reply back from chai
Hello,
You should receive 2 parcels.
One parcel is packed with the spindle and VFD and also 3sets BK/BF.
The other parcel is packed with other items
Thanks
Chai
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reply back from chai
Hello,
You should receive 2 parcels.
One parcel is packed with the spindle and VFD and also 3sets BK/BF.
The other parcel is packed with other items
Thanks
Chai
also just realised there is a tracking number on what they sent me
Attachment 7585
i've added steppers to my drawing.
brackets are made up of 5mm steel welded in to shape and i think maybe bolted to the box section, the top of the stepper supports will have slots for tension of the belts.
i've also beefed up the underside of the bed.
Attachment 7588
more goodies as expected the bf/bk blocks did come with the spindle and vfd
Attachment 7630
and heres a shot with them all together
Attachment 7631
just found a place that say they can deliver uk wide that sells some pretty reasonable priced box section..
for 2 x 7.6mtr lengths of 50 x 25 x 3 i'm getting it at £72 which all things considered doesnt sound too bad a price
http://www.fhbrundle.co.uk/groups/30SHS__RHS
If thats delivered and inc Vat then it's an excellent price for a Web based company.?Quote:
Originally Posted by wilfy
Edit: Just had a look and the 50x50x3 is £11 per length more than I pay my local supplier who I've dealt with for years so all-in-all think that's not unacceptable difference if only buying small Qty 7.5mtr gets you a fair way with a average sized machine and more than enough for a small machine.
jazz.. you do know my design uses 13+ mtrs of 50 x 25 and another 2.5+ mtr of 60 x 40.... i've a feeling it's massively over engineered
going to be redesigning this now which is a pain considering i have the rails and screws here today.
the reason for the redesign is i have been using a drawing of the rail bearings from zapp i think. looked at my rails today and thought they aint 60mm wide.. turns out they are 45 mm wide which means they will fit on a 50mm box section which will help me a lot as i only needed 3m of 60 x 40 and it was proving to be a bigger cost than i wanted.
so take note guys, make sure you are using the right drawings for your designs before you order
i fell into that trap aswell.
you've made me feel so much better knowing it wasnt just me.. i'm acctually quite happy i noticed as i didnt really like having an odd size box section in my build, so now i get to pull the design apart and possibly even gain some cutting area now... the only limit is i need to restrict myself to 2 x 7.6mtr lengths of steel which i think will be a push
in re-designing i cant keep the shape of everything i want if i fully get away from the 60x40 box section across the top and bottom of the y axis bearings as i need the spacing of the 60x40 so that the y axis carriage doesnt bind against the y axis rails
a picture might help
Attachment 7755
if i change the top and bottom yellow pieces to 50x25 i cant see any way it will work without wasting a whole load of 50x25 and i'll be honest since dropping the 60x40 i'm cutting corners to try and get all the cuts i need out of 2 lengths of 50x25 @ 7.6mtrs
Can you sub in some angle iron for some of the bits of box?
Angle Iron is £10-£20 for 6m and I think there are parts where you could get away with, for example the green bits on your pic?
Equal Angle Steel Bars - F H Brundle
while i wont rule that out my mission is to make the whole machine bar a few bits of steel plate i might need from just the 2 lengths of 50x25.
i acctually had an idea last night, i've been struggling since realising that the bearings are only 45mm to only use 50x25 as this way there is no spacing between the y axis rails and y axis bearing mounts, basicly the machine would rub against itself, where as when i used the 60mm across the y axis bearing mountings it spaced enough away from the rails.
now my choice was to stick the the 60x40 just for this bit, but even ordering to pieces cut to length is a big jump in cost that i dont really want/need.
so my idea is i'm bound to have some scrap pieces of 50x25, and thinking about it i could quite easily cut one side off a section and leave myself with some 3mm shims that i could use to space out my problem
Or just add a length of flat bar to your steel order and use that to bulk it out.
50x10x3000mm £12 ex
MILD STEEL FLAT BAR 50x10MM 3M LONG - F H Brundle
tell ya what the stuff you linked upped my order by £15 but.. looking around i found some 25mmx5mm x 3M which is perfect i dont really need 10mm thick, my only concern with doing it this way is if the box section is uneven, then adding an uneven piece of flat bar to the top will make it worse possibly?
I've done it!!!
that is designed the whole machine using only 50x25x3mm box section..... oh and a little bit of 25x5mm flat bar as very helpfully recommended above... i had to give in somewhere as i needed 60mm spacing in a few places which using 50mmx25mm box section wouldn't allow... the fact is the flat bar adds on £4 to my total order so i cant grumble about that.
so the picture below is obviously missing a bed, but i have basically spent the last week or maybe longer re-designing this whole machine within the limits of the screws and rails I've already received. the reason for this was due to me using the drawings from another site for the rails and bearings making basically all measurements out.. but it actually worked in my favour as it reduced the need to have 60x40mm box section in my build.
the colouring is purely to make it easier to count the lengths and for me to picture which bits move together, so purple is the x axis and the bed when its done, blue is the gantry, yellow is the y axis carriage and green is the z axis carriage. i am also yet to design a spindle mount as i am planning to do this in another program so that i can export it to dxf and have some lucky member from here cut them pieces for me, the plan is to mount it to the 2 pieces of box section that the rails are mounted to.
Attachment 7776
the biggest changes to this from my earlier designs are the x axis screw is now located a hell of a lot closer to the bearings which if i understand right should reduce any racking, my only concern here is do i need to add a length of box section on the outside of the screw bearing mounts to reduce flex here? in my mind they don't go under any stress when the screw turns but if someone tells me i'm wrong it'll be the next change.
I've also reduced the height of the machine which is one of the reasons there is no bed at present as the current z axis would smash straight through the previous design, the height now from x axis bearing center to y axis bearing center is 265mm.
all the bearing spacing's are as follows
z axis center of bearings on rails 120mm
z axis rail spacing 175mm ( should be 180mm actually)
y axis rail spacing 180mm
y axis center of bearings on rails 198mm
x axis rail spacing 804mm
x axis center of bearings on rails 255mm
this gives a total cutting area of x = 400mm, y = 529mm, z = 100mm which considering i originally said 15"x15" and its now more like 16"x20.5" i'm very happy.
the total length of steel up to here is around 8mtr's of 50x25x3mm and 1mtr of 25x5mm flat bar so i have around 7mtr's left to make the bed with which i know will take most of that 7mtrs. that brings the total cost of steel to £76.31 and the only other things i need to fabricate are the spindle mounts and stepper mounts which i have a feeling both will come from alu but i'm not sure yet.
so provided i dont need any more steel the total to date is £629.18 and thats for spindle, rails, bearings, screws, ball nuts, screw bearings plus all the steel to fabricate the frame
True unless you make a way to level the box a bit. There is the self levelling epoxy method or the grind bits off method.Quote:
Originally Posted by wilfy
This wouldn't correct a seriously bent or twisted piece but it would level most stuff enough for mounting rails on:
homemade surface grinding machine - YouTube
As long as you are starting out with a fairly straight piece this should sort out hot rolled steel, assuming you already have a variable speed drill press all you need is grinding head and a jig.
But if your steel looks like this abandon all hope now! :)
http://www.brindley-steel-forging.co...x-Section.html
PS - Have you thought about how you are connecting all this together? (welding/bolts/brackets/epoxy etc) It might be worth putting in all of your bolts and brackets or you will have a nasty surprise when you can't tighten the bolts you have bought because another bolt is in the way.
most of it is going to be welded, i will be bolting certain bits to leave room for adjustment
Attachment 7792
i am nearly there now, my main concerns are do i really need the turquoise bit?? would i get away with using a bit of flat bar instead? i have enough room in my steel for that piece but only just so i would rather use something else and keep that length spare incase i mess anything up.
also anything wrong with the bed? i dont know what i am going to cover it in yet, i would like to say alu but more than likely it will start out as mdf
re-designed again.. this time i've included a second ballscrew on the x axis, now due to my mis understanding of earlier comments i've kinda messed up a little bit in that i designed the machine to work around a single screw on one side. i've now been shown the errors of my ways and intend to fit a second screw. but i will go ahead and build the machine get it all wired and working to an extent before i order the second screw.
so here is what i hope to be my final design.
Attachment 7870
i may change it a little as far as mounting the bearings for the x axis screws as it's come to my realisation that the spindle will hit the cross beam at the front before it gets to full extension thus cutting about 40mm off my workable area. i've also realised that had i not rushed in to buying the bits from chai i could have either reduced the size of the axis screws for the length of rails i have or better still ordered bigger rails as there is about 75mm of wasted travel along the x axis, but i'll have to live with that as long as i get my 15" mininmum cutting area i'm happy.
this kind of stuff hurts far less when you have not yet started building!. Your far better at sketchup than I!!!.. Im no expert but do you think the gantry beams (purple) may be a little thin? not that it matters I suppose because you can always add extra support if it does flex. As the two beams are on their side I should think they will be ok on the X plane, however applied pressure on Z while Y is in the middle may perhaps cause flex? Mind you it is only around 15" wide so it might be ok... what do you think?
when do you hope to start building?
i had thought about them being a little flimsy but then again it's a 15" piece of 50x25x3mm steel box section, not alu extrusion so i dont really know, i would like to think it wouldnt bend but who knows. and for the record it wont be a simple change to strengthen it without making the machine bigger as the ball screw running through the center of the y axis would prevent any support being added between the 2
jazz is currently looking over this for me as i bust my 2 length limit by about 2 meters which i didnt want to do, but it's not the end of the world it's only another £30. however i have a feeling it's all going to change
Wilfy, its a good job you are such an expert with sketchup (wish I could hack it), but it looks like you are getting close to this build now Good luck, G.
i got all my help from this thread
http://www.mycncuk.com/forums/cad-ca...iscussion.html
In the corners of the machine you have a long vertical piece that the ballscrew mounts to and you also have a short vertical piece that doesn't seem to be doing anything, could you get rid of the short pieces to save your self some length?Quote:
Originally Posted by wilfy
If you have a load of flatbar left over you could also use that for the cross members of the bed instead of box section, that should get you back to your 2 length goal.
i cant see how 3mm flat bar can replace a 50x25mm piece of box section, the bed bending is the one thing i'd imagine u dont want. also the upright i could get rid of, but the little white spacers are all that the rails will be mounted to. i'd rather over spend and have solid for the sake of £30.. if it was another £100 i'd be more worried
Hi Wilfy,
Had a play see what you think to this.? It's well within the 2 lengths but it does use 50x6mm (or5mm) flat instead of 25mm but you'll see why.
Although slightly taller this way strengthens and helps with squareness of quite few area's and allows the screws to be brought down and to the side which will help with crap hitting them.
Because your using twin screws you can get away with slightly less bearing spacing so gained you about 90-100mm extra in the X axis (twinscrews) by shortening the bearing spacing slightly and off setting the rails back.
Let me know what you think and I'll tidy up the model and send back.!
Edit: Blue is 50x25mm Red 50x6mm
Edit2: Oh and if you don't like it then don't be afraid to say so you won't offend me.!
looks awesome and very professional and its funny cuz i had the screws there on the x axis the first time. i feel happier about the rails not bending on the x and y axis with the supports and i didnt realise i wouldnt need to support the back of the y carriage. and if you gained me back some x axis length then thats even better.
brilliant thanks a lot dude.. if you gonna send me the drawing can u send it as a dwg, dxf, skp, 3ds, dem or ddf... strangely enough sketchup lets you export as an OBJ but wont let u import as one :S
Looks like you are getting the hang of skp. What travel are you getting on you x and y?
that's google trying to annoy you into forking out for the full version!Quote:
Originally Posted by wilfy
it is the full version... erm travel i'm looking at 400+ on the x and 525ish on the y with 100 z in mm ofc
Fair enough, if you do end up with a load of flat bar left over it is quite easy to weld two pieces together into a single piece of angle.Quote:
Originally Posted by wilfy
never thought about that, but if you look back at the previous page, dean has kindly gone over my design and reduced it down and says that it should leave me with 3 meters now out of a full length and all i have to use is 50mm x 5mm instead. which outs the cost at £90 on the dot so i'm more than happy.. and it looks a damn sight better than mine lolQuote:
Originally Posted by D.C.
right, i've finally too jazz's drawing and re-drew it back in to sketchup. i couldnt get on with rhino, its possibly something i'll go back to as i'm aware sketchup isn't that great for actual cnc work.
any way here it is
Attachment 7900
all colour coded as previous designs, the white flat bits are 50 x 5mm flat bar.
travel is around 450mm x axis, 578mm y axis and 100mm z axis.
i havn't worked out how much steel is used here, but i know already it's going to come in well under the 2 lengths now.. but as a trade off i've gained 50x5mm flat bar so that total cost of the steel as i said before will be £90. i'm happy with that and i still feel it's going to come in under my £1k budget.
i think it's time to start clearing the garage up a bit and think about ordering the steel :D
just added everything up total length of steel is 11.7mtrs before cuts which will probs be closer to 12mtrs leaving me a good 3mtrs spare..
now i've just done this rough but with 3 mtrs if i extend the legs down by 500mm shown in white here, i have enough flat bar to put support where the longer bits are pictured and that will be pretty much it, but i have a feeling that wont be enough :s
in this picture i have dropped the legs down 500mm, as shown by the white bits, i've also moved the rail supports down and put a piece of 50x25 in the middle of the rail support. the turquoise blue bits can be removed i've just left them in so i can revert back.
my question is will this extension of the legs work or will it be a bit wobbly? this is the maximum use of the extra steel left over but it would make it better for me to have it floor standing as i know the bench is no longer big enough to support it.
Attachment 7906
Wilfy sounds like you need to take a trip to the scrap yard? Go have a poke around and you never know what you may come up with. look for old metal cabinets or similar. this would work for your base, stick a wanted on Freecycle? save your money for the best bits :eagerness:
Take this with a pinch of salt as my experience is with wood not metal but I'd say that your (white) bracing at either end is too long for that thickness of steel your using. I would shorten the bracing to roughly half way between old and new and then put stretchers between the legs (like a dining chair has). Grab a length of your 50x5 bar at the length you've drawn the brace and see if you can flex it by hand, if you can I don't think it'll be strong enough to act as a brace at that length.
it doesnt have to be done this way, it was just an idea i had to use the rest of the steel what you see in the picture is all the steel end of.. if it doesnt work, i'll just figure out a way to make it work as a desktop machine it might mean that 2 legs are secured to my worktops and with the left overs i will have enough to extend the other 2 legs down to the ground and do it that way and brace as you said like a chair.
is it likely i'll need any adjustment in the feet of the machine??
I agree with the earlier post - those strips are too thin to be useful for bracing. Your problem is they need to be strong in tension (which they are) and compression. A strip is the worst cross section under compression as it'll just bend. Angle would be better, or better still more box section. Also using thin strip for bracing is asking for trouble with resonance as the strip can vibrate, just like a rubber band. If the resonant frequency of the strips is a long way from the frequencies induced due to the motors and cutter then you wont have a problem, however calculating that is not trivial. Shorter strips will have a higher resonant frequency, so are less likely to cause problems, but clearly to an extent offer less support so it is is a compromise.. There's some good information on this site, Mechanical Resonance - Factors that Affect Natural Frequency.
Quote:
Originally Posted by Jonathan
sod it then i'll stick to the original plan above and find some other use for the spare metal.. i may cock bits up yet anyway so it's good to have back up i suppose.. plus i can use some scraps to set the welder up properly before i go at my good cuts
are these 100% the only steppers suitable for my machine??
Nema23 Stepper Motor 3.1Nm x 3
and these the only option for drivers to suit them??
Best Selling! Wantai Stepper Motor Driver DQ860MA 80V 7.8A 256Micro CNC Router Mill Cut Laser Engraving Grind Foam-in Motor Driver from Industry & Business on Aliexpress.com
i'm just asking so i can cost up the rest of the machine and them 2 seem to be the least popular models i'm coming across, seen plenty of 425oz steppers