The first samples made with all final manufacturing processes:
We just returned from another 2 week trip to California to work closely with our manufacturing partner. Above are the first units produced with 100% of the parts and processes that will be used in final manufacturing and they look great! The issues that remain are the bands, batteries and yield targets which we'll dive into below.
As we started to assemble our test units, we found that the batteries have some issues where some units have tabs that aren’t well adhered. The good news is that the battery supplier is extremely proactive in fixing the issue and we are working closely with them to document a testing procedure to weed out and replace problematic units.
Close-up showing a tab not well adhered
Dialing in the Process and Increasing Yield
Throughout this journey, our bill of materials has increased. From issues with E Ink displays, the original battery partner closing shop, and the move to Nitinol bands has left us with very little room for scrapping parts that don’t come off the line perfectly. With sample in-spec bands, we were able to assemble 7 working units. However, this was from a batch of 16 circuits. The main reason for the low yield is due to the aforementioned battery tab issue. We are addressing the issues in order to get the yield back to a reasonable number before we can pull the trigger on high volume manufacturing.
We’ve been working for weeks to get a schedule from the supplier for when we will be receiving bands in California. Delivery dates and quantities were in a state of flux, so we had been waiting to update until we had parts in-hand. Unfortunately, as of right now, the bands have still not arrived.
So, what’s been happening? At the point we approved the first article parts we were told that 200 parts a day was a safe estimate of what would be produced. It took us several weeks to track down why we were not receiving parts as promised. It appears as though the supplier was having some challenges meeting that estimate due to machining tolerance creating a lot of ‘scrap’ parts that were outside specification.
It turned out that the bands were not being measured according to our instructions, so many “scrap” parts were actually good, we also looked at their measurements and found ways to loosen tolerances without impacting the design in order to help them reach yield targets.
As of yesterday 200 in-spec bands were due on the loading dock in California, but we just received a note that the 200 units that were supposed to ship were not shipped since the vendor had missed a process step (cleaning) and the parts were out of spec, so they were returned to the vendor.
Our manufacturing partner has installed daily updates and check ins and have also mobilized a team to be at the band manufacturing site to oversee production in order to resolve the issues in getting these made. We will continue to update you as we get more information about the shipment.
The cautious approach and the careful delivery schedule from the supplier is likely due to the following reasons:
-The raw material costs for Nitinol sheet is incredibly high, running ‘failed parts’ and rushing them through the line is a costly error, running them slowly will get the supplier a better yield and less scrap parts...ultimately they will get more ‘good’ parts that pass inspection that we have paid for.
-In ‘mass manufacturing’ it would be normal to run 2,000 or so parts through the line to check and measure them to make sure consistency was reached, in our world that would be around $50,000-$100,000 in parts to ‘check’ the system..or roughly 10% of all backing Kickstarter backing money to ‘check’ the system.
-Internal systems are in place that check FAI (first article parts) and lead to PPAP (Production part approval process) these processes are internal to the supplier and it has taken sometime for those internal processes to be opened up to us in order for us to successfully collaborate on arriving at a solution. This supplier has invested a lot of time and effort so far in getting these processes fine tuned.
-Chinese “Golden Week” was the 1st of October to the 7th of October, this means the lines ramped down and came back up upon return.
We have been hand assembling circuits to bands and continue to refine and prepare all the other steps of the process for the arrival of these bands. Fingers crossed we will be receiving these bands at 1,000 to 2,000 units per week, meaning about a month of production time.
Having two people at CST handle the design, packaging, engineering, CAD, process development and documentation for a product has been quite a handful. In some ways this has been good for us allowing us to weather these numerous delays by staying small, but it also means that sometimes communication suffers and we apologize for this. The manufacturing partner is now providing more support to get us across the finish line and dial in these details to increase yield. We are systematically addressing these last few issues around yield and the bands. We understand that you are anxious to get the watches and we cannot wait to get these out to you too!
- Dave, Jerry and the CST team