Shedding light on the 1 Million line myth

[Brady Watson]

OK...I've had some time to look into the so called '1 million line limit' in the SB3 software. It turns out that this is not 100% true, and it boils down to how much available memory you have on your computer. We should all have a clean install of XP Pro with no excessive background resources or programs competing with SB3. This is standard for ANY Windows based controller or host running a CNC tool. Be sure to understand the difference between physical memory you have installed in your computer and available memory your system has left for SB3, after Windows and other processes take their share of the physical memory.

Here's how the line limit works:
If you have less than 500 Megs of memory free and available, you will be limited to 1 million lines of code per file.

If you have between 500M & 1 Gig of FREE memory, you will be limited to 5 million lines.

More than 1 Gig free memory is limited to 10 million lines. The memory to lines factor is scalable so if you have 2G of available RAM, then you can theoretically run a 20 million line file.

There comes a point where the number of lines becomes ridiculous since the size of the SBP starts getting into the 300-500Meg range...which is pretty large for an SBP.

If you are in doubt as to how many lines your particular system can handle, just type 'UD' into the control software & it will return the max number of lines your system can handle. This is a good yardstick for how your system measures up & may be a good indication that it's time to upgrade your computer if you do intensive 3D carving.

Keep in mind that your results may vary and the thershold numbers listed above are only approximate. I've got 2Gig of physical memory on my machine and only 1.3G of available memory for SB3. I am limited to 5 million lines...which is OK by me, since that would take quite a while to cut in one go.

-Brady

[paco]

Thanks for details Dr Brady!


Reminder that Bill young has made up a nice utility relate to this.

File Splitter (http://www.shopbottools.com/files/LabFiles/FileSplitter.htm): split huge part files into manageable bites

[bruce_clark]

Brady,

What is the rated "Lines per Second" on the controller? I know that there are some LARGE files but a 1 million line part file would be hours/days/weeks of run time.

I guess with me not doing any 3d stuff, I don't see it as a limit.

Bruce

[Brady Watson]

Bruce,
I really don't know. You should ask Ted about that one. I've had no problem running large files on my machine & have cut parts that have taken 22hrs to cut without stopping.

-B

[bruce_clark]

Brady,

Was that 22 hours with a spindle or a router?

I have always wondered how a router motor would handle a 24hour running. I guess it does not matter if you are making enough to pay for new bearings/brushes, but I could just see that thing seizing in the last hour and scrapping the whole job.

Now, I could totally understand leaving a spindle running for 24+ hours mainly because they are designed to run for long periods of time.

Bruce

[fleinbach]

One of the files that I ran for my ceiling medallions on my last theater room had 863,790 lines. It ran for more than 20 hours using a three horse power columbo spindle. Being a 3-D file the cuts were very light as I did a roughing Pass before running the final file.

[bruce_clark]

Frank,

So that is about 43,200 lines an hour is about 720 lines a minute or right around 12 a second.

So, for your BIG 3D files, figure about 12 lines a second will give you a rough idea of how long your file will take to machine.

Brady's 1,000,000 line file will require more than 23 hours 10 minutes or his machine's limit is 5 days non stop! That is a LOT of sweeping and cleaning!

Something to think about...

[Brady Watson]

Bruce,
It was using a 5HP Colombo spindle. It's been a great spindle for 5yrs. Next week it is getting fresh bearings top to bottom.

I don't think that you can calculate lines per second based on any given file. There are a number of factors that affect this, such as: Ramping settings, move speed, Z axis height delta and other factors. A 3D file with a large Z delta will take much longer than a file with a low relief/low delta in Z axis. Time per line really goes up when a tool encounters a straight wall and really any incline greater than 43°.

-B

[bruce_clark]

Brady,

I agree that there are factors that will very, but I am _betting_ that ramping makes a smaller difference that you think. Since most 3D moves are short, the machine does not really reaches full "ramp" and that really the cutting speed is the start "ramp" speed.

Second, these are just "rule of thumb" calculations. I would bet that your 22 hour file had about 950,000 lines, give or take a few thousand.

Bruce

[jhicks]

No to confuse the issue but I just checked a 3D file we had run which contains 112,043 lines of G code. The file was run at 120 IPM with an 1/8" ball nose on offset strategy with a maximum cut depth of .600". No roughing pass as the relief was a domed shape sunflower so we start in the middle at its high point and progressively machine outward and deeper with a 9% stepover.
My virtual test run shows up as a run time of 52 minutes on MACH software and actual run time was 58 minutes.
Not sure if this a difference between G code, Ascension control, MACH or just the way things work when taking RULE of THUMB guestimates but the 12 lines per second would indicate 155.6 minutes or 2.55 hours when actual is 58 minutes or 1932 lines per minute / 32 lines per second.
Quite a variation from 12 lines per second but I have no idea why.
I do know when we change the plunge speed from our typical 30 to 65 IPM the balance of x/y move speed to Z plunge depth not only improves overall speed but improves smoothness of the cuts since the x/y move speed does not need to slow down to compensate with the slower plunge speed.
Just putting it out there FYI.
4621

[applik]

Brady,
Thanks for the post. I was very interested in this informations since we only do 3D carving with very little else at the moment. Most of our files run for 10 to 12 hours. I ran the UD check on the bot computer and came up with the following:
Total memory 535,281,664
Start memory 421,740,544
Available memory 231,342,080
Max File Lines 5000000
Max stack 150000
So does that mean I can run 5 milllion lines of code?
There is absolutely nothing on this XP pro machine except shopbot software. I'm not sure how long we can run the Makita router either. It never seems to run warm. We just ran a file with just a few lines short of the one million mark and it took 11.4 hours. I do not want to split the file. I'll call Crucial and check on some additional memory later today. I want to do a deign 28" x 40" x .5 to 1" deep for a large slab of local cedar I just bought. Big mountain lion scene I'm working on. We tend to stay with the 5,5 on speeds. Faster seems to make things shimmy too much for our taste. Would like to cut the carving time, but don't want to shake the machine apart either.
Thanks for your help,
Shari

[Brady Watson]

Shari,
The 5 million line limit listed in your UD report is for your computer with whatever is running at the moment. Looks like you should be fine. I ran my UD test on my design computer which is loaded up with all kinds of stuff running in the background. My SB computer is clean just like yours.

In terms of 'shimmying'...you may want to experiement with the 3D threshold setting in VR. Try cranking it up a bit and see if this reduces the shimmy as you put it. 3D files vary quite a bit & I find myself tailoring the VR to the file itself. I typically change the slow corner speed the most, and then the 3D threshold. I recently ran an oval frame 3D file and it had a lot of starts and stops for no apparent reason. Increasing the 3D threshold, reduced the machines sensitivity and the part cut much faster with no jerkiness. Something to test anyway...

-B

[applik]

Brady,
I'm excited to think I can try a larger file. Just curious: what happens if it's too many lines? Does it give you an error message before you start carving? Don't want to get partially through something and have it crash on me. Oh..no. Thinking ahead.
Most of our files are pretty detailed so the z is jumping up and down like it has the hiccups all the way across. I'll try tweaking the settings in VR a little and see what happens. It just seems if it's over the 5,5 the cord/cable carrier on the top jerks more and it sounds different. The quality doesn't seem to suffer, just the poor machine. I've been keeping the Z speed at .5 so maybe I should try experimenting with that one too.

Thanks again,
Shari

[Brady Watson]

5,3 seems to be a good speed for most 3D files on my machine, but I have the PRS motors, so your results may vary. You don't want to restrict the Z speed to .5 since it will really slow things down unecessarily. I would try 5,3 or 3,2 if you want to be a bit more conservative.

Lines...I haven't run into a file larger than 5M lines, but the easiest way would be to open the file with the SB Editor (not FE from SB3) and do a <crtl> + <end> to get to the last line and see how many lines are in the file.

-B

[applik]

That's how I've been checking the line numbers is in the Shopbot editor. Not sure about the speeds you're listing. Is the 5 for both the x and y speeds and the 3 for the z speed? We have a PRT Alpha 48. The 5,5 I mentioned is for the X,Y and the .5 was for the Z. Haven't quite got the jist of the bot lingo down pat yet. I usually assign the slow start speed of 1.5 for x,y and .5 for z in the ArtCam file. Then as you suggested before do the insert after a few lines have carved and change speeds to 5,5 for x,y. Never changed the Z but will definitely have to give that a try. It's the 7,7 x,y speed that makes the machine do the jitterbug.
We are looking forward to seeing the new PRS up close. Will try a file tomorrow with some different speed adjustments. I get so caught up in designing the files, I forget to go and really work with the machine settings.
Ciao,
Shari aka Arizona Botgirl

[Brady Watson]

Just for clarity, MS,5,3 means Move Speed, XY @ 5 IPS, Z @ 3 IPS.

-B

[applik]

Brady,
Got it. I do appreciate your patience with my questions.
Thank you and have a great day,
Shari