B***er...can't remember getting any...I did move house back in March tho so maybe they're there?Quote:
Originally Posted by blackburn mark
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B***er...can't remember getting any...I did move house back in March tho so maybe they're there?Quote:
Originally Posted by blackburn mark
i think they where sent in may... PM sent
PM replied to Mark.....
I've got 150 off P188207 Belleville Washers coming early next week so think I should have enough for this and any other spindle I might be wanting to do :D
Question to you guys is how well do the DC motors handle heat when running at different RPM's? Also would setting up a PID type closed loop controller work with a DC motor? Looking at options with one of the other members and a DC brush-less motor is looking like the best option for providing the need power and from the looks of it the needed RPM's as well. Has anyone though of side mounting the motor and connecting it via belts to the spindle (possibly using a key way to help lock the pulleys to their spindles). This would some variance in torque and from what I can see would really make the spindle have a rather wide range of uses.
Just asking as kicking around ideas and designs and these are points that have run across. Anyone happen to know a source for variable speed AC motors in the 1.5kw range that don't cost the moon or come from questionable quality control?
Michael
I'm not sure if you're referring to the motors discussed in this thread, which are brushless AC motors, or normal DC motors? Either way a PID control algorithm can be used to improve the performance. A DC-servo motor is just the motor with encoder and PID control for position and speed.
http://www.youtube.com/watch?v=ghDez-3dpWs
I’v had no issues with motor heat... i could confidently push my spindles much harder if I needed to.Quote:
Question to you guys is how well do the DC motors handle heat when running at different RPM's?
Where i do have concerns is the ESP (speed controller) they do get hot... iv not blown one yet but i bought a spare because i thought i might with the amount of heat they push out (no problems though so far) at £20 (ish) its silly not to have a spare.
with a 12v 350w power supply the majority of my spindles are vastly under the “claimed” potential and iv not once thought I needed more power/torque… im sure our honorable speed freak friend Jonathan would want more speed n torque (you would need the extra speed if you wish to cut wood…I’m cutting plastic 90% of the time, I don’t cut any wood at all)
if your cutting wood and alli/plastics its worth weighing up if making two spindles is easier than dealing with pulleys on one ?
Most model ESCs are mounted where there us some airflow (the ones I have in my planes all have air ducts directing air onto them and the one on my Trex 500 heli is on the side so in the downdraught) so I'll be putting a 24V fan by mine for cooling.
http://img.tapatalk.com/d/12/10/15/abyze9y8.jpg
Belleville washers arrived today but just back in from a weekend away so will be tomorrow before I complete the spindle now :)
A fan does make a big difference to the ESC (not ESP! :playful:) temperature - I put fans on the ESC(s) in my model car for the same reason. A lot of model car ESCs include fans now since the airflow tends to be poor in that application.Quote:
Originally Posted by njhussey
Bit off topic, but is that a genuine T-rex or did you get a cheap copy? I got the latter, but can't say I've used it much yet as I always seem to have other things to do...
How much did all those springs cost?
It's a genuine Trex 700 nitro, don't think HK do a copy....yet ;)
The main reason I've not got further with this project is I've probably spent 2.5k on helis in the last 18 months to the exclusion of everything else!
They cost £15 + the dreaded and P&P so I think approx £25 in total...still got about 130 left :)
Just realised I'd said I had a Trex 500 in my text....yeah it's a genuine one...my Avatar is the 700...I did buy a HK450 but it's a bit like buying a router made from MDF with unsupported rails lolQuote:
Originally Posted by Jonathan
Assembled the spindle last night...well tried to anyway! Found that the Belleville washers don't compress much so you have to be careful how many you use otherwise you load the bearings too much.
Went to assemble it and put the motor bell back on and was putting the last bolt in when I noticed that it was a bit stiff. I bought a pack of 5 off SS 40mm long M4 bolts and on the first assembly used 4 and then obviously used the spare bolt when doing the final assembly. Took the offending bolt out and noticed that the first thread was damaged so I've only gone and flipping cross threaded 1/3 of one of the motor mounting holes grrrrrrr.......got to find my tap now and see if I can re-tap it and clean things up. Failing that I'll drill the cross threaded bits out and just use the rest of the thread with lots of threadlock!!
Will get it up and running tonight and power it from my Trex 500 for a test as I've not got the power supply and ESC for it yet.
Had the spindle running tonight, coupled it up to my Trex 500 esc...it works!!!
Attachment 7295
http://www.youtube.com/watch?v=3yaSp...e_gdata_player
Mark, you've got some smaller spindles haven't you? How have you done them? I want to make a smaller powered one but one that runs much quicker to cut balsa, but on looking the smallest shank of an ER11 collet holder is 8mm and I don't want to be messing around turning the shank down to 5 or 4mm if I can help it!
Look for motor with 1/8" shaft, buy 1/8" shank cutter, replace shaft with cutter...Quote:
Originally Posted by njhussey
Cheers Jonathan, I looked at that but I was looking to do one if possible where I can change the tool without having to remove it from the motor. I was having a look to see if there was anything out there like a pin vice that could be used but thought I'd float the question.Quote:
Originally Posted by Jonathan
I've got a Proxxon E50 that I was originally going to use but thought I'd go back down the brushless motor route.
RunoutQuote:
Originally Posted by njhussey
You might be able to do something like drill and ream/bore a 1/8" hole and hold the cutter in with a grubscrw. The force on the cutter will be very small, so it should hold perfectly well.
I've scoured the earth looking for a good quality pin vice type thing... it drove me up the wall... i even did a search for ER3 collets lol ... alas... there is no such thing :(Quote:
I was having a look to see if there was anything out there like a pin vice that could be used but thought I'd float the question.
I considered making my own but that is now on my "things to do in the next life list"
give us a shout if you find anything "posh"
i'm pretty sure it would cost a bomb if you find anything of quality out there
its a dam shame
I'm rapidly coming to the same conclusion Mark...there are pin vices out there that could be used but as Jonathan says...runout! Saying that for my balsa needs I could live with 0.25mm.
Saying that I've been thinking of going down the DIY laser route today. Could make a real lightweight router then ;)
Looks like ER8 is the smallest:
New Straight Milling Shank C10 ER8 100L Collet Chuck | eBay
The thing to do is have a go at making your own ER8 or ER11 collet chuck.
I'd love to see a router made with a laser...Quote:
Originally Posted by njhussey
Might have a look at making my own collet chuck to take the Proxxon collets...but there again I might just as well use my Proxxon :)
ahhh, yes... but will it run at 48000rpm :)Quote:
Originally Posted by njhussey
Erm....no 20,000 is it's limit. What you running a 4000kV motor??!!
eerm, yea its 4000kv but I tend not to run it passed 20000rpm if I'm honest... it might be fine flat out but I don't like it :)Quote:
Originally Posted by njhussey
iv got tons of spare bearings so I should go for glory and the fun of science and run it till it grinds to a halt but I never do
On my next spindle I'm going to cut the housing in layers (done on the Router) and have some water cooling to keep things cool. Looking at work to see what the smallest air blast cooler I can get is...
I've got lots of bearings too, comes from having lots as spares for the RC helis ;)
sounds posh ?Quote:
air blast cooler
what is it ?
Basically a car radiator with fan and motor, like this:
Attachment 7356
now that is POSH!Quote:
Originally Posted by njhussey
splendid :)
Hello folks,
Many thanks for sharing all this info, it has inspired me to build a spindle based on a 5045 motor & ER11 8mm spindle :-) I have a couple of questions though which I hope arn't too simple !!
- The bearing arrangement is along the lines of: for the chuck/housing interface a pair of Angular Contact (AC) bearings with 4 pre-load washers between them? And for the housing/motor interface a standard roller bearing? Where would be a good place to buy the AC bearings with matching pre-load washers (either UK or eBay).... any spec available so I know what to ask for?
- I'm guessing the AC bearing assembly needs to sit proud of the housing before the cover plate clamps it all in place - how much of the bearing should be proud?
- I am looking at 24V power supplies and wondering if I need to have one large power supply to run both the NEMA17 steppers and the spindle of if I should really split this into 2 suppies with about 5A @ 24V for the steppers and 20A @ 24V for the spindle?
Thanks for any tips :-)
belleville washers
708a bearings, these are a bitch to find at the moment so a search for magneto bearings would be my second choice
I'm sure mine has about 1kg of tension (on standard skate bearings) still runs ok but doesn't get used much compared to the larger ones... if your going to hammer it to death angular contacts makes sense and would need even less tension/pre-load than the skate bearings to perform the same task
I run all my spindles at 12v (350w power supply... its never tripped)
the 100A ESC gets pretty hot but the motors are fine at that
if your cutting wood and need the extra speed you will have to stick your neck out and let us know how you get on
mine was about 1mm proud... maybe a touch lessQuote:
I'm guessing the AC bearing assembly needs to sit proud of the housing before the cover plate clamps it all in place
i think there is 8 or 10 in mine, so with only 4 you want to be approx 0.5mm proud or less, it depends on your washersQuote:
bearings with 4 pre-load washers between them?
you could get really technical and do the maths but you would need to know your typical cutting force triple it, pray to the moon god and add some fairy dust :)
having at least some tension stops the bearings skidding and self destructing but if your cutting force or resonance overcomes the tension you will get a shit finish
Thanks for getting back to me Mark, much apprecited.
The Magneto Bearing looks ideal and avoids the need to install belleville washers by the looks of it? If going down this route would I use one magneto bearing between the chuck and housing and one standard bearing between the housing and motor?
I am hoping to cut wood but perhaps starting with an old computer ATX power supply will let me feel my way into the power question - sounds like this might be waht you are using.
You require two magneto/angular contact bearings and they need to be pre-loaded, hence Belleville washers are mandatory, unless you can find a matched pair of bearings but that wont be cheap. There are sellers with 8mm angular contact bearings on Aliexpress.com - Online Shopping for Electronics, Fashion, Home & Garden, Toys & Sports, Automobiles from China.
Thanks Jonathan - looks like finding the Belleville washers is going to be the hardest part, wonder why they are so rare.
I have spoken with www.simplybearings.co.uk but they need to know more tech info to allow them to advise - any idea what I should be asking for.... or perhaps there is another (afforable :-) bearing in their range which would get round the Belleville washer requirement?
Hi, I now have what I think I need - 2 Magneto Bearings and some Belleville washers :-).... now just wondering how to arrange the bearings and washers in relation to oneanother?
Do I put the 2 bearings back to back - ie with their 'open' faces both towards the inside and the washers separating them?
Thanks.
iv never looked at the implications I think back to back is the standard but id fit them in which ever way was easiest to implement
I had to make a couple of washers with a grove in the face for the outer Belleville springs to sit in to keep them central and clear of the shaft
I "think" I pulled tension on the inner races via the spindle.... errr, no hang in, I used epoxy to lock one of the races.... bollocks! I cant remember now? when you have all the parts in your hands you'll make sense of it
tight fit on the pointy end bearing (housing and the shaft) and allow the other bearing to float to some extent so the Belleville washers can overcome any movement (if that makes sense)
EDIT: i assumed "back to back" meant open ends out?
Thanks Mark,
I think I have this assembled right but thought I would post some pictures to confirm and help others who have the same question.
I didn't quite get what you were saying about fixing the washers - I guess the aim is to center them to stop them rubbing on the spindle - seems like that might be quite difficult?
Cheers.
Attachment 8316Attachment 8317
I think you where right in you description of "back to back" sorry :(
you are pushing the inner races apart
as long as the bearing closest to the tool end is tight on the shaft and in the housing I'm guessing all will be well
....now I think about it the inner races shaft and spring washers will all rotate which may be a good reason to go "face to face" because if the washers aren't perfectly central they will cause resonance at high revs
"face to face" would mean the washers don't spin with the shaft as they push against the outer races
that's why I remember "pulling the shaft" so to speak
with the springs between the outer races you need to grip the shaft to hold the tension... in my case I simply used the out runner bell to grip the shaft and hold the tension (not good for your outrunner bearings) what I should have done is add a collar with grub screws, I did have one but I hadn't accounted for the extra room it would take inside the bearing housing
if you don't get what I mean let me know and the next time I'm at home ill take some pictures of mine or knock up a drawing
in a nutshell, instead of pushing the inner races apart from the inside you are pushing them together from the outside
you may suss a better way of doing it ?
let us know how you get on
Hi there,
First post here and entirely new.
I just wished to contribute something. For my honours project for my degree, I made a desktop CNC machine.
Part of this project was to produce a simple spindle. To drive it I used a brushless motor, a small thing.
As you know, to control a brushless motor speed you need a servo tester. The trouble is, when you switch a brushless ESC on, you need to wait about 7/8 seconds with the servo tester at full off while the ESC initialises before turning up to the required speed.
Well, I designed my own speed controller using a simple PIC micro controller and program. It's designed as such so that it powers off the ESC's own servo supply. When power is applied to the ESC, the controller starts off at zero ignoring the speed dial for 8 seconds while the ESC initialises. Afterwards, the controller reads the dial and spins up the motor.
It makes the whole thing automatic and requires no manual intervention. Simply a delay from the control software on the host computer to accommodate for the ESC initialisation.
I'm curious whether there's any interest in this sort of thing as more brushless spindles come about? I've not seen anything like it before.
Yes I should think there is, at least for Mach 3 users. A long time ago I made a simple circuit using a PIC12F683 to interface between the parallel port PWM output and a standard ESC. However I didn't use it for long since, in addition to getting a standard spindle, I switched to LinuxCNC for which someone has already written the code to make the parallel port output the correct PWM signal for an ESC.Quote:
Originally Posted by booski
On a related topic, I recently put the motor I originally made into a spindle on to my Mum's bike. For that I used one of the electric bike speed controllers from eBay and added hall-effect sensors to the motor. As one would expect, it's far better than the sensorless controllers, especially at low speed, so if I was to make another brushless motor spindle I'd definitely control it with a similar controller:
48V/600W brushless controller for E - bike & scooter | eBay
They're also programmable, so you can set the current limit among other things, which could be useful for this application. I'll post a picture when I've got it off the other computer...
I use a comtroller from http://www.logicnc.com/rcnc.html
Its a bit strange at picking a speed at times but in a program it seems to run fine, many of hours running with this and enables fully automated control of my brushless spindle.
Also heres a video
http://youtu.be/XKCUqyvt1RA