Re: Seeking advice for cnc machine purchase
Hi Danny,
I posted some responses to you in the other thread you posted, but in further answer to these, if your looking at a 6040 then 1.5kw is really going to be the very upper limit, and it would likely need to be one of the rarer slimmer and less weighty versions of the spindle as the z axis on the 6040 is not that powerful. Generally they come with a reasonably good 800w VFD/spindle which really isn't at all bad considering, or they come with the crap DC brushed spindle/motors up to 400w or thereabouts, but these are pretty crap and don't last long generally, I would avoid them at all costs.
I think first and foremost you'll need to sit down and really work out what your buying limits are, and how committed you are to what your trying to achieve by buying a cnc machine!
The reason is that no matter what you buy, it will be a very large and expensive purchase that you will likely need to live with for some years. The forums are full of posts all the time from people who in my opinion make the same basic mistake repeatedly, they have an idea for a business that involves buying a cnc machine, they buy the cheaper (and less capable!) model with the view that they will sell it and upgrade to a more useful machine the second things improve, but what generally happens is that they realise cnc is a real benefit and quite empowering, but they are stuck with a machine of very finite capabilities (thus reducing production capability and income generation), but they aren't generating enough income to make it worthwhile selling the small machine at a loss, to then start the process of upgrading to a bigger and more expensive machine all over again.
It's horses for courses, and budgets are there for a reason, but if you have a good business plan and idea, and feel committed enough to make it work, no matter how long it might take, the trick I really believe is to buy once and buy well.
Having said that, if the 6090 with the better spindle and rails is an option, it will be one you won't regret, and will hold it's value far better than any 6040 variant.
All the 6040's available via Ebay and Ali are the bluebox controller variety, usually with round unsupported rails, lower quality spindle, and utterly useless TB6560 based controllers and power supply, that ultimately mean you will NEED to spend additional on a G540, and a decent 48V power supply to suit. For serious hobbyist use this will be more than adequate, to base a business plan on however, in my opinion not a good idea if there are any better options.
To answer specifically some of the questions you raised,
USB is perfectly fine along with ethernet for some of the better controllers/interfaces out there
I far prefer water cooled to air cooled, having been in IT most of my life "I don't trust no stinking fans", especially in an incredibly dusty environment such as a home workshop!
1.5kw is very adequate for all wood and plastic machining, and even aluminium, I do heaps of alu on my machine, but on a bigger machine 2.2kw is definitely better!
VFD's are base on budget, a Hitachi or similar would be good, but the cheap Chinese ones do work well, the SunFar 300E on my machine has been perfect all these years.
A G540 would be required for a 6040 or similar in my opinion to get any level of decent performance and reliably out of it, on a bigger machine it will come with Leadshine quite likely, and these should perform just fine. Mine are M542's.
The UC100 is quite popular and by all reports very reliable, but if you buy a bigger machine that has NCStudio as the control software, you wouldn't need any additional software or I'F cards of any sort. On a 6040 though, they would be sorta overkill I would think. A lot of money that could have been put to better use buying a better machine I reckon.
Shielded cables are good for the spindle/VFD, but not always necessary unless your really having interference issues, which if your using a 6040 you'll definitely be having plenty of those!
Mach3 is pretty much the industry standard for hobbyists, but if your somewhat comfortable with Linux then that's a nice free option. I must admit though that I'm really used to the NCstudio that came with my machine and find it just perfect for my needs, simplicity is always the best!
Any half decent machine will come with limit switches, if not you will need to fit them, as the machine ca do itself quite serious damage without them.
Earthing is a whole different kettle of fish, there's a really good long thread with input from from more knowledgeable people in these forums. Just do a search and you find it easy enough.
cheers, Ian
It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!