cheap cnc machine

[sizulku]

Gents,

I'm looking for a small cnc machine for hobby or personal use. I found a cheap chiness cnc milling as follow:

http://www.aliexpress.com/item/High-spe ... 70369.html

My question is will this machine capable to make 60* cones (or flutted cones) from 316SS / 17-4SS / titanium ? Thank you

sizulku

[Rich V]

"total weight: 72kg"

Not going to do what you want it to do. Probably OK for engraving or Aluminum milling.

[sizulku]

"total weight: 72kg"

Not going to do what you want it to do. Probably OK for engraving or Aluminum milling.

Hi Rich V. Thank you for your feedback. I'm not from machinist background so can you please more details why it can't do it? This machine rotate speed is 0-24000 rpm/min, from what I read on table speed & feed http://robbjack.com/technical/speed-and-feed, it should be no problem to cut SS or titanium.

[Rich V]

Simple physics, you need rigidity to prevent tool chatter. The forces exerted on the tool to cut SS, Titanium etc. are high and need a corresponding resistance to movement under that force. The only way that is accomplished is using lots of iron and good geometry in the design. 72kg total weight can not produce the rigidity this CNC mill will need.

Yes you could take very light cuts at high speed using carbide tooling but it will be very slow and eat a lot of carbide tools.

[sizulku]

Simple physics, you need rigidity to prevent tool chatter. The forces exerted on the tool to cut SS, Titanium etc. are high and need a corresponding resistance to movement under that force. The only way that is accomplished is using lots of iron and good geometry in the design. 72kg total weight can not produce the rigidity this CNC mill will need.

Yes you could take very light cuts at high speed using carbide tooling but it will be very slow and eat a lot of carbide tools.

How about if I bolt on this machine onto concrete or bench table? will it help ?

[silencertalk]

Go to practical machinist website and find something people recommend.

[sillycon]

You could "get away" with something like an X2 mini-mill converted to CNC, but even that is going to be pushing it.

Realistically, for what you're looking to do (making baffles), you'd be better off with an older manual bench lathe like a Logan or South Bend. If you've got the space for something like a Clausing or what not, then get it. It's always better to have "more" machine (bigger/heavier) than less.

If you want to be able to make baffles like that on a CNC mill in a realistic time frame, you're going to need an auto-tool-changer and a big heavy mill (on the order of at least a Bridgeport Series 1).

Beyond that, with CNC there is a huge investment in learning the modeling and tool-path software -- you don't just unbox the machine and hit "go".

[punkinhead]

How about if I bolt on this machine onto concrete or bench table? will it help ?

If you bolt a noodle to the floor it's still a noodle.

For the cost of that machine you can get a very serviceable lathe.

[Fulmen]

I agree with the other posters, this is a router not a mill. It simply won't have the rigidity to machine metals, nor is it intended for such.

[urban assault]

How about if I bolt on this machine onto concrete or bench table? will it help ?

If you bolt a noodle to the floor it's still a noodle.

You made me laugh, appreciate it.

-urban

[ghostdog662]

You arent going to cnc baffles for $2,500. You'll barely be able to buy american iron and tooling to be able to do it manually for that price.

Any tool you introduce to metal on that machine will deflect.

In other words, spend your money on quality tooling ONCE.

We are talking firearms here, save your face and everyone around them.

[gunny50]

I'm not saying that its the best solution BUT one can do much more on these (small) machines than most do think, you just need one with the right spindles and motor.

There are small machines that can do the job, it will take some time to machine them, and the right tools / bits but it will take long and a lot of tool paths.
There are also some with tool changers, automated hight sensors etc etc. 3D milling software options etc etc

check video below.
https://www.youtube.com/watch?v=JoI-nnipoxo
This machine is made by CNC STEP but there are more company's out there that might have the right machine just like this.

One can search for used large CNC machines but if one does not use it a lot, a router / CNC mill can come in handy for many jobs, including engraving parts, making spare parts, moulds etc etc.


Found this also.
https://www.youtube.com/watch?v=Z-_z0n1nRdk STEEL PARTS
https://www.youtube.com/watch?v=CLXTp1fqhQo RIFLE STOCK

Gunny

[pamrick]

As you can tell from my post count I'm new here, but not new to machining and firearms by any means. So I feel compelled to add my free advice, which is probably worth less than the cost, but...

First, the OP has no machining background. Kudos for asking for advice and input before you commit to a purchase. The advice you've received is very sound. Tiny machines are for tiny jobs and soft materials. I watched the videos of the router cutting steel and yes it can be done, but at what cost in tooling and time?

Long story, but about 35 years ago I purchased a Sherline mini mill for use in my gun shop. It was very limited but worked well for what I wanted. Flash forward... about two Years ago I decided to convert it to cnc. I shopped and talked and asked questions. I finally settled on an ebay seller who was most helpful. I did a full 3 axis conversion for around $300. It works great but you have to know the limits. You're much better off starting with a manual machine and learning the basics of machine work.

The other issue is programming. You will have to program each and every move the machine makes. G code is not complicated but you do need a basic understanding of it in order to avoid costly mistakes and/or bodily injury.

A bench top manual mill would be my first choice. You can do a lot with one and probably just as fast as the small cnc router your looking at. And for the cost you can tool up really well on your manual machine.