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Hi All
I was hoping some kind member(s) could offer some advice on the total cost to convert one of the chinese 2.7 / 3 milling machines to CNC on X, Y and Z
I need to understand how much to budget for on top of buying the mill
Thanks in anticipation
Monty
Hi Monty,
I went through this sometime ago, and IMO, don't bother - buy a CNC setup. Most 'manual' mills need so much work done to them to get them fit for CNC work, that the cost goes skyhigh. Usually the small mils have substantial axis backlash, so may need to be fitted with ballscrews - not cheap, because it may also need new bearings fitted, so machining work necessary. Then you need the steppers or servos to drive the axes - more cost, then add the cost of the controller system, and it starts getting crazy. A good CNC system isn't cheap, but still a better option than building one (unless you want to do it for fun!). A new CNC machine will come with a guarantee, you can be reasonably certain it will perform as specified, and you won't be involved in trying to build one for months (or years..:!).
That said, there is stuff on the web about building your own, so a bit of searching might help you work out what is to be done - unfortunately not always giving costs.
Thanks for the response - what does an entry level machine cost. I did look at this but the numbers seamed out of reach for me
I was considering 2k for the machine and £1500 for the conversion but still trying to cost all the parts needed to convert a machine and control it. Some of the want to do a conversion is for fun but also learning something new (if that makes sense)
Cheers
If set on doing a conversion then, at 2k get an Amadeal VM32L with R8.Quote:
Originally Posted by Monty_UK
I would say for 1.5k it is possible to convert it with the right choice of components.
80-90vdc or 60-70vac toroidal power. Drivers that can take 80vac/110vdc like:
DM860T drivers https://www.omc-stepperonline.com/di...or-dm860t.html
and these: X, Y
https://www.omc-stepperonline.com/ne...m-4-wires.html
Z,
https://www.omc-stepperonline.com/ne...m-4-wires.html
from stepperonline.
Combination of high voltage and lowish inductance will give good performance.
For ballscrews it gets trickier. If you can fit them in you want DFU2005 double nut all round (or DFU1605 on x, y if too tight a fit).
Now, some out there are total crap so watch out.
Good ones still likely need tweaking on the pre load.
Make your own bearing mounts, nut mounts, motor mounts and fit with AC bearings. Material cost is the main dilemma here.
For bearings I use Dunlop AC on my 25 mill, price is good afaic.
For controller I think a UC400eth, UCSB type breakout board, UCCNC software, and a cheap laptop from ebay, would be the best value.
I'll look at breakout boards later.
I converted manual first for x, y. Then used x, y to make z.
Then re-did x, y.
Thanks DazP - that is really helpfull information
Thank you very much :)
Is there a make for the ball screws and nuts you would recommend as suitable ?Quote:
Originally Posted by dazp1976
Hi Monty,
All good advice from Daz, and I think he has put the cost issue nicely in proportion. My thinking tends towards the practical use of the machine. I have nothing against building a machine for fun, but would say the end-purpose of such a machine is to use it to build something, so why spend a lot of money on converting a manual machine with all its possible pitfalls?. As Daz says, things like ballscrews can be problematic, and if they let you down, then its virtually a complete loss, but on a complete machine, you can go back to the manufacturer. This is why I suggest get a complete machine, and spend what money you have left on making something with it. I don't know how much experience you have with this kind of machine, but I found that it was only after some time did I understand what I actually needed the machines to do, which led to subsequent modifications.
You mention an 'entry-level' machine - i assume by this you mean something fairly simple and cheap. In general this means the range of 'chinese-type' clones these days, such as the Sieg series - all reasonable machines for the price, but they will be costly to upgrade to CNC, because you will probably have to change most things except the main castings. Again Daz has indicated the scale of this. But its your choice at the end of the day - just have fun doing it.
dazp - when you say "AC" bearings, what do you mean by that - are you referring to the seals? To minimise the backlash you presumably used back to back or double row bearings?
Hi KeithQuote:
Originally Posted by Keithw
First of all thanks for responding it's very much appreciated
I am limited on budget but still wanted to get the best I can for my money. You mention about buying a machine and using what I have left for making things - I was considering this to cost around £3500 in total plus time obviously. I have searched CNC machines but other than old second hand ex industrial I haven't found anything anywhere close to what I have to spend.
I'm a time served engineer trained the old way on basic machies but I covered a lot of CNC in later years (I'm 55)
If there is something in this price bracket I'd be very interested to look at one
Thanks agian
Angular Contact.Quote:
Originally Posted by Muzzer
I made my own bearing blocks (23mm thick with 2mm wide internal ridge) from 1 inch alloy stock.
Fitted 2x 7201-B-2RS in each for use on 1605 screws. Back to Back.
Adjusted preload on DFU with bits of 0.01mm thick alu foil between the nuts.
These are the screws and seller I used on x,y,z
https://www.ebay.co.uk/itm/263083205...4AAOSwal5YEjRE
(I think I got a slightly shorter 700mm one for z)
Haven't tried their 2005 ones. My 25 mill was fine with all 1605.
Changed my mind on controller.
Look at the AXBB-E. This simplifies things a little. Has controller and bob combined.
I wouldn't spend £2k on a manual machine like the Amadeal or any other Chinese-based machine because it's like building on quicksand.? Like any good structure, the foundation is everything and if this is poor the whole thing is a pointless exercise that quickly becomes a money pit that is difficult to get out of without blowing lots of cash.
If you need a small mill then look for a good second-hand Denford or Boxford that has good quality bases and components. Then spend a little on bringing them up to date with more modern controls and electronics.
If you have more room then look to buying an older purpose-built CNC machine with outdated or blown controllers, such as Bridgeport interact, etc, and then update with modern electronics. This way you start with a solid foundation built on good old cast iron. You still get enjoyment with the conversion or update and learn about the machine but without the stress from all the pitfalls which can and do come from converting a manual mill to CNC.
However, £3.5K isn't enough to do this properly even if you go with the Chinese manual route. My advice is to save your money, add more to it and look for some old iron.
https://www.ebay.co.uk/itm/175030848...waAoMFEALw_wcB
Quote:
Originally Posted by JAZZCNC
3 phase though. Can't use it without ripping elecs out first and replacing spindle motor. Not a fan of that style Bport.
Seemed risky to me in case I didn't have the skills to build the mechanics.
Now, if I could've got a blown out Haas mini mill type thing that may have been a different story!.
TBH I started with getting to grips with cad/cam side of things before touching anything else (inhereted pc).
If you can't get your head round that then there's no point getting a machine to mess with.
I'm doing mine as a hobby just to see if I could.
Other than that, Jazz has a valid point. But it's all about your budget in the end.
And just to add, the Amadeal isn't a bad machine afaic.
My 25 isn't anyway. Quill style spindle lets it down imo. Handy for drilling but I wouldn't push it too hard.
Slower and deeper seems to give less vibration than faster and shallow. Has the torque to do it too.
Castings did need some minor tweeking but the carriage and table were straight.
Not the case because they will happily run from a 3 phase rotary converter. Yes, this up's the cost but this is offset because of not messing around with converting, etc plus you get a real CNC machine, not a Dinky toy.Quote:
Originally Posted by dazp1976
The mechanics are not much different from any other CNC machine, the principles are exactly the same the differences being they are stronger and better built with accurate datum edges, etc.Quote:
Originally Posted by dazp1976
Given a choice between an old Bridgeport and a Haas Minimill I'd take the Bridgeport every time. The Haas is just a beefed-up Benchtop Minimill that sits on a steel frame.
The bridge port is one big lump of solid cast iron that will last forever and absorb vibrations like a sponge, it will give finishes and allow material removal rates the Haas Minimill could only dream about.
However, that was just one example and probably not the one I would go for either because there are better newer options if you watch for them, but the point is I wouldn't sink £3.5k which will quickly turn into £5k in all reality into a Chinese machine made from cast iron that is more brittle than a crunchy bar and about as stable as a quivers jelly when you can buy rock-solid old iron for not much more.
In all reality for someone wanting a small desktop machine then Denfords, Boxfords, Emco's, etc which are built from quality cast iron and with decent base components is probably the better way to go.
I'd just avoid converting a Chinese manual machine because it will always be a compromise at best and at worst it's a pig's ear that can't be turned into a silk purse no matter how much money you throw at it.!
TBH I dont have the space for that size of Mill - I've been using 3D cad for many years and CAM so no issue there
I will only be making small scale parts which are ideally suited for the VM32 size machine - I do fully get the potential pitfalls but for my use case and Bridgeport would be overkill
I trained on such a machine as an apprecitice - they are truly solid machines and I wish I had both the space and money for one
One of the reasons for doing the conversion was to give me a base machine early and then spend time building up parts etc for the CNC as I go but still have the use of the machine
Ideally I want to get the best Chinese mill i can get - any opinions on this would be appreciated
Fully understand and in that case, I would look for a used Denford, etc like I mention at the bottom of my previous post rather than look to Chinese mills which are like a box of chocolates with no lid.?Quote:
Originally Posted by Monty_UK
Edit: Also just because someone else found a decent Chinese mill does it follow all the others will be the same, even from the same manufacturer because I know if you search hard enough you'll just as many unhappy buyers as you will happy, if not more.!
Now regarding the small-scale parts what material will you be mostly cutting.? If it's aluminum your next battle will be spindle speeds as most mills don't come with fast enough spindles to suit cutting soft materials. This will be something you will need to factor into the cost/difficulty equation when converting.?
Hey JazzQuote:
Originally Posted by JAZZCNC
Aluminium, engineering plastics and some mild steel - I imagine the most common will the aluminium though. I had considered changing the main drive after the CNC to get higher speed and more constant torque
Thanks
DazQuote:
Originally Posted by dazp1976
What do you think to this model SIEG SX3.5ZP HiTorque Mill - more money ???
There may be a Warco WM18 on ebay ending soon (same sizes as WM32 I believe). Not sure on condition but states low use.Quote:
Originally Posted by Monty_UK
It's downfalls are MT3 taper and gear driven.
Looks in need of a right good clean but also means it might go cheap!.
https://www.ebay.co.uk/itm/125101856...YAAOSwbKNh4tn2
https://www.warco.co.uk/milling-mach...g-machine.html
MT3 no problem unless thinking tool changers or quick change as it's not that easy to release tools via drawbar unlike R8.
Gear driven may be easy enough to belt convert later.
Plenty info about that when searching G0704 belt conversion (25 size machine). Similar process, smaller size.
Not convinced for the price.Quote:
Originally Posted by Monty_UK
Well in that case I would look long and hard before buying a Mini mill because very few will have the RPM you need for cutting aluminium and soft materials correctly and converting the spindle is not a simple or cheap thing to do.Quote:
Originally Posted by Monty_UK
If you want a challenge you may be better off DIY building a strong Fixed gantry Router/Mill that will do everything you need and then some with the correct spindle fitted. It will certainly be more versatile and useful than a converted Minimill and won't cost much more. Here's one I built a few years ago (yellow one) with a 500 x 500 cut area and also one we built recently that is fully covered designed exclusively for cutting Aluminium moulds with a cut area of 600 x 400 which is more or equal to many industrial CNC machines but fits in a 1mtr/2 space.!
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Its amusing that this is where i started - then the thought process led me down the path of buying a machine and converting it :)Quote:
Originally Posted by JAZZCNC
The blue one looks very impressive - do you know the build cost of that ?Quote:
Originally Posted by JAZZCNC
ATC BT30 Cartridge and 5000rpm servo drive belted to 7500rpm at the nose, too heavy???.Quote:
Originally Posted by JAZZCNC
Or is there a 6k-8krpm ATC BT30 motor option out there?.
Yes, I do but that's not information I'm going to share on the forum unfortunately as these machines we build to sell, plus we buy components in bulk so wouldn't be relative to the average DIY builder.Quote:
Originally Posted by Monty_UK
However, for the machine in the picture you won't get any change from £10k given it's got a custom-built 40K spindle with ceramic bearings. But what I will say is that from the point of view of a machine builder the bulk of the cost isn't components but rather the time that goes into machining and building the machine. There are a lot of hours and work that goes into a machine like this which as a DIY builder doesn't come into play.
Yep Cartridge and motor setup would be too heavy but we can have custom-built water-cooled ATC electro spindles with BT, HSK, or ISO tapers in usual sizes 20,30,40,63,100, etc with power ratings from 1.8Kw up to 40Kw with speeds and torque ratings up to 60K and 120Nm.!Quote:
Originally Posted by dazp1976
So yes having an ATC BT30 with 6k-8k rpm is no problem, either flanged (cartridge) or straight body spindle type. Can even have with encoder for ridged taping or orientation and thru coolant.
I missed this post.!Quote:
Originally Posted by Monty_UK
Yes, it's funny how things are initially conceived but then go off at tangents, I see this all the time with customers, esp new users, who buy machines with a plan to use them for ideas they have but within a few months or certainly within a year when they realize just what a CNC machine allows and it takes them down paths they never even thought about or knew existed.
Converting works provided you buy the right machine to start with, but I've yet to see a good Mill come out of China.
The problem with converting a manual Mill is they were never designed for CNC in the first place so often you struggle to fit ball-screws and motors mounts etc without the castings or beds needing material removing and it's here when the shit hits the fan.?
The cast iron and steel are of very low quality and the casting doesn't undergo any stress-relieving so when you start removing material they have a tendency to shape-shift and twist etc.
Even buying machines from UK based companies like Warco or Chester tools, Axminster, etc doesn't help this because they are just made in China with the same low-quality iron, this is why I recommended looking at used machines like Denfords or Boxfords because the castings are made in the UK with good quality ductile cast iron and stress relieved.
You basically need a mill to convert a mill.Quote:
Originally Posted by JAZZCNC
I had to make casting adjustments and tidy up a lot of rough areas.
(About the only thing my Sieg X2 conversion has been useful for!. Twists and stalls like crazy)
At least the castings on the Amadeal 25 weren't totally like cheese. Got lucky I reckon.
A little late in the mix.
Total cost.
Depends how far you want to go. The type\brand\quality of ball screws can be a big factor. Then there's open loop steppers vs closed loop steppers vs servo.
After that is the control infrastructure, Mach, grbl, Linuxcnc or other. Then with Mach & Linuxcnc there is a choice of using Parallel Port hardware or external motion control. For Linuxcnc the most popular and well support external motion control is the Mesa FPGA cards, with them you have the choice of PCI, PCIe, Ethernet or SPI in the case of the Raspberry Pi. Tho there are a few projects that are repurposing the NVEM boards with custom software, another that repurposing ColorLight FPGA boards. Or there you can use a Orange Pi with the H3\H5 Cpu that uses the on die mcu.
Then after all that, there are PSUs and control boxes to think of, and of course wiring, switch, pendants, lights and a thousand other gubbins to think of. Then theres the chance you may need to buy quality crimpers, after a while you get sick of the cheaper stuff.
Now after all that here comes the expensive part. What vice are you going for, are you going to use standard collets or if you have an R8 spindle the Tormach system or the cheaper chinese knock offs.
Then after a while you are going to want a coolant system and then after dealing with the mess an enclosure\tray might be next.
After that point you kind of put the total cost to the back of your mind as you don't want to think about it.
And finally depending on the country you live in postage\delivery\taxes can add a fair amount.
Unless you're buying an actual factory cnc mill it's hard to put a price on it.
And here's something.......after a while you realise that some of the tasks you do were quicker when the mill was manual.
And the final kicker, the mill you have will be a little bit smaller for the task at hand.
That's the "Box of chocolates with no lid" problem I mentioned in an earlier post, you never know what you are going to get or what will happen when you start taking it apart or modifying castings, etc.Quote:
Originally Posted by dazp1976
Then if you are lucky enough that it doesn't let go when converting there is no saying it won't shapeshift when being used because it was never designed to handle the forces CNC is imparting on the chassis.?
Why anyone would want to invest the best part of £5k and 100+ hours of time into a machine that could shapeshift at random is beyond my understanding.! It's like playing Russian roulette with a full revolver.:cower:
Thanks for all the responses - a lot of good point have been made and has given me things to ponder :)
I was recently trawling Youtube and came across a channel called Ades Workshop - this guy bought a Warco 16B machine which looks reasonable both in terms of cost and quality
His output looks ok from a hobbyist persepective - so my idea now taking on many of the above comments is to buy a machine akin to the 16B, fit a DRO and then use that to make a purpose but smaller CNC milling machine similar but Jazzcnc but smaller
Sounds like you have a plan.Quote:
Originally Posted by Monty_UK
Buy a mill to make a mill/router.
I'd draw up some of the new machine first. Then you'll know which size Mill to get. Don't want to end up with something too small.
Warco16b & Amadeal 25L are effectively the same machine.
I've recently been looking at TBI C5 ballscrews for my 25L. I better get some cutting done so the machine can pay for them. They're tempting.
Thanks DazpQuote:
Originally Posted by dazp1976
Just found my Zeus book from 1982 - well happy :)