Hi from Perth Australia

[PK]

OK, so now I feel bad for lurking.  My name is Paul Kelly, and I'm a shed addict in Perth Western Australia.

I'm in the process of revising my old CNC site. For now you can find it here: http://www.caswa.com/cncathome
Just recently bought a new AL320, that's already in pieces. As well as a 60KRPM spindle I'm going to bolt onto my (nearly stock...honnest) X3 Mill...

MM seems like a site for people with dirty fingernails.... I like that....

Cheers

[SwarfnStuff]

Hi PK and welcome to the mad mob  er Mad Modders. I hope you find this as good a site as I have. I'm not into CNC and my Playpen = workshop is miniscule but I make swarf with my Sieg clone 7 X 12 and Sieg X2 mill, sometimes something useful emerges.   
Again, Welcome.

[AussieJimG]

Welcome Paul, that 60KRPM spindle sounds interesting.

Jim

[PK]

Welcome Paul, that 60KRPM spindle sounds interesting.

Yeah, it was prett much an impulse buy.  There's the beginings of a thread on it here http://www.westcoastmakers.com/threads/going-fast.1291/
PK

[PekkaNF]

Really mad at you not showing this stuff before

But I could calmn down fast if you would tell me more about the gripper on this page:
http://www.caswa.com/cncathome/spindles.html

Got some anecdotal information, but few things were not evident to me.
* Is that taper more or les SK15?
* Can I have dimenssions of the gripper collet and pull stud?
* How does it work?
* How much is the griping force? You probably had some some figures in mind when you were planning taper/force. Care to open a process a little?

Really liked the stuff you do. Enjoyed reading about X3 and ELS. "Spindle speed control for the mill" did not reveal me of it's secrets.

Stay here. Maill stuff.

Thank you,
Pekka

[krv3000]

hi and welcume

[howsitwork?]

Hi and welcome to the  play pen!

[PK]

Really mad at you not showing this stuff before

See the problem is that this sort of work is addictive, which is fine, but I only got into CNC to help make more rocket bits:




But I got hooked.
Years later I finally plucked up the courage to admit I had a CNC addiction and went cold turkey.. I left the site idle for years and it expired.

But I could calmn down fast if you would tell me more about the gripper on this page:
http://www.caswa.com/cncathome/spindles.html


Got some anecdotal information, but few things were not evident to me.
* Is that taper more or les SK15?

Its just an 8 degree taper, no idea who else uses it.

* Can I have dimenssions of the gripper collet and pull stud?

Tough, I don't use that spindle any more.  On a scale that small, I found the plain shank toolholders worked better.

Those are 8mm shanks.


re the studs:IIRC the heads of the studs were 5mm diameter.

* How does it work?

There's actually some deceit on that page (not everything you read on the interwebs is true you know).
The cad model shows a complex arrangement with three leavers and an o ring opening them.
With that spindle being so small, I got better results by making the claw look a lot like a tiny R8 collet with a groove just inside the nose to grab the stud. Then I bent the collet open and hardened it. Pulling on the drawbar would then close the thing around the studs.

* How much is the griping force? You probably had some some figures in mind when you were planning taper/force. Care to open a process a little?

Short answer, not enough. When you get that small, the overhead bits (pull studs, claws, springs etc) start taking up disproportionate amounts of room. That room comes off your friction surfaces and you loose grip.
Another bad bit is that the pull stud setup requires quite a lot of precision and hardened, high strength parts. I ran the plain shank ATC for about a year with a soft collet.


Finally though, when we started using the little router for production work, and employee cooked the magnets off the servo motor driving it. This triggered us getting our first water cooled, 24KRPM spindle. For a small machine, with a high resonant frequency, these are just the ducks nuts. I'm talking 6-10 times the metal removal rate. I'll be putting up a page specifically on them.

Really liked the stuff you do. Enjoyed reading about X3 and ELS. "Spindle speed control for the mill" did not reveal me of it's secrets.

TA, not much to say on the DC motor drive, you can just buy them for next to nothing these days...
Cheers
PK

[/quote][/quote]

[PekkaNF]

Scary looking stuff those rockets.

Thanks. Great info. While experience replaces nothing, nothing replaces first hand experience.

I have been drawing/toying (design is big word) some power bar or semiautomatic tool change. Not really into ATC, but some sort of quick change would be in order. Taper and retention force are variable that we can play with. Self releasing taper needs more force than MT.

I have seen three main DIY gripper designs: Balls, spring collet and lever style. They are very different and each has it's issues. Lever type seems to be only real choice with self releasing taper. You are right, all parts needs to be carefully designed and preferably heat treated (all my small bar stock is tempering steel, I can build parts out of this and anneal or harden them, but small parts only).

You also had interesting QCTP mount spindle:
http://www.caswa.com/cncathome/images/spindle_toolholder.jpg

Care to tell about motor power/rpm and what is that spindle good for? Looks like a 100W brush DC-motor?

I have tried dremel (not worth of unless you have nerves of budhist monk), I have Proxxon BFW 40/E which I think is a bit of a toy in performance and pig in size:
http://www.axminster.co.uk/proxxon-bfw-40-e-mill-drill-system

I was in process of putting an 3 phase AC motor with vector drive to get close to right rpm with belt drive, when I got slightly off the track with PM AC servo, less than 1/2 the size and more rpm, but I had stability issues (AC servo and old inverter).

I have been reading some stuff on BLD motors, but haven't been able to nail the motor/driver combination. I don't want to go RC stuff, and can't bring myself to pay real brand servo prices. Probably will build two. One rough one for drilling 2-6 mm dia holes and realatively low rpm and other with collets and high rpm. I like belt drive, gets the motor away from spindle and easier to align.

Pekka

[PK]

I have seen three main DIY gripper designs: Balls, spring collet and lever style. They are very different and each has it's issues. Lever type seems to be only real choice with self releasing taper. You are right, all parts needs to be carefully designed and preferably heat treated (all my small bar stock is tempering steel, I can build parts out of this and anneal or harden them, but small parts only).

Seriously, go with plain shank toolholders. Maybe take a look at how Tormach do theirs. They reference in Z against the spindle nose, so you can still use tooltables.  My preference was just to measure tool length every change. I hate tooltables....

You also had interesting QCTP mount spindle:
http://www.caswa.com/cncathome/images/spindle_toolholder.jpg

Care to tell about motor power/rpm and what is that spindle good for? Looks like a 100W brush DC-motor?

I have tried dremel (not worth of unless you have nerves of budhist monk), I have Proxxon BFW 40/E which I think is a bit of a toy in performance and pig in size:
http://www.axminster.co.uk/proxxon-bfw-40-e-mill-drill-system

Yeah, its a bit of a dilemma.  The requirement is for a small powered head that fits on your toolpost and can drill big holes.... Hmmmm. To get the performance, you need something about the size of an Seig X2 head, Which is too big.  So you go small and fast, which means small cutters and chatter.....  Dremels are a classic example of how far marketing can take a bad design. The overhang from the bearing is enormous. I've heard good things about the proxxon..  When I've really needed to get jiggy with a toolpost spindle, I've ended up with a trim router. Noisy but effective up to 1/4" cutters... To answer your question, the motor was about 150W. But driven by an O ring on those little pulleys, I doubt it could transfer 100W.

I was in process of putting an 3 phase AC motor with vector drive to get close to right rpm with belt drive, when I got slightly off the track with PM AC servo, less than 1/2 the size and more rpm, but I had stability issues (AC servo and old inverter).

I reckon you're on the right track with the FVD. Fractional horsepower 3phase motors still tend to be quite large though. Brushed DC is really the best power density per buck at low RPM's maybe add an encoder and run it from a Gecko DC servo drive. 
As you've figured out, adding an encoder gets you a brushless servo which can deliver high torques at low RPM's for medium bucks. IIRC I bought a 600w Servo for about AU$650 landed a year or so back.
Have you considered a little high speed spindle? I just bought a 60KRPM 350W job. Its about 48mm diameter...  If you go to 80mm you can get 1Hp at 24KRPM.  Simple, but limited to small cutters...


PK

[PekkaNF]

Seriously, go with plain shank toolholders. Maybe take a look at how Tormach do theirs.

Yea but, no but. I like taper, dogs are optional. Your preference is high speed, my mills are more often 20-50 mm dia than under. Now I have MT3 tooling, but next one should be ISO30 or 40 - manual mill, but let's see. I really could get away with ISO20 if I would have completely different mill, but that tooling is not for hobby price range.

'Brushed DC is really the best power density per buck at low RPM's maybe add an encoder and run it from a Gecko DC servo drive. 
As you've figured out, adding an encoder gets you a brushless servo which can deliver high torques at low RPM's for medium bucks. IIRC I bought a 600w Servo for about AU$650 landed a year or so back.

If I were into brushed integrated spindle my firs choice would be kress
http://cnc-plus.de/en/Spindle-Motors---Spare-Parts/Milling-Spindle-Motors/Kress-1050-FME-1-Milling-Spindle-Motor-with-1050W.html
Really no point of putting dremel/router or such when you can have this. This has limited life ofcourse and I have heard people using them on cnc routters pretty good time.

I'm seriously pondering between AC/BLD spindle motor, but it should have relatively low rpm (4000-6000 rpm ideal) and pretty close to 200w of power for a 1/2 minutes or so. Normal AC good insulation class AC motors you can run that hot, you don't want to touch them. There is latitude on duty cycle, specially if you have external fan.

Normal 0,25KW/3000 B14 frame SKg 63-2B 3-phace motor works out 3310 rpm on 60 Hz 0,30Kw and 68% efficiency. 4,2 kg, diameter 126 mm and total lenght 214 mm, body length 191 mm. It's not too heavy, but it is a bit big for QCTH.

Pretty much it all comes down to how low price and speck I can afford to go. Obiviously I don't want to get too cheap here but I can't bring myself to pay over 200 USD/EUR on chinese 200w spindle motor.

Have you considered a little high speed spindle? I just bought a 60KRPM 350W job. Its about 48mm diameter...  If you go to 80mm you can get 1Hp at 24KRPM.  Simple, but limited to small cutters... PK

I have considered, that would be "the other" spidle. Care to tell which motor/drive you got? There seems to be a lot of nearly/seemingly identical ones on ebay.

Thank you very much.

Pekka

[Meldonmech]

Hi Paul
                  Welcome to the forum, your Rockets look very interesting, can't wait to see more posts.

                                                                    Cheers David

[PK]

Yea but, no but. I like taper, dogs are optional. Your preference is high speed, my mills are more often 20-50 mm dia than under. Now I have MT3 tooling, but next one should be ISO30 or 40 - manual mill, but let's see. I really could get away with ISO20 if I would have completely different mill, but that tooling is not for hobby price range.

You are right, I missed the bit where you said you want to run big tools.  There's a reason all big machines use tapered spindles and draw bars under stupendous tension!

If I were into brushed integrated spindle my firs choice would be kress
http://cnc-plus.de/en/Spindle-Motors---Spare-Parts/Milling-Spindle-Motors/Kress-1050-FME-1-Milling-Spindle-Motor-with-1050W.html
Really no point of putting dremel/router or such when you can have this. This has limited life ofcourse and I have heard people using them on cnc routters pretty good time.

I'm seriously pondering between AC/BLD spindle motor, but it should have relatively low rpm (4000-6000 rpm ideal) and pretty close to 200w of power for a 1/2 minutes or so. Normal AC good insulation class AC motors you can run that hot, you don't want to touch them. There is latitude on duty cycle, specially if you have external fan.

There are a lot of mods for BLDC motor controllers that involve adding hall sensors to brushless motors.  The RC stuff is junk (as I guess you know), shafts and bearings just aren't up to the job, check out endless sphere for some guys doing really intetresting and open source stuff with controllers and motors for EV use...

Normal 0,25KW/3000 B14 frame SKg 63-2B 3-phace motor works out 3310 rpm on 60 Hz 0,30Kw and 68% efficiency. 4,2 kg, diameter 126 mm and total lenght 214 mm, body length 191 mm. It's not too heavy, but it is a bit big for QCTH.

yeah, thats about the size of a mini mill head.. Which is too big for a QCTH......

Pretty much it all comes down to how low price and speck I can afford to go. Obiviously I don't want to get too cheap here but I can't bring myself to pay over 200 USD/EUR on chinese 200w spindle motor.

I reckon it all comes down to whether you want to abandon the idea of getting this thing in a tool holder. If we look at, even small, commercial horizontal turning centers that have live tooling, then we see that that tooling is mounted in a turret that weighs a hundred Kg. Which brings up the other point: Even if you come up with a 1KW , 50mm diameter, 500rpm motor that weighs 5 Kg and mounts in your toolpost. You don't have any thing like enough mass around the thing to run those RPM's, it'll vibrate like a b*#ch..

I have considered, that would be "the other" spidle. Care to tell which motor/drive you got? There seems to be a lot of nearly/seemingly identical ones on ebay.

So I've got/had three of them. My first was a water cooled 800W 80mm motor.  You can get air cooled motors, which would be more useful in your application. It had an ER11 collet.
My next was a 1.5KW water cooled motor on our full sheet router. The most recent is the little 60KRPM model shown here: http://www.westcoastmakers.com/threads/going-fast.1291/
I really don't think it matters what drive you get. You are running these things at 400-1000Hz so flux vector is useless.

Its hard to describe how good these spindles are on small machines. 
On my little router, metal removal rates went up by a factor of 10 when I replaced the 7500 rm spindle with the 800W 24Krpm jobbie.  This is entirely because a cutter at 24KRPM (even a single flute) can only excite the machines structure at 400Hz. The resonant frequency of my router was around 300Hz so it just stopped ringing. This translated to massive reductions in cutter deflection, less broken tools, higher chiploads, it made me taller and more attractive to women....  Now if your machine weighs a ton then you won't see this improvement, but if you're putting the spindle in QCTP then you definitely will..

PK

[PekkaNF]

I hear what you are saying. It is all about getting the tool that will 80% job really well and rest of it I can make do.

I have one mill, it weight about 1500 kg or bit more, but it has no drilling spindle, and top speed is in order of 700 or 900 rpm. It has maybe 3 or 5 kW motor and seven speed box. Haven't stalled it yet. Not even with 25 mm drill. Although cranking knee up and down is excercise.

But I need something lighter, like bridgeport or RF45 size for drilling mainly.

And then I need something even smaller to slip into lathe and make 2-6 mm short holes (often smaller) and "spotting". This is work under progress (and sometimes impasse with myself, gobble something together and figure that it almost works, but nothing to get excited about). Experiments show that I "just" get away with 200w when holes are about 5-6 mm and 3 mm holes probably need 100W max, so there is room for optimisation and no reason to go overkill here.

I'm purely hobby person in home machine shop. I'm trying very hard not to take a step in the dark side (NC).

Pekka