It looks like a solid option that I will likely use in future. Thanks for being pioneers for the rest of us!
A lot of predictions of smoke and death early on… that usually means you’re onto something good!
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Vince,Griff
Got numbers!?
This weekend I put in the brushless and ran it pretty hard. 8mm Datron single flute
Actually stalled it when trying to cut like a corded Makita, dialed back 20ish%
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Cool! Why that K factor? Thanks for using the workbook!
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Good catch! Little bit of dyslexia, it’s supposed to be 3.344 for 6061 T6. Still getting comfortable with your worksheet!
Btw how close do you think that router power estimate is?
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Here’s what it looks like with a 3.344 K-Factor (proportionally reduced power and force) and the latest version of the workbook. I corrected an error in the bit deflection calculation when the shank diameter exceeds the cutter diameter.
2019-08-28 Speeds and Feeds Workbook.zip (155.7 KB)
NYCCNC’s K-Factor for 6061-T6 Aluminum is lower than the 4-5 most calculators use. So it’s probably conservative (overestimates the cutting power and force requirements). Once you start using your HF Spindle you’ll be able to measure it.
It’s also pretty easy and inexpensive to build an ac power meter to use with AC routers and power supplies powering brushless motors.
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I’ve determined that this plugin power meter is almost as accurate as the ones that this guy uses, and a lot faster. For those that may be interested he has a nice description of why a meter that corrects for power factor is necessary . Measuring input power to VFDs, AC routers, or DC router power supplies with this device should be sufficiently accurate for K Factor measurements and real time cutting performance monitoring.
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Well this sucks. Apparently my account and posts got wiped out when the forum server died.
Good news is I have been able to properly read the RPM sensor, so just waiting for my new ESC and power supply. Once I have that I should be able to make it so we can precisely control the spindle speed.
On a side note, I could really use some assistance identifying the stupid connector that Makita is using for the hall sensor.
EDIT :
Apparently new users cannot upload photos so if one of the other owners of this router could post a picture of the connector I would greatly appreciate it.
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I’ve upgraded your account to help make up for the inconvenience — post away!
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@WillAdams Excellent! Thank you for the upgrade.
@LiamN Thank you for posting those pics for me.
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Found the connector:
http://www.jam-net.co.jp/eng/product/connector/post1376/
Specifically need the female rm25-05m and female rm25-04m. Unfortunately I cannot find them from a distributor.
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The four contact is for the buttons on the front of the router which I was planning on re-purposing for controls on the Arduino.
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Is there a connector for battery - winding power?
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There is a 5 contact connector for the hall effect sensor, a 4 contact connector for the front lock and on/off buttons. Both of those are those connectors from JAM I linked earlier. There is also a connector for the illumination LEDs at the bottom which is different, but I have a few laying around. Will figure out the spec on that later. Then there are a +, -, and sense wires for the battery. Those are just standard locking spade connectors. The wires to the motor windings are using crimp style wirenuts which were a bitch to get off.
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Did you look at that linked possibly compatible JST that Digikey has?
What’s the resistance of the windings?
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Saw the connector, but I do not think that will work. Probably just going to put a Dupont connector on it.
The windings are 21ohms from pole to pole.
My ESC and PS arrived. The PS is a nice Mean Well with spot on 24 volts. The ESC however gave off magic smoke when I plugged it in. I am just going to get an ODrive (https://odriverobotics.com/). I know that can handle this motor. Its mostly meant for robotics so it is kind of overkill, but it is a place to start.
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Scratch that. I went with a VESC based option. They directly support the hall effect sensor and are used on electric skateboards so should have no issues handling this motor.
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Using the drill method for calculating KV rating it looks like this is a 800KV motor. Which does not seem right as it would take 38V to reach 30k RPM on that.
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