one thing to bear in mind - metal printing is still extremely expensive.
getting a metal part made would most likely cost more than the machine is worth.
a decent engineering firm would most likely make a part cheaper, through conventional methods.

You might be able to replace some of the metal parts with plastic printed parts. If they're just structural, that could work quite well.

I don't think of openscad as programming, more telling the computer what shapes to put where. What shapes to take away from other shapes, etc.
If you can visualise what you want to make and break it down into basic shapes, then openscad makes it really easy to produce models.