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We'll guys, after a couple weeks deliberating about an imported machine, I have decided to take it upon myself to just build bug myself.
router will be mainly constructed from the following
steel box section for the base
160x80 extrusion for the gantry
cnc router parts rack and pinion drives on the X
planetary gearbox on the Y
16mm ballscrew and 15mm Hiwin on the Z (thanks lateatnight)
20mm hiwin on the X & Y
Renderings and pics to follow.
OK so... We start off with a nice and heavy base.
Base is constructed of 100 x 100 Cold rolled box section for the main legs and 100 x 60 on the base table.
80 x 80 Extrusion will run alone each side of the table with smll slots in the box section to allow for slight adjustment. then locked off with angle brackets
http://www.mycncuk.com/attachment.ph...id=13897&stc=1
Im still not sure if i should lose the leg in the centre to allow me to run a brace under the table to help a little more to aid the crabbing of the gantry. this will also open up the possibility of using rotating ball nuts in the future.
Over complicated derek with not enough support for the bed. The spacing of the cross beams is too far apart and I would make them full width and support from under side.
Less is more.? Go bigger on the steel structure but have less of it. Check this out to get an idea what I mean.
https://www.youtube.com/watch?v=G90OmSleLAo
Now. you have really threw a spanner in the works! after seeing that i just want to buy one outright! haha
In terms of not enough support, shall i just run the crossmembers striaght through as you say? i had planned on putting an Ali extrusion bed over the top of this also...
Is this what you had in mind?
Ive turned the bed supports vertically to give a little more support and transfered the long one to the bottom to support
http://www.mycncuk.com/attachment.ph...id=13898&stc=1
Very keen to see how this goes as I'm thinking a 8'x4' machine could be my next build and have probably enough steal kicking around to build one. What are you designing it to cut?
Are you not tempted by ball screws for the long axis as well?
I'm thinking that by the time you do all the rack and pinnion stuf ball screws would probably not be much more?
Hey Charlie thanks for the interest.
I would live ballscrews but can't be chewed to sit and design the rotating nut for the screws. I already have the rack and pinion drives so it's not a problem just a case of getting some longer mod1 rack.
The toughest thing I plan to cut is ali. But the machine will mainly be for wood and acrylic.
Yes and No. Yes to one piece supports but the spinal beam needs supporting from below not just fastening under the bed supports as that's doing nothing really.!Quote:
Originally Posted by D-man
Yeah pal there is 3 pieces under the spine as per drawing 1. I ain't so quick with solidworks just yet so thought I would see if that's what you meant first.Quote:
Originally Posted by JAZZCNC
It's a shame your not closer Charlie, could of welded them both up in one shift haha not bad for the steel either. Total cost of just under 200 notes.
Unlimited supply of tea and coffee and access to on site cafe if anyone wants to venture down to help hold this thing together while i weld it up haha
Cnc4u have 2500mm x 20mm screws which I was wondering about using although I do also have enough mod 1.5 rack here that needs a home or selling.
were about's are you?
Im In Hebburn, Tyne & Wear.
Ive just changed the pinions over on the drives to mod 1 pinions so not really any use to me pal.
I thought you had used those drives on another build? The rack and pinnion does seam nice on my build I have done but I was thinking that screws would be the way to go posable. if you have the drives already though then your half way there.
Yeah they are on the 4x4,it was a 3mtr but had to cut it down due to a large contract coming in and needed the space. ive now sorted the shop so that it would not get in the way
OK ive managed to get a little more done this morning before the wife started chewing my ear.
Fingers crossed if all pans out, i can have the frame uilt for friday and into powdercoat for saturday/Monday.
Im thinking about servos on the X & Y and a leadshine on the Z. any suggestions?
http://www.mycncuk.com/attachment.ph...id=13902&stc=1
Best advice with regard to Z axis is to put rails on front plate, bit where the spindle mounts, and bearing blocks on back plate, i.e. opposite to what you've shown.
Is this to make it more rigid..? From the commercial ones ive seen they are all mounted like this. as i thought with it being the Hiwin rails with less play than the SBR stuff
I dont suppose anyone knows what this bar is for on the bottom of the gantry of the Techno machines do they? Im guessing that when its tightened it pulls it square of some sort?
http://www.mycncuk.com/attachment.ph...id=13903&stc=1
Nevermind ive found ou what it is
"a special steel backing beam and torsion bar are integrated into the axis for added stability. The torsion bar acts like a sway bar on a vehicle, which in turn keeps everything straight and taut when cutting loads change. The steel backing beam provides extra support to the linear rails, greatly improving the router's rigidity."
Hi D man
I would wait for conformation off one of our more experienced members but i would think the Z needs to be on the other side of the gantry so it is better centered over the X axis bearing blocks.
Regards
Mike
Yeah ive been thing about this myself, The setup works on my 4x4, however thats only cuttin MDF and light plastic. i have been toying with the itea of vertical ones on this one, but the side to side motion worries me as im not connecting the gantry under the table.
Normally Eddy I'd 100% agree with you but with such short travel then no I'd go with something like how it's set out now. Thou I would have the bearings on the front plate lower with next to no overhang and extend the spindle down in the clamps. This will give full support to spindle/front plate from the rear plate.Quote:
Originally Posted by EddyCurrent
If longer travel then I'd set it out other way.
Derek I wouldn't mix servos and steppers and go with same on all axis. Not that they can't mix but it keeps electrics all the same and there won't be much difference in price. If your going with servo's or even steppers for that matter then suggest you get a decent motion control card. Definately will need one for servo's to get decent performance out of them.
Any suggestions pal? I had read a post where you suggestion leadshine and some tricked up card from the US but I can't seem to find the thread
With servo's then Kinco's are ok. Regards Motion control then it's a no brainer for me it's the Cslabs Csmio-IP-S. It's just not cheap but by far the best in this price range.Quote:
Originally Posted by D-man
One more thing with frame I swap the sections around and make couple of length changes. I'd use single piece top rails from square section and rectangle section for lower pieces see pic to see what i mean.
Attachment 13906
Nice on Dean, I had originally drawn something similar in, but I was wondering if the extrusion would sit level incase a bit of warp creeped into it.
The way I have it I thought may compensate for any un level beams or warping
No I wouldn't have it like you have at really because any bending or warping of the cross beams will directly affect the profile and rails and take away accurecy. I drew it without the cross beams more to show the single piece top rather than 2 pieces but other than that it's meant to be just same as you drew it.Quote:
Originally Posted by D-man
I wouldn't do it your way at all because it will make getting rails on same plane harder and any movement of cross beams will directly affect profile. The surface bed sits on isn't so critical as you will surface the bed parallel to the spindle but the surface the profile/rails sits on must be flat and on same plane each side or allow for the profile to be adjusted onto same plane.
I'm not sure I follow what your saying pal... I understand removing the vertical from the centre and putting a cross base in as the sides. Are you saying not to use the 9 cross members on the top now? If so what would be the best way to mount the extrusion
Is this the board you mentioned Dean? Looks a nifty unit
I don't think you put the link in but here it is :- http://www.zappautomation.co.uk/elec...-step-dir.html there are 3 models. ..CliveQuote:
Originally Posted by D-man
Oops! morning brain fart!Quote:
Originally Posted by Clive S
This is the link http://www.cs-lab.eu/en/produkt-18,2...onnectors.html but its the same Clive cheers pal
I think Jazz is saying that using the 9 cross beams will make levelling the extrusion very difficult. In effect you will be creating 9 points along the length of the machine which will need to be perfectly level to get the extrusion flat. Looking at Deans drawing you can place the extrusion directly on the frame length or even better, do away with the extrusion and fit the rails directly to the frame.
Yeahi understand that bit, however bolting the extrusion to the box section would pove difficult without the need for brackets along the extrusion. The way i was looking at it was i would be able to bolt directly into the extrusion bu going into the crossmembers to add the nuts.Quote:
Originally Posted by IanS1
Something i havent mentioned, and i apolagise is the fact i would of been bolting the cross members onto the top of the frame. for ease of removal and any smimming that possibly would of been needed...
This is what i mean
http://www.mycncuk.com/attachment.ph...id=13907&stc=1
I would have thought bolting the 9 cross pieces to the frame would be just as much hassle and a real pain to get them all in the same plane.
If you drill access holes on the underside of the top beam you will be able to use a T Bar allen key to bolt the extrusion directly to that quite easily.
You need the ip-s if you are going to run two motors on the x axis. I got the m for my build and it does seam a very nice bit of kit and made a lot of other things a lot easer to do with all the built in features.Quote:
Originally Posted by D-man
Yeah i see your point, but its easyier than wedling it, warping it slightly then having to grind it off. once bolted its no hasstle to add a little tack weld that accessable for a grinder should i need it.Quote:
Originally Posted by IanS1
Good point on the hole on the underside of the beam!
Quote:
Originally Posted by charlieuk
You running servos too Charlie?
Jesus, just looked at the Kinco servos and drivers and have no idea where to start! i was just starting to get my head around steppers haha
Ok so all the parts for the table had been ordered and i was too late to cancel it, so i will have to work with what i have an modify the best i can.
No just steppers I'm using the ip-m
Ditch those vertical supports along the centre that just drop to the middle of a beam below. Instead triangulate them back to the feet.
Or have crossbeams that are stiff enough by themselves.
In other words, proper support or no support.