Desktop CNC Machines

[Shakey]

I've been happily running my 3D printer for a couple of years now and it's been amazing for helping me do some more interesting designs however it's still has its limits. Limits fixed using desktop CNC!

I'm trying to find a low cost (Sub £400) Desktop CNC machine that I can use to cut out polycarbonate pieces. The cutting area doesn't need to be big at all, I only really see myself doing antweights and maybe the occasional parts for beetle weights on it. I expect thicknesses of up to 6mm Polycarbonate. I've considered laser cutters but they aren't really suitable for my needs and most are just too big.

I've been looking around and it seems a shapeoko is popular but it's above my price range, other options are a MillRight Mk3, one of the generic ones off ebay or to buy another printer and convert (though often these aren't quite right for it).

I don't mine one that needs a good bit of tinkering as I'm pretty used to that but wondered if people here had any suggestions.

[daveimi]

I've been really interested in stuff like this recently. My brother was on holiday in San Francisco, and said there is a huge maker community and maker faires and stuff. Everyone has 3d printers, a desktop cnc and a decent laptop and it's given rise to this massive cottage industry of people making gadgets. I'm mid 30's, but am starting to notice the generation of lads younger than me that are into the beetles and feathers (especially on the sparc forums) using cad to gets the bits they need and then sticking them together like a mechano set. Utterly awesome. Am a bit gutted sometimes that I was that little bit late at college and school to have missed it. Thinking of having a go with getting a 3d printer and some decent cad and learning it, almost as a life skill.

[katch]

I have a 3d printer to get rid off, cost over £800 a year ago, only been used about 5 times. IF you want too tinker its a great tool !

I'm crap at CAD so going to a manual Mill and Lathe its faster for me to make it than draw it on a pc.

[bigsi]

Why don't the two of you find local Maker-spaces? There you will likely have access to Machining, CNC & printing - but with people who will take you through the basics and give useful advice on what to, and not to buy if you decide to.
At the very least it gives you workshop space and a group of eager assistants!

Si

[Shakey]

I've got my heavily customised printer already, I don't need a maker space. I want the convenience of having the CNC machine myself and be able to access it anytime without leaving the house.

[Eventorizon]

Could you modify a PCB mill for your needs? We had one at uni that had been extended to accommodate A4 sized sheets for board prototyping. I believe it started as 100x150mm.

Edit: Looked a little like this - http://www.ebay.co.uk/itm/3Axis-DIY-...gAAOSw9eVXUA78

[Shakey]

Could you modify a PCB mill for your needs? We had one at uni that had been extended to accommodate A4 sized sheets for board prototyping. I believe it started as 100x150mm.

Edit: Looked a little like this - http://www.ebay.co.uk/itm/3Axis-DIY-...gAAOSw9eVXUA78

Certainly an option, my worry is though that after all the conversion I'd be left with a lacklustre machine for not much less than doing an electronics swap on one of the china mills. It's going to be pretty heavily used so I'm going down the buy right buy once line.

[bigsi]

I've got my heavily customised printer already, I don't need a maker space. I want the convenience of having the CNC machine myself and be able to access it anytime without leaving the house.

OK then, my advice would not be to buy any of the Chinese machines. By the time you've 'fixed' the problems with it, you'll likely wish you hadn't

Look for an old Emco or Denford desktop CNC. They come up fairly often on eBay. They are perfectly usable on the whole - but the control side of them is very dated. However, converting them to run Mach3 is easy (easier than building a robot!) and it will transform it into a state of the art (almost) CNC machine.

I have A Denford EasyTurn CNC Lathe and a Bridgeport Interract 1 Mk2 4 Axis mill - both converted to Mach 3. It also makes them very easy to adapt / extend yourself - for example if you wanted to make an automated toolchanger or a bar-feed. The mechanics are the easy bit on most machines, its the integration with the NC controller that's virtually impossible. With Mach 3 however - it's easy!

I also have a home built CNC Plasma running Mach3 - which has been worth it's weight in gold!
This is my write up: http://www.instructables.com/id/CNC-Plasma-Table/
It gives a little insight into Mach3 too.

Si

[bigsi]

http://www.ebay.co.uk/itm/Denford-No...AAAOSwHoFXrwLU

http://www.ebay.co.uk/itm/Denford-Or...cAAOSw65FXtgcQ

Don't worry about it being 'spares or repair' you are going to replace all the bits that generally need repairing!

Both are good quality, precise machines.

[Shakey]

I quite enjoyed your plasma cutter CNC table writeup, I had some plans for my won hand plasma cutter and it gave me some ideas.

The denford looks nice but there were 2 reasons I was considering hacking a china CNC mill. For what I need they're actually fairly solidly built (As long as you're not aiming at the cheapest on the list) what typically lets them down is the electronics and that leads into my thoughts. My plan is to throw away the parallel port controller and convert it to more modernised controllers, there are a ton to choose from that will run them and allow it to be run from USB like my printer. This appeals as it keeps the flow of operating the machines similar and gives me the tinkering I'm used to having on the printer with familiar electronics. The other point is that I simply don't have the room for more fully fledged solutions!

[bigsi]

There's nothing wrong with a Parallel port controller. My lathe uses a Parallel port. The mill uses both the Parallel port and a Smoothstepper Ethernet controller and the Plasma is USB.

Be careful with the USB controllers - I had endless problems with a cheap one from eBay and eventually bought a UC100 which is spot on. It turned out the eBay one was supplied with a hacked version of Mach3 - and wouldn't work with a 'proper' one. Unfortunately, the 'hacking' rendered bits of it useless, made the behavior unpredictable and the PC crash a lot! You may be more lucky - but for me it was a waste of money!

[Shakey]

By USB control I mean along the lines of the CNC shield for an arduino based system. I don't actually have a parallel port to use and no space for another PCI card! Essentially I'm trying to keep my setup as neat as I can with the two machines being operated on in the same way. Plus this way I get open software such as GRBL so no running the risk of dodgy Mach 3 (which from a lot of the forums seems to be quite prevalent).

[bigsi]

I really like GRBL! I've used it with the Synthetos Shield on a commercial project. The NC Controller needed to be embedded - and it worked perfectly!

Si

[Shakey]

One GRBL converted Desktop CNC machine!