Getting ready for DVT (Trident Kickstarter Update #22)

Original post : June 22, 2017

Hello everyone,

There are a lot of things happening quickly right now, so for this update we’d like to jump right into specifics.

Quick summary: we’re very close (weeks away) to getting our first DVT units off the line, and are currently ironing out the final tweaks to our injection molds.

Over the last few weeks, we’ve received a large number of production parts and have been doing inspections of everything that has come in. We’ve already spotted a few issues with several of the parts which we are addressing now, but the vast majority of our incoming components look good and should be ready to use in final assembly. The most important parts we’ve received recently have been our first samples of injection molded shells:

OpenROV Trident
First T2 injection molded parts being unboxed

As we mentioned in our earlier update, injection molding is a complicated process that requires a lot of careful refinement. Not only must the parts be designed properly for the mold tool to work, but painstaking iteration must be done to determine the ideal injection temperature, flow rate, and other aspects of the process to achieve the right characteristics and consistency for each part. The image shown above is of our first “T2” parts, which have gone through several revisions.

Our hope was that the T2 shells would be production-ready, but after initial inspection we noticed that in addition to several cosmetic issues, several of the screw bosses used to hold the vehicle together were cracking below our required loads. We are actively working with the molder now to correct this issue, and hope to have “T3” parts in hand and ready for DVT by the end of this month.

As we address issues related to specific components, there are other aspects of our production line that we are setting up and validating in parallel:

Incoming QC

OpenROV Trident
Some of the first production Trident parts to arrive

As evidenced by the issues above, “IQC” or “Incoming Quality Control” allows us to identify and mitigate problems before they make their way into assembly. IQC mainly consists of looking at samples of each part and making sure they meet the specifications we sent to the manufacturer. We’ve already validated smaller prototype orders of each of our main components, but when larger quantities of something are made, the manufacturing process often changes, so we are being careful to ensure quality does not decrease as a result of that.

Integration Testing

The next step after validating each of the individual DVT parts is to make sure they work together as planned. Integration testing includes basic fit checks, as well as more complex testing procedures to ensure electronics subsystems are communicating with each other properly and that the entire system works as a whole. Of course, our prototype “EVT” builds also incorporated integration testing, but once again, because the process has changed, we want to make sure everything is still working as expected.

Performance testing

After assembling the first sample batch of Tridents with our updated shells, we will enter the performance testing phase of DVT, which is often the most critical (and exciting) part of the entire validation process. Performance testing Trident is similar to doing sea trials for a newly-built ship. With newly-assembled Tridents, we’ll do a myriad of field tests to make sure they meet our expectations, and take quantitative measurements of actual performance to compare to what we expected. Some of the main tests we’ll conduct during this phase will be a pressure test to confirm the true crush depth of the vehicle, battery runtime testing, thermal performance testing, and durability testing. This process will help solidify the final specs of the vehicle. To meet certification requirements, we’ll also do a set of mechanical and electrical tests in a laboratory setting to make sure we comply with national and international regulations.

Assembly line validation

The quality of a device isn’t solely related to the quality of its components. Many product shortcomings are the result of assembly issues. When we were designing Trident, we spent a lot of time considering how it would be manufactured in large quantities efficiently and consistently. As we’ve mentioned in the past, the assembly line validation step of our DVT phase ensures that the processes we’ve put in place work as expected, and that we can produce Tridents at large quantities reliably.

Production QC

The final step in our DVT process will be running quality control on samples of units that come off the production line. While earlier tests of units built with production parts validated the engineering, our final production QC testing will ensure that the entire process, including part quality assurance, assembly, and packaging, is in line with our requirements.

We’ve been in touch with many of you about the specific plans you have for Trident, and we'll continue to make our best effort to balance speed with quality assurance. As always, please feel free to reach out to [email protected] if you have any questions or concerns. We greatly appreciate everyone’s patience as we’ve taken the time to solve the challenges that come along with this stage properly.

More soon,

Eric