Ive got a model, the Z Axis has some options that will move the spindle location. I just wanted a sense check as such. I wont mount till I am certain.Quote:
Originally Posted by JAZZCNC
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Ive got a model, the Z Axis has some options that will move the spindle location. I just wanted a sense check as such. I wont mount till I am certain.Quote:
Originally Posted by JAZZCNC
Wasn't meaning just for this talking for every thing in general really. Like most things in life it's the little things that bite and sting the most, these are not always obvious until it's way too late into the build.!Quote:
Originally Posted by Chaz
Yep. I agree. I just wanted to be sure my logic was correct. Effectively being in the middle of the Y travel (lets assume its equal in both directions) maximises the size of table I can use.Quote:
Originally Posted by JAZZCNC
I do keep well oiled - rust protection+ anti splatter spray while MIG welding. TiG is clean so no needs for anythingQuote:
Originally Posted by Davek0974
So, keen to get some feedback on the Z Axis.
Nothing too controversial except for the use of concrete. The concrete will be formed around the spindle with a few mm spare and then once the concrete is set, the spindle will be installed via a plate at the bottom and then DWH forming epoxy (the liquid version of the stuff I used for the rails) will be cast around the spindle. This means that the spindle (it needs to be planned so it can be removed from the bottom) will be a 'press fit' into the concrete. The aim of this is to both strengthen the Axis (Axial and Radial) however absorb vibration and improve the Z Axis overall.
The concrete will be around 39 litres which makes up a weight of around 90 kg.
Thoughts / comments / concerns?
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I need to improve the area around where the pulleys will go to create more space.
Also, any view on how well UHPC will 'stick' to Alu compared to Mild Steel? I need to finalise the material selection for the main plate.
Not sure if this helps show the details in and under the concrete?
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Think I'd be more inclined to have sleeve machined for the Spindle then set this in concrete. Don't think you'll get the strength/accuracy required from casting alone and will be bitch to remove spindle.
With the DWH epoxy, it will follow the shape down to the micron. That is one of the uses of the epoxy and it doesnt shrink. Removing it, well, agreed, that might be interesting.Quote:
Originally Posted by JAZZCNC
The Concrete with a tight fit epoxy will provide a lot of strength and vibration damping. I need to check however, on the 4KW spindles, the pictures show that there are no 'lips' on any of the structure, so it can be removed once cast (lets assume its greased or similar). If it has a diameter larger anywhere, this will be the minimum I can do which means that the concrete is just there to provide overall damping and strength to the plate.
An idea that was provided was to cast the hole to the smallest possible. If I wanted to use a BT30 setup (I have one drawn), having a few mm spaced on the sides is not a major problem, just dont get the full benefit of the concrete.
For me, I love the idea of BT30, I already have tools for this however Id like something that can do at minimum 12K too, so might go with a dual approach on this one.
Yes Know about the accuracy of The DWH Epoxy but still think will cause trouble and then if you talking Chinese type spindles like 2.2kw how would you clamp it or stop it from sliding etc. Would need plates making or some form of fixture.?Quote:
Originally Posted by Chaz
Think I'd be going with more conventional Cartridge spindle into sleeve set in concrete. This will give more options for replacement etc. ie 40 taper
Also why not BT30 for 12K can get them with bearings rated at those speeds and plenty of holders that are balanced for higher speeds.
The idea is that it gets attached to a plate which screws in from the bottom.Quote:
Originally Posted by JAZZCNC
At the moment the only reason I have not gone for a BT30 setup is cost mostly. There are numerous on the market but what is the cost to entry - £1K upwards by the time you add the BT30, Drawbar? What about motors? Do you mount from the top and do a direct drive or some form of belt setup?
EDIT, I may do the cheaper route first. I Can always make another 'outer' Z part and swap it out later.
Never been able to understand this kind of approach if honest because it ends up costing more than twice the amount and wastes lots of time.Quote:
Originally Posted by Chaz
If going to all this trouble surely it's worth paying the extra and doing it correctly first time even if it delays the build for while.?
Perhaps. Something to consider.Quote:
Originally Posted by JAZZCNC
Problem as Dean noted, is that once you have all setup and running, the upgrade happens almost Never, as you will move on to other projects
Agreed. Im trying to balance spending money / finding a new role and a bunch of other things at the moment.Quote:
Originally Posted by Boyan Silyavski
Any suggestions on sourcing BT30 spindle / motors setups? Ive heard that the POSA BT30 from the far east is one of the better ones. http://www.posa-spindle.com/en/product-53-30
I also have the option on the Skyfire setup although there is a lot of bad press about them missing shipment dates and going off grid once you pay.
Any other suggestions? Anything locally that is worth a look. Ideally Id want at least 12K RPM if possible.
If i were you, i would evaluate what exactly i will be doing, as first jobs and jobs that i make money from. Then decide what spindle to put there, according to the jobs i will be doing.
If you are going to do engraving, aluminum and so on, then 24krpm will definitely be much better. Especially if you are going to use bits 6mm or smaller than that. Thats why i opted for 3kw spindle on my machine and i am very happy. But if you are going to do mild steel mainly, then you need the BT30 or other.
All in one is not a very good option. In fact your machine best will be fit with 3kw 24k RPM and BT30 or similar., both at the same time. I know, $$$, other wise i would have fitted High speed tool change spindle BT30 on mine.
Follow the $$ priorities and you will not do wrong / the making $$, not spending $$ :hysterical:/
In this, I was not specifically referring to making money from the machine to be it's purpose, was referring to my own day job but agreed, I need to decide what the machine will be used for.Quote:
Originally Posted by Boyan Silyavski
So are you saying doing both may be a good option or not? Sorry, not sure if the 'not' in your sentence is correct or not.
Ideally it would be good to have something versatile. If I can engineer a solution when you can almost do a 'multi head' setup. Heck, even look at some form of grinding attachment, potentially with a very high geared 2nd Z setup that can hang off the side or front of this Z Axis.
In my opinion both will be best. Then you dont need the spindle to be 3kw. It could be smaller. And cheaper. As the 3kw is almost 500 euros with the inverter.
Having machine built to this level of strength then fitting router spindle restricted to small tool sizes is little like using sledge hammer to crack nut don't you think.?
Don't stray from the path Chaz.? . . . .If want router/Engraver then build router/Engraver.! . . . If want machine to Hog out aluminium/steel with meaning full DOC and tool sizes like what you intended with this build then you need spindle with some muscle.! . . . . Never the twian shall meet and if they do they never get along very well IME.!
For me machine built to this level of strength requires minimum of BT30 and proper motor with plenty of torque/speed.! . . Down side is Not cheap but that's the nature of the game. If want to play like the Big boys do and with big boys toys get the cheque book out.! . . . . Any other way is false economy and will always be lacking.!
Mchine build like this requires 15kw Spindle, toolchanger and so on.
I've just re-read the first 8 pages of this excellent project and the subject of spindle power was discussed in depth, i would tend to agree that using a small spindle will be limiting its use, I would be looking at a decent BT or INT taper spindle with tool change ability and a large motor maybe 7-8Kw and possibly a two speed pulley to give maximum speed range or the choice of steel vs alloy machining etc. ;)
Thing is (and Dean has commented since), going lightweight on this machine is a waste. I already have a 4KW VFD that I bought some months ago (did not get the spindle at the time) as I wanted something to run a 3 phase vacuum pump and then later potentially use it on my machine.Quote:
Originally Posted by Boyan Silyavski
Another option is to look at the spindles like they use on Datron machines - up to 60K RPM, 5 KW typically. Not cheap, probably £3-5K Id guess.
15KW, I cant power that (and I know Thor wont be stressed) - even the weight of that will be interesting to move around.
Anyways, Jazz, I did send you an email a few days ago about AC Servo setup in case you had time to look at it please?
Thanks
Thanks. Our posts just about crossed over.Quote:
Originally Posted by Davek0974
Any suggestions on what type of pricing for something in that range (7-8KW)? Secondhand may be an option. I may be able to get my single phase power increased (in terms of available current) but not by much, so not sure if I can drive it with the power I have available to me at present.
Where about in the world are you based?
In the UK 7-8kw is less than most electric shower heaters now so it may need a new cable running but should be do-able (providing no one in the house takes a shower at the same time ;) )
There are second-hand options but rare, have you got a "watch" registered on the 'bay so it emails you if something pops up ??
Seems the spindle is always the worst / most expensive part of any build.
Domestic properties are often supplied with a 100A fuse these days so that about 23Kw. The neibours electric might not like it though with the lights dimming etc.
West London however in a rented property (I know, major pain, maybe one day we can own property). We managed to get a 32A supply installed in the garage which gives me around 7KW of power. I could possibly get a 2nd 32A installed, perhaps use that alone for the spindle - not sure.Quote:
Originally Posted by Davek0974
I have had watches on ebay before, may set something up again. Ive seen before a lot more options from either the US or Germany (seems typical).
One thing getting the motor, the other is the controller. If they are a closed loop system Id expect that the motor / drive are a matched set however with 'just' a normal 3 phase motor (irrespective of RPM) I assume a more generic VFD should work. Correct logic?
Ive read that these can be upgraded but then of course all the relevant conductors need to be suitably sorted. For us being in a rented place has limitations.Quote:
Originally Posted by Clive S
I have looked at getting a workshop with 3 phase but anything near London is very expensive.
We are looking at moving away from London at some point but not there yet. This may limit Thor in the end with a 4KW spindle setup.
Fair-do's, you have to go with what you can do in the end ;)
At least with such a heavy built chassis, a later upgrade would be on the possible list.
Yep.Quote:
Originally Posted by Davek0974
I am currently also looking at 'better' quality spindles than the cheaper ebay ones. So perhaps only still 4KW but potentially better.
Ive contact HSK and looking at getting a price for a Giordano Colombo unit. Pity the air cooled units are so noisy.
You mean 4kw direct drive spindles? Or belt driven BT and similar by 4kw motor?
Cause if first i dont see a reason why not to go with 4kw water cooled spindle. less than 400$ now that you have the drive. Bearings are cheap to change one day. What would bring the more expensive ones to the table that the Chinese one can not do??? for 1/5th or 1/10th the money?
But if i was to make it BT30 driven i dont see any option save servo driven. Why to put so much money and effort and not be able to do rigid tapping and similar??
Yep, at the moment the likelyhood will be either -Quote:
Originally Posted by Boyan Silyavski
Just use a Chinese Spindle, I have the VFD already.
Get a BT30 Spindle, belt driven and use the same Chinese spindle to power it. This allows me some gearing options too.
Use the same BT30 Spindle and go AC Servo. Anything over 1.5KW needs to be 3 Phase and is fairly expensive. £1500 probably for a 4KW AC Servo and Drive.
Might have to look at belt specifications to see if and how is possible. It must be HTD obviously as its made especially for that purpose.
Yep. Loads of options at least.Quote:
Originally Posted by Boyan Silyavski
Sorry Chaz you'd been dumped into Spam box and I've been really busy so not checked lately. When get chance later in week I'll reply.Quote:
Originally Posted by Chaz
One other thing not mentioned or consdiered is weight.?
The combined weight of Spindle cartridge, motor and all that concrete will most likely require some form of counter balance. Servo alone unless large KW won't be enough I think.
My big mill has got Int40 (Same as taper BT40 with slightly different holder) spindle with 5.5Kw Inverter Motor which spins at 7500rpm and the motor alone is too heavy for one man to safely handle. The pulley alone (which uses 2 x multi V belts not HTD.!!) must weigh same as 2.2Kw spindle.
Recently I removed the head unit from column and reckon it must weigh 500kg. There is 10" sqr 3ft long Solid steel block runs down the centre of column that counter balances it. The whole thing can be lifted up/down turning the ballscrew by hand.!!
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Thats a beast JAZZ, what sort of size rail does the head/bed run on??
Certainly is That's the Full beast before took it from my friends place, just need to get it finished it's in lots of heavy pieces at minute. Been going to update thread I started so watch out you'll see it in pieces.!! . . . . Built like tank and weighs about same.!Quote:
Originally Posted by Davek0974
The head and carriage run on 3" chromed box ways the bed runs on chromed Dove tails all fitted with piped lube system handled by controller so constant lube while moving.!! . . . Floats like butterfly stings like Bee-astard if get in it's way. . .Lol
1.8Kw Ac Servo's connected to 32mm 5m pitch C3 Ground ballscrews with 2:1 ratio with 5.5Kw Spindle spinning 6" face mill in back gear and don't stop for anything, be that clamps , vices, people or walls.!!! . . . . Scary Can't wait to get it chomping properly.
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Thanking you.Quote:
Originally Posted by JAZZCNC
Yep, this is a valid concern. This is probably another reason why I will be a bit limited. That said, I could look at doing something to counterbalance - just adds some cost / time to the project.Quote:
Originally Posted by JAZZCNC
Time and cost yes, but your head is going to be pretty heavy so i reckon it will be best building in some sort of counterbalance now, could be hard to add later. This is likely why bigger machines have a fixed head/column and moving X/Y bed - you cant slam the head around if there is half a ton of counterweight hanging off it ;)Quote:
Originally Posted by Chaz