High speed machining- 200ipm/5000mm or bust

There may not be many endmills rated for that speed, but there apparently are some. But, unless you can find/use 1/4 - 3/8 inch endmills, aren’t you “going backwards” on MRR?

Plugging the maximum recommended speed and feed data for that 1/8 inch cutter profiling 6061 - T6 aluminum at the recommended depth and width of cuts into the Kennametal calculator generates the following result.

For comparison, here’s what may be achievable with a Makita 0701 and a 1/4" endmill.


IMO, if the stock S3 steppers/drivers provide 19 lbf per motor, “upgrading” them isn’t necessary. Especially considering the above predictions and Vince’s most aggressive reported results, which likely took less than 4 lbf to cut! Cutting force, which is proportional to the width of cut, depth of cut, and feed rate, is mostly perpendicular to the feed direction.

There’s also acceleration/deceleration forces parallel to the feed direction (F=Ma). There’s a handy online calculator for that too. The following shows the calculation with the “Shapeoko 3 - Default GRBL Settings” accelerations of 0.4 m/sec^2 and a gantry assembly that weighs 20 lbs being moved along the Y axis.
Acceleration%20Force

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This air spindle would only be for 0.125 and smaller bits. To match the same SFM of 0.250 I need to run twice the speed. This should only be for high speed contouring and finish work.

I’m wary to run the single flute carbides due to balance but the 2 flutes should be fine. I have 1/8th plexiglass and the cnc area is enclosed in case things go boom boom.

Polycarbonate might be the way to go. Or at least turn to the side, cover parts you want to keep and squint.

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V3 spindle mount, getting closer

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Ha! Love it.

@Vince.Fab I like where you’re going with this. If initial tests are good Will you take the Makita out to reduce weight of the gantry / increase acceleration?

@stutaylo If everything goes to plan…the air motor might be replaced with a brushless 60k unit. Also been throwing around the idea if a lightweight Z wirh 100mm travel with ballscrew X to move the motor weight off. The large spindle will be removed when using the air spindle for clearance purposes as well. I always dream big though.

Really looking forward to pushing the machine as stock as possible. It’s a great design and I don’t want people thinking that they have to modify it heavily to get it to machine well. I’ll be testing on the stock Z too.

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Loaded in a “hot tune”

250ipm, 700 accels

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Vince,
I suspect that you’ve seen this (Datron’s approach) and their associated videos, but those that haven’t might find it instructive.

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I hadn’t read that paper yet but I strive to apply Datrons style of machining to the shapeoko platform. It just makes sense. Thanks for those links!

I’ve actually been talking with Dann at Datron and he’s sending me a sample pack of their single flute flat and ball cutters! I’ll be pushing them as well and can’t wait! They should be very interesting on full depth adaptive and I expect beautiful wall finishes!

Also I’m currently running a secret sauce ethanol/synthetic/water coolant mix through the Trico Microdrop. Planning to cut the water down and up the ethanol mixture.

It’s my birthday tomorrow and i’m going to spend all day doing epic things on the s3 lol

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That was most interesting, thanks for the links.

I’m no machinist, just read a bit. I’ve moved from using a Super PID to slow things down to a 30k router to speed things up. As I learned about speeds and feeds it became quite clear that, with the exception of large facing mills, our machines work really well at high to max rpm.

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You might find this YouTube video and its comments informative as well. I’m no machinist either, just an engineer trying to understand this stuff.

Yup - reducing spindle speed proportionally increases machine forces at any given MRR. It will also reduce achievable MRR because of the reduction of power available from the router.

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60,000 rpm is fun. Air spindle is usable for high speed finishing and I’ll be buying a 60k er11 brushless spindle when funds allow.

I’m no engineer, just a Weldor with a passion for all things metal and a sucker for a good challenge. I’ll be designing a superlight Z with Generative Design on Fusion 360, maybe even a completely new x rail. Skys the limit.

400ipm or bust?

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So how long did this take to mill?

This spindle was designed primarily for high speed finishing work and not high MRRs or heavy adaptive. It took longer to dial in the optimum load to match the available torque than it did to machine. But that’s what it’s all about, once you understand how everything works, just about anything is possible.

Total machine time was 10 minutes I think.

I might bug Dann @ Datron to see how much for a spindle…he said he had a couple on the shelf.

Heres a look at the prototype mount.

KISS method, little machine and melt. The Makita cast Al was decent to weld to, little had to be adjusted to deal with contamination or weld porosity. It was fun to keep alignment during the fabrication process. The billet mount machined beautifully! Wall finishes are some of the best I’ve had, not perfect but decent. Full width straight contour cut 1" deep with superglue and tape holding. Holding 2-3 thou tolerance no problem

This is a modular mount and I’m going live with insert #2 today. However that one isn’t meant for speed…but I cant say anything more. It’s a whole nother thread.

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Ok, now I understand, ha. Ha.

It looked like you had welded directly to the Makita case in the original pics. I thought you must be really committed to the corded router. Or, I wasn’t seeing what I thought I saw.

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I was on the same page as Griff, the pic really clears that up.

So you’re a welder, a very good one.

Love these threads, learning so much.

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It does totally look like it’s welded solid huh, lol. Naw, I reached the tq limit of the Makita and really want to push some 0.250s to 45,000rpm. Modifying that clamp was the easiest and least invasive way to prove the concept. That mount also fits the brushless btw :wink: and keeps the gear micro adjuster which I thought was cool.

@cgallery yes sir, been fabricating for 18 years now, cnc machining for 1. They go together like turbos and ethanol fuel! This new project will blend those lines even more and I’m very excited to embark on this path.

Learning is what it’s all about. Finding true limits and problem solving. Going past “good enough” and hopefully creating a spark of inspiration in others. I’m definitely not among the smartest of members on this forum, hell, I don’t even have a degree :rofl:

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I’m sure you know, smart and degree quite often are mutually exclusive…