Starting a project with a good plan and process is key to success but you have to also be flexible and be receptive to changes as the project evolves. When we started the Belt Envy Project we conceived a mechanism concept. We made a
breadboard, or proof of concept model, which was different from that initial concept but designed for speed because we needed information quickly. We then planned to make a separate breadboard of our initial concept to prove its design and then reproduce a final machine from the breadboard’s design. It was that last step where we deviated slightly. We found that our breadboard was really working very well and could be a work in process, slowly changing over time to become the final machine. In essence instead of building a completely new machine, we replaced parts as we used the machine and discovered what could be improved. The breadboard transformed into the final machine instead of rebuilding from scratch. This allowed Jackie, the owner of Belt Envy, to get product much earlier than expected.
When we did the initial mechanism concept it was created in Solidworks as a rough conceptual drawing. Much like the process that the machine went through, this drawing was changed to create the engineering file that the team would use to build the machine. The initial parts were machined out of various plastics with the expectation that they would be later machined out of metal. Some parts needed to be made in low durometer material so we made a plastic mold and poured a two part material in the mold to make those parts. A lot of R&D was done for the materials that came into contact with the heated acrylic. We had to make sure that the material would withstand the heat and not leave any marks on the soft acrylic. As the design progressed, we found that actually using a harder Delrin material proved better.
As we started the trial and error phase of the development we found that with the heated plastic, gravity was really working against us. The plastic was drooping and cooling so fast that we were not getting the form around the mandrel as nicely as we had hoped. Sometimes you just need to "turn things on their head" to figure a problem out. We did just that. We turned the entire machine upside down. Some things had to be reconfigured and we had to completely rethink our loading mechanism but the material conformed much better to the mandrel when we flipped the machine upside down.
There still will be development on the machine as move forward. Everything we do after this design phase will be done to speed up the process and automate the handling of the material, but we have just about reached a stage where we can produce cuffs for Belt Envy while we are improving and enhancing the process. I will keep you posted on the progress and promise a video of the machine in progress in a few weeks.