What is a CNC router? Why use it over other tools?

CNC, or Computer Numerically Controlled, is a process by which a machine tool may use files developed on a computer with a proper program to produce things. There are good and not-so-good things about using a CNC router. I will assume that your product is wood and in a single-plane like a flat board rather than multiplane such as a statue since with this is what I have the most experience:

1) If you have any inside corners they can be tricky. Routers use round bits so inside corners will not be sharp unless you use some very tricky manipulations;

2) If the cuts are very fine then you will have to use small tools. You can only make a small shaping tool “so small” and “so long” before it doesn’t do the job… if you have a 3mm slot through a 30mm item the chances for success are, um, limited;

3) With flat cut items it is usually MUCH faster to use an appropriate saw and do it by hand rather than attempt to program it on a CNC. I once developed an item where each part had to fit every other part interchangeably and developed the file. No good. I then made a very accurate template from acrylic sheet, sawed the material to a very accurate nominal size, took a pencil and traced the template. We made more than 250,000 pieces that way and every one fit every other one… and every one was hand cut.

4) If high precision is necessary THIS is where CNC shines. You can get that hole drilled or that slot milled or that shape cut perfectly… well… within 0.01mm and it will never vary from piece to piece unless there is a problem somewhere else;

There ARE CNC saws that make very short work of optimizing sheet goods and there ARE CNC routersthat can reproduce set patterns in a hurry, but unless you will be producing large quantities of something and it has to look/feel/fit the same way every time then in my opinion CNC is pretty much a curiosity.

I know there are some crackerjack CNC programmers out there that have unfailing knowledge on how to get a router to do what it wants with a minimum of grief but in my experience it is significantly faster to do MOST things with mechanical means.