[szymonm2]

I'll try to keep this as simple

Im looking to build a cnc machine similar to the size and power of the "Stupid Strong CNC" machine on youtube.
I have a budget of 700$ excluding the price of stepper motors and electronics.
I live in a country where importing anything from anywhere is very expensive (shipping, import taxes etc).

Materials I want Machine:
Aluminium (replacement parts for my 3D Printer)
PCB's
Plastic.

I can get trapezoidal screws and round stainless steel rods (not supported) locally. This would save me alot of money from importing "expensive" stuff from china.

My Questions:
1) Anyone have plans of a machine of that caliber I described?
2) Is it worth paying the extra cost for the linear rails/ supported rods and ball screws from china.

PS: Hiwin and such brands are out of my range. One such ballscrew would cost 1/2 of my whole budget.

[wizard]

I'll try to keep this as simple

Im looking to build a cnc machine similar to the size and power of the "Stupid Strong CNC" machine on youtube.
I have a budget of 700$ excluding the price of stepper motors and electronics.

That is a very tight budget if you want to build a machine for aluminum machining (in a meaningful manner).

I live in a country where importing anything from anywhere is very expensive (shipping, import taxes etc).

You dind't mention the country but that may or may not be a big deal. Generally if you look hard enough you can find a machine shop in just about any country. The same thing goes for building materials, steel and aluminum can often be found at junk yards. If materials are really hard to find you can smelt and cast your own aluminum frames and components. You end up with a much longer development cycle but you can achieve just about any tool with enough effort put into casting. You might be surprised to find a foundry locally too.

In any event casting is only really justified if you can't find the material locally or can't import them at a reasonable cost.

Materials I want Machine:
Aluminium (replacement parts for my 3D Printer)
PCB's
Plastic.

I can get trapezoidal screws and round stainless steel rods (not supported) locally. This would save me alot of money from importing "expensive" stuff from china.

Unsupported rail isn't good enough for your desire to do aluminum in my opinion.

My Questions:
1) Anyone have plans of a machine of that caliber I described?

The "Stupid Strong CNC" really doesn't look that bad for a table top machine! You didn't mention the machine size but you might want to investigate moving table designs. It is generally easier to get a stiff nicely performing machine, with minimal materials and equipment, via a moving table design. For a small machine I try to make sure that people at least consider the option. I'm also of the belief that it is easier to align such machines and more so they will keep themselves in alignment.

2) Is it worth paying the extra cost for the linear rails/ supported rods and ball screws from china.

In general yes but the guiding factor is your expectations. Perfectly good machines have been built with rack and pinion drive, acme screws, even belt drives and all thread have been used. It really depends upon what the builder expected the machine to do. If you have a massive budget you can get rid of screws altogether and use linear motors. Most of us go with the far cheaper solutions. Ball screws h9owever have pretty good value for the buck invested and are likely a good choice for a desktop machine.

PS: Hiwin and such brands are out of my range. One such ballscrew would cost 1/2 of my whole budget.

There in lies the problem we all have. Generally your best bet is to design with a future in mind where you do have a budget for ball screws. You then upgrade the critical axis as you can and when you see a need. Doing the general mechanics right at the beginning keeps you from having to throw out the whole machine when you do upgrade. To that end be careful about what design you do choose and more so be flexible enough that you can adapt to the materials you can find locally.