing small improvements upstream. We have successfully managed to place a number of different sized components with reasonably good accuracy - we even tried 0201 (0.6 mm × 0.3 mm) just for fun and some of them ended up in the right place :) . In general, we still see room for improvements - like higher resolution cameras (these have been ordered and are on the way), the calibration procedures or with the way we install components in tapes on the table, or custom designed semi-manual feeders. We are rather confident we will be able to produce the first AXIOM Beta PCBs this way soon.
The custom DIY Machine
In parallel to the Liteplacer efforts, we are also working with a much more solid/robust DIY pick and place machine built by Amescon (who provide office facilities where we are currently building the AXIOM Betas). So far this project has not got off the ground as we haven't found a software developer who could make the existing software work with our PCBs (it was designed for another use-case). As we recently got to love OpenPnP, we decided to give it a try with this machine. We can already move and home the head and receive images from both top and bottom vision cameras. This machine has slots for 24 pneumatic component feeders. Controlling these feeders and the vacuum valve are still work in progress. All in all we hope to have a robot army at our disposal soon, an army that can build cameras day and night - that would leave us more time to develop new camera hardware, feature and software and actually make movies with our cameras - we can still dream :).