I was amazed at Milwaukee’s M18 Fuel segmented brushless motor when they walked me through the new tech, and am still excited about what they might use it for beyond the high powered circular saws it’s already shipping inside.
In this post, we’ll touch upon the fundamentals and what they did here.
This is the most power-dense motor that Milwaukee tool has ever produced.
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In real-world “why should I care?” terms, this motor can deliver more power and higher efficiency (longer runtime) in a smaller and lighter package.
The motor – and its complementary components – were designed to match the full capability of Milwaukee’s M18 FORGE 12Ah battery, their most powerful M18 battery they ever launched.
Hopefully you can see why I was so excited last year. MORE power, HIGHER efficiency, SMALLER size, LESS weight. (See Milwaukee Tool’s New Brushless Motor is a Big Deal)
In my mind, this shattered the “what more can 18V-class tools be capable of” performance ceiling once more.
Milwaukee has confirmed that, aside from their M18 Fuel circular saw – and the new One-Key model – they will use segmented motors in “more tools where high power in smaller size is a top priority.” They wouldn’t go on record with any teasers.
Here is one of Milwaukee’s older M18 Fuel brushless motors, from their previous generation circular saw.
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And here’s a look through their segmented motor.
Fewer air gaps between the stator coils mean a smaller size, and if you fill those gaps with more copper windings, that means greater power.
Segmented? Yes! Here are two such segments. They are wound separately and then joined together,
If you take a closer look, you’ll see how the stator coils are welded together.
Due to the cost, Milwaukee won’t leverage this technology for all of their brushless motor tools. However, it should be scalable. I don’t see any reason – aside from price – why it couldn’t be used on other tools where power density – high performance in a smaller size – is a top priority.
Frankly, while the segmented motor is novel and definitely going to be impactful, it’s only part of the full picture.
Milwaukee also engineered new electronics to match the performance of the motor and FORGE batteries.
The most obvious difference is the upgrade to thicker (~8-gauge) “superflex” wire.
They also reduced the size of the overall packaging.
It’s not apparent from the images, but Milwaukee described how the board uses more copper layers for more efficient current transfer. They said this is the most efficient electronics package they’ve ever made.
Milwaukee says they partnered with a semiconductor company to co-develop the new power distribution chips – lower impedance components specific for this electronics package.
While these components won’t be exclusive to Milwaukee, they described two benefits from their partnership.
As a co-developer, the chips were designed for the way Milwaukee’s system operates, and so it’s reasonable to expect they will get the most out of it.
Additionally, as Milwaukee co-developed the components, they were able to integrate it into their systems, giving them a significant head-start and “speed to market” benefits.
The electronics are unlikely to be exclusively connected to the segmented motor, and I anticipate we might see similar electronics package improvements in some of Milwaukee’s other high-demand tools.
There are engineering challenges involved in launching higher power 18V-class cordless power tools, stemming from the higher electrical current requirements compared to higher voltage tools.
In a simplified example, if you have an 18V power tool and a 36V power tool, both with comparable Li-ion batteries and application performance, and identical electrical power requirements, the 18V tool will draw twice the current as the 36V tool.
Over the years, Milwaukee has pushed the boundaries of what can be achieved from 18V-class cordless power tools. As they have done here, Milwaukee has partnered with chipmakers because the capabilities they needed simply didn’t exist in off-the-shelf components.
They took a similar approach when making generational improvements in the past.
They showed off the thermal dissipation package of the previous circuit board.
And here’s the heatsink on the new electronics package.
All of this contributes to tools that deliver “way more power than the prior generation.”
With the newest circular saws, this means no power or speed sag even when under load, translating to faster application speeds.
I found the segmented motor tech to be fascinating, but it’s also exciting to know that a lot of Milwaukee’s power and performance innovations trickle into broader product categories.
M12 Fuel Motor Tech Teaser
Milwaukee showed off their segmented motor tech last year. I was hoping to see it built into more new tools, but that hasn’t been the case yet.
There was more new motor tech this year – the new M12 Fuel ratchets all feature a brushless “outer rotor motor.” I had the opportunity for a quick overview, but didn’t get into the finer details in the way I was able to with the segmented motor and other M18 Fuel tech.
Let me know if you want a deeper dive into the outer rotor motor!
Also of course let me know if you have more questions about the segmented motor, electronics package, FORGE batteries, or any other Milwaukee cordless power tool tech.
Here’s the Interview
Milwaukee gave me a “show and tell” opportunity ahead of the Pipeline event last year. It’s a bit lengthy, but choc full of details.
OldDominionDIYer
I’m really curious if the newest circular saw from Milwaukee that employs this latest tech really is much better or maybe only slightly better. I suppose we would need to see an “apples to apples” comparison of them both to see if the tech translates to the working end. While I love that Milwaukee continues to innovate, and I am heavily invested in their tools (both M12 and M18) I would still need some real world verification that this Tech actually translates to jobsite performance improvements. before laying out for the cost of this kit (to include the Forge battery).
Stuart
It is definitely significantly more powerful. While you get top performance with a FORGE 12Ah battery, there are still improvements when using a FORGE 8Ah and even older/other batteries.
Whether that translates to faster application speeds *for you* depends on what you’re cutting and how.
Leo B.
It really is much better. I had the old rear handle, and now have the new one. I bevel ripped a 16 foot 2×8 with a well used thick kerf blade, and it cut about as quickly as I could walk with a rip guide. Absolutely no burning, either. I’ve had full days of cutting, and haven’t drained a 12.0 Forge yet. I haven’t had a full day of rafters or rake wall studs yet, but I usually have multiple saws rolled out for that sort of thing anyways.
The only issue I’ve had was getting the base plate square to the blade. The base was skeletonized so much for weight, I think it flexes a little more than the last saw, and can be harder to square. I ended up around -2 on the gauge, and had multiple that I tried with the same issue. Once it’s dialed in, though, no issues. Noticeably lighter and more powerful. The updated safety switch is great as well. Being able to make some out of position cuts more easily, like cutting off form stakes, is huge. I’m a fan!
fred
Bravos are due Milwaukee to trying to keep our 18V batteries and tools relevant into the future. I’m guessing that Makita more than annoyed some customers with the move to 40V XGT that caused worries about the longevity of the LXT 18V lineup. Because of Milwaukee’s apparent commitment to 18V – there was probably less customer anxiety produced when they launched their MX platform. One has to wonder, however, when the limits of I²R heating will force them to introduce more higher-voltage tools – and whether the MX platform will be that vehicle.
Ben
I’d argue that they’re probably getting close, and that the I²R heating problem was precisely what they were designing against for the redesigned electronics package, with lower impedance and much beefier heat sink. Obviously you’re going to get much more benefits lowering the current (and raising the voltage, to keep power constant) than lowering the overall impedance or resistance, but this to me seems like they’re just trying to squeeze every single milliwatt of performance out of the 18V platform, and will likely do 2x18V where feasible before that large performance (and pricing) leap to MX.
Stuart
The MX system isn’t just about higher voltage, but also a more robust connection. Milwaukee emphasized at the time that MX Fuel isn’t a cordless power tool system, but a light equipment system. They have since launched a backpack blower that has strong parallels to the M18 system, and the high capacity battery ensures extended runtime.
The move to a segmented motor for the new circular saw allows for more power in a smaller size.
I think it’s no longer about “can it make the cut?” but “can it make the cut effortlessly and seamlessly?”
With tabless batteries, there’s less resistance in the battery packs. With the move to a next-gen electronic control package that can keep up with the FORGE batteries, I think that thermals considerations are as good as they’ve been.
The goal seems to be “tools and batteries that don’t need a break.”
One of the reasons I didn’t like Dewalt’s FlexVolt snow blower was because it lacked the endurance to keep clearing snow until the batteries were depleted. https://toolguyd.com/dewalt-cordless-snow-blower-review/ The batteries overheated and were useless until they cooled off, which too far longer than I expected. Higher voltage didn’t make much of a difference.
Milwaukee is launching a cordless blower as well, https://toolguyd.com/milwaukee-cordless-snow-blower-3036/ , and I’m extremely hesitant that it’ll struggle to match the performance of higher voltage cordless blowers from consumer brands. I expect it to do better than Dewalt’s when powered with FORGE batteries, but MX Fuel would have been a better choice. Maybe they’re saving that for a future dual stage model.
@Ben, Milwaukee has reached an 18V power and performance ceiling several times now, and broken through each time. They’re apparently not yet at the point where 2x18V is a necessity. They do have a couple of dual battery tools, but the main benefit there – in my opinion – is the interruption-free continuous use runtime, with performance boosts a welcome but lower priority for most users.
Ben
I for one would love a deep dive into the outer-rotor motor tech. I love articles like this. Thanks Stuart!
MM
Agreed. I know that outrunner style motors have been around for many years in applications like radio-control airplanes and drones but I’d be curious to learn how the tech might benefit power tools.
Pablo
I was thinking the same thing. I haven’t made any rc plances in a while, but they were always called outrunner vs inrunner motors. I believe the inrunners always ran at a higher RPM and needed gear reduction for propellers. Outrunners could usually be used to directly drive the props. Lots of variables, like number of windings, poles, etc., but I think lower RPM would be better for a lot of applications.
Scott F
Likewise – I know nothing about any ratchet motor technology and would welcome the ability to learn more about it here. The ratchet is one of my most-used tools outside of the drill and impact driver!
Reed Prince
Based on what I can quickly find out, Milwaukee didn’t invent segmented BLDCs, but it appears that they are pioneering the adoption of this technology for cordless power tools.
Jamie Lee Davis
That electronics package would look better to me if it had solid capacitors…
Stuart
Why?
NoDak Farming
It’s good to read about developments like this. Like myself and others have said before, it promotes healthy competition and other advancements by other companies.
From a personal standpoint I’ve become more and more open to the idea of large cordless tools using two batteries. With all of the batteries that people own, it just makes sense for some tools. Seems like it would be just standard for chainsaws that are inside 18 volt ecosystems. I don’t own any of these tools myself. But I’ve been thinking of buying the Hercules miter saw that uses two batteries to create a 40 volt system. Comparatively I’ve also been looking at MetaboHPT’s miter saw with Torque Boost Technology. Apparently the motor is wound in two different ways, and can switch automatically. Or it can be switched to stay in torque mode by the user. “The new motor wiring structure enables automatic switch between High-Speed and High-Torque motors “ is the way it’s described.