[4NG3L]

Hello
So I want to start with small volume manufacturing (custom car parts, drone frames, tactical accessories etc), and I'm looking for the optimal CNC to get started. I'm not looking for any big brands as they always cost more than people usually can afford on entry. I sometimes see how people make $500k a year on a CNC but they always mention they borrowed money to buy a $5k CNC to get started. I won't be doing that.
I'm a DIY guy and I love learning stuff, so upgradeability would be a big plus when choosing. I work as a 3d artist so I won't be relaying on this CNC for my income any time soon, but I want to be able to upgrade it and eventually turn it into a business.
I'm looking for a CNC that can machine aluminum with the best precision. My budget is currently under $2k but this tells you nothing since you don't know the buying options in my region.

I'll post few examples in the following posts, please give me your opinion which one would be better.
You can ask any questions regarding them and I'll find the specs (or ask their manufacturer).

[4NG3L]

Variant 1 (4060, Z range 100mm)
Spindle Kraissmann 910W
Rails: SBR20
Motors: NEMA 23
Y-axis - single central motor

[4NG3L]

Variant 2 (4060, Z range 170mm)
Spindle: 800W
Rails: SBR20
Motors: NEMA23
Y-axis - 2 motors, next to each rail.

[4NG3L]

It seems to me it's a good idea to have 2 Y-axis motors so it moves evenly when the spindle is in the end positions on the X-axis.
However I'm not sure about the locations of those Y motors, is it good/bad they're this high, or I'm overthinking it and it doesn't matter?

I will be able to buy a better table, so I actually wonder which of these two would you consider a better initial design, not by motor parameters but by the geometry/location of its parts and therefore later upgradeability.

[difalkner]

Hello
I'm looking for a CNC that can machine aluminum with the best precision. My budget is currently under $2k

Not sure that's going to happen. To get precision machining aluminum you probably need to add a zero to that $2k.

[BubbasDaddy]

2K will get you nothing that can hold a tolerance

[peteeng]

Hi - I think the $500k USD per year by spending $5k is a furfy. If it was true then spend the $5k !!. Don't expect to spend the $2k and earn $200k either. Making the parts is easy getting the business is tough. Anyways the machines you have shown are good learner machines. Try to get a square rail machine vs a round rail machine. Variant 1 looks a bit stiffer then 2. Peter

[pippin88]

Agreed

$2000 will not get a machine you can use for aluminium with good tolerances, or any decent machining speed

Anyone claiming to make 500k a year with a machine that cost 5k is BS. Let me guess, you need to follow the link and watch the video...

[joeavaerage]

Hi,
machining metals, even soft metals like aluminum requires a VERY rigid machine, especially if you want to hold tight tolerances and good finish.

May I suggest you look at one of the many drill-mills out there. This is an example:

https://rongfu.com/mill-drill-machin...-machine-rf45/

Note that this has a rectangular column, and is preferred over a round column being somewhat more rigid. There are many companies making machines of this type, and they are pretty good value for
money, and very often come onto the second hand market, where you could make a very good buy.

This machine is not CNC, but you could convert it. There are threads on this forum about people who have done just that. Not cheap, or easy, but satisfying. Note also that this is not a big machine,
you would not expect to make big parts. The machine is quite rigid and does a good job is aluminum, and with care and patience does a fair job in steel. Steel is very tough to machine and takes
a way more (x5) rigid machine than even aluminum.

A machine such as this would absorb you entire budget or more just to buy the basic machine.....without considering a CNC conversion. I have posted this so you can see just the sort of machine rigidity
that is required to mill aluminum with good accuracy and finish. Machines like this are adequate....not over the top, or even very good, just adequate!.

Craig

[4NG3L]

Not sure that's going to happen. To get precision machining aluminum you probably need to add a zero to that $2k.

I didn't say anything about precision machining, I'm talking about choosing the best precision of those two variants.

[4NG3L]

Hi,
machining metals, even soft metals like aluminum requires a VERY rigid machine, especially if you want to hold tight tolerances and good finish.

May I suggest you look at one of the many drill-mills out there. This is an example:

https://rongfu.com/mill-drill-machin...-machine-rf45/

Note that this has a rectangular column, and is preferred over a round column being somewhat more rigid. There are many companies making machines of this type, and they are pretty good value for
money, and very often come onto the second hand market, where you could make a very good buy.

This machine is not CNC, but you could convert it. There are threads on this forum about people who have done just that. Not cheap, or easy, but satisfying. Note also that this is not a big machine,
you would not expect to make big parts. The machine is quite rigid and does a good job is aluminum, and with care and patience does a fair job in steel. Steel is very tough to machine and takes
a way more (x5) rigid machine than even aluminum.

A machine such as this would absorb you entire budget or more just to buy the basic machine.....without considering a CNC conversion. I have posted this so you can see just the sort of machine rigidity
that is required to mill aluminum with good accuracy and finish. Machines like this are adequate....not over the top, or even very good, just adequate!.

Craig

I'm asking which one of the two I posted would be structurally better in terms of precision and upgradeability
, I know for a fact they're able to somehow machine aluminum as they have videos of it, I'm just not sure which one theoretically does it better.

- - - Updated - - -

Agreed

$2000 will not get a machine you can use for aluminium with good tolerances, or any decent machining speed

Anyone claiming to make 500k a year with a machine that cost 5k is BS. Let me guess, you need to follow the link and watch the video...

What video?

[joeavaerage]

Hi,
I think both of those variants have round rails, which might be OK for engraving and woodwork, but aluminum.....no.....I don't think either will do a good enough job that you'd be happy with.

Craig

[4NG3L]

"don't be poor" is the most useless advice there can be, please keep this in mind.

[joeavaerage]

Hi,
fine, just buy one and try it out. peteeng suggested the first one looked best, and that as good recommendation as any. Good luck.

Craig

[4NG3L]

Hi,
fine, just by one and try it out. peteeng suggested the first one looked best, and that as good recommendation as any. Good luck.

Craig

My post wasn't exactly directed to you, I didn't see your message when I was writing it.
What's up with round rails? Could you explain please?

[joeavaerage]

Hi,
round rails are very flexible leading to the lack of machine rigidity, and hence poor performance in metals.
Square rails and cars are very much better, but they cost that much more.

Craig

[4NG3L]

Hi,
round rails are very flexible leading to the lack of machine rigidity, and hence poor performance in metals.
Square rails and cars are very much better, but they cost that much more.

Craig

They both use fully supported SBR20 rail, they don't flex as the fully round ones do.

[joeavaerage]

Hi,
that is correct but the pedestal is just a piece of extruded aluminum, so they are better than unsupported, but not that much better.

Square rails are much better, maybe a factor of five or so.

You choose.

Craig

[4NG3L]

Hi,
that is correct but the pedestal is just a piece of extruded aluminum, so they are better than unsupported, but not that much better.

Square rails are much better, maybe a factor of five or so.

You choose.

Craig

Got it, I'll have to ask them if it's possible to change the rails.
Thanks!

[joeavaerage]

Hi,
good idea, all comes down to how much you want to spend. At every step up in terms of rigidity, precision and speed the cost keeps going up. Best you can do is get
what you think is the best machine for the money you've got. That does not change whether you've got $2000 or $20,000.

Craig