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The motors spec were in the first post. 1.5 KW servo for Y, 750W for X and Z.Quote:
Originally Posted by Davek0974
Spindle power will likely be around 4 KW / 5 HP.
One of the goals of this machine is to be able to run this all from single phase, 32A supply.
The higher feeds allow for more creative milling techniques like Adaptive clearing. Having good speed and acceleration opens the machine up for more uses and will hopefully reduce the typical times currently experienced with my Denford.
Agreed. The 'aim' here was for a machine of total weight of somewhere between 1 and 2 ton. I can move 1 ton with engine hoist but once assembled, its going to be more tricky so looking at options for wheels or some form of lift / move system.Quote:
Originally Posted by Davek0974
Well you better get ready for dissappointment if you think 4Kw spindle is going to let you cut at 10mtr/min with any DOC.! There's Reason why Industrial Strength VMC's have 15-20Hp spindles.Quote:
Originally Posted by Chaz
The plan is not to cut at 10m/min. It will be nice to do some tracordial milling and not be limited by speed of 'non cutting' movements. Id rather have too much speed than to little, even if its not used all the time.Quote:
Originally Posted by JAZZCNC
This is more for the ability to cut at lower spindle speeds the metals and have there enough power, and i agree with that, but i wonder then if the small mill head rated 10 000rpm, BT30 spindle coupled with servo motor would not do the job better here? I can not remember if there was 10 000rpm variant, cause typically it was 6000rpm. Or just have to be ordered with other bearings.Quote:
Originally Posted by JAZZCNC
That could change the design so should be clear before hand. But will give ability to tool change, and hard tap. Cause at the end of the day, why so fast machine if then you will loose time changing tools.
I read a study that said most time in production was spend changing tools, and we are talking a bout machines with tool changers. So obviously not only a tool changer, but a fast one is better.
But i like to say, if the purpose is not clear, the result could be mediocre
My thoughts too, I do spend more time changing tools on my manual mill than cutting, also setting up etc. I just am not sure of the design here, especially with only 4Hp on the spindle, still limited to light cuts at average speeds, there is a reason large mills weighing tons have 20-30-40Hp spindle motors and only move at reasonable speeds.
Agreed. The current idea was a 4KW Chinese (or better) spindle.Quote:
Originally Posted by Boyan Silyavski
Three points. This design is not final, could look at changing it.
Second point, It is possible to do a tool changer directly into a non geared spindle setup (like the Datron tool change setup).
Lastly, If I am doing masses of small things, like a pallet of 10 things, using the same tool for an extended period of time and then changing will have less time impact. Of course, doing a 1 off with 5 changes will struggle.
The Tormach setup is interesting, no real ATC however has the drawbar, if you manage your tools properly (heights preset etc) doing a manual change during cycles is not too bad.
But please keep the feedback coming, this is useful.
Understood. Perhaps 'all' Ill get is a very sturdy accurate 'average' machine. I cant fit a 20 HP spindle. The point here was to prove a few points.Quote:
Originally Posted by Davek0974
1. How much better will something be with higher end kit?
2. The kit I have bought wasnt cheap, but it was not new, so I did not pay full price.
3. I want to see the 'max' of what can be done using single phase power.
4. I like playing around, this is my fun that detracts from a fairly tough day job :-)
Thanks
That is the important bit i think, you will end up with a machine that has capabilities beyond the average frame-build unit, but most likely not something that can rip through metal like chocolate;)Quote:
Originally Posted by Chaz
I have a feeling resonance and vibration will not be an issue:)
The machine will only be has good as the weakest link.! . . . No point fitting high end parts and then throw cheap under powered chinese spindle on it IMO.
Datron Spindles are 60K rpm and not your average Spindle, very expensive I'll guess.? If you notice they also mostly only use smaller diameter tooling and the machines are much more agile.
IMO with all those oversized heavy weight components and Frame design your building Sledge hammer to crack an EGG if all your doing is cutting aluminium with small tooling. Even then it probably won't give better results than lesser built machine with quality spindle on it. (ie Datron)
If you want to HOG aluminium out then you'll want larger tooling and this will require HP from the spindle. Fast tool changing is easy enough.? It just costs lots of money.!
All very true. The smallest Datrons cost £35K. Ill be happy to get anywhere near the performance as Ill not be spending near this kinda money.Quote:
Originally Posted by JAZZCNC
Out of interest, with the components that I have thus far, what would you do with them?Quote:
Originally Posted by JAZZCNC
Charl, i think you are missing the point. Depends on what you want to do exactly with the machine, you construct it around that idea. So thats what you should concentrate on, nbot making the best machine possible.Quote:
Originally Posted by Chaz
But i think Dean had already shown what he will do, same as what i would do- buy me a big beast VMC and retrofit.
Im not picking a fight. Just asking. Curious.Quote:
Originally Posted by Boyan Silyavski
Ive been eyeing out lathes for ages. This one came up, not too far from me, needs a bit of TLC. Came with a metal cabinet full of stuff. Just tried it, I know little about speeds / feeds, but it will work and allow me to make a few parts. Wondering if I should CNC this or leave it original and find an Emco or something to CNC.
A bit tight ... just as well I rented the larger van.
https://c2.staticflickr.com/2/1667/2...4857940e_b.jpg
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Quote:
Originally Posted by Chaz
I'd Carry on and use them but I'd make sure the whole machined was matched and balanaced. This was my point really.! The Spindle will be woe fully pathetic in comparison to rest of machine.Quote:
Originally Posted by Chaz
The other point i'd like to make because I see it happening more and more is that BIGGER isn't always better.? Often it makes for poorer performing machine.!
The WHOLE machine must use balanced components otherwise it's wasted.!
In your case you have Rails and Ballscrews that you'd likely see on VMC's 4 times the size of what you have planned. Those same machines would be using Servos's matched to the screws etc and running spindles in the 15-20HP area. Theses machines would be built like this because they are intended to cut steels or Hard allloys with high MRR.
While they will equaly cut soft materials there main advantage would be they can use much larger tooling for higher MRR when roughing etc.
For 3D and general machining of softer alloys you wouldn't buy that machine because you'd be paying lot of money for Strength and componets which are not required for aluminium.
Machines like Datrons which are designed cut soft alloys while still using quality componets and matched components wouldn't use the size of linear rails and ballscrews you have bought because it would be harder or much more expensive to make them reach the accelrations and feeds required. For there intended purpose they will also more than likely beat a large VMC in cycle times.
Thanks. So in effect I need to potentially ditch the Chinese spindle idea and get something 'decent'?Quote:
Originally Posted by JAZZCNC
Quote:
Originally Posted by Chaz
Its a Boxford, either CUD, BUD or AUD model i think, with quick-change threading/traverse gearbox, nice little lathes, I have one myself :)
Sadly not the AUD but an older A model with motor at the top. It will do what I need so all good.Quote:
Originally Posted by Davek0974
Love that first picture, looks like WW1 in the back ground -smileyface-
Small update. Ive decided to get longer rails for Z, 700mm, this will arrive in the next two weeks. I am starting to look at building the moulds for the base and gantry systems. I have also ordered the epoxy as well as putty / liquid for levelling that I need.
Hope to provide some updates again soon on this build.
Did some turning to make some spacers for the ballscrews. Also started with some layout ideas for the electronics.
https://c2.staticflickr.com/2/1464/2...0ebd45f3_h.jpg
This must be the most elaborate drawing of enclosure that i have never dreamed existed:triumphant:
I do this so I dont mess up the planning / sizing of stuff I need to order (like plate etc). It also helps with not making it up as I go.Quote:
Originally Posted by Boyan Silyavski
Forgot to ask, why 700mm Z?
That's the rail sizes available to me 2nd hand. Im not paying new price for any of this kit, too expensive otherwise.Quote:
Originally Posted by Boyan Silyavski
So I am designing around what I have available.
Are you following the manufacturer's guidelines for ventilation around those drives? ;-)
I've been working on the layout for my big mill cabinet, and I'll be opting for a bank of fans blowing air between the servo drives, as if I follow the dimensions in the manual, I'll not have enough room in the cabinet. And the cabinet is over 2' wide and 5' tall!
Looks like you've got a good project going here Chaz! :thumsup:
You seem responsive to feedback/criticism so I'll give you my two cents given I've been thinking of a very similar project.
First of all it really will be too 'solid', there isn't a need to make the frame so large with cavities to reduce the weight. Any cavity you introduce to the frame is just another process that needs to be worked out, why make it more complicated than it needs to be?
The A frame you've introduced will indeed be stronger but if you ever need to machine something that overhangs the table it may interfere with the frame. All commercial machines I've seen are vertical to make best use of the available space, if any extra strength is required it can be put at the back like your original design showed. It's a less 'efficient' use of material in terms of outright rigidity but is the best solution to the problem.
Attachment 18477
This is a pretty typical design, as you can see not much is allowed to get in the way of the workspace.
UHPC/EG may be weaker than steel and cast iron in every way, but it's also 1/3 of the density and less expensive. Use this to your advantage.
You appear to have the Y axis rail spacing as wide as possible, is there a good reason for this? If you bring them closer together you can create a more rigid table while at the same time reducing the width needed for the base of the frame. less width = more thickness = more rigid frame (for the same weight).
I think you really should look into getting a proper spindle, they really do make the biggest difference. Why cheap out on the thing that matters most? There are options available. I think a good question to ask would be, do you really need a high speed spindle? A 10,000 rpm milling spindle will be far more rigid and can make up for the slower speed by using bigger tools. Datron often use single flute tools, one of these at 30,000 rpm is similar to a 3 flute tool at 10,000 rpm.
I look forward to seeing how you progress, and remember there's more than one way to skin a cat. There's the right way, and there's the way people say it should be done.
Cheers,
Fenza
Thanks for the input. Ill try and answer where I can.Quote:
Originally Posted by Fenza
The plan is to revise the gantry to provide more clearance. Id prefer to over engineer than under, even if it costs a bit of extra time / effort.
In terms of the Y spacing, the guidance I was given was something like 4/6. So divide the width into 6 and space it about 2/3 each way. My understand is that wider = more resilient to any yaw movement.
In terms of spindle. Nothing is decided yet. The design is currently with a 4KW Chinese spindle but happy to change this. The reason I am looking at higher speed spindles is that I will primarily machine aluminium. Ive already taken a look at the spindles that Datron use and might go down this route.
The last comment is interesting. The right way and then what people suggest. I like the commentary and certainly makes me think about options. Of course not everyone will agree and some of what has been suggested I have either ruled out or accepted and changed accordingly. The person that I buy some of the hardware from has sent me images of what he works on for his day job. I cant share the images as they are proprietary and copyright but they show interesting machines, typically make from UHPC or EG on a massive scale (think of machines with beds in meters, not millimeters). The nice thing is that you can see how some of the designs took shape as well as some interesting structural methods of creating strength / rigidity. I dont have a mechanical background, so some of it looks 'odd' to my untrained eye but we are talking of machines that cost £500K upwards, its good to see what's out there and available. In some cases the structures are really 'basic'. In some cases, not.
2/3 of X travel? That sounds about right. Is your table not much larger than the travels of the mill? Not that it matters much just explains why the spacing looks so wide.
Maybe it'd be a good idea to show the guys here some pictures of the kind of work you want this machine to do? High speed spindle are great if the work can take advantage of it.
Cheers,
Fenza
If you take the width across (X), split into 6. The rails are basically _|____|_ So Space, One, Space, Space, Space, Space, One, Space.Quote:
Originally Posted by Fenza
The type of stuff that I want to do is fairly simple, motorcycle bar risers, RC car parts etc.
Have you seen drill tap machines like these? https://www.youtube.com/watch?v=-fcWdMVVbEs
Most have BT30 spindles at ~10,000 rpm
Cheers,
Fenza
Lovely that. If I can get anywhere near that Ill be happy.Quote:
Originally Posted by Fenza
I am thinking BT30 if possible. My Denford VMC is BT30. Does anyone have any experience with the Chinese / Asian supplied BT30 (with drawbar) item that sells for around $1800?
Check out http://www.cells.com.tw/en/products.php?m_sn=6 I haven't used CELLS TEC but I believe they make good spindles, both motorised and non motorised.
Stuff like http://www.aliexpress.com/store/prod...643490383.html might be worth looking at.
Are you more interested in built in motor spindles?
Cheers,
Fenza
Thanks, will take a look. Interested in all things at the moment.Quote:
Originally Posted by Fenza
That spindle looks decent. The Posa website actually looks like something proper and not the typical crap you see. Certainly worth a look. Have you ever used one or seen one?Quote:
Originally Posted by Fenza
Started with the layout for the electrics. Ill mount onto a stainless plate most likely, this was just on MDF to get a feel for the size and get the basic X axis movement sorted.
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A quick video, nothing is really calibrated but the motor seems happy to spin to 4000 rpm. Its a Panasonic 1.5KW motor and A4 drive powering it.
https://www.youtube.com/watch?v=Az4RkyfsDTE
A number of hours later, some marking, measuring, drilling, fitting, wiring and we have the bulk of the electronics mounted.
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isn't that panel a bit tiny for your machine? don't you want more room in case you missed something
Its 800 x 800. There is space to the right of the servo drives. I doubt much more will be needed, that is virtually all the electronics I need. The spindle drive goes to the top right, there is enough space for at least another 2 servo drives if I want to do more axis.Quote:
Originally Posted by Noplace