Use of STEP-NC with LinuxCNC

Dear Members.

Greetings. First post ever on LinuxCNC forum! I am relatively new to machining, so kindly condone my lack of knowledge in the area.

I would like to implement STEP-NC format on LinuxCNC. I have found a toolkit online (code.google.com/p/iso-14649-toolkit/ ) which allows me to convert STEP-NC to canonical machining commands (CMCs) directly. Is it possible for me to use these commands to drive a CNC machine? From what I have understood so far LinuxCNC needs G-code as an input to drive the CNC machines .

Thanks a lot!

I would like to implement STEP-NC format on LinuxCNC.

Linuxcnc uses ISO 6983/RS274D G-codes, so without rewriting the entire parser / interpreter you cannot.

If you have a lot of STEP-NC code you wish to use, the best you could do would be to write a conversion program that turns the ISO 10303 STEP code back to RS274, but thereby losing all the advantages of the former.

I have found a toolkit online (code.google.com/p/iso-14649-toolkit/ ) which allows me to convert STEP-NC to canonical machining commands (CMCs) directly.
Is it possible for me to use these commands to drive a CNC machine?

Undoubtedly, but you will be writing your own controller, not using Linuxcnc.

It is an interesting toolkit which I must look at properly, but what it is giving you

2. A parser for STEP Part 21 files.
3. A simple stand-alone parser/printer.
4. An ISO 14649 interpreter for 3-axis machining.

are C++ classes to build a controller, not anything that will assist you use Linuxcnc, unless you use them as the basis for a complete rewrite (and it certainly needs it).
The project is archived and has not been added to for 6 years, so unsure of the usability of it.

I don't know if there are any open source STEP software controllers out there, suspect not.
The industrial implementations are Siemens, Fanuc etc.

The big question is "do you need STEP-NC to make whatever you intend making"?
Probably not.
It may be the current top of the range machining standard, but unlikely to hit mainstream amateur milling and lathe work any time soon

regards

what is your reason to use step nc ? , is it to interface from a cad system ? if so which specific one .

Hi all

Thanks for replying. It is for a masters project. There is a budget of around $10000 for the same. We were thinking of development of a Linux based CNC machine which would use STEP-NC as an input.

what is your reason to use step nc ? , is it to interface from a cad system ? if so which specific one .

We would like to move away from G-Code, as it doesn't give a lot of flexibility in terms of feed rate optimization or storing shop-floor level changes during the manufacturing process. STEP-NC seems to an interesting format, in that it allows the use of a single file across the CAD-CAM-CNC chain. The primary advantage being the ability to use multiple CAM software on the same part and capturing different ideas on toolpaths for development of a specific feature. At the shop floor the appropriate strategies could be selected to make the best part possible, resulting in reduced planing time and costs.

The big question is "do you need STEP-NC to make whatever you intend making"?

As written above, it is for a project. The idea for the project over the next 2 - 3 years is to develop an OS where people could write apps for interacting with CNC machines.

ArcEye: You noted correctly that the toolkit gives C++ classes to build a controller. Could you expand on what that means? My knowledge is woefully inadequate right now on the topic.

ArcEye: You noted correctly that the toolkit gives C++ classes to build a controller. Could you expand on what that means? My knowledge is woefully inadequate right now on the topic.

It just means the classes should provide a means to build a simple STEP-NC controller.

That would be a replacement for Linuxcnc, rather than an augmentation to it.

At the very least it should be useful to study the parsing and interpreting side, to see how code is converted into machine movement instructions.

It would be a useful exercise to build modules 2 and 3 and get a print from a STEP-NC input, to demonstrate the output.
Would be similar in some ways to the lex / yacc bits of compiler parsing

regards

There is a stand alone interpreter interface in linuxcnc - not sure if it still works or not.
It work take basic machine movement commands.
maybe you could feed it NC-step converted commands.
I'm looking for a reference...

I have just built the modules from the toolkit on Jessie with g++-4.9

The iso14649parser.cc file requires an additional include of

#include <string.h> to get it to build.

I assume the header files for strcmp etc. have changed at some point over the years since it was written.

A lot of it is essentially as I said, lex and yaccs like parsing of STEP code, which allows for writing out in a format more useful for machine control.

andypugh wrote:

That isn't quite true. He would be writing a new interpreter for LinuxCNC. The motion controller from LinuxCNC, HAL and the GUIs could all remain unchanged.

Well yes.
However I don't get the feeling that your masters will be in software design from previous questions and was heading off the "How do I do that".

You will still be writing your own controller, just re-using relevant bits of Linuxcnc and getting them to mesh.

How successful you will be merging proper C++ code with the code Andy once characterised as Fortran++ is another matter
Depends upon the modularity of each stage.

Good Luck with it.