PCBA updates and troubleshooting
After busy two weeks of working side by side together with our manufacturer we finished the last week with planning the second iteration of the insides of MIITO. During the last two weeks we tested the first PCBA that fits inside MIITO and already improved the first version. Troubleshooting always takes a lot of time and brainpower, but doing these kinds of things on location not only speeds up the process, but also showed us the great value of a committed manufacturer.
We successfully powered up the first PCBA, which delivers 1000W, but quickly noticed some overheating inside the switching circuit. While having much more buffer in our bigger test-setup, it prevented us from increasing the power with the new, smaller and round, PCBA. During the following 15 days we tested and changed components, validated temperature-calculations with various heat-sinks and even had the manufacturers CEO himself adding his knowledge, we are confident that we have found what caused the overheating and we have ordered a new iteration of the PCB.
Luckily these kind of things are not a huge set back when working directly with manufacturers who are ready to help when needed. During Christmas this new iteration of PCB will be manufactured, assembled and powered up. Then we have to run the same test cycles to make sure we have eliminated the problem of overheating switches. We expect to have results from these tests by the end of this year. If everything goes as planed, this PCBA will be in the final form factor and delivering the right amount of power to the rod to heat the liquid.
This PCBA will then be tested for EMC and safety. Our team has already prepared everything possible:
- The EMC lab for initial tests and troubleshooting that we have chosen is on standby and ready to start as soon as the PCBA passes the functionality tests (see above)
- We have organized all necessary components (filters etc.) that can be used for troubleshooting the system during these tests
- We have gathered the relevant standards and directives
- We have prepared a test plan to run the relevant tests
Product certification is extremely important for MIITO as otherwise it will not be possible to send MIITOs out into the world (without the necessary certification the product would get stuck at customs). That is why this phase of testing for certification and debugging in a thorough matter is extremely important. We hope this phase will go as planned, however that is not guaranteed. We expect to be able to share a summary of the initial test results in the next update.
There are the steps required in order to reach the “Looks like- works-like” prototype (Target end of February)
- PCB layout (V1 done, V2 done)
- PCB print (V1 done, V2 in progress)
- PCB assembly (V1 done)
- Power testing – (V1 tested: problems with over heating switches - new layout: V2)
- EMC pre-certification
Other things we learnt during the troubleshooting :
All of these tests are done together with our manufacturer, therefore we have two great benefits:
a) working side by side with the manufacturers now reduces the risk of implementation of the results into mass production (the manufacturer recommends changes that are also manufacturable so we should have as little surprises later on as possible)
b) since our manufacturer has years of experience with induction cooktops, he has already spotted issues that would come up in the future and we were already able to revise them and implement them in the V2.
Some of them are:
- The low-power side of the PCB will need more protection (already implemented in the V2 layout)
- The switches need to be re-positioned next to each other
- We need a better, custom heat sink (new iteration already started)
- We need to design a shielding the coil (to be validated during pre-certification tests)
From development to preparation for manufacturing
We have invested unexpectedly long months in development that were not planned in our initial timeline (we have explained this topic in our previous updates) but we are happy to move along into the next phase where we are working side by side with our manufacturers.
In December our team has visited multiple coil manufacturers. We have seen various manufacturers who are delivering coils for various applications: from very big and powerful coils to small low voltage coils for example wireless phone chargers. We have selected two strong candidates. The decision was made based upon a few aspects that we keep in mind when evaluating partners:
- Ability to produce one-offs
- Flexibility and willingness to work with us
- Experience in manufacturing similar types of products
- ISO certified
- Quality checks (we have selected manufacturers who do outgoing QC on 100% of the coils, ensuring consistently high quality)
- Transparency of the company: we are able to visit all their locations and we can trace the raw material during the production runs
During the last few months our team has been incredible efficient and all of us are pushing towards the next big milestone in February. The “To do” list is still very long and demanding yet our team and partners are convinced that we can keep up the speed. Despite the holidays- our work will proceed and we are looking forward to bring you more news in January. We hope you can celebrate with us the little wins along the way share the excitement of seeing how this project come together. And finally it feels like its not too far to wait.
Enjoy this precious holiday time with your loved ones with a warm mug of tea. We will continue working on the above mentioned subjects and we will share the results in our next update.
You MIITO friends