Thinking of buying a CNC router...

[heathyoung]

After seeing all of the nice goodies people knock up on their CNC routers, I've decided that its time to buy another new toy

I'm looking at a Tonsen 3020T (a chinese 3 axis 300 X 200 working area, with a stepper controller and inbuilt spindle speed control)

(http://www.cnczone.com/forums/benchtop_machines/84512-tonsen_-_ebay_readytorun_mill.html)

I have done some research - the spindle is 3mm, 200W brushed (yeah yuk) that works OK for small stuff, but a lot of people upgrade to an 800W watercooled with a VFD later on - from what I can tell, this is a $300 upgrade (but comes with no mounts, so you need to make your own with - um a CNC

There are known problems with wires breaking to the steppers, and no home switches (and the spindle is manually turned on and off) but these are fixable - for the money ($900 delivered) I couldn't build my own for that much.

Now - a couple of questions for the CNC guys...

I'm probably looking to be doing 6061 aluminium, and probably be using a 4 flute carbide 3mm end mill - I don't expect to be able to bore through it in nothing flat, but I have no idea of the feedrate and depth to expect from a 200W spindle.

I'm looking at a software package called CAMBAM - it has its own CAD editor (so can create the DXF's and GCODE), and MACH3 for the machine control. Is this an acceptable way to do this - I'd prefer not to purchase 3 pieces of software rather than 2.

When I upgrade to an 800W spindle, will this have sufficient power for mild steel (again with a 3mm end mill, I don't expect miracles)

And finally is 300 X 200 a useful size - or do you find larger is better (there is a 300X400 available, but more expensive obviously).

 

[iamsofunny]

200w will take a long time to cut
you can use chainsaw wax on the endmill otherwise little bits of aluminum get stuck on the edges
steel is pretty slow and it messes up the bits without coolant but you can cut it with super light passes

 

[heathyoung]

Thanks for that - yeah, aluminium is a bit of a bitch with sticking to everything - usually use kero, but chainsaw wax - interesting - doesn't smell near as bad or make a horrible mess either.

The 800W spindle with VFD is definitly on the cards, even though it needs watercooling - fan cooling 800W could be noisy... I may just have a use for that transmission cooler I bought many years ago and never used.

 

[Jeremy Harris]

I run my small Taig milling machine with an outrunner RC motor driving the spindle (I use an old Turnigy 6374, 170 Kv). Works great, and I only have about 500W maximum available, as that's the power supply limit. I've machined everything from plastics through to stainless with it, it even drives a 1 1/2" fly cutter OK, and I've milled steel with 10 to 12mm cutters OK, although I need to take small cuts.

I fitted some external Hall sensors to the motor and a 6 FET Xiechang controller to give me a fully variable speed spindle. I belt drive the spindle, with a couple of off-the-shelf 5mm HTD pulleys and a 15mm wide HTD belt. You can buy just the Taig headstock from Taig as a spare part, with an ER16 collet chuck and the Taig motor mount, fairly cheaply and it would easily mount to a small router. Fitting an RC outrunner is easy, all I had to do was drill four new mounting holes in the little Taig motor mount plate.

 

[Kin]

Be sure to look into the rpm and feedrate for whichever steel you use, and do light passes. I have no idea if your lower power works in your favor or against, but I know that Alu you have a lot more fudge room [it cut like butter] and with O1 steel for my torque arm we broke two carbides because for the first the passes were too deep and then for the second the feedrate was off a bit. :O.

 

[heathyoung]

I've had a look at the headstock - looks pretty decent, but I think its going to be a bit of work to adapt it to the tonsen unfortunatly - I do like the idea of using the turnigy outrunner as a spindle motor

I found some photos here of a supplier who has it with an ER16 collet.

http://www.a2zcorp.us/store/ProductDetailNP.asp?Cguid={6300AAFA-1FAC-4B84-8FD9-185EDBADB805}&ProductID=1561&Category=Taig:Accessory Mill

I could cut off the bottom slide rails and make an adaptor for it, and run the outrunner next to it with a belt drive. Do you have any photos of your setup? Sounds interesting.

Though a VFD and 800W/1.5Kw spindle is available for these pretty cheaply. Decisons, decisions.

More reading here : http://www.cnczone.com/forums/chinese_machines/157193-experience_carving-cnc_com_6040_router.html

Here is someone who modifies the standard stepper driver design to something far better, with component swaps and redesign - interesting. Apparently the stepper cables are also crap, and need replacing with shielded cable (not a major issue).

Other people suggest throwing the stock drivers and running something better. Why do I research these things?

 

[Jeremy Harris]

I've had a look at the headstock - looks pretty decent, but I think its going to be a bit of work to adapt it to the tonsen unfortunatly - I do like the idea of using the turnigy outrunner as a spindle motor

I found some photos here of a supplier who has it with an ER16 collet.

http://www.a2zcorp.us/store/ProductDetailNP.asp?Cguid={6300AAFA-1FAC-4B84-8FD9-185EDBADB805}&ProductID=1561&Category=Taig:Accessory Mill

I could cut off the bottom slide rails and make an adaptor for it, and run the outrunner next to it with a belt drive. Do you have any photos of your setup? Sounds interesting.

Though a VFD and 800W/1.5Kw spindle is available for these pretty cheaply. Decisons, decisions.

More reading here : http://www.cnczone.com/forums/chinese_machines/157193-experience_carving-cnc_com_6040_router.html

Here is someone who modifies the standard stepper driver design to something far better, with component swaps and redesign - interesting. Apparently the stepper cables are also crap, and need replacing with shielded cable (not a major issue).

Other people suggest throwing the stock drivers and running something better. Why do I research these things?

Here's a photo of the outrunner fitted to my Taig headstock:



The blue plate is a the standard Taig motor mount, all I had to do was drill four new holes to suit the motor. The existing Taig belt tensioning system works fine. The only other mod was boring the big alloy pulley to suit the size of the Taig spindle.

 

[nechaus]

Can you get a small unit to carve up a big block of aluminium in a few hours?
like say you wanna make tools that are a solid piece... or something like that..

I dont know much about this stuff, i just got a plastic printer that i can use to make pretty much anything i want out of plastic which is pretty damm handy.

 

[heathyoung]

Yep thats the idea, the cheapies need some work, and the 200W spindles are underpowered, but for big stuff you need time and power - 50mm thick, 200X300 maximum workpiece.

My plans have been put on hold due to an accident that resulted in me being down an arm for about 3 months - sigh.

 

[bobc]

Just made a damn big "zoltar" CNC router. It's quite a big machine, cutting area probably 1500 x 500 x 75mm & so far it has just simply worked. It cost me and a colleague about £1500 altogether. We're using a kress 800W spindle & it's not too noisy - a USB CNC control board & 4.1Nm steppers on 10mm pitch ballscrews X & Y (so it will traverse at 2500mm/m). To date it's been used to cut styrofoam body parts for our new greenpower car; my excuse for making it is to make the 3D curved parts of the landspeed record car - anyway heres a couple of piccies. The machine is impressively substantial BTW..

 

[nechaus]

sound interesting
your machine is close to the size i want, that's totally awesome !!

 

[Arlo1]

Very cool stuff guys.!

 

[Ypedal]

Subbed.. i so badly have to make time and read about this topic....... it's the next logical step ! 8)