Wed 10 Oct 2012
Posted by Marcin
We have demonstrated initial results of open source, social production applied to hardware. It took us 4 days to produce a complete Compressed Earth Block (CEB) Press in a Collaborative Production Run. A mixture of 7 unskilled and skilled people swarmed on a build of the Block Press. While this first test run had many inefficiencies – the 240 human hours that it took for the build still net us an equivalent of $20 per hour per person for the entire team. This is based on our selling price of the machine after materials and supplies are considered. This data point of Collaborative Production indicates a viable, economically-significant route to Distributed Production in the realm of physical infrastructure machinery.
Our next goal is to build the complete brick press in one 8 hour day day with 8 people – using a CNC Torch Table to optimize production ergonomics – translating to $80/hour/person equivalent earnings. We aim to demonstrate this by the end of this year.
Based on these results, we will shift our GVCS deployment strategy to a higher emphasis on design – while reorganizing our fabrication strategy around Collaborative Production swarms. This is feasible because of the sprint nature of the Collaborative Production process – where a highly synergistic production environment is combined with an emphasis on rapid learning.
Marshall Hilton prepared complete fabrication drawings, a Fabrication Diagram, and sourced the materials for the production run. You can download all the files from our last blog post on the CEB. The social results were positive, while production efficiencies need work.
Overall, the social result was spectacular. With access to the Fabrication Diagram, everyone dove into the production run, while Marshall oversaw the operation. This was the first time that I have seen where a group of volunteers was self-guided because of the availability of the fabrication drawing – and finished components were churned out consistently – boosting the morale of the group. Everyone left the day feeling accomplished and having learned new fabrication skills.
We pursued an increased level of modularity in the machine. Marshall designed a hopper seat which allows the improved hopper assembly to sit on top of the machine securely, with the 4 hopper supports being the only points of mechanical attachment. We planned on modular roller holders and made all hydraulic connections quick-connect. We also made the compression sides modular for replace-ability. Inspired by modular design – we added 3 elements of modularity on the fly. (1) We added modular hopper support holders on the rear of the machine to facilitate hopper mounting. (2) We made a modular mount plate for the solenoid valve to make it readily interchangeable. (3) We ended up mounting the sensors and the controller with clamps instead of using other forms of attachment fixtures.
We used a modular Terminal Case, PCB Mount, new version of magnetic sensors, open source Terminal Block, and a Solenoid Driver version on a solderable breadboard. The latter takes 1/2 hour to solder by a skilled person, and is relevant for ready fabrication when someone does not have access to a circuit mill or cannot outsource controller fabrication. The current hydraulics design is compiled in a schematic diagram.
While the social aspects of production were encouraging, we were unprepared on several fronts:
- Quality Control. We had no quality control procedure. At least 30 hours were spent on redoing parts.
- Preparation – People were not trained prior to use our new the band saw, and we dulled a 14 TPI blade within a few hours of cutting. One annular cutter was broken due to improper mounting. We did not use a frame jig. The workshop was not organized or cleaned up thoroughly prior to the production run, so time sinks were found on basic ergonomics. No roles were allocated prior to the production run, so some efficiency was lost on coordination.
- Equipment preparation and allocation – Access to welders was a bottleneck. We had 2 welders available, while we could have used 4. We did not have our plasma cutter, so acetylene torching the hopper and other thin plate took much more time. We did not have any 1″ annular cutters or punches on hand to facilitate making of 1″ holes.
- Fabrication drawings and procedure review – we did not review the complete fabrication drawing set because the drawings weren’t ready in time. Some mistakes were corrected in the drawings during the production run. The fabrication drawings need procedural annotations to clarify fabrication sequence beyond the information found in the Fabrication Diagram, and participants should study the drawings beforehand for building complex assemblies (drawer, cylinder mounting, shaker) and for understanding the overall assembly process.
Replication Notes and Learning
We now recommend CEB Prototype IV as the official version for replication. Overall, the machine is solid, and the increased modularity makes the machine easier to assemble. The simplified hopper design looks promising – the smaller hopper size with flanges appears to be a sound idea to reduce complexity while allowing a 6 foot wide bucket to be used for loading. We have not done field testing yet. If you want to build one, please share your results with us by emailing opensourceecology at gmail dot com.
One note on cylinder fitting – before you start – make sure you follow a careful procedure – as proper sequence of fabrication will save you a lot of time. Use a jig to build the frame. Don’t align the drawer aperture with the cylinder under pressure – as the press foot will adjust to become exactly flat – but it may not be perfectly flat when relaxed.
Machine Improvements and Future Direction
We look forward to further ergonomic optimization in the next production run – scheduled for mid-November. See planned improvements for CEB Press Prototype V.
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