今年我们的工作已经顺利展开,继续使加工方面更完美,并为耳塞的大规模生产做好前期准备。

目前我们已经向终极里程碑迈进。我们会把所有的时间和精力都花在测试和微调的步骤上。

在此更新中,与往常一样,我们将与您分享研发的详细信息,然后总结。模式切换按钮,传声器垫片,扬声器垫片,生产线和超声波焊接,这些方面都在不断的测试和改进中。研发的具体细节和总结部分将会在英文的更新中具体解释。

我们会反复测试直到达到完美境界。塑料部件和焊接工具的变化需要额外三周,但4月的时间表仍然可以实现。

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We’ve been off to a great start this year, working towards getting our tooling perfect and preparing for the earplugs’ mass production.

Since we’re reaching the very final milestones, February is a heads-down-working kind of month. That’s why we want to dedicate all of our time and effort into testing and fine-tuning steps. In this update, as usual, we’ll share with you the details on the R&D and the next steps will conclude the update.

How things have progressed

Mode switching button

As mentioned in the previous updates, the unnecessarily big gap between the button and the actual switch component on PCB made the button feel stiff. The gap between some components and the elastomer was also too small.

We figured out the solution by reducing the gap and adjusting the elastomer in the tooling. The new plastics arrived at the factory and were assembled with other components. The button works well with our latest modifications. Some material was added to the bottom of the button, so it rests closer to the switch component.

The tactile switch is located between charging contacts on the PCB.

You can press the button to change modes if needed. It’s a neat and important addition in this model since it can come in handy if you have small kids. You don’t have to take the earplugs out while taking care of the kids during the night. When travelling by airplane, you can also switch modes to listen to announcements or to communicate with flight attendants.

Microphone gasket

The mic gasket seals now since the surface of the PCB was made smooth.

In the earlier revision of the PCB, there was a track going across the area where the microphone gasket should seal. A track causes small unevenness to the surface of the PCB. The track has been moved away from the critical area. The height of the microphone gasket made from soft elastomer was also increased. These changes ensure that the gasket seals properly against the PCB.

Microphone gasket in the top cover is pressed against the surface of the PCB.

Production line

As it’s very critical to make sure every small step is well verified and tested before the mass production, we have had different builds and been conducting the testing iterations. After each round, we realize issues that can have some certain effects on the performance of the products, so we conduct fixing as we have updated.

At the moment, we have some working products from the work completed at the factory with our partners. We are testing the different assembly methods to find the most reliable one that can be applied for the whole production line.

Ultrasonic welding is employed as the method used in our production line.

It is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid-state weld. It is commonly used for plastics, and especially for joining dissimilar materials. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together.

This technology is used to get perfect welding of the components. The process needs to be airtight, durable and does not make any sharp edges.

By using this, we are able to make the devices super small, because it does not need any room for connective mechanics like screws.

 

The sonotrode (a tool that creates ultrasonic vibrations and applies this vibrational energy to a gas, liquid, solid or tissue)

 

This is where the top cover of the earplug will be attached to be welded with the earplug’s body.

 

This is the bottom part of the ultrasonic tool used to assemble the top cover with the earplug’s body. Here we used a universal “spike bed”. It will later be replaced with a machined fixture.

 

The air flow resistance of the pressure release channel was measured before the welding process. 6 pairs were ultrasonic welded at the factory.

At this step, we see that the soft elastomer part in earplug top cover easily melts and gets perforated during ultrasonic welding. On tightly welded samples the ultrasonic energy was too high for the elastomer to handle. We had some parts without any damage in the elastomer but at the same time the welding result of the hard plastic was weak.

In the following week back at the office, the airtightness of the weld and gaskets was measured, and the faulty ones were opened. The welds were analyzed.

Some of the unwelded devices were glued together and functioning earplugs were made.

Solution and fixing time:

Improvements to the welding rib and ledge are ongoing. Suggestions to improve the sonotrode of the ultrasonic welding tool have been proposed to the welding tool supplier. The idea was to modify the shape so it doesn’t touch the elastomer part which could reduce visual defects.

 

The height of the ultrasonic welding rib was increased to improve the welding strength.

 

Pressure release channel

Speaker gasket

The tooling has been improved, yet in the latest plastic samples, there were some inaccuracies in dimensions and defects on the surface quality. This is partly because the tool maker didn’t have enough time to properly finalize the molds, and partly because of the difficult design that requires very small and accurate features.

We have discussed with the plastic maker about the importance of the properties for functionality. The width and depth of the channel were increased slightly for easier manufacturing without compromising the quality.

Next steps

As mentioned earlier in the update, we keep these iterations till we achieve the perfect quality. The changes in the plastics part and the welding tool take three more weeks extra, yet the April timeline is still attainable.

 

The working products assembled at the lab and the factory.

Best regards,

QuietOn Team

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