differences between NC code & G code

I don't know what's the differences between NC code and G code, I think they are the same, but some files metion that they are quiet different. so is the NC code generated in CAD/CAM? but what about the G code?

G-code is a colloquial name for Numeric Code. However, there are many different styles of G-code/NC. EMC2 happens to use its own variant (officially titled rs274ngc) based upon the NIST standard. I might be screwing up the names and timeline here, but I believe the NIST standard was developed from rs274d, which originated in the 1980's. There are varying degrees of interoperability between styles, and most "professional" CAM programs have post-processors to convert between styles. The simplest styles of G-code programming is nothing more than a list of movement and coordinate commands. rs274ngc on the other hand, is structured like a high-level programming language and includes arithmetic functions, variables, conditions, loops, and sub-routines.

The online g-code reference manual for EMC is a great source for learning about G-code BTW. One of the best available.

Hope that helps a little.

thanks a lot, Rturner. This makes the concepts more clear to me.~ And one more question, does EMC2.3.3 is able to work with B-splines? For example, how can I display a curve in the preview plot??

Hi Vincent,
I have to claim ignorance on the subject of B-splines within EMC2. I *thought* that b-spline support is more-or-less still being tested in the development version, but I'm not certain since I use an older version and don't really work with splines anyways. I think there's a conversation about this very things somewhere else on the forums though.. Possibly one of the moderators would have an answer too. good luck!

vincent wrote:

thanks a lot, Rturner. This makes the concepts more clear to me.~ And one more question, does EMC2.3.3 is able to work with B-splines? For example, how can I display a curve in the preview plot??

I don't know what a B-spline is but if your asking about Nurbs only the development version 2.4 has that and it is AFAIK not tested.

John

Just so that we're on the same page: NURBS is a sub-set of B-splines.. With regards to CAD the two terms are often used inter-changeably... And yes, I did have to double-check this on wikipedia