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Comments sought on new build: A CNC Router for RC Gliders and Planes
I've been wanting to build a CNC Router for some time now to help with building RC Gliders and planes. After much searching and looking on forums I've been recently collecting bits to make a CNC Router. I'm going the "skinflint" way at first to get into it before upgrading/re-designing later once I've had a good play! Bits I've bought/collected so fare are:
- 3 x Nema 23 Mineba Astrosyn 23LM-C355-P6V 1.5A/winding 550g/cm torque Steppers
- 250W 24V 10A Switching Power Supply
- 3 Axis TB6560 Stepper Motor Driver Board Controller
- TR12x3D Trapezoidal Spindles for the X & Y and TR10x2 for the Z Axis
- 6 x V£ type micro switches (limit & home)
- Emergency stop switch
- Delrin for antibacklash nuts (will make them myself from homemade tap)
- Performance Pro 701W Rotary Cutter
- 24V fans for cooling electrics
- 300x20x120 Plastic enclosure for electrics
- Screened Cable for wiring (from Work)
- Armoured cable sheath for running the wires in
- 100x100x19 block of Aluminium for making the router holder/mount
The frame is going to be made from 40x40x5 RHS steel (sourced from the scrap bin at work), the X axis rails are going to be from 1" NB CS Sch40 pipe (again from the scrap bin) the Y & Z rails from 3/4" NB Sch40 CS pipe (scrap bin raiding again!! :smile: ) The bed will be 18mm MDF. The Y Axis sides and frame are going to be from either 5mm steel or 10mm Aluminium. I'm going to use skate bearings for the runners, a combination of skate-o-rail (Z & Y Axis) and joes2006 design (Z axis)
I've had the electronics together and working, see => http://www.youtube.com/watch?v=eJ9uujaey-0 so now I'm just drawing up the machine and starting to dimension the parts.
I'm going to make as much as I can. We have a Colchester Bantam lathe and Bridgeport milling machine at work so If I can remember how to use them (it's been over 20 years since I was last in a machine shop) I'll make all the bearing shafts, machine the leadscrew ends and drill/tap all the plates etc.
I've uploaded a PDF of what I've drawn so far (minus all the scrap bits round the side) for you all to comment on. All I want to machine is balsa and ply and possibly some plastic. Not sure it will be up to doing Aluminium so maybe that will be phase 2!
Cheers,
Neil
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Re: Comments sought on new build
Hi Neil
Looks like you have it all planned out, and realistic with what you want to cut, and will be good to see a machine using skate bearings take shape.
I couldnt see any reference to dimensions or table size so its a bit difficult to check, the main bit I can see you might have a problem with is the close spacing of the bearings on the x axis gantry plates. also is it possible to design the bearing holders with a slot in the bottom? that way you could support the rail with a small plate on its edge, similar to the supported round rail design.
Any way good luck
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Re: Comments sought on new build
Quote:
Originally Posted by
Ross77
I couldnt see any reference to dimensions or table size so its a bit difficult to check, the main bit I can see you might have a problem with is the close spacing of the bearings on the x axis gantry plates. also is it possible to design the bearing holders with a slot in the bottom? that way you could support the rail with a small plate on its edge, similar to the supported round rail design.
Hi Ross77
The table is 1190 x 470. I haven't dimensioned much up yet, was just looking at the plates for the skate-o-rails and they were odd sizes so I guess things will change a bit once I start getting the dims to round numbers. I was wondering whether to do that but left it for the time being as I was getting the design roughly finished. I thought of welding a 6mm plate between the two rails to stiffen it but wasn't sure quite how accurate I'd get it, I was then thinking of how to make an adjustable design so decided to leave it for the time being. The plan was then to get all the experts out there to comment on it and see what modifications were recomended!! :tongue:
I've attached a dimensioned sketch of the gantry bearings. One of the things I need to do is make at least one of the bearings adjustable (see other attached drawing) so I can take up any slack when setting up.
Cheers
Neil
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Re: Comments sought on new build
Hi njhussey,
Sorry to jump in with a sales pitch (!), but as an upgrade could I interest you in some bits to replace your pipe and skate bearings:
http://www.mycncuk.com/forums/showth...l-and-bearings
I noticed that the sizes were close, so may be an option. Still open to offers . . .
As for the design, reasonably traditional layout so good start. But the gantry sides look too thin. Consider welding angle iron onto the 5mm plate, or some other upgrade. Same goes for the flat plates holding part of the Z axis rails on (if I understand the dwg).
Otherwise, for balsa and liteply it should get you going . . .
Barry
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Re: Comments sought on new build
Nice design,
Whats the exspected Outgoing costs of this build so far and projected?
Stu
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Re: Comments sought on new build
Quote:
The table is 1190 x 470. I haven't dimensioned much up yet
So you have approx 1200mm long rails on the x axis? I feel they could do with some support really. I also noticed that the bearings are quite a bit lower than the table, could this be reduced to help with the gantry stiffness?
I guess with a design like this it will be a work in progress and you will tinker and tweak the parts as you make them, you'll soon get a feel for what works and what doesn't, allowing for adjustment is always a good idea. :smile:
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Re: Comments sought on new build
Quote:
Originally Posted by
routercnc
Sorry to jump in with a sales pitch (!), but as an upgrade could I interest you in some bits to replace your pipe and skate bearings:
http://www.mycncuk.com/forums/showth...l-and-bearings
I noticed that the sizes were close, so may be an option. Still open to offers . . .
As for the design, reasonably traditional layout so good start. But the gantry sides look too thin. Consider welding angle iron onto the 5mm plate, or some other upgrade. Same goes for the flat plates holding part of the Z axis rails on (if I understand the dwg).
Otherwise, for balsa and liteply it should get you going . . .
Hi Barry
I think I'll stick to my pipe and bearings as I've already got the bearings thanks. Also I'm doing this on the tightest budget ever...well trying to anyway! For my next machine (oh noooo I sound like everyone else on here now, not even built my first and already planning the second!!) I'll use fully supported precision ground rails or linear rails as I'll probably want to cut ally. I'm going to stiffen up the gantry, just not figured out quite yet how. Was thinking of a back, top and bottom welded to the sides from 6mm steel. Guess with all the weightI'll need to support the rails!
Neil
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Re: Comments sought on new build
Quote:
Originally Posted by
cooliced
Nice design,
Whats the exspected Outgoing costs of this build so far and projected?
Cheers Stu, I reckon I've spent just a smidge under £180 so far, as I'm making the rest out of scrap bits from work I don't think there's too much extra to come in terms of expense. I've an old PC that I'm planning to use, might get a 15" flat screen to save space. All the machining I'm planning to do myself, might pay to get the steel plates cut for me by one of our work suppliers, been quoted £17 per gantry side and £6 per skate housing side which comes to £130...but still might do it mysef yet. Will probably try the first one and see how it goes!
Neil
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Re: Comments sought on new build
Just gone through my purchases to date and costs are as follows:
30 x 608 2RS 8MM BALL BEARING SKATEBOARD = £11.91
6 x micro switch V3 type microswitch 16 amp = £4.19
1 x Aluminium Plate 105x103x15mm = £4.80
1 x 3 Axis TB6560 Stepper Motor Driver Board Controller = £41.67
1 x Acetal plastic sheet 215x110x20 = £10.23
1 x 10mm Round Bright Mild Steel = £2.10
1 x 250W 24V 10A Switching Power Supply = £21.29
1 x 1000mm TR12x3D Trapezoidal Spindle - Acme Ballscrew Leadscrew = £20.30
1 x 500mm TR12x3D Trapezoidal Spindle - Acme Ballscrew Leadscrew = £5.70
1 x 100mm TR12x3D Trapezoidal Spindle - Acme Ballscrew Leadscrew = £3.08
1 x Performance pro 701w rotary cutter = £15.00
1 x 8mm Round Bright Mild Steel = £1.65
1 x 200mm TR10x2D Trapezoidal Spindle - Acme Ballscrew Leadscrew = £3.96
3 x Stepper Motor MINEBEA Astrosyn 23LM-C355-P6V = £23.99
Total so far....£169.87
I'm back at work tomorrow (had 2 weeks off) so will begin machining and turning (in my lunch times) to make a skate-o-rail housing to test the theory! Been doing more draughting today, looking to support the 1" NB pipe by welding to 40 x 40 angle and also to put a 6mm steel web betwen the 3/4" gantry rails for support. should stiffen things up a bit!!
Neil
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Re: Comments sought on new build
Where did you obtain the power supply from at that price? HongKong?
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Re: Comments sought on new build
Quote:
Originally Posted by
GeorgeD
Where did you obtain the power supply from at that price? HongKong?
How did you guess?? :tongue: Yep good old eBay...http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=180406610821
I must admit that after reading lots about the cheap Chinese rubbish around on other forums I was a bit hesitant but it has worked well the 4 or 5 times I've powered the controller and stepper up to test so far...As long as it gets me into the CNC hobby and lasts a little while I'll be happy. Got a list coming together for my second one already with much better kit on it...
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Re: Comments sought on new build
Nah,you got swindled...bouht a 15amp job last week for the same price as yours,mind you it really only delivers 13 amps... unless my meter needs caliberating?
http://cgi.ebay.co.uk/350W-24V-15A-S...t_Equipment_ET
oops! I got swindled you didn't pay any postage. lol
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Re: Comments sought on new build
Quote:
Originally Posted by
GeorgeD
oops! I got swindled you didn't pay any postage. lol
I did £8.19, total price was £21.29...I only need 4.5A so this is larger than my needs, I hope! :naughty: Hope yours comes better packed than mine, it was ratling about in the packing box, no damage tho luckily!!
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Re: Comments sought on new build
That all in one driver board you have from china.... try and keep it down below 24volts any higher than 26v and you're as for pops bangs and whistles. :smile:
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Re: Comments sought on new build
I read Irving2008's and others warnings about trying to put 36V through them. As I've only got 1.5A/winding Nema 23 steppers the PSU and controller should be ok!!
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Re: Comments sought on new build
Well been far too busy last week at work (clearing up all the bits and problems that had accumulated after 2 weeks on holiday :eek:) and out of work (been doing DIY :confused:) but today managed in my lunch 3/4 hr to do a little something on my skate-o-rail bearing.
The problem with only having 3/4 hr is that by the time I've set the lathe up (read cleaning everyone else's muck off it!) I've run out of time to do anything!! Will have to set aside a saturday morning for a more serious production run! Anyway all I managed to do was cut 2 off 10mm sq steel axle supports, drill a 6mm hole in them and turn a rough (and I mean rough as the tool needed sharpening) axle.
Pics are attached. Ends need drilling and tapping yet and another 2 off units and the end plates making...still it's further forward that I was!!
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Re: Comments sought on new build
Hmm! can't quite make out whether these will cause friction,the washers at the outside of the bearing will rub against the rubber housing and cause some degree of friction.
Personally the washers shouldbe the size of the middle outer bore with at least a 2mm gap between support and bearing.
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Re: Comments sought on new build
Like this.....
Attachment 2833
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Re: Comments sought on new build
Hi mate, I think ideally you should look at re doing the axle stud, only this time start with larger stock and turn it down leaving a nice set of shoulders for the bearing inner race’s to home to. (Sleeves with shoulders)
The rubber shields on the bearings will turn but its not ideal and they could end up jamming.
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Re: Comments sought on new build
I'm also guessing that those bearings are 8 to 9mm wide? if so that spigots bearing spindle is far too wide and will cause the bearing to side travel.
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Re: Comments sought on new build
Attachment 2834
The washers do not rub on the rubber shield, see attached pic. But I was going to turn down some custom ones on the lathe if they did instead of using std M8 BZP washers. The bearing is a 608RS which is 22*7, the washers are 1.5mm wide and the centre of the axle is 10mm.
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Re: Comments sought on new build
Hi.
Newbie here.
Thanks for posting this thread as I too am working on collecting bits for my first build, which is to be for PCB issolation milling in the main, but would like to dabble in other stuff.
I am also working to a budget and looking to 'recycle' stuff where I can. Have just bought the same motors and have spent several days checking out the threads on the same driver board and PSU that you have gone for. Will be really interested to see how yours holds up.
Thanks again for the thread and good luck.
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Re: Comments sought on new build
Hi mudscience,
I've come to a bit of a stop at the moment due to various reasons. Hope to be able to kick start it again next week or so when things get back to normal, will keep posting any advances!!
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Re: Comments sought on new build
Thanks for the heads up. I know you said in your original post that you were looking for comments, but I wonder if I could ask a question to help me on my quest ... you've calculated that the motors will pull 4.5A. Depending on where I look I get different advise on what the 'guesstimate' total current will be. Some indicate # motors x A x 2, which in our case with the C355-P6V's will be 3 x 1.5 x 2 = 9A or # motors x A +2A = 6.5A. Any which way I think your covered, but I was wondering what 'rule of thumb' to use, because my next acquisition will be a PSU.
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Re: Comments sought on new build
Well I used the first one you mentioned, i.e. double the total amps for the 3 motors. I'm sure someone like Irving2008 will be able to tell you far more accurately! :)
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Re: Comments sought on new build
Quote:
Originally Posted by
njhussey
Well I used the first one you mentioned, i.e. double the total amps for the 3 motors. I'm sure someone like Irving2008 will be able to tell you far more accurately! :)
I think to an extent it's the more the merrier!
For my 3N.m motors it's 4.2A in bipolar parallel. [bold]You need 66% of the total peak current.[/bold] So three motors, that's 4.2*3*0.66=8.3A. I used a 500VA toroidal transformer, so 10amps. The motors did work perfectly well with a 325VA toroid but I couldn't get quite as high feedrates. I think because the internal resistance of the power supply was too high.
So anyway with your motors in bipolar series it's 3*1.5*0.66=3A. Or in bipolar parallel twice that, but I don't think your driver board will cope with parallel.
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Re: Comments sought on new build
Well after about 6 weeks of doing other things (scratch building a RC glider DIY etc...) I spent a couple of hours in the works on Sunday cutting up some steel for the frame and the rails, see attached pics. Just got to cut some angle for the rail supports and do some welding and things will be progressing...think it's gonna take a bit longer than I thought given the limited time I've got to put into it.
Still like British Rail....(as was!) I'm getting there :smile:
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Re: Comments sought on new build
Quote:
Originally Posted by
njhussey
Still like British Rail....(as was!) I'm getting there :smile:
Hmmmm....well it's taken me a year to weld up the baseframe, did it last saturday morning. Got into RC helicopters in the last year which has taken up all my time and money (costs alot to crash, well it does when you crash like I do:naughty:) also started selling Velcro on fleabay which has recently taken over my free time and what little money I had left. Anyway....I also drilled the rail holders I'm planning on using in my lunch hour. Now hoping to crack on with this build.
Will post pics as and when I get stuff done!
Attachment 4769Attachment 4770Attachment 4768Attachment 4767
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Re: Comments sought on new build
Did a bit of drilling and tapping in my lunch today...
Attachment 4775
Attachment 4774
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Been playing with Sketchup to see what my router will look like. Think I'm going to have to beef up my long (X axis?) rails as the gantry is going to be heavy...thinking about it might have to lighten it a bit else the stepper will struggle. The base is 1000mm x 500mm, box is 40x40x3 steel, plate is either 3mm or 6mm steel (all used as available from my works scrap bin!)
Comments???
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Re: Comments sought on new build
Been playing a bit more with Sketchup and added the spindle (see seperate thread for details on the spindle as designed by blackburn mark http://www.mycncuk.com/forums/showth...shless-spindle) steppers, leadscrews etc...
The more I look at it the more I am going to have to re-design the gantry as at the moment it will be too heavy. Will have to apply the KISS principle I think...
Below is a quick walk round video exported from Sketchup.
http://www.youtube.com/watch?v=v1R0T5tqzWw
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Re: Comments sought on new build
Been chopping up some Delrin for lead screw nuts tonight, couldn't find my chop saw plastic blade so used my mitre saw instead :naughty:
Will finish off the round nuts in the lathe tomorrow lunchtime and finish tap them and also drill the white delrin and tap that as not sure which ones I'll use yet.
Hopefully my boring bar also comes in the post tomorrow as I can't wait to carry on with my DIY spindle :smile:
Still playing with my design...:whistling:
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Re: Comments sought on new build
i always use my mitre saw on delrin that i cant get to with a slit saw, a bit of elbow grease LOL.... id almost forgot what that is :smile:
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Well after doing nothing on this for months I'm going to cheat and use MDF to make the gantry sides (yes I know I know!!!) to get the project back under way as I'm spending all my money on RC helis. Then once it's working I'll use the machine to make upgrade bits for itself. The second router is already in the design stage, going to be a supported rail, twin leadscrew design...
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Hmmm seem to have been away for ages again...still now bought a small welder so will start cracking on with the fabrication.
Attachment 6731
Finally decided to do 2 machines, one for balsa and one for ally...the one for ally will be a small one I can also use for labels etc...
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Re: Comments sought on new build: A CNC Router for RC Gliders and Planes
I really should stop playing about with the design and get on and build the damn thing.....but I keep reading posts on here and changing things. Was going to go with a framed gantry but then everyone says to keep the sides down to a small height to increase the stiffness.
Here's my latest design, can you guys comment on it please? It's going to be predominantly for cutting balsa and ply, the odd bit of plastic, carbon fibre and possibly aluminium components for RC planes, helicopters etc. There's only 100mm of height, but as the thickest balsa I'll be cutting is probably 1/2" it should be fine.
The box frame is 40x40x3 mild steel, the flat plate is 12mm 5083 Ali, the rails are SBR 16, most probably from linearmotionbearings2008. There are a few things which need tweaking to make them fit (Z axis bearing plate needs to be made the same width as the bearings etc.) so I'm aware of them, it's just the basic concept/design.
Attachment 7207Attachment 7208Attachment 7209
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Re: Comments sought on new build: A CNC Router for RC Gliders and Planes
I would make the mounts for the X and Y stepper motors/ballscrew fixed end bearings stronger since they have to support the axial force on the ballscrews, so any deflection in those mounts directly causes inaccuracy in the tool position.
On my machine I have SBR20 and SBR25 rails and it is clear that the 25mm rail system is substantially stronger, presumably (apart from the obvious reasons) because the bearing blocks have an extra row of balls. I urge you to consider at least using 20mm rails as it shouldn't cost that much more, although it does mean increasing the box section size to 50mm.
Have you considered using pulleys and timing belts to drive each axis? This can simplify mounting the motors, reduce resonance, improve feedrates or resolution, among other things.
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Comments sought on new build: A CNC Router for RC Gliders and Planes
Thanks for the comments Jonathan, I'll beef up the mounts and possibly look at pulleys. This router will be used for mainly balsa and ply so I cant see the need for the 20mm or 25mm rails, surely the 16 will be strong enough? The only Ali I'll be cutting on it will be thin stuff for horns, brackets etc. out of 1mm or 2mm thick.
If you look at the below router it's made out of 30x30 Ali and skate bearings and cuts balsa fine for making models! Yes it's not fast or particularly accurate but was fit for the purpose it was built for...
Attachment 7210
I will be making a smaller stronger router/mill for doing Ali blocks/brackets etc at some stage in the future and this will be made with linear rail and all the other goodies!!
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Re: Comments sought on new build: A CNC Router for RC Gliders and Planes
Just got myself some 10mm Ali plate from fleabay for a (what I think is) bargain price.....aluminium plate 10mm thick 2200 x 950 mm approx 87" x 37 1/2" Pickup floor | eBay Now going to look at the design and get drawing some parts to get made :D Need to invest in a pillar drill now to get all the holes drilled nice and square!
Jonathan, I've been looking at the 20mm rails and you're right they're not that much more so will get them...
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Re: Comments sought on new build: A CNC Router for RC Gliders and Planes
Chai quoted $246 for the rails for my router so I think I'll get them when I've got the money soon. Picking up the Ali plate in a bit and have someone with a CNC router going to cut the bits for me :D
Just one thing to ask. would it be better to have the y axis rails spaced apart and the ball screw (well trapezoidal rod for now) through the middle and have some plate on the back to stiffen it up? This would bring it nearer the spindle and reduce the twisting when cutting?
Very quickly moved things around as per the below (yes I know things need sorting but just wanted to show what I was on about...picture paints a thousand words and all that!!)
Attachment 7287Attachment 7288