Newbie I am new to CNC machine and not a professional machinist, but still hoping to get one

I am new to CNC machine,
i would like to ask few simple questions before i make purchase.

I have no experience at all, but i studied some theory from internet resource.

1) What can 3axis and 4axis cnc machine does? Is there any significant example of parts which can be done in 4axis only and not in 3axis?

2) From what i understand is that i need to program the CADCAM program to route my cnc machine to work, which means that for some special and complex shape which is not easily done in 3axis can be done with complicated CNC programming? which i mean is that i can use hypothesis programming to make the part to be done even in 3axis, with 4-axis is easier to get things done, but with 3axis i can use hypothesis programming or even seperate operations to get complex shape done.

3) Is bevel gears, helical gears, and even worm gears able to be done using 3axis? or 4axis is required?

4) How about the bending of the parts? for some spare part like a L-joint connector, is it wise to use cnc machine? or any suggestion for automatic operation?


I am new to CNC machine and my background is not a mech engineer, however i stil hope to get one for designing small to medium scale robots.

Thank you so much =)


Regards,
Daniel.