Re: [CAD_CAM_EDM_DRO] Re: How to Program a CAD / G-code/Machine commands freesource code?

Peter:

>>Is everybody here trying to sell software or hardware

I think youve misunderstood. Most of us in software never try to sell anything here, I certainly never do.
My comments were not meant to discourage this persons investigations, quite the contrary. While pointing
out the difficulty, I also pointed to the information he should use to make it possible. This group is exactly where I started,
and got much of the information to do what I do in Mach3. I thought it only fair to point out the difficulty involved.

The questions were a bit too general to get answered in any detail, the best thrust was for him to read others
code to see how things such as Gcode to machine specific instructions are generated. I certainy wasnt trying to
get him to feel overwhelmed, but it may interest you to know that I was told here that what I was seeking to do way back
when was impossible. Period. I hate to be told that though, so it was a major incentive for me. If I left the wrong
impression, I appologise, but from the perspective of an author, ( and I think I speak for most of us that have written such software )we commonly see emails from people that think its not a hard process, and theyd like to do it. We look on those
with an understanding of exactly what a person is up against. Heck, if I were a high dive artist and a layman said " I think Ill try a dive" , it'd only be fair to warn of the impact one gets when you hit the water.

Thats not to say you shouldnt dive, but its an act of charity to warn of the impact... As you say, the knowledge is invaluable,
and I help a great many people each year with information about how specific things are done. The quality of the question
inspires the warning of the difficulty. If you were to tell me you want to write an operating system, and asked what a disk drive is,
youd get the same sort of warning. Now if you wanted to write an OS, and asked, "How would a kernal switch to ring zero most efficiently, then likely you'd just get the answer to the question.

Anyway, all OT, just thought Id point out were were'nt trying to discourage, believe me, so such protective instict exists.. this is
an industry that welcomes all comers. We answer more questions in that vein in a month, than most see in a year..


Thanks,
Art
www.artofcnc.ca

Videos And Support Forums http://www.machsupport.com
Users Map: http://www.frappr.com/machsupport

----- Original Message -----
From: Peter Rosenholm
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Friday, August 24, 2007 12:35 AM
Subject: Re: [CAD_CAM_EDM_DRO] Re: How to Program a CAD / G-code/Machine commands freesource code?


I thought the point was he wanted to understand the science and over come it, he listed his objectives, and they discribe what steps are involved accurately. If he does one it would be great. He can then decide to go on or stop. An understanding of the fundamentals is great, and we can help. If he feels he is overwhelmed he can give up. Is everybody here trying to sell software or hardware. I've noticed that some sights are completely sales orientated. That is like an infomercial, and that sucks for free thinkers.
Peter Rosenholm

art <fenerty@...> wrote:
>>If you want to spend the next year of your life writing a real-time
CAD to Machine controller (provided you are a good C level programmer)
then you will certainly have something to put on your resume.

A year? Wow, that woudl be quick. :-)

A realtime controller, at least under windows will take 3 years to write. I know, I did one. :) ,
its never ends really, 6 years now and still growing..

It took about 10,000 hours of programming, but to be fair, good operation will happen at
about the 4000 hour mark. Windows wouldnt be a good idea, unless you like to torture
yourself, real-time under windows is hard to say the least. To my knowledge only 4 programs
do it. and only 2 of those are cnc. ( Indexer and Mach3). Each uses a different method, each with
pluses and minuses, each requires alot of study of CPU interfacing within the windows kernal.
Its great to work in if you like the colour blue.. youll see alot of it..

But if you want good code, look to emc, its the best tutorial in the world on how to write a cnc
program, but will take you a few weeks to truly understand how it functions in all its various areas.
The EMC programmers are the most dedicated and selfless group you will find in the cnc world.
Reading their code, and understanding their workflow is the first , best step to understanding how
all cnc machines work. Read my manuals as well, they try to gently ease you into it, and are used all
over whether with or without mach3, simply as a starting users guide to cnc stuff.

If your intent is to send to something like a G100 or serial device, the job is much easier, and the EMC code,
being open source, is a true university of cnc programming. I think I have my doctorate in EMC, and it was
a fantastic learning experience..

Thanks,
Art
www.artofcnc.ca

Videos And Support Forums http://www.machsupport.com
Users Map: http://www.frappr.com/machsupport
----- Original Message -----
From: caudlet
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Thursday, August 23, 2007 11:50 AM
Subject: [CAD_CAM_EDM_DRO] Re: How to Program a CAD / G-code/Machine commands freesource code?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "elwolv" <elwolv@...> wrote:
>
> hello;
>
> thanks to Dan Hudgins for referencing this forum for my project.
> I building a micro CNC machine
> I want to write SW for simple CAD front /to G-code / to Machine commands
>

If your goal is 2.5D machining (Z is straight sided cuts) then the
easiest way is to process the CAD export (DXF or HPGL) into SheetCAM.
and take the resulting g-code into MACH3 for movement.

If you want full 3D and have a 3D drawing package, then you need to
look at MeshCAM. Once again it outputs g-code that will run in MACH3

If you want to spend the next year of your life writing a real-time
CAD to Machine controller (provided you are a good C level programmer)
then you will certainly have something to put on your resume.

If approx $300.00 USD is too much, then for motion control you can
take a look at EMC (free but runs on Linux) or TurboCNC (runs in DOS)

You will still need a CAD to G-code piece (called CAM). The problem
with just writing an output is that you need to give toolpath
definitions (how you want the cutting to happen on a specific machine)
and that needs human input. Typically the drawing (2D or 3D) is
brought into a CAM program (GUI interface) and the human selects the
tools, feedrates, number of passes, offsets, lead-ins and other
machining parameters for that job.

While the cost of CNC has dropped dramatically in the last 5 years
it's still a challenge to try and do something that is actually usable
and reliable for free.

As many find out the software side of the CNC equation often is the
more difficult to implement.

To give you some frame of reference MACH3 (which started out as
Master5) and is a real-time Windows Machine Controller and generates
the Stgep & Dir pulses you need, probably has well over 2000 man-
hours in programming and upgrades. If MACH were a true commercial
software venture structured like other commercial software, it would
cost at least 10X the $159.00 asking price and upgrades would not be
free for life!

My suggestion is to not try and re-invent the wheel (unless someone is
paying you handsomely for the effort). With EMC being free and
SheetCam at slightly over $166.00 you can bypass hundreds of hours of
programming and spend the time using the machine to make back the
initial investment.

Going from nothing to full 3D machining is like strapping a rocket
motor to a beach chair......rough on the passenger.

You can download free demos of all the programs listed.

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