TLDR: Hemera is back in stock! You can buy Hemera again!
When we last released Hemera, stock sold out in a matter of minutes. Since then, people have been asking us on a daily basis when Hemera will be back in stock. That time is now. Buy Hemera here.
“What took you so long?!”
Thanks for bearing with us. We realise it took a while to get to this point.
It’s no secret there were some teething troubles with previous iterations of Hemera. We’re determined to deliver reliable, premium-quality 3D printing products without compromises, so we’ve spent considerable time revamping our production processes to make our latest units robust against issues that some of the last batches encountered.
Thanks to the global pandemic, we also faced huge lead times to obtain samples and then test them, even when processes were accelerated to the max.
We’re happy to report all issues reported to us have been addressed. Our talented engineering team have put in 19,500 hours (that’s approximately 2.23 years) of drivetrain testing in parallel to get to this solution, and have developed new processes, including commissioning a custom designed grease dispensing robot for more streamlined and accurate unit assembly.
No shortages are expected. Supply chain roadblocks exacerbated by COVID-19 have been resolved, enabling us to keep up continuous production and supply of Hemera. Our hardworking production team have expanded capacity with an entirely new production floor (during a pandemic!) to keep up with demand, and our dedicated quality assurance team have been working overtime to make sure all units arrive in your hands in top condition for the best 3D printing experience possible.
Sanjay, who is more excited than anyone to get Hemera back on the shelves, had this to say:
“We’ve spent months painstakingly unpicking the bottlenecks in our manufacturing process that were preventing us being able to make an incredible extruder consistently at the scale we now operate at. By diving deep into the minutia of heat-treatment atmospheres, automated grease dispensing robots, and multi-axis machining, we’ve been able to fix everything that was holding us back.
I’m so proud of the team for pulling this off in such adverse circumstances, while still ensuring that we got prototyping, testing, and scaling done right. I’m happy to say that I’m now equally as proud of the product after this monumental effort.
My personal apologies go out to all those who have been waiting for what has felt like an age, and to those we’ve had to ship replacement parts to get back up and running. I’m now more confident in this product than anything we’ve ever released, and I’m looking forward to seeing what our customers do with it!”
Gear cracking. The previous Hemera batch had some reports of gears cracking due to stress from the press fit. Changes have been made to and heat-treatment to combat this. The latest gears have dynamic improvement of approximately 500% more elongation to break/toughness.
Wear and corrosion. To eliminate any wear or corrosion issues to moving parts, gears are now lubricated. For repeatable reliability, engineering commissioned a grease-dispensing robot to apply a precisely measured amount of grease to every unit.
“I already have a Hemera. Can I upgrade the old drive train with a new one?”
Yes, if you want to, although it isn’t a requirement if your Hemera already works as expected.
We’re selling replacement Hemera drive train parts for those who wish to buy them. These parts are pre-lubricated to keep everything running smoothly. If you go down this route, be sure to keep the grease on the gears intact and free of dust or debris - this is required for optimal wear performance.
“I've received my Hemera, but the motor still says 'Hermes'. Why?”
Customers for 24V Hemera may receive a unit with 'Hermes' branding on the motor. This is because there was some leftover motor stock to use up. Motors are functionally the same, have been 100% tested and are fit for production. The only difference is branding.
If you want more nitty-gritty engineering detail about Hemera, keep reading…
Nitty-gritty engineering detail
Gear material issues addressed
- Preventing 0.5MOD 20T gears from cracking due to press fit ~1% failure rate
The revised heat treatment process that we had performed and tested internally was not repeatable in production parts and gears started to crack with an unacceptable failure rate. Many options were investigated to resolve this and were tested thoroughly. The result was to change to a different steel, which has significantly improved toughness for the design situation.
Press fit interferences have been modified to account for the new material so that the gears transmit the required toque without being put under stresses above the material’s yield stress.
- The new material is slightly shinier than its predecessor
- Lubricant is needed to provide required wear performance
Gear lubrication issues addressed
- Improved upon previous wear performance of 0.25MOD 22T and 0.25MOD 73T gear pairing
- Due to the change in material of the 0.5MOD 20T gears, lubricant was required to produce acceptable wear performance
- Improved the application process for production
A new grease was validated to work with the new gear materials used in the 0.5MOD 20T gears to produce acceptable wear performance. This grease does not migrate to the filament path when the extruder is in operation. These parts were validated to the required 2000 cycles on our accelerated life test rig, which represents two years of printing life. They are now being run until failure to determine their full life. At the time of writing, they have since passed 6000 cycles and still have acceptable wear.
The use of this new grease was validated for the 0.25MOD 22T and 0.25MOD 73T gear pairing which showed much improved wear performance over the 2000 cycles compared to previous lubrication.
A grease dispensing robot has been commissioned to apply the required 10µl of grease accurately and reliably to each of the gear pairings. This also tests for any binding in the drivetrain, and all results are logged to a database that can be used to cross reference any customer issue to ensure that no processes were done incorrectly.
Buy Hemera now
We hope all your questions have been answered here. If you have more, join the conversation on our official Discord and ask us directly. But don't forget to buy a Hemera first!