Making decisions about my first CNC

[JAZZCNC]

You have conflicting goals for your limited budget.?

Woods plastics etc are no problem as accurecy isn't critical but PCB works requires accuracy and this means building to higher standard which means higher quality components and these cost money.

Also like John points out the motors you have probably won't help you anyway if your going the threaded rod, skate board bearing and MDF route as efficiency is very very low so friction high.

Cutting aluminium on limited budget is doomed from the start so I'd forget that instantly.!

In a nut shell what you get from CNC is directly proportional to what goes into it and if your limited on budget with limited tools then expect limited results and accurecy.

Whats your budget.?

[Neale]

I have built and use an MDF router, although with a larger cutting area (around 900x400). I use skate bearings on 2" steel tube for X and 1.5" tube for Y. I would try to avoid using the skate bearing approach as they are a fiddle to build and set up, and probably a bit big and clumsy for this size machine anyway. Supported rail and linear bearings would be much easier to install and set up. I've seen working routers using this approach and although it is not as good as profiled rails, it's probably a good engineering compromise for this purpose. I would go up a couple of sizes from your "8mm" comment above, though - my 3D printer uses these and they are only just enough for a machine that hardly generates any cutting forces!

[Neale]

I would say that you have the skills to build a decent machine. You have the big advantage of having an electronics background. On the whole, it's easier to pick up "mechanical" skills as you go than to pick up electronics skills although you may be a skilled machinist/welder. Trying to explain to someone the how and why of, say, an NPN open-collector output or ground loops is harder than how to level rails with epoxy or even basic welding! Just go for it - there's plenty of advice available on this forum.

[Boyan Silyavski]

Here and there you could do cheap. But if i were you, Nema 23 motors and profile rails like hiwin, new or used from ebay, these 2 are a must.
On such a small machine you actually need 4 rails, 2 left right, gantry, Z. Yeah, the Z will work ok with even 1 proper rail. With spindle 0.8kw i mean, no bigger.
Moving table and fixed gantry will even give further possibility to your build.

You could perfectly make the machine using belts without problem, though the 3 ball screws for that machine will be like 150. So not so much.

Having a drill is a must.

So if you are clever you could build a beauty on a budget. Spend more time designing and considering and less money wasted.

Don be shy from steel, cause thats the cheapest way to go. You will spend how much , 50-70 for the steel.

Better dont be in a rush, buy when you can and build slowly something that can make you money.

Or if you want your hair to be white soon, do a crappy machine that will make you swear every time you look at it.