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4 Attachment(s)
Fingers crossed it'll cut ally
Iv been having way too much fun researching, learning new skills and dreaming about how well it will all work out… I guess its time to put my penis back in my pocket and crack on with actually getting somewhere
This will be a small and hopefully stiff machine, I’m only really nervous about my choice of stepper driver kit (Chinese 5axis TB6560) I could do with the extra axis to run a 4th axis…… So….. If anyone can offer any optimistic words about these Chinese driver kits pushing a router like this through ally and delrin I would be much obliged.
Ballsrews 1605s
THK-HSR25 pre-loaded for the X and Y
NSK-LH20 for the Z axis but I’m not to sure I want to use these as they are not pre-loaded but I couldn’t resist them at £16 for 4 (new)
The spindles I’m in the process of building... the small one I’m trying skate bearing on with Belleview washers (not to optimistic about those but A/C bearings with an 8mm id are hard come by) it runs at 10000rpm flat out with 12v
The larger motor runs 2800rpm flat out on 12v and maintains loads of torque down to about 1000rpm, Iv an ER11 collet chuck with a 10mm shaft on its way which should drop straight in with the double row a/c bearing at the nose
Anyway… cheers to anyone who has ever posted on mycncuk, Iv had a lot of fun reading of your trails and tribulations
Ps the gantry sides are heavy extrusions… I couldn’t be arsed drawing them in :)
Attachment 2551Attachment 2554 Attachment 2552Attachment 2553
http://www.mycncuk.com/forums/images/misc/pencil.png
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Re: Fingers crossed it'll cut ally
Nice design, I'm not sure I can find anything wrong with it :smile::smile:
maybe a slight tweak here and there but everthing seems to be where it should be, I like the Z axis thats how I think is the best way to do it, rails top and bottom on the gantry keeps the Z in nice and close and the wrap around connector is good to.
The only thing is wether the RC motor will cut Ali !!! engrave yes but cutting ???
Nice work cant wait to see it built and running
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Re: Fingers crossed it'll cut ally
Hi Mark,
I'm struggling to get past the first paragraph - did you mean pens back in your pocket !
As for the machine, looks good, with some good features - upside down Z axis, Y axis ballscrew low down to reduce gantry side bending, twin X axis ballscrew, very stiff frame etc. etc.
You can always sell the Chinese board when you outgrow it, safe in the knowledge that the basic m/c is sound.
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Re: Fingers crossed it'll cut ally
cheers ross,,, i spent bloody ages trying to find a way to get the overhang down, i had the Y screw on the back of the gantry to kick off with but there is quite a bit of drag with the linear bearings and it seems to make sence to off set some of it with the screw at the front...... errrr if that makes sense:)
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Re: Fingers crossed it'll cut ally
Personally I don't like the motors showing on the sides of a CNC,so I've takenthe liberty of relocating it.
This would mean its belt driven and would have to have some clearence between Y axis and rail support.
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Re: Fingers crossed it'll cut ally
sorry man.. yea i really did mean penis :wink:
for 5axis the chinese boards are hard to ignore
iv read plenty about them on this sight but i have no idea how much they lag behing the so called good stuff
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Re: Fingers crossed it'll cut ally
Hi Mark
You could add another worktable on top of that one, but a bit wider, to protect the expensive X axis bits from dust and debris to some extent.
By the way, one of the x axis motors is making a break for it!
Anyway, nice one.
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Re: Fingers crossed it'll cut ally
i know exsactly what you are saying about the motor hanging out and iv scratched my head over and over trying to tidy them away but at this point the design is an order parts and bolt together job, there is very little machining needed to get this one up and running... i can always make it look posh when iv got the ability to machine:naughty:
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Re: Fingers crossed it'll cut ally
what power output do those spindles give?
Other than the machine rigidity, which looks quite reasonable (tho if you wanted to improve it take the side panels down under the table and crossmember there with a diagonal gusset) the main limitation on machining ally with any reasonable effectiveness will be spindle power.
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Re: Fingers crossed it'll cut ally
i was thinking of a rubber skirt attached to that bed to protect the rails
i know the drawing isnt perfect but the meat of the idea is there and i had to start buying in the gear before i started putting go faster stripes on my drawing!!! :heehee:
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Re: Fingers crossed it'll cut ally
Ah.. irving2008, iv read a thousand and one of your posts,, you always seem to go above and beyond the call of duty... mucho respect xx
the large motor is 1700W at 37v and the smaller one is 700w at 22v
im not to bad an engineer but the electic stuff is a bit rocket science to me
i have thought about going all the way around with the gantry but i do like the simplicity of it at the moment
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Re: Fingers crossed it'll cut ally
Well 1700W input is 850W+ output, ~1HP theoretically you have the power to take around a 5mm deep cut with a 8mm 2 flute cutter at a feed rate of 500mm/min... but in reality your rigidity probably won't be up to that... but I reckon 0.5mm cuts would be possible, maybe a little more with a brand new very sharp cutter...
thanks for the compliments
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Re: Fingers crossed it'll cut ally
Quote:
Personally I don't like the motors showing on the sides of a CNC,so I've taken_ the liberty of relocating it
PS.ive taken the liberty of adding spaces to your post so its easier to read.....:naughty:
George (what are we going to do with you?:heehee:) CNC machines are not Art and don't have to be pretty just functional. Direct mounting a motor is the best solution as far as backlash and accuracy are concerned, all the professional machines Ive seen use this setup.
Its is only worth while using belt drive if you need to change the gearing.
Quote:
i can always make it look posh when iv got the ability to machine:naughty:
Damm right, get it working first. If your milling Ali have you looked at the coolant side? Pumps, catch tray etc...After a few uses you wont care what it looks like only be amazed at the pieces you make with it.
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Re: Fingers crossed it'll cut ally
nice one irving ! it sounds possible then
most of the work done on it will be in acetal delrin type plastics but i do need the odd ally bits and bobs
them motors nice and quiet!! :smile:
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Re: Fingers crossed it'll cut ally
iv been collecting surgial tube at work to make a peristaltic pump with,
they have a low flow rate but must be worth a try for a giggle
they look pretty simple to make
i am sort of worried about coolant though... i wanted to put all my electrics under the base
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Re: Fingers crossed it'll cut ally
Hi Mark,
Those brushless motors look like the type I use in my model aircraft. I was wondering how you are controlling them, and what power source you are going to use. Looking at your stats for the big motor:
2800rpm for 12v is a 233Kv motor. This will obviously give you 8633rpm at 37v no load.
1700W is achieved at 45A for 37v. Do you have a 37v supply, and more to the point, can it give out 45A at the same time? The 12v 60A supply we have at work is the size of a suitcase, and probably cost us a bit, so I'm interested in the bench supply you have in mind. If you have simply read the motor spec, then you might like to know that on aircraft, when run from Lipo cells (37v) these motors run at about 45A on average (depending upon prop and throttle), and last for 8 - 9 minutes before a recharge is required. If your bench supply can't give this kind of current, then your actual power will be down (plus not so efficient), and you may have to back off on the ali cuts. But then maybe you have a cunning plan for all this . . .
I assume you are using a speed controller to run the brushless from. What amp rating are you running on that, and are you using a servo simulator to control the speed on a dial?
If you can get this all to work, then you're right about the noise, very quiet. I did consider this route myself, but the above put me off. Keen to see more . . .
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Re: Fingers crossed it'll cut ally
Quote:
Originally Posted by
blackburn mark
...to make a peristaltic pump with,
they have a low flow rate but must be worth a try for a giggle
they look pretty simple to make
Hi Mark.
You can get peristaltic pumps on the 'bay reasonably cheaply. Do a search for 'condensate pump' or 'Aspen peristaltic'. I got one a couple of years ago for a tenner. For the last week it's been pumping dilute citric through a crudded-up coffee machine heat exchanger.*
Sorry, rambling again. Where did I put the Jaffa cakes?
John
*another ebay win.
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Re: Fingers crossed it'll cut ally
5 of those cheap 50v supplies from ebay in parallel will give 43v-56v @ 50A for £12 each, not bad for £60...
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Re: Fingers crossed it'll cut ally
lol Irving,how much will the electricky bill be?
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Re: Fingers crossed it'll cut ally
im using a servo tester with an 80A speed controller
i bought the motor as a 250kv at 2000w but a review i read has it at more like 1700w
i have two server power supplies at 12v 45A each... im hoping to stick with 12v to keep
the speed down for ally
i can use the smaller motor at 12v for up to 10000rpm
im also hoping to replace a 3.17mm shaft in a 4000kv helli motor with a 3.18mm shafted
engraving bit... not sure how practical this will be as ill have to strip the motor every time the bit wears out... worth a try if im desprate to do some really fine work
this one should run up to 48000rpm on 12v (i think) it will be interesting to see
how the bearings hold up
feel free to critiqe... im sure youll know more about these rc motors than i do
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Re: Fingers crossed it'll cut ally
ha,,,, sod off George... i got the server power supplies for nowt!!
the speed controller was 15 quid and the servo tester was a fiver.... maybe a teners worth of postage
EDIT: sorry george, i miss read you,,, electricity bill !!
dont put me off now man im on a roll :)
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Re: Fingers crossed it'll cut ally
Irving,,, you seem to have it all worked out,
if i have any dastardly electrical plans im hoping youll stop me from blowing myself up :)
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Re: Fingers crossed it'll cut ally
cheers z3t4
iv been keeping my eyes open on ebay,,, iv never searched for 'condensate pump' ill give it a go
Errrrr... dilute citric ?? heat exchanger??? are you making rocket fuel to dip your jaffa cakes into !!
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Re: Fingers crossed it'll cut ally
Quote:
Originally Posted by
blackburn mark
cheers z3t4
iv been keeping my eyes open on ebay,,, iv never searched for 'condensate pump' ill give it a go
Good luck!
Quote:
Originally Posted by
blackburn mark
cheers z3t4
Errrrr... dilute citric ?? heat exchanger??? are you making rocket fuel to dip your jaffa cakes into !!
lol
The ex-commercial ones get really badly scaled. Citric is a really good, food-safe descaler and is gentle with copper boilers and HX's; you just have to be patient, which is where the peri pump helps.
I would never knowingly so abuse any Jaffa Cake in my care.
John
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Re: Fingers crossed it'll cut ally
Hi Mark,
Sorry this thread is splitting in two. Referring back to your earlier reply, 80A S/C is OK, and for £15 is probably the low voltage type so don't run it at the 37V (12V is OK). Servo tester is OK and at some point I expect this could be speed controlled from the PC since there is a pot behind the dial. Not done speed control from a PC myself, but plenty of experts on here who could help . . .
I only use outrunners, so don't know about the inrunners or high Kv motors you are considering (from helis and ducted fan models). Nice idea about the engraver using the motor shaft.
Watch out for the heat buildup since these motors are all normally in the airflow. Especially if you go down Irving's route and go for the full 1700W. Some inrunners have finned sleeves which you can buy and fit over the outside of the can. For outrunners you might be able to fix a fan to the outer case, since this rotates, and it will blow air down through the holes into the windings. Bit of noise i'm afraid, so you'll have to see how it goes.
Wonder if you bolted a prop adapter on the back face and added a very small prop, instead of a fan. Mind your fingers, or add a guard if you do!
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Re: Fingers crossed it'll cut ally
cheers routercnc
will i be ok using the 80A speed controller on a much smaller motor... it would be nice if i could use all three motors without having to swap about with diffrent ESC's
im not sure ill bother linking my spindle to the PC, iv got an optical rev-counter, i think ill just dail in whatever speed i want and stick with the simple life
im considering a goverer speed controller.. iv heard they will hold the revs steady under diffrent loads
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Re: Fingers crossed it'll cut ally
Quote:
Originally Posted by
blackburn mark
cheers routercnc
will i be ok using the 80A speed controller on a much smaller motor... it would be nice if i could use all three motors without having to swap about with different ESC's
Yes, any motor up to 80A should be fine with that speed controller. Is the speed controller programmable? You may find that adjusting some settings (such as 'timing' and 'frequency') will make the ESC run different motors more efficiently.
Quote:
Originally Posted by
blackburn mark
im not sure ill bother linking my spindle to the PC, iv got an optical rev-counter, I think ill just dial in whatever speed I want and stick with the simple life
I wonder if mach3 can do this. The input to the speed controller is just a simple PWM signal and mach3 can output PWM for spindle control at a set frequency.
I've got a huge 130kv brushless motor I think I might try as a spindle when I've bought an ESC for it. It's rated for 48v and claims to be 6500W(!) ... hadn't thought of controlling the speed from the computer though.
I agree about using a fan - these motors do get hot even running with no load from my experience. If you've got a lathe then you could make a pretty nice heatsink just by starting with a bar, bore it to fit the motor and add fins using the parting tool...
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Re: Fingers crossed it'll cut ally
nice one jonathan, yea iv programmed the ESC for soft start, 14 poles etc.
iv run both large motors for 5mins 12v no load without to much heat in the ESC or the motors
i exspected way more... we'll find out eventualy what they do under load
the huge 130kv brushless motor you have (if its the one im thinking it is) has a 12mm
shaft wich is good news as far as A/C bearings are concerned and if you have a butchers on ebay you should be able to find an ER11 C12 L100 straight collet shaft,, that should drop straight in:naughty:
cheak how much shaft you need though as these have only 100mm of shaft!
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Re: Fingers crossed it'll cut ally
Yes it's the motor you're thinking of! It's currently in pieces since I'm altering the wiring so that I can change it between star/delta for higher torque/rpm etc. You may mant to consider this for your motors? Easier to swap a few wires than change the motor, perhaps.
I've found the straight collet holder - that looks ideal (thanks!), except the shaft is a bit short! I'd prefer ER25 though since I've just bought a set of ER25 collets for my milling machine. I'll have a look around for one / make one if necessary.
The bearings in the motor are already pretty huge. The one at the 'back' is a large thin section bearing about 65mm diameter if I recall correctly.
Maybe create a thread about using these motors?
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Re: Fingers crossed it'll cut ally
jonathan... good luck with the ER25, iv seen a few of these ER straight shafts with 150mm to play with,,
cant remember seeing an ER25 though
if you get chatter i would consider at least a double row A/C bearing at the sharp end,
they are already pre loaded and ready to go
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Re: Fingers crossed it'll cut ally
Quote:
Originally Posted by
Jonathan
Maybe create a thread about using these motors?
Yes please!
There was an article in MEW (Feb 2008 issue, No 135 ) about making outrunner motors but there wasn't much about how to power them. I'm guessing that the 'servo tester' provides a PWM pulsetrain and the speed controller (is this aka an 'ESC'?) sees the pulsetrain and uses electromagick to provide a 3-phase supply to the motor.
John
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Re: Fingers crossed it'll cut ally
[QUOTE=z3t4;14653]Yes please!
it will be a while before i can report any findings on mine... i cant wait to see how jonathan gets on with that monster motor of his:smile: and what he gets with the "star/delta" wiring (i have no idea what that is and im just about burnt out on research)
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Re: Fingers crossed it'll cut ally
Quickly sketched this to show aircraft vs cnc application for those interested:
(You could probably delete the 4.8V supply if using a BEC ESC)
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Re: Fingers crossed it'll cut ally
nice one... im not so good with the electronics but all this stuff is nice and modular,, for those that dont know BEC is just a set of 5v power leads coming out of your Electronic speed controller to run your servo tester
anyone using small motors (engraving) might get away with an old PC power supply... they have 5v and 12v coming out of them
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Re: Fingers crossed it'll cut ally
Quote:
Originally Posted by
blackburn mark
anyone using small motors (engraving) might get away with an old PC power supply... they have 5v and 12v coming out of them
If you're careful you could even put the computer PSUs in series. Just need to make sure they're isolated. I considered doing this for my stepper motors since I've got plenty of 350W (or so) PSUs from the local car boot and if I put 6 in series that would have given a nice 72v for my stepper motors. I decided against this as 6 of those would have been a bit bulky and a good toroidal transformer came up on eBay.
A cheap way of providing the 5v supply is just using a 5v voltage regulator. Any would probably suffice since it's only providing a few miliamps in this application.
With regards to my big motor I think I could get away with the 100mm shaft collet holders. I'd probably get the 1/2" one and reduce it down to 12mm. The motor contains 4 bearings, 3 of which are 2112 bearings and one big 6089. I shouldn't be too difficult to change them but it is worth it? The biggest external diameter bearing that would fit without doing something imaginative is maybe 24mm. I can't find any angular contact bearings that would fit there.
I've been thinking of using this motor for a 4th axis / lathe but I wont go too off topic!
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Re: Fingers crossed it'll cut ally
yo jonathan,
i was terrified of turning down an over sized shaft so i spent weeks looking for the right size, its being shipped as we speak
im gutted you didnt find a 150mm one, im convinced it would have been easy to stick double row A/C on the nose in a shallow housing,, ill find out as soon as my shaft turns up ill start doing a bit of turning
im not totaly convinced a double row A/C bearing will be tight enough for ally, the ones iv got dont feel like they have that much pre-load, i might end up stacking the two of them
4th axis... mmmm im thinking a 100mm rotary table with my 5th stepper melded to it
im not sure anything is off topic,, is it?
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Re: Fingers crossed it'll cut ally
Quote:
Originally Posted by
blackburn mark
i was terrified of turning down an over sized shaft so i spent weeks looking for the right size, its being shipped as we speak
Hah, I was pretty scared dismantling this motor. It was all glued/loctited together and needed some persuasion with a hammer.
Quote:
Originally Posted by
blackburn mark
im gutted you didnt find a 150mm one, im convinced it would have been easy to stick double row A/C on the nose in a shallow housing,, ill find out as soon as my shaft turns up ill start doing a bit of turning
There are 150mm ones, but they're more than twice the price of the 100mm. I could probably extend the 100mm one if it came to it - definitely some thinking to do before I buy anything!
Quote:
Originally Posted by
blackburn mark
im not totaly convinced a double row A/C bearing will be tight enough for ally, the ones iv got dont feel like they have that much pre-load, i might end up stacking the two of them
I see, so you don't think the ones that are currently in my motor would be up to it? Maybe I could link this motor to the existing milling machine spindle via a pulley...then I needn't worry about angular contact bearings. Having said that I don't know if the bearings in the spindle of my machine are up to 6000rpm.
Quote:
Originally Posted by
blackburn mark
4th axis... mmmm im thinking a 100mm rotary table with my 5th stepper melded to it
Yep, that's what I did except with a 150mm vertex rotary table. It's excellent for making pulleys:
Attachment 2562
And making 4th axis'
Attachment 2566
Quote:
Originally Posted by
blackburn mark
im not sure anything is off topic,, is it?
:) well in that case this is the 4th axis/lathe design I've started making:
Attachment 2561
Attachment 2563
Attachment 2564
Attachment 2565
I'm using two tapered roller bearings in that. The gold things are solenoids to create a sort of disk brake which I'm hoping will hold it steady enough for me to mill will it aswell as using it as a lathe by swapping to a bigger motor...the brushless one.
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Re: Fingers crossed it'll cut ally
SWEEEET!!!! im intimidated,,, and its not just a drawing, youve made a start
are you not happy with the rotary table?
are the solenoids air?
EDIT: iv just spotted the wires
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Re: Fingers crossed it'll cut ally
Thanks!
I'm happy enough with the rotary table - it's very well made. If you get one I'd advise a vertex one as I've used this and a bigger one at school and they're both good. It's good in that it uses a worm gear (90:1) which means it wont move when milling but equally the worm gear is bad as it severely limits the rpm I can run the table at. I'm making the new axis because I want it to double up as a CNC lathe. My mini lathe (C3 from arc euro) isn't up to much so I'm hoping this will be sturdier.
I've machined the shaft of the axis the same as the mini-lathe so it can take the same chucks. Ideally I would have gone for bigger than 80mm diameter for the shaft...but turning that down to 35mm for the bearings took long enough and annoyed my teacher at school a bit... any bigger would have been pushing my luck I think!!
Any ideas for materials to use for the disk brake are welcome. The brake will only be used to hold in position, not for stopping, so heat build-up isn't an issue.
I'll go and take another photo...
P.S. Someone's bound to point this out, so before they do...If you look carefully on the renders of the 4th axis you'll see the disk brake is impossible to assemble! I've since fixed that by putting the disk the other side of the flange.
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Re: Fingers crossed it'll cut ally
Ah, im with you on the speed issue, i think i get you with the large motor to,, im guessing you would be fitting a rotory encoder for position feedback if you use the large DC motor ? (im no expert with these)
for the brake i would be looking at a motorcyle cluch plate maybe, im not sure youll get the force with electric solenoids to lock it for milling though but thats my guesstimation... id be tempted to consider an actual disk brake and caliper... the caliper would have to be beautfully fitted and have oposing pistons (you couldnt have it floating like you do on a vehicle)
im really not sure though im just thinking out loud :)