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I need a mill ? Manual or CNC??

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EtheAv8r30/06/2011 14:39:58
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OK maybe I don’t need one, but I want one and am going to get one. Initially I planned to do milling on my lathe, a Wabeco D6000E. However events conspired to make this not possible with the Wabeco vertical slide, so that went back to the supplier.

I decided (like I did originally with the lathe….) to get a small budget mill and indeed got offered a great deal on a second hand MiniMill (Sieg X2 clone) with lots of kit for little money and nearly bought it. But I figured that it would be limiting in the future and it is better to get bigger than I currently need (but not too big as to make transporting to the workshop and installation an issue) and buy once, rather than upgrade later (and upset SWMBO further “what on earth do you want that for?”.

So I started looking into it and drew up a list of the usual suspects:
~ Sieg X3 or Super X3 from Arc Euro Trading
~ AMA25LV from Amadeal – the version with x-Axis powerfeed and DRO looks particularly appealing
~ Champion 20V (looks like the AMA25LV) or Century from Chester Tools
~ WM16 or WM18 (but this is getting a bit too heavy) from Warco
But then there are these intriguing threads on new technology and CNC. The idea that I can produce a drawing on a PC and have the mill accurately make that part is of great interest.
 
I have a manual lathe. I have a lot to learn. I want to make ‘stuff’, and in CNC for the mill will get me there quicker and I can afford it, then I am very tempted to go the extra 5 miles (cost-wise) over the mil acquisition if it is going to save me several miles in getting to actually make ‘stuff’. Some of this stuff will be parts for model helicopters and aircraft. Accuracy and repeatability are essential.

I am particularly attracted to the preparation service offered by Arc Euro, though I believe that with an appropriately detailed instruction guide I could do this myself – most of the machines do not have such a guide.
Ideally I would like CNC with some manual capability so that I could just do some simple milling and drilling tasks without having to produce a drawing.
 
One solution here might be to buy the Super X3 from Arc and the Syil Super X3 Milling Machine Conversion Kit from Amadeal.
 
The Syil X4 plus CNC looks very nice, but is way too expensive, and also is really too big and heavy. The 'manual' over-ride with an electronic hand controller looks great!

CNC versions on the Sieg Super X2 and the Sieg KX1 CNC Mill Bundle are affordable, but too small and limiting, and the Sieg KX3 Hobby CNC Mill Bundle from Arc looks to be the best compromise – size and capability are in the right area, still too expensive…. But doable!

So I open the discussion to the forum (no anti CNC ranting please – I am after useful help and advice):
 
Should I simply stick with a manual machine (and which one – I would probably favour the Sieg Super X3 from Arc – and add a DRO), or shall I make the leap to CNC (and again how and which? - I want to use it, not spend a great deal of time and associated hassle building it).
 
Edmund
John Stevenson30/06/2011 22:01:09
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Observations in no particular order and no particular hat on.
 
Keeping a mill manual and CNC isn't very easy.
X and Y is OK as you can fit double ended motors and fit handwheels to the blank end. The problem is the Z where you hide the motor away inside the column.
 
The WM14 - 18 series can mount the motor outside the column but it leaves the handwheels at the back, top of the column and not handy to get to.
 
X3 and SX3 could also be done like this if needed but again , and with the taller columns not easy to reach.
 
X3, WM14 series and 20V can have the spindle controlled by the computer as regards on/off and speed.
The SX3 cannot be computer speed controlled at this point. KX1 and 3 are but they have different speed boards.
 
Steer clear of the X4 at this point in time and I'm saying nothing more.
 
Hard choice to make IMHO.
 
John S.
EtheAv8r30/06/2011 22:12:58
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Thank you John.
 
Is having only a CNC mill do-able or will I miss not having manual capability, or is it just as prictical - but different - to do small simple jobs (e.g. hole drilling, simple surfacing etc)? Or should I consider having a small mill (thinking Super X2 Plus..) as well? Just not sure SWMBO would understand.... however they are not a lot of money and both can be R8.
John Stevenson30/06/2011 22:26:09
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Once you get used to working the machine I think you will find that you will use the CNC part for all jobs.
 
I have done quite a few conversions now over the years and this is a question I get asked a lot. Quite a few insist that handwheels are fitted to the tables for the 'odd job'
 
Later on when speaking to these people they come up and say quite knowingly "I have taken the hand wheels off "
 
Mach3, the controller has quite a decent selection of what they call wizards and what i call Conversational programming where you get a 'picture' of the job on screen and you fill the boxes in.
 
Once completed the wizard then sends the code back to the program run page of Mach3 ready for you to run this.
 
Wizards cover facing a surface, round contour, square and rectangular contour, circular pocket, square and rectangular pocket, bolt circles, drill holes array, thread milling, keyways, spline and gear cutting to name the popular ones.
 
Most simple jobs could be machined with just a series of these wizards.
Versaboss30/06/2011 22:52:11
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John, does what I see above mean that one can make parts just with the wizards of Mach3 alone? For a complete part one can run one wizard after the other,; the difference (compared to the 'usual' way via CAD-CAM) is only that the operator has to be near the machine for every step?

If that's correct, then it seems that this would make life much easier for many among us.

Greetings, Hansrudolf

Andrew Johnston30/06/2011 23:10:58
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Hi Edmund,
 
The correct, but not necessarily domestically sensible, answer is to have both.
 
I'm not familiar with any of the machines that you mention, so I'll limit myself to a few general comments.
 
There are things that are easy on a CNC mill that are difficult and time consuming to do on a manual mill. Conversely there are things that are quick to do on a manual mill that would be more time consuming on a CNC mill. Small repeated parts for R/C helicopters and aeroplanes would, I think, tend to lean towards CNC.
 
I rather expect that a manual/CNC mill will be a compromise, and possibly not ideal for either. If you have both, the CNC mill can be whizzing away while you do something else on the manual mill.
 
Spindle speed is important. With CNC mills one tends to use smaller cutters at higher speeds and feeds compared to a manual mill. On my CNC mill the maximum spindle speed is a tad over 5000rpm, and it's way too slow for small cutters.
 
Remember that table size and table movement is not the same as the size of part you can machine. You need room for clamps, fixtures and for the cutter to clear the part. Think about Z height carefully; if you need holes on the edge of a block with a drill in a chuck it can soon get eaten up.
 
A CNC mill will do exactly what you tell it, sensible or otherwise. There is quite a lot of information that needs to be explicitly stated when using a CNC mill, such as speeds, tooth loads, depth of cut, width of cut, direction of milling etc.
 
Either coolant or airblast is important on a CNC mill, not so much for cooling, as getting rid of the swarf. Not many things badger a cutter quicker than recutting.
 
For any mill(s) you will need to budget a not insignificant amount for tooling, clamps, vices, accessories, cutters and more.
 
On a manual (vertical) mill a DRO is near essential for any sort of productivity, in my view.
 
It can be mesmerising watching a part appear step by step out of a block of metal on a CNC mill, especially if it is a part you have designed yourself.

I agree with John S, it's a non-trivial decision, and one to which I think the correct answer is both. Which is where I started.
 
Regards,
 
Andrew
Tony Jeffree30/06/2011 23:12:05
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Posted by Versaboss on 30/06/2011 22:52:11:

John, does what I see above mean that one can make parts just with the wizards of Mach3 alone? For a complete part one can run one wizard after the other,; the difference (compared to the 'usual' way via CAD-CAM) is only that the operator has to be near the machine for every step?

If that's correct, then it seems that this would make life much easier for many among us.

Greetings, Hansrudolf

That is correct. As long as you stay within the capabilities of the wizards, Mach 3 is all the software that you need.
 
Regards,
Tony
Spurry30/06/2011 23:58:10
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Edmund
 
The machine (s) you purchase will depend on your aeromodelling requisites. If they are more towards Fixed Wing, then you would not beat a cnc router, especially for cutting ply, carbon sheet, grp sheet, and hardest of all - balsa.
 
If you want to make helicopter parts, primarily out of aluminium, then a cnc mill would be preferable.
 
In the last few days, I have made, on the cnc router, some carbon sheet motor mounts for an electric aircraft . It would have been almost impossible to machine the shape by manual means. For the same aircraft I am now making a complete prop driver assembly on the manual lathe. I guess it would take a fraction of the time on a cnc lathe...but that is on the wish list..
 
If the items you need are composed of straight lines, then manual lathe or mill is fine, but once you start with curves and arcs, cnc is the only way to go...but the learning curve (oh the irony ) is very steep.
 
Pete
EtheAv8r01/07/2011 09:38:36
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Pete
 
From the model milling aspect it would be more helicopter parts than fixed wing, but to be honest I really don't know where this will all lead, I am just off on an adventure and following a path that leads to I don't know where and I just love making stuff and then using it. This is how I ended up bulding and flying my own 2 seat light aircraft....
 
Is there any reason why a CNC mill cannot be used as an occasional CNC router for ply and carbon sheet? Surely they mill has more cabability than the router?
 
All this is leading me down the CNC route and I have booked myself into the Arc Euro CNC demo day next Saturday.

Edited By EtheAv8r on 01/07/2011 09:40:27

Spurry01/07/2011 10:15:50
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Edmund.
 
I found myself in a similar position as you in 1998, except that I already had a manual lathe and mill.
 
In exploring the cnc route I travelled all round the UK with my wing rib *.DXF file and a 36" piece of balsa and asked various companies to cut a rib from my sheet using their machinery. As a result I was able to choose a suitable machine.
 
A mill-style machine could cut plywood and carbon. I would suggest though, that the results would in no way compare to my router which can run at 24.000 rpm. Large sheets of ply, grp, and carbon are can be perplexing when trying to mount to the mill-style machine. My machine is limited on width to about 910mm. It does not matter if material is longer, but it wil only machine 1510mm on the X axis.
 
The router has mucnched it's way through dozens of 8x4 18mm mdf sheets. The 8x4's are precut at the woodyard or B&Q to 910 x 1220 (2). These can be picked up easily and placed on the vacuum bed, Just try that on a mill......So it all depends on what you might want to end up making.
 
If you ask Arc to machine you a piece of ply and carbon at the demo, I would be quite happy to cut tthe same shape on my router for you to compare.
 
One of the things most firms had difficulty with was positioing the part-to-be-cut on a scrap of material. This happens a lot when cutting bits and bobs from carbon. I can usually put a part within 0.5mm of where I wanted it, with very little effort in the time stakes.
 
Pete
Clive Hartland01/07/2011 10:17:11
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I too have had my eyes on a mill, the one I am looking at is the Wabeco with a longer table.
It is available with motorised feeds but at a cost.
I even have a PC ready for it.
As a first timer you may as well jump straight in at the deep end as cnc has a steep learning curve but as stated the mach 3 software is intuitive and will lead you through the most difficult processes.
Higher spindle speeds are a must as you may sometimes need to engrave legend on parts or even cut house name plates for a fee.
It would seem there is a long delivery time on any mill that you may order so bear that in mind as you make your choice.
Mention has been made of allowing for the cost of accessories for the mill. Clamping sets and rotary tables come to mind.
As an aside, all my working life I have had access to machinery and it is only now when I am retired that I need that access but will now have to buy my own machines.
There is nothing like 'Hands on' when making a choice of machine and you have done right by going on the Arc Euro demo day. Ask all the right questions and look carefully at the machine to make sure it covers all your requirements.
Again as an aside, If I could afford it, I would buy a Schaublin 13 or later number mill. but would need to win the Euro Lottery for that.
 
Clive
Roderick Jenkins01/07/2011 12:23:47
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Can I just emphasize the need for headroom in a milling machine. This is hardly an ambitious setup yet the table is at the bottom of its travel (it's a rising knee - no quill) and the 5.6mm jobber drill is hard against the inside of the 1/4" chuck. There is no chance with a 1/2" chuck. If I had to choose between a small CNC mill and a larger manual one I would go for the manual one (but I'd like the small CNC as well please).
 
Rod
 
Tony Jeffree01/07/2011 12:54:07
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Posted by Roderick Jenkins on 01/07/2011 12:23:47:

Can I just emphasize the need for headroom in a milling machine. This is hardly an ambitious setup yet the table is at the bottom of its travel (it's a rising knee - no quill) and the 5.6mm jobber drill is hard against the inside of the 1/4" chuck. There is no chance with a 1/2" chuck. If I had to choose between a small CNC mill and a larger manual one I would go for the manual one (but I'd like the small CNC as well please).
 
Rod
 
Rod -
 
That is a good point - there have been a couple of times when I have had to improvise in order to get sufficient height. Happily, on my Taig CNC mill you can unbolt the Z ways & shift it up a few inches to get a bit of extra headroom; the rigidity suffers but a useful get-out if you are desperate.
 
The ideal; combination is a small CNC mill and a larger CNC mill IMHO

Regards,
Tony
Tony Jeffree01/07/2011 12:59:46
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Posted by EtheAv8r on 01/07/2011 09:38:36:

Is there any reason why a CNC mill cannot be used as an occasional CNC router for ply and carbon sheet? Surely they mill has more cabability than the router?
 
No reason other than suitable spindle speeds. My Taig mill is capable of reasonably high spindle speeds; it will actually do 15000 RPM but I think that is probably more than the design limit of its headstock bearings, so I keep it down a bit. However, the way that mill is constructed means that it is asy to swap out the existing head for another one, e.g., something like a Kress router spindle, which would make short work of ply & carbon sheet.
 
Regards,
Tony
blowlamp01/07/2011 13:26:17
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It's a good point Rod, but it's possible to do things differently with CNC and drilling can be a good example.
 
For instance, much of the time it's far easier and quicker to use an endmill for hole drilling. This can done by defining the hole as a pocket and letting the CAM system take care of all the maths.
 
So if you've got a plate with say 5, 6, 6.6 and 10.2mm holes in it, you can use a 4mm endmill/slotdril to cut them all without changing tools, with no worry about different length drills.
 
 
Martin.
Tony Jeffree01/07/2011 13:47:39
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Posted by blowlamp on 01/07/2011 13:26:17:
It's a good point Rod, but it's possible to do things differently with CNC and drilling can be a good example.
 
For instance, much of the time it's far easier and quicker to use an endmill for hole drilling. This can done by defining the hole as a pocket and letting the CAM system take care of all the maths.
 
So if you've got a plate with say 5, 6, 6.6 and 10.2mm holes in it, you can use a 4mm endmill/slotdril to cut them all without changing tools, with no worry about different length drills.
 
 
Martin
 
Of course, that doesn't work for deep drilling, because end mills tend to be pretty short, but apart from that, its a great way to go.
 
Regards,
Tony

Edited By Tony Jeffree on 01/07/2011 13:48:06

EtheAv8r01/07/2011 14:11:14
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Pete
 
What CNC router do you have?
 
Oh my this could all get rather expensive.... didn't want a holiday this year anyway.....
Spurry01/07/2011 19:18:12
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Posted by EtheAv8r on 01/07/2011 14:11:14:
Pete
 
What CNC router do you have?...
 
It's a Pacer Compact 1502. Pacer was an outfit in Nottingham, but they got taken over by AXYZ. It seems the smaller Pacer machines have now been dropped from the line-up, so you can keep your 24K in your pocket.
 
As an aside, AXYZ was one of the companies who could not make a decent job of cutting out my wing rib.
 
Pete
Ian S C02/07/2011 11:57:36
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I find it handy with my Rexon mill to have a collection of very short drills. With work held in the four jaw chuck, mounted on the six inch rotary table, there is very little head room, so I see what you mean when you say look out for that sort of thing. Ian S C
John Stevenson02/07/2011 12:11:46
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Also handy to have the popular drills like tapping drills available in stub form with turned down shanks so they can fit into standard collets.
 
Things like 6.8 which is tapping for 8mm reduced to 6mm so you can do away with a chuck and using a centre drill.
 
Far more rigid, far more room and a lot quicker, applies to both CNC and manual machines in equal order.
 
John S.

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