Honestly, IDK. Not sure I trust the lost in translation support when I inquired Jianken (manufacturer) about the sensorless vector control. I also haven’t found any examples of HF spindles in use with vector control other than CNC Depot’s passively cooled spindle.
The main reason I started looking into it was because I’m used to the Makita feedback loop built-in (or in my case with the SuperPID) and it tries to keep up with my aggressive cuts and moving to a HF spindle got me worried I’d be losing that feedback loop that could cause the spindle to bog down and chip load to spike. It mostly seems to be a non-issue for anyone else and has just become an interest/overthinking/experiment while I still have yet to even use my spindle
I pictured it could be useful for drilling ops and maybe if I ever dabble in steel
I’ve been surprised not to see more mention of this tooling size — it’s markedly more rigid than 6.35mm (1/4") and affords some interesting tooling options — I’d be glad to know of other folks using such tooling and the specifics.
From the reading gmack and I did whilst digging into how current relates to torque on the spindles the slip angle of the motor is < 5% when you hit the break away torque and the motor speed collapses so you’re not really losing much speed (i.e. less than 5% of the drive speed). As you say, it also gives you an audible indication of the load on the spindle as feedback.
Once the spindle reaches breakdown torque is when things get interesting, there’s a bunch of different ways the VFD can respond, from momentary over-current, through re-start attempts to throw alarm and shut down.
So far as I can tell vector control is more useful in applications where the exact speed is really important or for things like pumps and fans where reducing the energy consumption is important and being able to back the drive current way off without risk of hitting break away torque when the motor has little load is useful (that’s where optimising the torque producing current is key).
I’ve used drills in the 1,500 to 2,500 RPM range and there’s no lack of torque from the 2.2kW spindle. The limit I’ve hit so far is machine rigidity, at 8mm dia in 6061 Aluminium the dril just starts to chatter horribly and bounce the whole spindle around, I’ve not found any combination of speed and feed rate that behaves nicely at that size yet. Of course, you have linear rails and I’m still on V wheels for now…
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Griff
(Well crap, my hypometric precursor device is blown…)
46
was given to me by a person that received it as a gift for writing a favorable review. Suspect, to say the least.
Sat in a drawer for 6 months before I thought about using it. Seller claims top rpm 16k, you have to ask, this number is nowhere in the description.
Added another sheet of lexan to my door, tightened the 1/2” collet extra tight, ran it at 1000 rpm on my 2.2. Gradually bumped the rpm up to, eventually, 12k with no adverse effects. Then commenced facing a pile of secondary waste boards. Worked great.
Use these as well. The ones with inserts for 6061.
Now I need to go and read to learn about what difference the tip angle makes whilst I’m trying to learn how to calculate moment of inertia and deflection
It’s the vibration that’s the issue, not the torque, above the 5mm bit, the next I tried was 8mm and it builds up that characteristic triangular wavy pattern in the cut and vibrates vertically.
The 3, 4, 5mm are all fine at sensible mm / rev and produce a nice pre-drill that can then be quickly opened out with an end mill without having to get anywhere near a plunge, which is what I’m using the drilling for, having had “mixed success” doing boring ops at close to the slot drill / end mill diameter.
Here’s what Guhring says about their spot drills:
“NC spot drills are high precision drills designed specifically for creating an accurate hole location for a secondary drilling operation. NC spot drills due not have body clearance and are not designed to drill greater than the depth of the point angle. The 90º and 120º spot drills are primarily used to create an initial spot for 118º and 135º secondary drills respectively. The 142º point NC Spot drill, series 546, is designed to help center carbide drills with an angle of 140º.” @Winters636 reported some impressive results with one of their 2mm drilling endmills.
My experience with Hitachi has generally been good, they’re still pretty Japanese in terms of quality, irrespective of where the actual units are manufactured or assembled (don’t be fooled by "made in the "). I’ll wager the RS422 actually meets spec too…
The feature;
Capable of driving permanent magnet (PMAC) as well as standard induction motors
is interesting, it seems that the drives are becoming more defined by their control software than the electronic components, that can only be good for our sort of uses.
Thanks for all your guys’ suggestion. Ended up upgrading to linear rails and also an aluminum bed from Saunders Machine Works. Really wanted to push the limit of the machine after the mod.
I have the Shapeoko XL so sourcing the linear rails was basically impossible on eBay or Amazon. Ended up getting it from Aliexpress. Actually decently fast shipping! Came sooner than the ATP5 aluminum stock I ordered at the same time.
