Editing G-code for max speed

[ccarv]

I ran across the g-code editing post at: http://www.cncsharktalk.com/viewtopic.p ... dit#p10181
and it does not seem to recommend hand editing g-code, calling it "high adventure".

Regardless, I'm game for anything...here's the issue:
After many hours of close observation, I have noticed that the rough tool path created by Cut3D has added quite a few redundant "finishing" steps that are obliterated as the tool steps down deeper into the work. I'm not sure if it's Cut3D that needs tweaking or if I could just cut out the lines of code that are redundant.

As an example, when cutting with the grain, it cuts straight & fast, but against the grain it does a square wave zig zag pattern parallel to the cut line. I can understand the reason, but then it comes back for a second "clean up" pass that removes no new material, but repeats the tedious zig zags then plunges down another .2" obliterating the cleanup steps.

I am running a trial of G-Wizard Editor, but I am less than impressed with the program's editing capability and performance (jumpy display even on a high end PC).
I am curious if there are other editing programs out there and if the are machine profiles available for the CNC Shark that would work with such programs.
Something more elaborate than Notepad to be sure.

BTW, the program I'm working in is about 40K lines. It's a combined rough and finish program using a .250 ball nose mill.
It looks good, but it's a tad over an hour, but it seems if the "dawdling" could be eliminated, it could be closer to 30 or 40 mins.
I'm already taking .2" off on each pass in the rough tool path and the HD Pro seems to be handling it just fine.

Any speed tips or advice is appreciated.

[Eagle55]

I understand your desire to speed things up, but my first reaction when people talk about editing G-code is to cringe. I realize "back in the day" people used to manually right g-code for most all of the CNC operations, but when it gets down to tens of thousands of lines of code, I just can't see going in a changing it. "High adventure" is probably quite accurate. You may be able to do it and may be successful at it but one little slip can be devastating to the machine, bit or project... or all three. Personally, I feel that trying to understand the program and thereby discovering where to tweak the program values would be about as far as I would be willing to go. I'm sure G-code isn't as deep and dark a secret as I make it sound, but before I would attempt something like that I would want to be very familiar with both the vectric methods of writing G-code as well as well versed in the g-code commands and the parts of the G-code syntax that the Shark uses (Realizing that every CNC has their own little "versions" of g-code... hence the great number of post processors to choose from. I'm sure there will be some to jump in here and say.. pssst, no sweat, manually editing g-code is easy. I'd be interested in hearing your results after you do it. Maybe you can teach an old dog a new trick

Roger

[thepuchman]

For complicated projects make the edits in the design software. Many of these software packages with shallow learning curves do not allow much in fine tuning though.

Note Pad and Word Pad are just fine for manual editing. A couple of clicks and you can change all of you feed rates. Example 50 IPM to 150 IPM. Select the Find Replace All option from the edit tab. Type F50 in the find box and F150 in the Replace All box. Just becareful when making changes because there may be some F50 moves that you do not want to change. First step would be to use the Find option and see what you are dealing with. Type F in the Find cell and all you have to do is hit Find Next to jump to the next one. You can step through a program really quickly this way. Just because you have a program with over a thousand lines does not mean there are that many feed rates. A feed aret has to be entered every time you plunge to a new depth, rapid to a new location, and begin a finish cycle. Programs with more of these moves will have more places to tune the program.

Side note about decimals. Some machines need decimals in feed rates or it will interpret your number as a 3 or 4 place decimal internally. So, F50 could be read as F.050 or F.0050. My point is if you make a change and the program appears to stall while running on the machine look at the digital read out and see if the numbers are changing. If yes then you missed a decimal. Just simply fix it and rerun the program.