Two foot delicious!

[praetor]

Can I make a heavy duty compact cnc machine, more or less a small gantry, only 2' sq. that would be able to machine SS, Mild steel and all the soft metals? What kind of metal(s) do I use to make it out of? After researching this site, I understand that making one out of aluminum would probably be considered light weight, what if I beef up the aluminum material used to make the frame such as 3/4 to an inch thick, would that help?

I am going to be using this prospective machine to make logos, signs and lapel buttons 2"-3" in dia. and company logo coins, this venture would fund future backburner projects.

[little bubba]

Are you looking at 2'X2' travels or total machine size? If thats the size of the machine what kind of travels are you looking for? If your looking for small travel, maybe 8X8" you could probably make a fairly stout little machine. For a little perspective, a machine we have at work 16X22X18 travels sits 7 feet by 7 feet and weighs 8600lbs. For me, thats just about right, especially since I didn't have to pay for.

[praetor]

Yeah, I wanted to achieve 2'x2' travels but then again, you pose a good question. Yeah, what about overall size? If the one you have at work is 7'x7' and weighs 8600lbs at less then 2'x2', then obviously this is not what I want, I want to be able to travel with it, compact enough to store in a Large van with no lifting problems...well atleast not 8600lbs, obviously. Yeah, I guess I'll go for overall size. I'm quite sure a relatively good machine that can do the things I want it to do at a much consederably less weight can be made. I'll research it some more. I'll post my findings and if it's all good, I'll post pics of the design and construction. Thanks.

[balsaman]

convert an existing milling machine...

Eric

[praetor]

What's the fun in that? The real satisfaction is in building a machine from the ground up/from scrap and tweak it sooo precise you split an atom, you may end up living in a post apocolyptic world, but you have a very precise machine.

[Hobbiest]

I think/hope you're joking at least a bit here. I thought you said "lapel buttons", not "nuclear reactor". Maybe I read that wrong though. You would have to limit the sizes of the signs that you could produce, and SS may be stretching it for a small machine. Keep in mind, that the larger mini mills, still weigh a lot. Take a look at the Harbor Freight website to get an idea. Sherline/Taig minimill conversion may be the best bet. It will still take plenty of time, and you aren't even building the whole thing. Thought about starting with a smaller project first to get your feet wet?

[ViperTX]

Well the gantry router I'm building is about 2' x 2' and I'm using linear rails mounted on 80/20's 2040 extrusion....the y-axis is using size 45 linear rails....most everything except the extrusion that supports the x-axis and connect the front and rear of the machine is 1 inch Aluminum jig-plate....and I'm only planning to machine wood and aluminum.

The z-axis has size 30 linear rails....the x-axis is using the low profile size 15 linear rails.

I certainly would not try to machine steel with this gantry router system.....machining steel on my Rong Fu 30 is always interesting....

[wizard]

Originally Posted by praetor Can I make a heavy duty compact cnc machine, more or less a small gantry,

Sure!

only 2' sq. that would be able to machine SS, Mild steel and all the soft metals?

Well that makes if a bit more difficult and depends on what you mena by machine. In any event you have limited yourself to moving table gantry type machines im my opinion.

What kind of metal(s) do I use to make it out of? After researching this site, I understand that making one out of aluminum would probably be considered light weight, what if I beef up the aluminum material used to make the frame such as 3/4 to an inch thick, would that help?

Elsewhere you mentioned potability. If you are serious about that the only way I could se success here would be with aluminum castings. I'd suggest looking into the Gingery concept of machine tool building.

Even with Aluminum it would be tricky getting the stiffness required and maintianing low weight. I'd expect at least a couple of hundred pounds of aluminum in a machine like you describe. You really don't want a bolted up machine if you want stiffness for metal machining. Thus think serously about casting the machine.

I am going to be using this prospective machine to make logos, signs and lapel buttons 2"-3" in dia. and company logo coins, this venture would fund future backburner projects.

Well you seem to have an idea of what you want to build and that explains the potatbility issue, the question I have is why such a big machine? You could easily get the results you want in a much cmaller machine and have success with metals machineing. I'd suggest a litle tought in how big your products are likely to be, double that size and allow for clamping / work holding. You should still end up with a machine smaller than 2' x 2' and if done out of aluminum very light weight.

The bigger issue I see in a compact portable machine is the spindle especially considering the wide range of materials you are considering machining. You will need the higher speed spindles normally associated with routing and a lower speed spindle to machine Stainless Steel. Stainless Steel is a whole different ball game and I'd have to suggest that to keep the machine portable you would need two intechangeable spindles.

I've actually flirted with a very similar idea for making signs. Of course that limits the machine to higher speed spindles for routing. Also since stiffness is not an issue it would be for metal machining you can produce a lighter machine. I do not see much of a problem with producing a machine that has a gantry with 6" of Y travel and virtually unlimited X travel. You can also go moving gantry here and not have the stiffness issues you would with the machining of Stainless or any metal for that matter.

Thanks
dave